Users Guide for Deployment of Stationary Fuel Cells 22 August 2014 Fuel Cell Focus Group Focus Group Scope: The scope of this Focus Group is to develop a comprehensive understanding of the fuel cell codes for both stationary and mobile fuel cells for specific use with telecom, wireless, datacom, emergency 911, police radio, security and surveillance, and catastrophic infrastructure for commercial, military, or residential use at ground level, on rooftop, or on platform applications for backup, supplemental and/or alternative electric power sources as well as associated fuel storage requirements. Document Scope: The Users Guide for Deployment of Stationary Fuel Cells for Wireless and ICT Infrastructure will support the deployment of fuel cell technologies for the wireless and ICT industries. Table of Contents 1. Introduction 2. Use of Fuel Cells In the ICT Industry 3. Benefits of using Fuel Cells 4. Overview of Fuel Cell Technologies 5. Generic Diagram for backup Power System 6. Fuels table 7. Summary C&S Sheet 8. Basic Principles of Fuel Cell Safety 9. Fuel Supply Considerations 10. General Criteria for Fuel Cell Siting (use detailed information already written) 11. Comparison of Fuel Cell technologies to other Power Generation Technologies /Cost Comparison of Backup Power Technologies Annex A Supplementary Information Annex B Example Systems Annex C Example Permits Introduction The purpose of this document is to support the deployment of fuel cells by providing background information on fuel cell technologies, fuel sources, and permitting that would help a project developer. The Guide may also be helpful to other parties involved in project deployment such as: - Equipment manufacturers - Fuel suppliers - Code official - Municipal planners - Emergency responders Use of Fuel Cells in the ICT Industry . May 28, 2013 Telecom networks require significant energy to operate. Even though energy prices are presently at relatively reasonable levels, the operators are trying to reduce the energy consumption of their networks. There are several factors behind this focus. For example, energy bills contribute to more than half the operating cost of the network. In addition, lower energy usage is an effective way for operators to minimize their environmental impact, reduce carbon footprint and use more sustainable forms of energy. Since telecom networks typically have tens of thousands of sites, operators must reduce operational and maintenance costs to compete effectively. Operators around the world are exploring applications of alternate energy solutions in their networks. Solar arrays, wind turbines and fuel cells have all been implemented in various telecom applications with varying degrees of success. These solutions have higher initial costs but offer significantly lower costs of operation and maintenance with substantially lower carbon footprint. The options for reducing costs and the environmental impact of running a network are not only good for the environment; they also make excellent business sense for operators and support sustainable, profitable business. Some governments, such as the United States, are even offering tax incentives to help foster the adoption of these technologies. This paper provides evidence that hydrogen fuel cell back-up power systems are not only reliable and green, but result in real operating expense reduction. Fuel Cells Fuel cells are electrochemical devices that convert chemical energy in fuels into electrical energy directly, thereby generating power with high efficiency and low environmental impact. There are a variety of different types of fuel cells. This paper focuses on the Proton Exchange Membrane (PEM) fuel cell which utilizes hydrogen as a fuel. PEM fuel cells are best suited for backup power applications as they provide high power densities and operate at low temperatures (60 to 80°C), which allows them to startup faster than other fuel cells. Typically, backup power for telecommucation sites is provided by lead-acid batteries and diesel generators, which have considerable environmental impact. Fuel cells provide an eco-friendly backup power solution as the only byproducts are heat and water. They are efficient, reliable, quiet, and designed to last a long time. Advanced Fuel Cell Solution for Telecommunications Networks Wireline and wireless telecom networks have a wide range of power loads and an extensive set of compliance requirements. The CommScope solution incorporates a compact fuel cell solution in an enclosure, which has been deployed over the past 6 years with other active electronics in the outside plant for several other applications by leading telecommunication companies. The combination of existing industry knowledge and numerous field deployments was instrumental in development of this highly reliable solution for outdoor power backup applications.4 Figure 1 illustrates a 8-kilowatt fuel cell module housed in a 63-inch (H) x 45-inch (W) x 52-inch (D) cabinet, which is Telcordia GR-487 compliant. The cabinet contains all necessary power conditioning equipment for providing regulated DC Voltage to match site requirements, typically at battery float voltage. The system provides instantaneous power upon loss of AC or DC power using a small bridge battery located in the battery compartment of the cabinet. Figure 1The equipment stack in the cabinet from the top to the bottom includes the following: 1. AC to DC Rectifier, used to provide primary power when grid electricity is available 2. Overall System Controller (OSC) 3. A Power Conditioning Modules (PCM) – a DC-DC converter, which provides regulated voltage to load 4. Wireless Radio and Microwave backhaul equipment 5. An 8-kilowatt Fuel Cell Power Module (FCPM) – Proton Exchange Membrane (PEM) based hydrogen fuel cells In addition, the cabinet has a DC distribution panel with breakers for connecting the DC load, the PCM and bridge batteries. The OSC provides the necessary means to detect loss of AC or DC power in order to turn on the FCPM for providing power when needed. The PCM’s prime function is to take unregulated DC voltage from the FCPM stack and convert to a steadystate DC voltage as required by the telecommunications application. Typically 54 volts of direct current (VDC) is provided with a +/- 0.5 volt variance. The system operates in a hydrogen fail safe mode in accordance with ANSI/CSA FC-1 requirements. The OSC also provides a series of alarms such as open door intrusion, power major/minor and other alarms along with those specific to fuel cell technology. In addition, the OSC controls the time necessary to purge five volumes of air from the system, per the FC-1 requirement. This purging operation followed by turn up of the FCPM to full power is about 90 seconds. The cabinet equipment configuration discussed above is recommended for new site installations or for sites where the existing radio equipment can be accommodated in the fuel cell cabinet to reduce the overall site footprint and power consumption. For existing sites, the fuel cell cabinet can also be installed with only the fuel equipment in the cabinet, and it can interface with the existing power supply, batteries, and radio equipment located in other cabinets or shelter on the site. Key Features of the Advanced Fuel Cell Solution The following list highlights the key features of the solution: • No monthly start up requirement • Unlimited start/stop capability • Industry leading fuel cell efficiency • Patented Dry/Dry Operation – No humidification required for the hydrogen or air feed to the fuel cell • Highest power density in the industry • Single footprint capable of accommodating electronics in the cabinet, which houses the fuel cell • Power conditioning with a range from -42 VDC to -58 VDC, which matches most telecommunication sites. Typically these sites are set at battery float voltage around -54 VDC. • Design in accordance with ANSI/CSA FC-1, CE and Telcordia requirements • All aspects pertaining to the proper and safe handling of hydrogen fuel source. • A system controller capable of maintaining all aspects relating to fuel cell operation and safety as well as providing all Telco required alarms • Cabinet thermal systems and controls required to meet Telcordia -40°C to +46°C ambient temperature conditions • Cabinet ventilation controls required to operate the fuel cell to their maximum efficiency • Electrical system including bridging power in order to ensure no loss of DC power to the site load during an AC power outage The hydrogen to the fuel cell cabinet is provided by hydrogen cylinders stored in a hydrogen storage cabinet (Figure 2), which has the capacity to store 16 standard hydrogen cylinders. The hydrogen cylinders are configured in two banks of eight with an automatic switch-over from one bank to another. This cabinet includes the pressure regulator, manifold, flexible hoses, check valves and safety relief valve. The storage cabinet can be placed next to the fuel cell cabinet or located away from it for hydrogen logistics reasons. The hydrogen pressure of each bank is continuously monitored and an automatic email can be issued when it reaches a preset threshold. This feature allows notification to the hydrogen distributor for refueling the cylinders in the cabinet. Figure 2All aspects of the fuel cell operation are monitored by the system controller and can be communicated remotely using an Ethernet connection or a wireless modem. Several alarms are also reported by the system controller. Following is a partial list of these alarms: • Door Open Alarm • Ventilation Fan Alarm • DC Power Major and Minor Alarms • AC Fail Alarm • Battery on Discharge • Ambient Temperature (Internal and External) • Hydrogen Storage Pressure for each Bank • Cabinet Low Temperature Alarm • FCPM Major and Minor Fail Alarm Data collected through remote fuel cell activation or as gathered when actual power outages occurred can be used to evaluate the reliability and durability of the fuel cell. Global Field Installations and Results The fuel cell solution was installed in various configurations at several locations around the world to test the operational reliability and durability of the system in different climate conditions with varying quality of power grids. These deployments ranged from outdoor and indoor wireless cell sites to wireline huts and shelters in Asia, Europe and North America. Asia Field Installation Figure 3 illustrates an application on a cell site in an emerging wireless market in Asia. The existing backup power solution on this site included several strings of lead acid batteries and a diesel generator. The site has numerous power outages every day and considerable amount of diesel fuel is consumed, thereby creating significant air pollution. In addition, diesel pilferage is rampant, which increases the cost of operating the site. Figure 3 The fuel cell and the hydrogen storage cabinets were placed next to each other on an existing concrete pad on this site. The DC bus of the wireless site was connected to DC distribution panel in the fuel cell cabinet. The system controller monitored and recorded data on all aspects of the fuel cell operation. The data was transmitted remotely through a wireless GPRS modem. This site experienced frequent power outages and as such the fuel cell operated each day to provide power. The daily power outages ranged from as low as 15 minutes to as high as 17 hours. The fuel cell provided the required power load and kept the wireless cell site operational at all times. The system monitored the hydrogen fuel consumption at the site and generated automatic e-mail for the local hydrogen distributor to schedule hydrogen delivery on the site. This notification scheme worked very well in ensuring timely delivery of the hydrogen to the site. Figure 4 depicts the power outage on this wireless cell site for a 50-day period, during which there were 235 outages. The fuel cell supported all the outages and operated for a cumulative time period of 126 hours. Figure 4 Another installation in Asia was on a cell site shared by several wireless operators and owned by a tower company. Figure 5 illustrates this application. The fuel cell provided backup power for two operators on this site. The DC bus for the wireless operators was tied to the DC distribution panel in the cabinet. This site also experienced frequent power outages and the fuel cell provided backup power during all outages. The setup of this installation was similar to the one described above with respect to monitoring and data collection. Figure 6 depicts the power outage on this wireless cell site for a 30-day period, during which there were 48 outages. The fuel cell supported all the outages and operated for a cumulative period of 31 hours. The ambient temperature during these operational periods at these sites was about 45ºC. Both of these field installations have demonstrated the high reliability and durability of the fuel cell cabinets in providing backup power. Figure 5 Figure 69 Europe Field Installation Figure 7 illustrates the deployment of the fuel cell cabinet on a wireless cell site in Europe. Prior to this deployment, the BTS equipment on the site was housed in a shelter with an air-conditioner, which consumed considerable amount of power. The shelter was removed from the site and all equipment in it accommodated in the fuel cell cabinet within 6 hours. The site footprint was reduced by over 50 percent and the energy consumption was reduced as the air-conditioner was eliminated. This site is located in a remote area in Eastern Europe and it experiences several utility outages. Figure 8 depicts the power outages on this site for a 6-month period, during which there were 82 outages, which ranged from a few minutes to up to 8 hours. The fuel cell supported all the outages and operated for a cumulative time period of over 56 hours. This fuel cell controller on site is connected to a GPRS modem and the wireless operator can remotely log in to monitor all aspects of the fuel cell operation. Contrary to the initial perception, hydrogen delivery to the site was not an issue. Figure 7 Figure 810 North America Field Installation Figure 9 illustrates the deployment of the fuel cell cabinet outside the headquarters of the Society of Cable Telecommunication Engineers in Exton, PA. This building has solar panels on the roof, which are connected to an inverter to provide AC power. When required, the AC power from the inverter provides backup power to the data center located in the building. Otherwise it offsets the AC load in the building. In this installation, the fuel cell was tied to the DC side of the solar power system. The fuel cell operates when there is an AC outage and the solar panels can’t provide the power required, because either it is nighttime or there isn’t enough solar irradiance due to cloud cover. This office building has few power outages during a given year. Figure 9 During Hurricane Irene, the office building had an 18-hour power outage. The fuel cell provided the backup power during this period. The office building has recently experienced other power outages due to bad weather in the area and the fuel cell has supported all these power outages.11 Key Observations The field installations in various parts of the world, and with different equipment configurations, have demonstrated that the advanced fuel cell solution provides a reliable and cost-competitive means of providing backup power. A summary of the key observations from these field installations is listed below: • The fuel cell operated in diverse environments with 100 percent availability • Average maintenance costs were reduced by 77 percent and average operational costs were reduced by 37 percent • On average, the footprint space was reduced by 50 percent • Real time remote monitoring of power backup reduced truck rolls • Hydrogen is widely available and misconceptions about safety easily were dispelled after installation and operational experience Conclusion The fuel cell application, in various geographical locations around the world and in different equipment configurations, has demonstrated that it is a highly reliable, durable and cost-competitive solution. Several telecommunications companies around the world have started to evaluate the fuel cell technology for backup power. Some governments and agencies are providing incentives to help companies embrace this environmentally friendly technology and deploy it in significant volumes. www.commscope.com Visit our website or contact your local CommScope representative for more information. © 2013 CommScope, Inc. All rights reserved. All trademarks identified by ® or ™ are registered trademarks or trademarks, respectively, of CommScope, Inc. This document is for planning purposes only and is not intended to modify or supplement any specifications or warranties relating to CommScope products or services. Benefits of Fuel Cell Technologies Stationary fuel cells range in power from hundreds of watts to multiple megawatts, and power everything from remote telecom towers to large office complexes. Fuel cells offer choice of feedstocks. Many stationary fuel cells run on hydrogen; however, stationary fuel cells are often powered by natural gas or biogas at facilities dealing with organic waste streams. Larger fuel cells using molten carbonate or phosphoric acid technologies can use a variety of hydrogen-rich feedstocks and convert the fuel into hydrogen using an internal reformer. Stationary fuel cells offer a number of advantages over competing power sources. One such advantage is that fuel cells produce exceedingly reliable, high quality power. This is important for many types of business users. Natural variance in voltage from the grid can damage sensitive electronic equipment. US businesses lose $29 billion annually from computer damage due to power outages. This is why many data centers have ditched grid power and invested in fuel cell systems, which can be up to 99.9999% reliable. That translates to roughly one minute of downtime in a six year span. Since fuel cell systems keep running during power outages, they also eliminate the need for backup generators. – http://www.fchea.org/index.php?id=55 Fuel cells are used for primary power, or as back-up power in grid-powered locations for applications such as telecommunications, security, transportation communications and others. Fuel cells are also being used in remote and offgrid applications as one component to a hybrid power solution which can involve other power sources; such as solar arrays, wind turbines, batteries, and generators. According to a recent whitepaper from ReliOn “There are currently more than 1,000 telecommunication sites using fuel cell power solutions in North America alone. While this represents a small percentage as far as total telecom sites, it is clear that fuel cells are a growing solution to the need for reliable energy for sites in locations as diverse as cities, suburbs, rural, off-grid and environmentally sensitive areas.” Using fuel cells in telecommunication facilities increase reliability, decrease maintenance costs, and decrease emissions. Reliability is increased because a number of system solutions, using a variety of hydrogen-rich feedstocks, can be utilized independently from the grid. These fuel cells will continue to operate as long as fuel is provided to the fuel cell. Fuel cell systems offer lifecycle cost savings for backup power distributed at telecom nodes over a range of requirements; from short duration runtime applications to extended duration runtime applications. Fuel storage can be provided on site, allowing the site to operate for longer periods. Fuel cell-based backup power systems are designed to operate for approximately ten years, while battery strings may need total replacement every three to five years. Additionally fuel cell solutions require only minimal annual maintenance compared to quarterly site visits to service diesel generators or batteries. Unlike generators, fuel cells do not use combustion and therefore there are no NOx, SOx or particulate emissions at the point of use. A fuel cell utilizing hydrogen fuel produces no harmful emissions at the point of use. Because of this, they are exempted from emissions permitting by the California Air Resources Board as well as many other states. Fuel cells are also quiet. This makes them suitable for places where noise is an issue, including environmentally sensitive areas. Emergency Preparedness Recent events, such as the Hurricane Katrina disaster of 2005 and Superstorm Sandy of 2012, to name just two, have increased focus on availability and reliability of telecommunications services. Telecom systems, whether wireless or wireline, must be able to provide continuous, reliable service to customers at all times, and in particular during extended power outages. The choice of backup power technology has a direct impact on the availability of services to the end-user and contributes significantly to a telecommunication company’s market success. Traditional solutions include batteries and diesel generators. During extended-duration backup power needs or in urban locations where noise and pollution are a particular concern, fuel cells offer a practical solution. Fuel cell backup power solutions offer numerous compelling advantages over conventional battery and diesel generators in emergency backup power applications. These include environmental benefits, improved reliability and durability, scalability, and lifecycle cost savings – particularly at telecom nodes which require relatively low power over a long duration. Further Reading: Back-up Power and Fuel Cells Fact Sheet, FCHEA, http://www.fchea.org/core/import/PDFs/factsheets/Backup%20Power%20Fuel%20Cells%20Fact%20Sheet.pdf The Business Case for Fuel Cells 2012, Fuel Cells 2000, http://www.fuelcells.org/uploads/FC-Business-Case-2012.pdf Fuel Cell Basics for Communications Industry Professionals, ReliOn Power, The Alternative Energy e-Magazine: http://www.altenergymag.com/emagazine/2012/10/fuel-cell-basics-for-communications-industry-professionals/1988 Using Fuel Cells for Backup Power for Telecommunications Facilities, U.S. Department of Energy Hydrogen and Fuel Cells Program, http://www.hydrogen.energy.gov/permitting/telecommunications.cfm Why Fuel Cells for Telecoms Backup is a Good Call, Fuel Cells Today, http://www.fuelcelltoday.com/analysis/analystviews/2013/13-06-05-why-fuel-cells-for-telecoms-backup-is-a-good-call Benefits of Fuel Cell Solutions for Backup Power Needs in Telecom, Dantherm Power, dantherm-power.com/files/PDF/DP_Telecom_Advantages.pdf Overview of Fuel Cell Technologies A fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity; heat, and water (see Figure 2.1). The hydrogen comes from any hydrocarbon fuel such as natural gas, gasoline, diesel, or methanol. The oxygen comes from air around the fuel cell. Because fuel cells are electrochemical devices that operate without combustion, they do not generate combustion emissions. A fuel cell can operate at high efficiencies and provide an opportunity for the capture of heat that is given off by the process (cogeneration). The fuel cell itself has no moving parts, making it a quiet and reliable source of power, electricity, heat, and water. Fuel cell equipment comprises individual fuel cells “stacked” to make a fuel cell stack that is the heart of the fuel cell equipment or power plant. In addition, there may be a fuel processing section of the equipment that is separate from or integral to the cell stack. Where alternating current (ac) power is needed, Figure 2.1. Fuel Cell Configuration there will be a power conditioning section to convert the direct current (dc) power produced by the fuel cell into ac power. Although all fuel cell power plants contain these components, the assembly of these components into the actual equipment is very important. Stationary fuel cell equipment can be categorized as either unitary, matched modular, modular, or sitebuilt. A typical fuel cell is composed of a fuel cell processor/reformer, electrodes, electrolyte, oxidant, fuel cell stack, and power-conditioning equipment. These components are described briefly in the following paragraphs. • Fuel Processor/Reformer The job of the fuel processor/reformer is to provide relatively pure hydrogen to the fuel cell, using a fuel that is readily available or easily transportable. The hydrogen comes from any hydrocarbon fuel such as natural gas, liquified petroleum gas, or even diesel fuel. The generic term generally applied to the process of converting liquid or gaseous light hydrocarbon fuels to hydrogen and carbon monoxide is reforming. A number of methods are used to reform fuel. The three most commercially developed and popular methods are steam reforming, partial-oxidation reforming, and autothermal reforming. These processes involve heating the hydrocarbon fuels to the point of vaporization and then injecting superheated steam to help force the reaction to completion. The heat source for the reaction is usually an immediately adjacent high-temperature furnace that combusts a small portion of the raw fuel or the fuel effluent from the fuel cell. Rejected heat from the fuel cell system also can be used for the heat source. The reforming of hydrocarbon-rich fuels is often not complete, and gases including carbon monoxide pass through the reforming process. These gases are converted to water and carbon dioxide with a catalyst. • Electrodes A hydrogen-rich gas from the reformer (or hydrogen from storage on the site) is fed continuously to the electrodes where an electrochemical reaction takes place to produce an electric current. As with a battery, two electrodes—the anode and the cathode—are used to produce electricity. Anode The anode, the negative post of the fuel cell, has several jobs. It conducts the electrons freed from the hydrogen molecules so they can be used in an external circuit. The anode is etched with channels that disperse the hydrogen gas equally over the surface of the catalyst is used to split the hydrogen molecules into positively charged ions, giving up one electron each. The positively charged ions then migrate through the electrolyte (see description of electrolyte below) to the positive post (cathode). The negatively charged electrons travel through the external circuit to produce electric energy. Cathode The cathode, the positive post of the fuel cell, also is etched with channels that distribute the continuous supply of oxygen from air (oxidant) to the surface of the catalyst. It also conducts the electrons back from the external circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water. • Electrolyte The electrolyte transports the positively charged hydrogen ions to the cathode and thereby completes the cell electric circuit. It also provides a physical barrier to prevent the fuel and oxidant gas streams from directly mixing. • Oxidant The most common oxidant is gaseous oxygen, which is available from air for stationary fuel cell applications. The oxidant is introduced into the system at the cathode (see cathode above). Stationary fuel cell equipment can be categorized in a number of different ways: • unitary – All the components (fuel processor, cell stack, and power-conditioning unit) are matched together and assembled in one complete piece of equipment. • matched modular – One or more of the components are separate from the others but have been designed to work together and are provided by one manufacturer for assembly in the field. • Modular – The components have not been designed specifically to work together and are not provided by one manufacturer but by separate manufacturers for assembly in the field. • site-built – This field-erected fuel cell uses components and pieces from various sources to make up a fuel cell power plant. Unitary equipment will typically provide a smaller output (up to ~500 kW) due to the limitation on the size of the equipment posed by the single package in which it would be provided. Matched modular or modular would have larger outputs. Sitebuilt fuel cell power plants would provide large outputs, on the order of a few megawatts or more. • Fuel Cell Stack A single fuel cell produces only about 0.7 volt. To increase the voltage, many separate fuel cells must be combined to form a fuel cell stack. The fuel cell stack is integrated into a fuel cell system with other components, including a fuel reformer, power electronics, and controls. Simply stated, the more cells in the stack and the more stacks in the equipment, the greater the power output. The term stack power density describes how much power is produced for a given area of fuel cell. • Power-Conditioning Equipment The fuel cell system can provide either dc or ac power. Power conditioning for a fuel cell power plant used to supply dc rated equipment includes current and voltage controls. Power conditioning for a fuel cell power plant used to supply acrated equipment includes dc to ac inversion and current, voltage and frequency control, stepping the voltage up or down through a transformer depending on final equipment utilization voltage, and maintaining harmonics output to an acceptable level. In addition, transient response of the power-conditioning equipment should be considered. For utility grid interconnection, synchronization, real power (watts) ramp rate, and reactive power (volt-amperes reactive, or VAR) control also must be addressed. 2.2 Types of Fuel Cells Four primary fuel cell system types have been utilized in stationary fuel cell equipment installed in commercial buildings. The descriptions that follow provide specific detail on the following fuel cell system types: • • • • molten carbonate fuel cells (MCFCs) phosphoric acid fuel cell (PAFCs) proton exchange membrane fuel cell (PEMFCs) solid oxide fuel cells (SOFCs). Alkaline fuel cells (AFCs) are not discussed in this document because they are not usually installed in commercial buildings. They are a type of fuel cell with low overall efficiencies and low operating temperatures. Fuel cells are classified primarily by the kind of electrolyte they employ. This determines the kind of chemical reactions that take place in the cell, the kind of catalysts required, the temperature range in which the cell operates, the fuel required, and other factors. These characteristics, in turn, affect the applications for which these cells are most suitable. Table 2.1 provides a comparison of the four fuel cells discussed. Table 2.1. Fuel Cell Comparison Molten Carbonate Fuel Cell MCFC PAFC 10-kW to 2-MW MCFC systems SOFC have been tested. Ion exchange membrane Solid metal oxide MCFC systems promise high 140–212°F 1100–1830°F fuel-to-electricity efficiencies, (60–100°C) (600–1000°C) about 60% normally or 85% with cogeneration, as the excess heat External External/Internal generated can be harnessed and O2/Air O2/Airheat and used in combined power plants. 35-50% 45-60% PEMFC Electrolyte Molten carbonate salt Liquid phosphoric acid Operating Temperature 1100–1830°F (600–1000°C) 300–390°F Reforming External/Internal External Oxidant CO2/O2/Air O2/Air Efficiency (without cogeneration) 45-60% 35-50% Maximum Efficiency (with cogeneration) 85% 80% 60% Maximum Power Output Range (size) 2 MW 1 MW 250 kW 220 kW Waste Heat Uses Excess heat can produce high-pressure steam Space heating or water heating Space heating or water heating Excess heat can be used to heat water or produce steam 2.2.1 (150–200°C) Electrochemical Reactions 85% Anode: Molten Carbonate Fuel Cells The molten carbonate fuel cell (MCFC) uses a molten carbonate salt as the electrolyte. It may also be fueled with coal-derived fuel gases or natural gas. MCFCs are high-temperature fuel cells that use an electrolyte composed of a molten carbonate salt mixture suspended in a porous, chemically inert ceramic lithium aluminum oxide (LiAlO2) matrix. Because they operate at extremely high temperatures of 600ºC (roughly 1100ºF) and above, nonprecious metals can be used as catalysts at the anode and cathode, reducing costs. Manufacturers claim that fuel efficiencies approach 60%, considerably higher than the 35%–50% efficiencies of a phosphoric acid fuel cell plant. When the waste heat is captured and used, overall fuel efficiencies can be as high as 85%. Unlike alkaline, phosphoric acid, and polymer electrolyte membrane fuel cells, MCFCs do not require an external reformer to convert more energy-dense fuels to hydrogen. Due to the high temperatures at which they operate, these fuels are converted to hydrogen within the fuel cell itself by a process called internal reforming, which also reduces cost. H2+CO3 2- ⇒ H2 O + 2eCathode: ½O2+CO2+2e ⇒ CO 3 2- Cell: H2+½O2+CO2 ⇒ H2O+CO2 MCFCs are not prone to carbon monoxide or carbon dioxide "poisoning"—they even can use carbon oxides as fuel—making them more attractive for fueling with gases made from coal. Although they are more resistant to impurities than other fuel cell types, scientists are looking for ways to make MCFCs resistant enough to impurities from coal, such as sulfur and particulates. The primary disadvantage of current MCFC technology is durability. The high temperatures at which these cells operate and the corrosive electrolyte used accelerate component breakdown and corrosion, decreasing cell life. Scientists currently are exploring corrosion-resistant materials for components as well as fuel cell designs that increase cell life without decreasing performance. 2.2.2 Phosphoric Acid Fuel Cells A phosphoric acid fuel cell (PAFC) consists of an anode and a cathode made of a finely dispersed platinum catalyst on carbon paper, and a silicon carbide matrix that holds the phosphoric acid electrolyte. Phosphoric Acid Fuel Cell International Fuel Cells has installed many of these 200-kW phosphoric acid fuel cells. This one is situated at a hospital and provides power and heat. PAFCs are more tolerant of impurities in the reformate than proton exchange membrane fuel cells, which are easily "poisoned" by carbon monoxide—carbon monoxide binds to the platinum catalyst at the anode, decreasing the fuel cell's efficiency. They are 85% efficient when used for the cogeneration of electricity and heat but less efficient at generating electricity alone (35% to 50%). This is only slightly more efficient than combustion-based power plants, which typically operate at 33% to 35% efficiency. More than 200 PAFC systems have been installed all over the world including hospitals, nursing homes, hotels, office buildings, schools, utility power plants, military bases, an airport terminal, landfills, and waste water treatment plants. Most are the 200-kW PC25 fuel cell power plant manufactured by the ONSI Corporation, including one that powers a police station in New York City's Central Park and two that provide supplemental power to the Conde Nast Building at 4 Times Square in New York. The PC25 is a prepackaged tested and listed unit delivered on a skid to facilitate installation and interconnection with the building systems and fuel source. The largest PAFC system to be tested is an 11-MW power plant sited in Japan. Many of these installations have operated for more than 40,000 hours without interruption. Photo courtesy of International Fuel Cells More than 200 of the International Fuel Cells 200-kW ONSI units have been put into service all over the world. Photo courtesy of International Fuel Cells Electrochemical Reactions Anode: H2 ⇒ 2H+ + 2eCathode: ½ O2+2H++2e- ⇒ H2O Cell: H2+½O2 ⇒ H2O 2.2.3 Proton Exchange Membrane Fuel Cells The proton exchange membrane fuel cell (PEMFC) uses a fluorocarbon ion exchange with a polymeric membrane as the electrolyte. These cells operate at relatively low temperatures and can vary their output to meet shifting power demands. These properties make PEMFCs the best candidates for light-duty vehicles, buildings, and much smaller applications. PEMFCs operate at relatively low temperatures, around 80°C (176°F). Low-temperature operation allows them to start quickly (less warm-up time) and results in less thermal stress on system components. However, this low-temperature operation requires that a noblemetal catalyst (typically platinum) be used to separate the hydrogen electrons and protons. The platinum catalyst is extremely sensitive to carbon monoxide poisoning, making it necessary to employ an additional reactor to reduce carbon monoxide in the fuel gas if the hydrogen is derived from a carbon-containing fuel. Developers are exploring different catalyst formations that are more resistant to carbon monoxide. Manufacturers claim that the PEMFC system efficiencies range from 35% to 50% and, with capture and use of waste heat, can have an overall efficiency approaching 60%. Proton Exchange Membrane Fuel Cell Avista Labs has developed a modular technology, allowing “hot swapping” of stack subcomponents and on-line maintenance. Photo courtesy of Avista Labs Ballard Generation Systems' first field trial of a 250-kW Natural Gas PEM Fuel Cell Power Generator is sited at the Crane Naval Surface Warfare Center for a two-year demonstration and testing program. Photo courtesy of Ballard Electrochemical Reactions Anode: H2 ⇒ 2H+ + 2eCathode: ½O2+2H++2e- ⇒ H2O Cell: H2+½O2 ⇒ H2O 2.2.4 Solid Oxide Fuel Cells Solid oxide fuel cells (SOFC) currently under development use a thin layer of zirconium oxide as a solid ceramic electrolyte and include a lanthanum manganate cathode and a nickel-zirconia anode. This is a promising option for high-powered applications such as industrial uses or central electricity generating stations. SOFCs operate at very high temperatures—around 1000ºC (~1800ºF). High-temperature operation removes the need for a precious-metal catalyst. It also allows SOFCs to reform fuels internally, which enables the use of a variety of fuels and reduces the cost associated with adding a reformer to the system. SOFCs are the most sulfur-resistant fuel cell type. In addition, they are not poisoned by carbon monoxide, which is actually used as fuel. As a result, SOFCs can use gases made from coal or other gas-fired fossil fuels. High-temperature operation has disadvantages. It results in a slow start-up and requires significant thermal shielding to retain heat and protect personnel, which may be acceptable for utility applications but not for transportation and small portable applications. The high operating temperatures also place stringent durability requirements on materials. The development of low-cost materials with high durability at cell operating temperatures is the key technical challenge facing this technology. Currently available unpressurized SOFCs provide electric efficiencies in the range of 45%. Argonne National Laboratory suggests that pressurized systems could yield fuel efficiencies of 60%. Power generating efficiencies could reach 60% to 85% with use of waste heat to facilitate cogeneration. Solid Oxide Fuel Cell This system, developed by SiemensWestinghouse, is the world’s first fuel cell/gas turbine hybrid., It began operation at the University of California–Irvine in May 2000. It integrates a microturbine generator with a solid oxide fuel cell and produces 220 kW at a system electrical efficiency of 58%. Future SOFC/gas-turbine hybrid plants are expected to have electrical efficiencies of 60%– 70%. Photo courtesy of SiemensWestinghouse Electrochemical Reactions Anode: H2+O2- ⇒ H2O +2eCathode: ½O2+2e- ⇒ O2Cell: H2+½O2 ⇒ H2O Basic schematic showing equipment and purpose of equipment Figure 1. shows a basic fuel cell system. The key components of the system are as follows: -Fuel -Fuel cell -Battery (provide reserve power) -DC Bus -Rectifier (convert DC to AC) -AC distribution Fuels Table Fuel Physical Properties Regulations MSDS Links Hydrogen, Gaseous Colorless, Odorless, Tasteless and NonToxic; 14 times lighter than air; Flammable range 4%-75% Light, volatile, colorless, distinctive odor, Toxic; The 64%/36% methanol/water mixture by weight used in methanol reformers is flammable Naturally occurring gas consisting mostly (95%) of Methane; 1.7 times lighter than air; Flammable range 4%-16% Colorless, Tasteless gas with an odorant added; Non-Toxic; 1.5 times denser than air; Flammable range 2.15%-9.6% OSHA 29CFR1910.103 MSDS OSHA 29CFR1910.106 MSDS NFPA30 OSHA 29CFR1910.101 MSDS NFPA54 OSHA 29CFR1910.110 MSDS NFPA30, NFPA58 Methanol Natural Gas Propane Applicable Code(s) for Fuel Storage NFPA55, NFPA2 Notes: Hyperlinks on first column linked to requirements for fuel storage and fuel cell design and installation, which cover C&S, OSHA, EPA, DOT, DOE resources, current FEMA and Zoning requirements Summary of Codes and Standards Applicable to Stationary Fuel Cell Installations Title of Code/Standard 2015 International Mechanical Code (IMC) Contact ICC Regulates and controls the design, construction, installation, quality of materials, location, operation and maintenance of use of mechanical systems. 2015 International Fuel Gas Code (IFGC) ICC Regulates and controls the design, construction, installation, quality of materials, location, operation and maintenance or use of fuel gas systems. 2015 International Fire Code (IFC) ICC The purpose of the IFC is to establish the minimum requirements consistent with nationally recognized good practice for providing a reasonable level of like safety and property protection from the hazards of fire, explosion or dangerous conditions in new and existing buildings, structures and premises. 2015 International Residential Code (IRC) ICC Provides minimum requirements to safeguard life or limb, health and public welfare for one and two family occupancies and townhouses. 2015 International Building Code (IBC) ICC Establishes the minimum requirements to safeguard the public health, safety and general welfare through structural strength, means of egress facilities, stability, sanitation, adequate light and ventilation, energy conservation, and safety to life and property from fire and other hazards attributed to the built environment. 2015 International Plumbing Code (IPC) Regulates and controls the design, construction, installation, quality of materials, location, operation and maintenance or use of plumbing equipment and systems. ICC Title of Code/Standard NFPA 70 (NFPA 70) Contact NFPA 2014 National Electric Code §692, Fuel Cell Systems—Requirements for the installation of fuel cell power systems, which may be stand-alone or interactive with other electrical power production sources and may be with or without electrical energy storage such as batteries. NFPA 55 NFPA Gaseous Hydrogen Systems Covers the general principles recommended for the installation of gaseous hydrogen systems on consumer premises where the hydrogen supply to the consumer premises originates outside the consumer premises and is delivered by mobile equipment. Liquefied Hydrogen Systems Covers the general principles recommended for the installation of liquefied hydrogen systems on consumer premises where the liquid hydrogen supply to the consumer premises originates outside the consumer premises and is delivered by mobile equipment. NFPA 54 - National Fuel Gas Code NFPA Natural Gas Systems Applies to the installation of fuel gas piping systems, fuel gas utilization equipment, and related accessories. NFPA 58 -Liquefied Petroleum Gas Code NFPA LPG Applies to the highway transportation of liquefied petroleum gas and to the design, construction, installation and operation of all liquefied petroleum gas systems. NFPA 853-2013 (NFPA 853) NFPA Standard for the Installation of Stationary Fuel Cell Power Plants Applies to the design and installation of 1) a singular prepackaged self-contained power plant unit; 2) combination of prepackaged self-contained units; 3) power plant units comprised of two or more factory matched modular components intended to be assembled in the field. ASME AMSE Boiler and Pressure Vessel Code The International Boiler and Pressure Vessel Code establishes rules of safety governing the design, fabrication, and inspection of boilers and pressure vessels and nuclear power plant components during construction. Title of Code/Standard ANSI FC1 Contact CSA Standard on Stationary Fuel Cell Power Plants Provides fire prevention and fire protection requirements for safeguarding life and physical property associated with buildings or facilities that employ stationary fuel cells or all sizes. ICC — International Code Council, 5203 Leesburg Pike, Suite 600, Falls Church, VA 22041, (703) 931-4533, www.iccsafe.org NFPA — National Fire Protection Association, 1 Batterymarch Park. Quincy, MA 02269-9101, (800) 344-3555, www.nfpa.org ASME — ASME International, Three Park Avenue, New York, NY 10016, 1-800-843-2763, or 1-973-882-1167, Fax: 1-973882-1717 UL — Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096, Tim Zgonena, (847) 272-8800 Ext. 43051, timothy.p.zgonena@us.ul.com CSA — CSA International, 8501 E. Pleasant Valley Road, Cleveland, OH 441310-5575, (216) 524-4990 Ext. 8303, http://www.cas-international.org Basic Principles of Fuel Cell Safety The fuel cell engine uses hydrogen (directly, or indirectly produced from other fuels) to electrochemically produce electrical power. The hazards of fuels, electrical power, machinery, etc. are well understood and addressed by multiple safety standards and codes for fuel cells and their fuels. The important safety categories that apply to fuel cell power systems are: Flammability, Hazardous material, Ventilation, Mechanical, Electrical, and Electromagnetic. Fuel cells do not employ radioactive components or materials, nor produce ionizing radiation. The following categories are addressed by codes and standards for product safety: o Flammability - Flammable Gas and Liquid - safety concerns: potential fire, explosion risk o o Protection against fire or explosion hazard addressed by FC 1 for stationary fuel cell systems and FC 3 for portable applications, and repeated in NFPA 853. o Fire prevention, pressure relief, and leakage containment or venting of fuel storage per NFPA 2, 30, 55, 58, 853. Hazardous Material - safety concerns: inhalation, skin exposure, oral poison, etc. o o Occupational Health & Safety Organization (OSHA) per Code of Federal Regulations 29, Part 1910 (29CFR1910). Ventilation and Make-up air - safety concerns: potential asphyxiation, removal of excess heat o o room ventilation & fuel supply ventilation per OSHA (29CFR1910) and International Building Code (IBC) o NFPA853 ventilation requirements for fuel cell power systems. Mechanical - safety concerns: personal injury hazard due to contact with moving parts (fans & louvers), compressed gas o o o Addressed by FC 1 & FC 3: physical inspection & protection (IEC/ANSI/NEMA 60529 rating: IP2x for indoor or outdoor applications). compliance to NFPA 79 for machine safety. compressed gas rupture risk is addressed by International Fuel Gas Code (reflected by state fire codes), and NPFA 55. Electrical - safety concerns: shock hazard, discharge hazard, possible ignition source. hazardous voltages, currents, energy - if touched, insulation & critical spacing to prevent accidental discharges & resulting molten material, and possible ignition sources for flammable gas. o Addressed by FC 1 & FC 3 for power generator o o compliance to IEC/UL 60950-1 for electrical spacing & insulation. Installation per NFPA 70, especially Article 692 for fuel cell systems. Electromagnetic - safety concerns: unexpected interference and loss of safety controls due to Radio Frequency (RF) energy RF radiated emissions (ElectroMagnetic Compliance - EMC) o EMC: RF radiated emissions are addressed by the Federal Communications Commission (FCC) per Code of Federal Regulations 47, Part 15. Fuel Supply Considerations Fuel cells convert the chemical energy of a fuel to electrical energy. The fuel cell operates for as long as fuel is available. Hydrogen is often the chemical energy source for the system; alternatively, hydrogen carrying substances such as methanol, natural gas, propane, and ammonia can also be used, depending on the fuel cell design. The choice of catalyst in the fuel cell determines whether a given fuel can be used directly, or must be processed (reformed) before the core electrochemical reaction takes place. The fuel cell design also determines the operating characteristics, such as start-up time and loadfollowing ability – some designs are better aligned than others to wireless and other critical ICT power requirements. Compressed hydrogen and liquid methanol are commonly used today by stationary fuel cells for backup power at cellular sites (10 kW or less). The vast majority of deployments are PEM fuel cells that require pure hydrogen which can be supplied directly or reformed (e.g. from methanol) on site. Direct Methanol Fuel Cell (DMFC) technology is also used today for backup power, but in smaller numbers. As the name suggests, DMFC technology is designed to use methanol directly without a reformer. Natural gas is used today in larger prime power fuel cell power plants (100 kW or more, e.g. for large servers), and both natural gas and propane are used by micro-Combined Heat and Power (CHP) fuel cells. Smaller (5kW or less) Solid Oxide Fuel Cell (SOFC) technology, used mainly in prime power applications, can flexibly accept any of the fuels mentioned above. Natural gas, propane, and ammonia fuel cells for telecom backup power are in active development. The fuels chosen for the scope of this document are hydrogen, methanol, natural gas, and propane, based on the applicability of fuel cells that use these fuels for wireless and other critical ICT infrastructure and on availability of commercial products. Hydrogen Hydrogen is the most abundant element in the universe, but stable molecular hydrogen gas is rare on earth because it is so diffusive and buoyant (characteristics that also make it a safe fuel). Hydrogen is found abundantly in many chemical compounds (e.g. water), and is easily manufactured from feedstock fuels such as methane. It is also often produced as a by-product of chemical processes, and can be created as a form of renewable energy through electrolysis and reformation of biogas. Hydrogen fuel cells have the simplest design, but there is a tradeoff with fuel logistics, as hydrogen is often stored and transported at high pressure. Fuel cells typically require a hydrogen purity of 99.95%. Sources In addition to being a source of energy, hydrogen is used in a number of industries today: float glass manufacturing, metal production and welding, chemicals, refining, automotive and transportation equipment, and aerospace and aircraft. The primary source of hydrogen for these industries is industrial gas companies, and several other options are available as listed below: Industrial Gas Companies Industrial gas companies are well represented across the continent, and have the widest selection of delivery options. Most offer both gaseous and liquid hydrogen. As a compressed gas in smaller quantities, hydrogen can be sourced in a variety of cylinder sizes and bulk packs. For larger quantities, gaseous hydrogen can be delivered in tube trailers. When cooled to liquid form, hydrogen can be transported in tanker trucks and transferred to bulk liquid tanks; however, it needs to be converted to gaseous form before use in fuel cells. A sampling of industrial gas companies supplying hydrogen include: Air Liquide, Air Products, Airgas, Linde, and Praxair. Hydrogen Vehicle Re-Filling Stations The number of hydrogen re-filling stations continues to grow as the infrastructure is being established for hydrogen fuel cell vehicles. In addition to vehicles, these stations could sell hydrogen to anyone who is licensed and equipped to re-fill hydrogen storage containers. http://commons.wikimedia.org/wiki/File:Hydroge n_fueling_nozzle.jpg Public domain; author: EERE http://cafcp.org/getinvolved/stayconnected/blog/cec_ann ounces_funding_28_hydrogen_stations Figure x. Hydrogen re-filling station. Hydrogen Re-Sale by Heavy-Use Industries In addition to automotive, the material handling industry is becoming a significant consumer of hydrogen as warehouses and industrial facilities migrate from battery-driven and combustion-enginedriven forklift trucks to new hydrogen alternatives. These facilities need to store a sizable amount of fuel – in liquid form if the truck fleet is large enough – and the managers of that fuel could re-sell some of the hydrogen for backup power, providing an alternate source of revenue. http://www.lindeus.com/en/innovations/hydrogen_energy/hydro gen_energy_applications/forklifts.html Figure x. Hydrogen fuel cell forklift being refueled at warehouse facility. Chemical Plants Producing Hydrogen as Waste By-Product Industrial facilities, such as sodium chlorate, chlor-alkali, and caustic soda plants, often produce massive quantities of by-product hydrogen that can potentially be captured and sold for other purposes, such as fuel cell backup power. As an example, in India, Aditya Birla Group operates a caustic soda plant in Nagda, Madhya Pradesh. Byproduct hydrogen from this process is captured, purified, stored in cylinders, and used to power fuel cells in a cellular network operated by IDEA Cellular, part of the Aditya Birla Group. The IWHUP project featured a Combined Heat and Power fuel cell powered by hydrogen recovered from a nearby sodium chlorate plant. http://www.americanoilinvestments.com/articles/Oil-GasNews_4618.html http://www.htec.ca/#!history/c588 Figure x. Waste hydrogen capture facility. Photo courtesy HTEC. Gas Pipelines Hydrogen gas pipelines are often found in oil refinery zones such as in Southern California and Texas. This continuous flow of fuel is ideal for fuel cells that produce high power and/or run continuously. http://commons.wikimedia.org/wiki/File%3AHydrogen _pipelines.jpg Public domain: EERE Figure x. Section of hydrogen gas pipeline. As an example, Toyota Motor Sales, USA, Inc. operates a 1.1 MW hydrogen PEM fuel cell at its Sales and Marketing Headquarters in Torrance, CA. The fuel cell is used to satisfy peak and mid-peak power needs. The pipeline that provides hydrogen to this fuel cell also supplies a nearby hydrogen fueling station http://www.ballard.com/aboutballard/newsroom/news-releases/news10171201.aspx Figure x. A 1.1 MW fuel cell at Toyota Motor Sales, USA, Inc. fueled by pipeline hydrogen. Photo courtesy Ballard Power Systems, Inc. Renewable Sources Hydrogen can be produced renewably through the electrolysis of water, where electrolysis (and optional compression) is powered by energy sources such as wind, photovoltaic panels, hydropower, biomass, and geothermal. A few examples of trials of electrolyzer/fuel cell systems are identified in the following link http://fuelcellsworks.com/news/2014/07/03/hydrogen-production-systems-provider-acta-s-p-aannounces-commercial-update/ Although early in its development stage, manufacturing hydrogen from biomass is another alternative for the renewable production of biomass1. Fuel Delivery/Storage Options Hydrogen is delivered and can be stored as a compressed gas, a liquid, or bonded in matter; however, liquid hydrogen must be gasified before delivery to the fuel cell, and bonded hydrogen must be released, as fuel cells consume hydrogen in gaseous form. Hydrogen is stored as a compressed gas at the point of use. Compressed Gas Pressure vessels of various sizes, shapes, and composition are used for the transport and storage of compressed hydrogen gas. 1 http://www.hydrogen.energy.gov/pdfs/51726.pdf In small quantities, steel cylinder tanks are the most common form of delivered gaseous hydrogen, but aluminum tanks are also available. The cylinders can also serve as the storage medium on site, and are swapped when empty (or near empty). In this “cylinder swap” case, the cylinder tanks typically remain the property of the fuel supplier, and a monthly rental fee is applied for each cylinder at the purchaser’s site. Alternatively, a permanent installation of cylinders on site can serve as the storage medium, and is refilled by transferring hydrogen from a delivery vehicle. In this “fill-in-place” scenario, the storage medium is often purchased as a package with the fuel cell. (a) (b) (c) http://www.airgas.com/content/details .aspx?id=7000000000234 Figure x.(a) Steel cylinders installed in a cabinet for individual cylinder service (photo courtesy Ballard Power Systems, Inc), (b) Steel cylinders installed in a cabinet – manifolded together for “fill-in-place” service (photo courtesy Air Products and Chemicals, Inc.), (c) sample range of steel cylinder sizes (photo courtesy Airgas). In larger quantities, compressed hydrogen can be delivered in bulk trailers. Capacities for conventional tube trailers typically range from about 25,000 – 140,000 scf (60 – 330 kg). A variety of advanced highpressure solutions are now available that can double capacity with the use of composite materials that withstand higher pressures. The trailers can be used to refill on-site storage vessels or can be left on-site as a form of storage. A monthly rental fee may apply if the storage asset remains the property of the hydrogen vendor. http://commons.wikimedia.org/wiki/File%3ACo mpressed_hydrogen_tube_trailer.jpg Public domain; author: EERE (a) (b) Figure x.(a) Conventional steel tube trailer, (b) trailer with 450 bar (6,500 psi) composite cylinder blocks (6 x 89 kg of hydrogen) (photo courtesy HTEC), As mentioned above, cylinders made of high-strength carbon composite materials enable storage at higher pressure, and increase the density of stored hydrogen. These cylinders can be manifolded together in modular bulk packs, or installed as individual cylinders into hydrogen cabinets. Carbon composite cylinders are not a standard offering from hydrogen vendors, so these assets are often purchased rather than rented. Composite cylinders were developed primarily by the automotive industry demanding lightweight, high-density hydrogen storage tanks for hydrogen fuel cell vehicles. The lighter weight and higher pressure attributes make them attractive also for stationary applications where weight and/or space must be minimized. (a) (b) (c) Figure x. (a) Cutaway of composite cylinder bulk pack (photo courtesy HTEC), (b) Arrangement of composite cylinders in trailer from Figure x-1 (c) above (photo courtesy GTM Technologies), (c) Composite cylinder installed in a wheeled cart to facilitate rooftop delivery (photo courtesy GTM Technologies). Liquid Hydrogen Transportation and storage of liquid hydrogen is an economical option for applications where large amounts of hydrogen are consumed. As a fuel cell requires hydrogen in gaseous form, additional infrastructure is needed at, or near, the point of consumption to convert liquid hydrogen to gaseous hydrogen. At atmospheric pressure, hydrogen exists as a liquid below 33 K, but must be cooled to about 20 K (-253 ⁰C / -424 ⁰F) for it to exist in liquid state without evaporating. Storage and handling procedures for cryogenic liquids must be employed. Liquid hydrogen is transported by trailer trucks in large cryogenic tanks ranging in capacity from 7,500 to 13,000 gallons (28,400 to 49,200 L), which equates to about 2,000 to 3,500 kg of hydrogen. An example is shown below of a cryogenic tanker trailer as well as a liquid hydrogen storage and gasification facility at a site employing a fleet of fuel cell forklift trucks. The additional capital required for storage and gasification of the liquid hydrogen is economical in warehouse facilities that deploy at least 40 fuel cell forklift trucks. Although not common today, there may be applications where liquid hydrogen is economical for stationary fuel cells that produce large amounts of power and/or experience heavy use. http://hydrogentank.en.busytrade.com /products/info/2087771/LiquidHydrogen-Transport-Truck-Tank.html (I’m sure there’s an NREL photo to replace this) (a) (b) http://www.plugpower.com/Libraries/Documentation _and_Literature/Whitepaper_Debunking_Hydrogen_F uel_Cell_Myths.sflb.ashx Figure x. (a) Liquid hydrogen transport tank, (b) Liquid hydrogen storage and gasification facility at a warehouse deploying a fleet of fuel cell forklifts. Advanced Hydrogen Storage Technologies There are many new technologies being developed for hydrogen storage motivated primarily by the growing number of hydrogen applications, including hydrogen fuel cell power generation. These new technologies include, for example, metal hydrides, ammonia, formic acid, and carbon nanotubes, to name just a few. As these technologies are in the development stage, they are not included here as commercial options at time of publication, but industry is moving quickly. Refueling Hydrogen is refueled either by replacing or re-filling the storage container. Storage Container Replacement For hydrogen storage cabinets designed for cylinder swapping, individual cylinders are delivered to the site by truck, and technicians move the cylinders to and from the storage location with hand trucks. In some cases, bulk solutions are designed to be “drop-and-swap”, allowing a large amount of hydrogen to be replaced in a short period of time if the site area is large enough to accommodate the heavy equipment required. http://h2bestpractices.org/storage/com pressed_gas/storage_vessels/cylinderh andling.asp (Look for generic NREL photo) (a) (b) Figure x. (a) Hand-truck for moving individual cylinders to/from storage location, (b) “Drop-and-swap” of a bulk container of composite cylinders (photo courtesy HTEC). Storage Container Refilling Compressed hydrogen storage systems can be designed to be “fill-in-place”, allowing refueling from a truck through a hose. This model avoids wasting any hydrogen remaining in cylinders that are swapped, and as well allows heavy fuel storage vessels to remain in place. This model is suitable for accessible sites in regions where there are trucks equipped to re-fill cylinders at high pressure. http://www.hydrogen.energy.gov/pdfs/rev iew12/h2ra006_maxwell_2012_p.pdf Photo on Slide 18. (a) (b) Figure x. (a) Fill-in-place delivery by a hydrogen bobtail truck to compressed hydrogen storage at a cellular site, (b) Fill-in-place delivery by composite bulk storage cylinders on a trailer (photo courtesy GTM Technologies). Liquid hydrogen storage tanks are always re-filled (as opposed to swapped), and refueling must be done with attention to cryogenic procedures. For a fuel cell application, stored liquid hydrogen must be converted to gaseous form before it can be used by the fuel cell. Site Considerations For ground-based sites, replacement and refilling modes are both viable options for refueling gaseous hydrogen. The refilling mode is desirable as it avoids moving heavy storage containers; however, site accessibility can limit its use. Although a slower and more labor intensive mode of refueling, cylinders can be moved safely by hand-cart through spaces that cannot be navigated by a vehicle. For rooftop sites, replacement and refilling modes are both viable options, but more challenging than for ground-based sites. It is assumed in both cases that the hydrogen storage is on the roof with the fuel cell, as there often is no suitable space available around the building at ground level or inside the building. For the fill-in-place mode, if allowed by the building owner, hydrogen piping can be installed from the storage tanks down the outside of the building to ground level where the delivery truck can connect a refilling hose. For the replacement mode, cylinders (steel or carbon composite) can be taken up an elevator, after which there may be some stairs to roof level. During a power outage or other times when elevators are not operational, cylinders can be carried with a cylinder hand-truck up the stairwell if the building is not too tall. For both ground-based and rooftop sites, compressed gas fuel such as hydrogen is almost always stored separately from the fuel cell cabinet, so compressed gas fuel cell systems tend to have a larger physical footprint compared to liquid-fueled systems, where fuel can be stored in the base of the fuel cell enclosure. Storing hydrogen in higher pressure carbon composite tanks can help to reduce the footprint required for fuel. Taking appropriate setback distances into account for hydrogen storage, the effective footprint (i.e. the physical occupied footprint plus the clearance area required for regulatory compliance) of the hydrogen solution tends to be the largest of available options. Hydrogen is a very safe fuel for use on a rooftop, as it is the most buoyant of all gases (relative density of 0.0693 relative to air), and disperses quickly (diffusion coefficient2 of 0.61 x 10-4 m2/s, compared to gasoline diffusion coefficient3 range of 0.006-0.02 x 10-4 m2/s). In the unlikely event of a leak, hydrogen rises straight up into the open air and rapidly dilutes to noncombustible concentrations. The Lower Flammability Limit (LFL) of hydrogen is 4%4, which is higher than the LFL of gasoline at 1.2%5. Methanol The methanol/water mixture used in fuel cells exists naturally as a liquid at room temperature and atmospheric pressure, and typical blends freeze at around-73 ⁰C (-100 ⁰F). As it is a stable liquid, it can be transported and stored in plastic or metal containers making fuel logistics simple. Methanol can be used directly – for example, by DMFC and SOFC systems – or indirectly – for example, by PEM fuel cells with a suitable reformer. Sources Pure methanol is one of the most widely distributed chemicals in the world used in numerous products such as windshield washer fluids, automotive fuels, furniture refinisher, paint remover, windshield deicer, and household cleaners/solvents, as examples. The water in the methanol/water mix must be purified and de-ionized before blending with methanol at the prescribed ratio. Methanol Sources Methanol with the required degree of purity can be obtained from many sources worldwide. Please see, for example, the list of member companies of the Methanol Institute (http://www.methanol.org/aboutus/member-companies.aspx). Renewable Sources Methanol can be produced renewably and sustainably through conversion of bio-mass. For example, BioMCN6, a company in the Netherlands, produces and sells industrial quantities of “bio-methanol” that is chemically equivalent to methanol manufactured conventionally, and meets IMPCA standards. The process implemented by BioMCN converts crude glycerine, a residue from biodiesel production, into 2 http://www.hysafe.org/download/997 http://www.jocet.org/papers/012-J30011.pdf 4 Hydrogen density and LFL from http://www.hysafe.org/download/997 5 https://www.mathesongas.com/pdfs/products/Lower-(LEL)-&-Upper-(UEL)-Explosive-Limits-.pdf 6 http://www.biomcn.eu/ 3 bio-methanol. The product is either physically shipped to consumers of the chemical, or alternatively, BioMCN has established a certificate trading system whereby the sustainability rights of the biomethanol produced by BioMCN in the Netherlands are transferred to a chemical consumer, while the chemical consumer sells back to BioMCN an equivalent amount of conventional methanol. The certificate trading system saves freight costs and avoids unnecessary production of CO2 by transport of bio-methanol. Methanol/Water Blenders For pre-blended fuel, the fuel supplier is responsible for sourcing methanol, sourcing or producing water, and blending it such that the final product meets the requirements of the fuel cell. One such company supplying methanol/water fuel under the brand name, HydroPlus™7, is Brenntag Pacific, who can distribute the product throughout North America.8. The HydroPlus mixture is between 61-63% methanol by weight, which is approximately 70% methanol by volume. Other blending ratios may apply to specific products or as required by local authorities. Fuel Delivery/Storage Options Generally, there are two methods for delivery of fuel: (a) deliver pre-blended fuel, (b) deliver pure methanol. In the latter case, blending with water can be performed on site before transfer to the fuel storage tank, or it may be blended internally within the system if it can provide its own water. With either form of delivery, the storage medium for the fuel is very commonly a fixed tank that remains on site. The tank may be internal – located within the envelope of the fuel cell solution, or external – located outside the envelope of the fuel cell solution, but nearby. (a) (b) Figure x. (a) Internal methanol/water tank (part of base), (b) external tank supplying three 5 kW fuel cells electrically connected in parallel. Both photos courtesy Ballard Power Systems, Inc. Fuel can be delivered to the fixed tank in a variety of transportable container sizes: 7 8 HydroPlus™ is a trademark of Ballard Power Systems, Inc. http://www.brenntagpacific.com/en/ (a) (b) (c) (d) Figure x. (a) 275 or 330 gallon Intermediate Bulk Container (IBC) totes, (b) 55 gallon drums (4 per pallet), (c) 5 gallon pails, (d) 1 gallon jugs. All photos courtesy Ballard Power Systems, Inc. Alternatively, the external fuel tank can be swapped out, similar in concept to hydrogen cylinder swapping. An IBC tote can be used for this mode of delivery. Common IBC capacities are 275 gallons (1,040 L) and 330 gallons (1,250 L). Unlike the more common cylinder swapping for hydrogen fuel cells, this method of fuel delivery is less common for methanol/water fuel cells. The tank can be swapped while the fuel cell is inactive, or to avoid loss of availability, the tank may be hot-swapped with one or more other tanks on a manifolded fuel supply. Refueling Once delivered to the site, the methanol/water fuel can be transferred to the storage tank by a variety of mechanisms: Fuel in smaller containers (1 gallon jugs and 5 gallon pails) can be poured directly into the fuel tank with an appropriate spout or funnel to avoid spillage. Fuel in larger containers (55 gallon drums and larger IBC totes) can be pumped out with AC or DC-powered pumps, hand pumps or siphons, or tanker trunk with a hose. (a) (b) (c) Figure x. (a) AC powered pump, (b) hand pumps and a jiggle siphon, (c) fuel delivery system in pickup truck with extendable hose, All photos courtesy Ballard Power Systems, Inc. Site Considerations For ground-level sites, methanol fuel can be delivered and dispensed easily from containers such as drums or pails or directly from a fixed-tank fuel truck if the truck can get close enough to the site to be reached by hose. For rooftop sites, liquid methanol/water fuel can be transported by elevator in drums, pails or jugs to the top floor, after which there may be some stairs to roof level. During a power outage or other times when elevators are not operational, fuel can be carried up the stairwell in pails or jugs, whichever is more manageable for the service personnel. As a liquid fuel, methanol/water has a higher energy density than a gaseous fuel, and so occupies less volume, and can be integrated into the fuel cell cabinet, saving physical footprint. For quantities less than 60 gallons9, there are no setback requirements, so the effective footprint can be very small, particularly advantageous for rooftops where available area is scarce and expensive. 9 NFPA 30, Chapter 21. The Lower Flammability Limit (LFL) of methanol is higher (6.7%10 by volume) than the LFL of all of the other fuels considered here (see Summary Table x), meaning more of it needs to accumulate before it can ignite. Methanol vapor density is slightly heavier than air (1.1111), but it disperses (with diffusion coefficient12 of 0.15 x 10-4 m2/s, compared to gasoline diffusion coefficient13 range of 0.006-0.02 x 10-4 m2/s) 50% faster than propane and similar to natural gas. The volatility of methanol is relatively low (32 kPa14 Reid Vapor Pressure (RVP) versus 48-62 kPa RVP for gasoline15). Methanol’s relatively neutral buoyancy in air, low volatility, higher dispersion relative to propane and gasoline, and flammability only at high concentrations are properties that contribute to its safety in general, and particularly for rooftops. Propane Propane or Liquid (or Liquefied) Petroleum Gas (LPG) is a hydrocarbon that is widely distributed in a variety of containers. In the US, propane is available in three grades: HD5, HD10, and Commercial, where the constituents vary amongst the three grades: HD5: At least 10% pure propane, and no more than 5% propylene and no more than 5% butane/methane. All residential propane service is HD5, and it is also commonly used in vehicles. Defined by GPA 2140: https://www.gpaglobal.org/publications/view/id/36/ HD10: Can contain up to 10% propylene, which can lead some engine components sticking. “HD10” means fuel that meets the specifications for propane used in transportation fuel found in Title 13, California Code of Regulations, section 2292.6. Commercial: Less controlled mixture of propylene, butane, and methane; not used in vehicles. The HD5 fuel grade is preferred for fuel cells16. It can be used directly – for example, by SOFC systems – or indirectly – for example, by PEM fuel cell systems with a suitable reformer. Sources There are many propane dealers distributed throughout the US. Check local directories to find propane dealers who offer HD5 grade propane fuel. Fuel Delivery/Storage Options Propane is already used at cellular sites today to fuel combustion-engine generators, and the propane is stored in tanks most commonly external to the generator, but sometimes within the generator enclosure. Fuel is delivered by bobtail truck to refill the tanks. The tank must be placed where it can be 10 http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html http://www.epa.gov/chemfact/s_methan.txt 12 http://www.gsi-net.com/en/publications/gsi-chemical-database/single/343.html 13 http://www.jocet.org/papers/012-J30011.pdf 14 http://www.methanol.org/Technical-Information/Resources/Technical-Information/Physical-Properties-of-PureMethanol.aspx 15 http://www.epa.gov/otaq/fuels/gasolinefuels/volatility/standards.htm 16 http://www.propanecouncil.org/uploadedFiles/REP_11071%20Propane%20Issues%20for%20Fuel%20Cell%20Ass essment%20Vol1(1).pdf 11 accessed by the delivery truck. At sites where less energy is required (less required power and/or operating time), a smaller tank may be used which could be replaced rather than refilled. (a) (b) (c) Figure x. (a) Vertical swappable propane tank, (b) Large-capacity fixed propane tank at cellular site, (c) Propane bobtail truck used for delivery of fuel. Refueling At ambient temperatures, propane exists as a liquid only under pressure, so special nozzles and tank hardware is required for the transfer of fuel to a tank. An example of bulk propane tank valves and gauges is illustrated below, showing that both the liquid and vapor phases of propane must be accommodated during refilling. Figure x. Propane tank valves and gauges. Site Considerations For ground-level sites, propane tanks can be swapped, or the fuel can be dispensed directly from a propane bobtail truck if it can get close enough to the site to be reached by hose. For rooftop sites, propane can be transported by elevator in smaller tanks, after which there may be some stairs to roof level. During a power outage or other times when elevators are not operational, fuel can be carried up the stairwell in tanks sized to be manageable for the service personnel. As propane exists as a liquid under pressure, propane has a higher energy density than a gaseous fuel, and so occupies less volume. The fuel tank is often external to the system, which adds to the physical footprint; however, the high energy content and volumetric density of propane enables long run times in a relatively small fuel storage space. No setback requirements apply to tanks smaller than 125 gallons17; however, in prime power applications, larger tanks are desirable to reduce the frequency of refueling visits. Propane vapor is heavier than air (1.56 relative density18), so propane vapor tends to pool, and it tends not to disperse well (diffusion coefficient19 of 0.10 x 10-4 m2/s, compared to gasoline diffusion coefficient20 range of 0.006-0.02 x 10-4 m2/s). The Lower Flammability Limit (LFL) of propane is comparable (2.1%21 by volume) to the LFL of gasoline. Leaks are in gaseous form as propane cannot exist in liquid form at atmospheric pressure. In practice, propane systems can be difficult to site on rooftops for the same reason that gasoline combustion-engine generators are not permitted on rooftops – the safety concerns of heavier-than-air vapors, low LFL, and high volatility are similar. Propane is common for residential and commercial use, and siting of propane systems is straightforward for ground-based installations. Natural Gas Natural gas is a common fuel with residential, commercial, and industrial service for heat and power generation. If it is available in piped form, power can be generated for as long as gas is supplied in the pipes. Natural gas can be used directly – for example, by Molten Carbonate Fuel Cell (MCFC), Phosphoric Acid Fuel Cell (PAFC), and SOFC systems – or indirectly – for example, by PEM fuel cells systems with a suitable reformer. Sources Natural gas is widely available throughout the US, predominantly delivered by pipe infrastructure, but also available in compressed gas cylinders. Fuel Delivery/Storage Options Piped natural gas does not need on-site fuel storage as it is dispensed on-demand from piped infrastructure. The local gas company supplying the fuel must verify that the service is compatible with the fuel cell in terms of pressure and available flow rate. 17 NFPA 58, Chapter 6. http://www.engineeringtoolbox.com/gas-density-d_158.html 19 http://cafr1.com/Hydrogen_vs_Propane.pdf 20 http://www.jocet.org/papers/012-J30011.pdf 21 http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html 18 Figure x. Outdoor natural gas connections. As with hydrogen, natural gas can be stored and transported as a compressed gas in high-pressure cylinders; however, this mode of storage/delivery is used predominantly by motive applications. For stationary applications, if piped natural gas is not available, and if there are no issues with siting, propane is used instead. Refueling As referenced above, piped natural gas does not need on-site fuel storage, so no refueling is required. The supply of fuel continues as long as it is available from the gas supplier. Although piped fuel obviates the need to visit sites to deliver fuel, security of gas supply is out of the control of the gas consumer. Site Considerations As no fuel needs to be transported, there are no special transportation considerations for rooftop sites relative to ground-level sites. Piped natural gas can be used both at ground-based sites and rooftop sites, as long as the infrastructure is available, and the building owner and local authorities allow it; however, natural gas infrastructure is often only present in residential and commercial buildings, so natural gas is a good option for rooftops, but simply may not be available at standalone ground-based telecom sites. If natural gas service is available, consultation with the gas company and landlord is advised to ensure that: (a) the gas service meets the pressure/flow-rate requirements of the fuel cell, and (b) the landlord/other tenants agree to share the gas supply. Natural gas is lighter than air (0.55 methane/air relative density22), and its dispersion rate (diffusion coefficient23 of 0.16 x 10-4 m2/s, compared to gasoline diffusion coefficient24 of 0.006-0.02 x 10-4 m2/s) is comparable to that of methanol vapor. Natural gas leaks tend to rise in air, and disperse 8-27x faster than gasoline. The Lower Flammability Limit (LFL) of methane (the principle constituent of natural gas) is slightly lower (5%25 by volume) compared to that of methanol, and higher than the LFL of gasoline and propane. The high buoyancy of natural gas, coupled with its relatively high LFL and good dispersion properties are factors that contribute to its safety. 22 http://www.engineeringtoolbox.com/gas-density-d_158.html http://cafr1.com/Hydrogen_vs_Propane.pdf 24 http://www.jocet.org/papers/012-J30011.pdf 25 http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html 23 Fuel Comparison Some properties of hydrogen, methanol/water, propane, and natural gas for fuel cells are compared in the table below. Data reflect information at time of publication. Hydrogen Small Fuel Cell Status26 Methanol/Water Propane Natural Gas Commercial Commercial Early Commercial Early Commercial FC Module Size27 0.2-10 kW 0.3-7.5 kW 0.25-5 kW 0.25-5kW Small Fuel Cell Vendors Many Few Few Few Typical Usage Backup power Backup power Prime power Prime power Fuel state Compressed gas Stable liquid Liquid under pressure Compressed gas 0.0693 1.11 1.56 0.55 4% 6.7% 2.1% 5% n/a (gas) 32 kPa n/a (gas) n/a (gas) 30-102x faster 7.5-25x faster 5-17x faster 8-27x faster Mode of transport Steel or composite cylinders Plastic or metal totes, drums, pails, jugs Mode of storage Steel or composite cylinders Integrated tank or external metal tank Mode of refueling Cylinder swap or fillin-place Pour or pump liquid Portable tanks or bobtail truck Integrated tank or external pressurized tank Swap tanks or refill with propane-specific nozzles/valves Common sources of fuel (who to call) Industrial gas companies Density relative to air28 Lower Flammability Limit29 Reid Vapor Pressure30 Diffusion relative to gasoline31 Minimum quality Ground-based site considerations Rooftop-based site considerations 99.95% industrialgrade hydrogen Suitable given sufficient space for fuel storage respecting setback limits Safe given hydrogen properties; fuel logistics challenging, especially when Methanol/water blenders (e.g. Brenntag North America) Methanol: IMPCA specifications; Water: ASTM 1125, ASTM D5907, IMPCA 004-08, ASTM D4517; 61-63% methanol by weight Integrated tank less than 60 gallons allows deployment in tight spaces Safe given methanol properties; liquid fuel simplifies fuel logistics – delivering to site and Piped infrastructure n/a No refueling - direct feed from piped infrastructure See local directory for propane distributors Determine supplier of gas to a specific site HD5 Contact gas company/landlord to assure adequate pressure and flow rate for application Suitable given sufficient space for fuel storage May not find natural gas service at all ground sites May be challenges due to properties of propane; small tank delivery enables service If natural gas service available, no site visits required for fuel delivery; current 26 “Commercial” means products that are available for sale in meaningful numbers, are supported with service and spare parts, and have evidence of deployment in significant numbers. “Early Commercial” means products that are available for sale, but no evidence yet of deployment in significant numbers. 27 Modules can be cascaded for higher site power requirements. 28 For reference, typical gasoline density is 3-4 relative to air: http://tsocorp.com/wp-content/uploads/2012/12/Gasoline-Unleaded-Regular.pdf 29 For reference, compare to typical gasoline LFL of 1.2%: https://www.mathesongas.com/pdfs/products/Lower-(LEL)-&-Upper-(UEL)-Explosive-Limits-.pdf 30 For reference, compare to typical gasoline RVP of 48-62 kPa: http://www.epa.gov/otaq/fuels/gasolinefuels/volatility/standards.htm 31 For reference, diffusion coefficient of gasoline ranges from 0.006-0.02x10-4 m2/s: http://www.jocet.org/papers/012-J30011.pdf elevator not available carrying up to roof to roof when elevator not available architectures more suitable for prime power than backup power Table x. Comparison of fuel attributes. Footprint vs. operating time with a 5 kW load is charted below for six different potential fuel options: Hydrogen fuel cell, 8 cylinders, 300-series steel, 2,400 psi, swappable. Hydrogen fuel cell, 16 cylinders, large steel, 3,000 psi, fill-in-place cabinet. Hydrogen fuel cell, 8 cylinders, 90 L carbon composite, 5,000 psi, fill-in-place cabinet. Hydrogen fuel cell with methanol/water reformer, 59 gallon internal tank (located within fuel cell enclosure under fuel cell equipment – no incremental footprint for fuel) Hydrogen fuel cell with methanol/water reformer, 275 gallon Intermediate Bulk Container external tank. Propane fuel cell with propane reformer, 125 gallon propane tank. Figure x. Comparison of footprint vs. operating time with 5 kW load for six different fuel cell systems. General Guidance on Site Selection Site assessment and selection is the most critical components to ensuring that a fuel cell candidate site can be carried through the entire design, permitting, and construction process. Fuel cell generators can be located in metropolitan, rural, and remotely isolated locations. Any existing documentation such as a property lines, construction drawings, and an internet search can be a quick and efficient way to make an overall determination of existing conditions of a site location. The physical site audit is where the most information can be collected about the layout of a site, the existing conditions and proposed equipment, and the overall viability for the installation of a fuel cell generator. During this process you should first document the exact location of the project and any obstacles that may potentially affect the ability of a candidate site to be constructed, fueled, or maintained for the life cycle of the fuel cell. These considerations should include the use or storage of any alternative fuel types, generators, or other back‐up power equipment, and the main utility or power supply. Gathering as much information about the current operation and functionality of the equipment or facility, along with taking a real time measurement of the actual DC or AC load will provide the framework for determining the type, size, and runtime of a fuel cell system deployment. When siting an area or location for a fuel cell generator it is important to consider the optimal installation location, but to also investigate the surrounding areas and make considerations for how the property or adjacent properties may be developed or utilized in the future. There are several national, state, and local jurisdictional codes that must be adhered to when deciding the final location of a fuel cell generator. Code compliance is not necessarily reflective of the type of fuel cell system being installed, but typically is more influenced by the fuel type, quantity, storage and delivery pressure at which the fuel is kept during standard operating conditions. Below is a list of the most common site conditions that must be observed when evaluating the viability of a fuel cell generator. Buildings and structures on the same property Openings in adjacent buildings Above ground and underground flammable or combustible liquid and gas storage Ignition sources Overhead electrical utilities Public streets, walkways, and gathering areas Property lines The purpose of this guide is to provide a high level overview of fuel cell technology and hydrogen safety with regard to site selection. This information is provided as reference material for the siting of hydrogen fuel cell systems that will be reviewed by an authority having jurisdiction (AHJs), installation contractors and end-user customers. This document will assist decision-makers in determining the applicability of permitting for fuel cell system siting and installation. The siting of a fuel cell power system depends on many variables relating to the power generation unit size, type of fuel source, and safety compliance. A fuel cell power system and associated equipment, components, and controls shall be sited and installed in accordance with the manufacturer’s instructions and meet the following requirements: Location, Capacity, Siting, & Setbacks Siting Fuel Cell Power Systems: [NFPA853-2010 5.1] o Fuel cell systems shall be installed on a firm foundation capable of supporting the equipment, components and physically protected. o It shall be located so the foundation of, and access to, associated components and the fuel cell power system are above the base flood elevation. The equipment should be resistant to rain, snow, ice, freezing temperatures, wind, seismic events and lightning. The selected site locations should allow for service, maintenance and emergency accessible to service & fire department personnel. The system shall be located so the power systems and components of a matched modular or fieldengineered fuel cell power system and their exhaust vent are separated from doors, windows, outdoor air intakes, and other openings into a building. Fuel cells shall be located 5 ft. away from flammable or combustible materials, hazardous chemicals, high stacked materials and other fire hazard exposures. It shall be located such that a fire or failure of one of the systems does not present an exposure hazard to an adjacent fuel cell power system. Fuel cell systems shall not be located in areas that are used or are likely to be used for combustible, flammable or hazardous materials storage. o o o o o o Outdoor Installations: [NFPA853-2010 5.2] o o Do not direct exhaust vents onto walkways or pedestrian paths. Fuel-bearing components should be located 15 ft. from building openings, including HVAC intakes. o If fuel cell power system is 50kW or less, this is modified by Section 9.2 to: fuel-bearing components located 10 ft. from building openings, including HVAC intakes, and exhaust outlets not directed onto pedestrian walkways. Indoor Installations: o o o o [NFPA853-2010 5.3] Fuel cell power systems in a room shall be separated from the rest of the building by floor, wall, and ceiling (including piping seals and joints) with at least a 1-hour fire resistance rating. Key feature include fire doors, ventilation dampers and egress routes. If fuel cell power system is 50kW or less, this is modified by Section 9.3 to: fuel cells supplied by natural gas, propane, or fuel oil and located in residences do not require fire-rated separations. Fuel cells supplied by methanol or other alcohol fuels and located in residences do not require firerated separations if meet requirements of Sections 9.3.6.1 through 9.3.6.4 For liquid fuel: o o o o o o [NFPA853-2010 9.3] Less than 5 gallons of liquid fuel is allowed within the entire system including piping, during all modes of operation, standby, and shutdown. Bulk fuel storage systems shall be located outside. Solid pipe or tube, all-welded, soldered, or brazed construction shall be used for indoor piping up to and through the fuel cell power system enclosure. The fuel cell system requires leakage detection and automatic isolation of the indoor fuel piping from the outdoor bulk fuel supply upon detection of fuel leakage (using pump stoppage, valve closure, or other manufacturer supplied control). Requires an automatic isolation valve at the tank for outdoor bulk fuel storage located at an elevation above the fuel cell power system. Liquid fuel systems shall be provided with curbing, diking, or drainage in accordance with NFPA 30, Flammable and Combustible Liquids Code. Rooftop Installations: [NFPA853-2010 5.4] o Any roofing material below and within 12 inches horizontally from the power system, or its components shall be non-combustible, or have Class A rating per either ASTM E 108 Standard Test Methods for Fire Tests of Roof Coverings or UL 790 Standard Test Methods for Fire Tests of Roof Coverings. Hydrogen Fuel Safety The fuel source utilized in a fuel cell power system is industrial-grade hydrogen. Compressed, bottled hydrogen is the most readily available commercial source of industrial grade hydrogen and can be found throughout the world and at over 2,500 locations in the U.S. Compressed hydrogen is a versatile fuel having a wide operating temperature range. The telecommunications industry is currently deploying systems to the field that incorporate a hydrogen storage and delivery system. This system is provisioned for use with compressed hydrogen gas cylinders. When designing systems which store, distribute and utilize hydrogen gas it is imperative to address the characteristics of hydrogen to ensure a safe operating environment. Hydrogen is the lightest gas known, with a flammable range from 4% - 74% by concentration (see Figure 1). It is useful to compare this to a known quantity. By way of comparison, propane has a flammable range from 2.4% - 9.6%. Propane’s flammability concentration is nearly 2 times lower than that of hydrogen. While hydrogen has a wider flammability range, it can be reasonably acknowledged that the more important metric is the lower flammability limit. Figure 1 Hydrogen Storage System The hydrogen storage cabinet utilized in a standard deployment is a passively ventilated enclosure open to outside air. The electrical equipment installed in this cabinet is rated for use in a hydrogen environment. While a leak is not likely to occur, the system is designed to ensure a safe operation if one were to occur. Hydrogen is 0.0695 the density of air, or 14 times less than the density of air. The storage system is designed to ensure that in the event of a hydrogen leak, the hydrogen gas is vented to atmosphere and allowed to disperse. Hydrogen’s dispersion characteristics will ensure as distance from the leak source increases, the density of hydrogen will quickly drop below the flammable limit. By comparison, propane is denser than air at 1.5 times the density of air and will tend to fall or settle at ground level. Propane may gather in low spots along grade and not disperse without the use of forced ventilation. Hydrogen is colorless, odorless, tasteless and non-toxic. Therefore, it is necessary to utilize gas detection equipment when using or handling hydrogen gas. These hydrogen sensors are capable of activating and shutting the systems down at 7,500 ppm, or less than 1/5th the Lower Flammable Limit of hydrogen, which is 40,000 ppm. When replacing gas cylinders in a bottle exchange storage system, it is recommended that the use of handheld combustible gas detectors be used to verify that there is no leakage. Hydrogen gas detectors are commercially available and affordable. Liquid soap solution also works effectively to locate any leaks. Outdoor Enclosure utilizes stainless steel and/or brass connection fittings. It is recommended that the use of non-sparking cylinder wrenches be used for connecting the gas cylinder fittings. Rooftop Installation of Hydrogen Fuel Cell Systems Though a rooftop application may not be ideal for a diesel or propane generator, due to the possibility of liquid fuel spillage issues, this application is ideal for a hydrogen fuel cell, since the hydrogen fuel is much lighter than air. Any unintentional release or seepage of the fuel dissipates rapidly and simply escapes into the upper atmosphere. A fuel cell system can be installed on a rooftop as a complete unit including the fuel storage, or alternately, can be installed with the fuel cell equipment cabinet located on the rooftop and the fuel storage cabinet located on the ground as a separated system. This design may be preferred in some instances where delivery of the hydrogen fuel to the rooftop is unfeasible or where the rooftop cannot bear the additional weight of the fuel storage vessels. In addition to the codes and standards that are relevant in general site selection and installation, the document, NFPA 853, Standard for the Installation of Stationary Fuel Cell Power Systems, specifically addresses rooftop installations in Chapter 5, “Siting and Interconnections, Section 5.4, Rooftop Installation”. The extent of the NFPA reference is to ensure that the rooftop material under the fuel cell system and within 12 inches horizontally is non-combustible, or that it has a Class A rating. It could be suggested that a metal plate, grate or raised platform, concrete or other such stable and nonflammable base be used beneath the fuel cell system when installed on a rooftop to meet this requirement. Otherwise, the installation is considered an outdoor installation. The International Fire Code (IFC) and International Building Code (IBC) consider this an outdoor application with setback to exposure requirements listed in table 3504.2.1 of Chapter 35 of the IFC. Another important consideration is the delivery of the hydrogen cylinders to the system by the gas supplier. In our experience, the use of a service elevator is the preferred method for delivering compressed gases to rooftops. Compressed gases are delivered in this fashion on a regular basis to laboratories, medical offices, and other commercial facilities located above the ground floor. If a service elevator is not available, a public elevator or other similar means is typically acceptable. Contact the local gas provider for additional recommendations. As stated in the general discussion on installation of fuel cells, the final decision regarding acceptable placement of a fuel cell system and hydrogen storage ultimately resides with the customer and the local AHJ. Recommended Setback Distances As a standard practice, we offer the following hydrogen storage setback distance/clearance recommendations shown in Figure 2. Which are based on fuel cell industry recognized practices and cross-referenced with the International Fire Code Chapter 35. The IFC is recognized by most AHJ’s to be the controlling code for flammable gases. These manufacturer’s recommendations are also in alignment with the Hydrogen Executive Leadership Panel (HELP) document titled, “Site Evaluation Worksheet for Flammable Gas Storage; Stationary Fuel Cells”. The Hydrogen Executive Leadership Panel is a joint initiative of the National Association of State Fire Marshals (NASFM), the Research and Innovative Technologies Administration of the U.S. Department of Transportation, and the International Consortium for Fire, Safety, Health and the Environment and can be found at the following website: http://www.nasfmhydrogen.com/. These recommendations are offered for the convenience of the customer; however, ultimately it is the responsibility of the customer and/or the AHJ to select the setback distances which are both appropriate and reasonable. Note that the recommended setback distances shown in Figure 2 are intended to extend from the hydrogen storage cabinet /or system to the type of specific exposure. In issuing and making this document available, is not intended to render a professional or other services for or on behalf of any person or entity. This document makes no guarantee or warranty as to the accuracy or completeness of any information within the following table. General Criteria for Fuel Cell Siting Site Evaluation Worksheet for Flammable Gas Storage Stationary Hydrogen Fuel Cells Typical hydrogen storage criteria Building for Controlling Code Setback CodeSetback 2010 editions of thesiting International Code, International Mechanical quantities and lessInternational than 4,226 Fuel standard cubic feet Gas Code, which have references to the International Fire <4,226 scf 4,226 to (scf) and 4,226 to 21,125 scf. Interpretation by Code. Buildings on the same Non-rated(AHJ) will IFC Table 3504.2.1 5 ft. 10 ft. the Authority Having Jurisdiction 21,125 c construction or determine final setback distances. property scf 2-hour construction IFC Table 3504.2.1 0 ft. 5 ft. openings within 25 ft. and no openings 4-hour construction IFC Table 3504.2.1 0 ft. 0 ft. within 25 ft. and Underground flammable or combustible liquid Recommend 5 ft. 10 ft. no openings within 25 storage, ft. Ignition sources (including appliance burner Recommend 5 ft. 10 ft. distance to vent or fill openingb igniters, hot work and hot surfaces capable of Overhead electric vapors)b Overhead electric wire Recommend 5 ft. 10 ft. ignitingbflammable utilities Overhead bus, trolley Recommend 5 ft. 10 ft. or train wire Public streets, public alleys or public ways IFC Table 3504.2.1 5 ft. 10 ft. Distance to lot lines of property that can be built IFC Table 3504.2.1 5 ft. 10 ft. uponvegetation and combustible materialsc Dry IFC 2703.12 / 2704.11 15 ft. 25 ft. Diked, distance to dike Recommend 5 ft. 10 ft. Above ground Not diked, distance Recommend 5 ft. 10 ft. flammable or to tank combustible liquid Additional flammable gas storage areasc IFC Table 3504.2.1 5 ft. 10 ft. b storage a. The minimum required distances shall not apply when fire barriers without openings or penetrations having a minimum fire-resistance rating of 2 hours interrupt the line of sight between the storage and the exposure. The configuration of the fire barrier shall be designed to allow natural ventilation to prevent the accumulation of hazardous gas concentrations. b. These distances are recommended based upon the distances contained within IFC Table 3504.2.1. c. These distances are specified in the International Fire Code, 2010 edition. Revision Date: June 25, 2010 Narrative: There are questions regarding minimum setback requirements for hydrogen fuel storage. Please accept these example calculations as a reasonably allowable “minimum distance” for fuel storage setbacks for the quantity of hydrogen storage at 8,000 scf, with a storage pressure of 3,000 psi. “Exposures” noted in Figure 3 for the HSM (Hydrogen Storage Module) supporting the Fuel Cell system(s) under your authority. This table of calculated sited requirements is a Reference to Chapter 10, Gaseous Hydrogen Systems, NFPA 55, 2010 Edition. Discussion: As allowed in section 10.3.2.2.1.1, paragraph (C), equations will be used to determine the actual setbacks for all 16 “Exposures” expressed in Chapter 10 of NFPA 55, 2010 Edition. Using equations in table 10.3.2.2.1.1 (B) Separation Distance Based on Alternative Pipe or Tube Internal Diameters, we have determined the allowable setbacks resulting for ¼ tubing at pressures >250psi to ≤ 3000psi. There are two tubing diameters in this discussion; 1. The high pressure fuel lines located inside the fuel storage system (Hydrogen Storage Module) 2. The low pressure fuel line outside the Pressure Control Manifold that supplies hydrogen to the ReliOn® Fuel Cell System. The high pressure fuel line located inside the HSM is constructed of ¼ x 0.035 WT stainless steel tubing. The service pressure for the fuel lines in the HSM is 3000psi maximum. The low pressure fuel line located outside of the HSM is constructed of 3/8 x 0.035 WT fuel line tubing. The fuel line from the *HSM to the fuel cell system has an operating pressure <10psi thus is not applicable to this Chapter and not relevant for the setback distances in this case. For discussion sake however, the equations provided in Chapter 10 allowed by section 10.3.2.2.1.1, paragraph (C), were used for the fuel line tubing outside the HSM; the setback calculations for the >250psi to ≤ 3000psi formula using the ¼ inch tubing supersedes the lower pressure 3/8 fuel line tubing outside the Hydrogen Storage Module directly supplying hydrogen to the ReliOn Fuel Cell System. As an example, provided in Example 3 is the equation and resulting calculation for the actual setback for “note” (a) Exposure (1) Lot lines. The formula is called out on page 55-45 of NFPA 55, 2010 Editions under table 10.3.2.2.1.1 (B) for >250psi to ≤ 3000psi. Example 1: Solving for Lot lines greater of a or b the minimum distance would be as follows; Note (a) Da = 0.73903d0.99962 d = the tubing ID in millimeters or in case is 4.572 mm (0.180 inches) derived by subtracting the wall thickness (multiplied by 2) from the OD of the tube. Da = 0.7390(tubing ID in millimeters) 0.99962 Example 1 Result: Da = 0.7390(4.572)0.99962 = 3.35 meters or 11 ft. The allowable minimum distance setback for “Exposure” (1) Lot lines at 11 feet is result of whichever is greater of note (a) or (b) as allowed in the equation in Table 10.3.2.2.1.1 (B) Separation Distance Based on Alternative Pipe or Tube Internal Diameters on page 55-45 of NFPA 55 2010. The formula for note (b) is provided in Table 10.3.2.2.1.1 (B). Summary: The minimum setback allowed is the greater of the a or b calculation. The note (b) result is 5.46 feet so in this case, the note (a) result of 11 feet would be your minimum distance setback for Exposure (1) Lot lines. There are 16 Exposures noted in Chapter 10 of NFPA 55, 2010 Edition. For your convenience, provided below in FIGURE 3 are the minimum allowable setback distances in Feet (ft.) resulting from the equations allowed in section 10.3.2.2.1.1 paragraph (C). It us suggested that you confirm the below setback values and this information is available in Chapter 10 of NFPA 55, 2010 Edition Exposure (1) Lot Lines (2) Exposed Persons… (3) Buildings and structures… (4) Openings in buildings… (5) Air intakes… (6) Fire barrier walls… (7) Unclassified… (8) Utilities… >250psi to ≤ 3000psi (in ft.) 11 4 d = 5, e = 5, f = 5 a = 11, d = 5 11 5 15 5 (9) Ignition… (10) Parked cars (11) Flammable gas storage… (12) Aboveground vents… (13) Hazardous materials… (14) Hazardous materials… (15) Ordinary combustibles… (16) Heavy timber… 11 11 d = 5, b = 5.5 5 5 5 5 5 FIGURE 3 Comparison of Fuel Cell Technologies to Other Power Generation Technologies/Cost Comparison of Backup Power Technologies Hydrogen 10 kW Outdoor Enclosure H2 Fuel Cell Hydrogen 10 kW Indoor rackmount H2 Fuel Cell Diesel 50 KVA Outdoor installation Diesel genset w/ ATS Combustion Engine Fuel storage in base 140 gal subbase tank 70 Operating Hours Batteries 10 kW Outdoor installation VRLA Battery No Reformer No Reformer Fill-in-Place (FIP) Storage FSM 16 - 285 kWh 28.5 Operating Hours Outdoor FIP Storage FSM 16 - 285 kWh 28.5 Operating Hours Equipment Cost $ 50,000 $ 45,000 $ 30,000 $ 72,000 Federal Tax Credit State Credits $ (15,000) $ - $ (13,500) $ - $ $ - $ $ - Permitting/Insta llation $ 13,500 $ 13,500 $ 18,000 $ 15,000 TOTAL FIRST COST $ 63,500 $ 58,500 $ 48,000 $ 87,000 Annual Maintenance & $ 700 $ 700 $ 5,000 $ 4,500 Energy Storage 4 x 420 Ah 8 Operating Hours Capital Cost Operatin g Costs Fuel Lifecycle costs after 1 year Lifecycle costs after 5 years Lifecycle costs after 10 years $ 49,200 $ 52,000 $ 55,500 $ 45,700 $ 48,500 $ 52,000 $ 53,000 $ 73,000 $ 98,000 $ 91,500 $ 109,500 $ 132,000 10 Kw Backup Methanol/Wate r 5 kW Outdoor Enclosure H2 Fuel Cell Diesel Batteries 5 kW Outdoor installation VRLA Battery 40 Operating Hours 25 KVA Outdoor installation Diesel genset w/ ATS Combustion Engine Fuel storage in base 26 gal sub-base tank 30 Operating Hours Equipment Cost $ 25,000 $ 25,000 $ 36,000 Federal Tax Credit $ (7,500) $ - $ $ - $ $ - $ $ $ Methanol/wate r Reformer Internal Storage Tank 59 gal - 200 kWh Energy Storage 2 x 420 Ah 8 Operating Hours Capital Cost State Credits Permitting/Installa tion 10,000 16,000 10,000 TOTAL FIRST COST $ 35,000 $ 41,000 $ 46,000 Annual Maintenance & Fuel $ 300 $ 5,000 $ 2,250 $ 27,800 $ 29,000 $ 30,500 $ 46,000 $ 66,000 $ 91,000 $ 48,250 $ 57,250 $ 68,500 Operating Costs Lifecycle costs after 1 year Lifecycle costs after 5 years Lifecycle costs after 10 years 5 Kw Backup Natural Gas 5 kW Outdoor Enclosure H2 Fuel Cell Natural Gas Reformer Piped Natural Gas Piped supply Capital Cost Diesel 25 KVA Outdoor installation Diesel genset Combustion Engine External tank 500 gal sub-base tank Monthly refueling Equipment Cost $ 56,000 $ 30,000 Federal Tax Credit $ (15,000) $ - $ $ - Permitting/Installation $ 25,000 $ 20,000 TOTAL FIRST COST $ 81,000 $ 50,000 Annual Maintenance & Fuel $ 5,100 $ 25,400 $ 71,100 $ 91,500 $ 117,000 $ 75,400 $ 177,000 $ 304,000 State Credits Operating Costs Lifecycle costs after 1 year Lifecycle costs after 5 years Lifecycle costs after 10 years 5 Kw Guide Cummin http://www.cumminspower.com/w s DGCA ww/Commercial/Diesel/d-3423.pdf Standby Prime kW (KVA) kW (KVA) 40 (50) 36 (45) Lo 1/ 1/ 3/4 Full 1/4 1/2 3/4 Full ad 4 2 US, 1.2 1.8 2.5 3.3 1.2 1.7 2.4 3.0 gp h L/h 5 r 7 9 12 5 6 9 11 Ge ner ic Lo 1/ 1/ 3/4 Full ad 4 2 US, 1.5 2.2 3.0 4 gp h http://www.cumminspower.com/w ww/Commercial/Diesel/s-1012.pdf 14 gallon 0 tank 35 hrs at 10 0% 47 hrs at 75 % 64 hrs at 50 % 93 hrs at 25 % Est 2 im ate 70 gal 10kW DC + rectifier /hr loss + other AC hrs MQ Power DCA25SSIU3C Sta 27 KV nd A http://www.multiquip.com/multiquip/pdfs/SuperSilent_25_150_Spec_ Sheet_V2_0912_DataId_91330_Version_1_DataId_295333_Version_1.p df Pri 25 KV me A by 22 k W Lo 25 50 ad % % gal 0.5 0.8 /hr 8 5 L/h 2.2 3.2 r 26 15. 7 21. 5 30. 6 44. 8 Pri me 20 75 % 1.2 1 4.6 kW 10 0% 1.6 6 6.3 gal ta nk hrs at 10 0% hrs at 75 % hrs at 50 % hrs at 25 % 50 gal 80. /yr 8 4 US D/ gal 20 US 32 D/ 3.2 yr DG Specifications Po 10 kW 3 US 12V we r Vol tag e Cur ren t 155 FT Batt 48 V 208 .33 33 A 1 stri ng 2 stri ngs 3 stri ngs 4 stri ngs $7, 208. 333 33 104. 166 67 69.4 444 44 52.0 833 33 12 A/s trin g A/s trin g A/s trin g A/s trin g D/ Ah US D/ Ah < 0.5 hr 1 hr 1.5 hrs 2 hrs bloc k 48V string 208 .33 33 208 .33 33 208 .33 33 208 .33 33 A tot al A tot al A tot al A tot al 104 .16 67 208 .33 33 312 .5 Ah Exp ect ed 105 Namepla Pri te ce Ah 210 Ah 31 0 Ah Ah 315 Ah 46 5 Ah 416 .66 67 Ah 420 Ah 62 0 Ah Ah 15 5 Ah $1, 86 0 $3, 72 0 $5, 58 0 $7, 44 0 erie s Enclosure Rec tifie rs 500 $7, 500 $3, 000 $18 ,00 0 $36 ,00 0 $72 ,00 0 4 7 155 FT http://parts.arrow.com/item/detail/elt ek-valere/h2500a1-vv#JzRR for one 2-hour cabinet for a 4hour system for an 8hour system x 4strings year replacem ent $30, 000 $4,2 85.7 1 Po we r Vol tag e Cur ren t 5 kW 48 V 104 .16 67 A 1 stri ng 2 stri ngs 104. 166 67 52.0 833 33 battery blocks amortized replacement cost A/s 1 trin g A/s 2 trin g hr hrs 104 .16 67 104 .16 67 A tot al A tot al 104 .16 67 208 .33 33 Ah Exp ect ed 105 Namepla Pri te ce Ah 15 5 Ah Ah 210 Ah 31 0 Ah $1, 86 0 $3, 72 0 3 stri ngs 4 stri ngs $18 ,00 0 $36 ,00 0 $72 ,00 0 2 34.7 222 22 26.0 416 67 46.2 10 0.01 0.462 4,047 Nm3 /h scf/h USD/1000 cu ft USD /cu ft USD /h USD /yr hrs hrs 104 .16 67 104 .16 67 A tot al A tot al 312 .5 Ah 315 Ah 46 5 Ah 416 .66 67 Ah 420 Ah 62 0 Ah $5, 58 0 $7, 44 0 for one 4-hour cabinet for a 8hour system for a 16hour system x 4$15, strings 000 7 year $2,1 replacem 42.8 ent 6 Battery Specifications 1.24 A/s 3 trin g A/s 4 trin g battery blocks amortized replacement cost http://www.clearedgepower.com/downloads/files/datasheets/DS0101 _PureCell_M5_011014.pdf http://www.eia.gov/dnav/ng/ng_pri_sum _dcu_nus_m.htm 1 12 2.54 100 30.48 0.304 8 0.028 317 43.79 019 ft in/ft cm/i n cm/ m cm/f t m/ft m3/f t3 Ncf/ h Natural Gas Annex A Supplementary Information Annex B Example Systems Annex C Example Permits