STANDARD PROTOCOL FOR ESTIMATING SAVINGS FROM AGRICULTURAL IRRIGATION PUMP MOTOR VARIABLE SPEED DRIVES REGIONAL TECHNICAL FORUM Release Date: April 16, 2013 Regional Technical Forum i Standard Protocol - Agricultural Irrigation Pump Motor VFD TABLE OF CONTENTS 1. PURPOSE............................................................................................................ 1 2. SUNSET DATE ...................................................................................................... 1 3. DEFINITION OF KEY TERMS ..................................................................................... 1 4. ELIGIBLE PROJECTS ............................................................................................... 1 5. REQUIRED KNOWLEDGE AND SKILLS OF PRACTITIONER ................................................... 2 6. DELIVERY VERIFICATION ......................................................................................... 3 7. DATA COLLECTION REQUIREMENTS ........................................................................... 3 7.1. Pump and Pump Motor Specifications .............................................................................. 3 7.2. Specifications for Additional Equipment on the Metered Circuit ..................................... 3 7.3. Specifications for Additional Program Measures Affecting the Metered Circuit .............. 4 7.4. Baseline Electricity Consumption ...................................................................................... 4 7.5. Inputs for Cost-Effectiveness Analysis ............................................................................... 4 8. PROVISIONAL DATA REQUIREMENTS ......................................................................... 5 9. SAVINGS ESTIMATION STEPS ................................................................................... 5 9.1. Determine Average Annual Baseline Consumption for the Pump .................................... 6 9.2. Compute Savings Using the Simplest Reliable Method ..................................................... 6 9.3. Compute Savings Using the Best Practice Method ........................................................... 6 9.4. Life Cycle Costs and Benefits ............................................................................................. 7 10. SAMPLING PROCEDURE ........................................................................................ 7 11. RELATIONSHIP TO OTHER PROTOCOLS AND GUIDELINES ............................................... 7 12. TYPICAL COST OF APPLYING THIS PROTOCOL ............................................................. 8 13. USER’S GUIDE TO THE SAVINGS CALCULATOR ............................................................ 8 ii Regional Technical Forum Standard Protocol - Agricultural Irrigation Pump Motor VFD 1. PURPOSE This provisional protocol establishes a method by which annual electrical energy savings (kWh) can be estimated for a turbine style pump in agricultural irrigation applications that has been upgraded by the addition of a Variable Frequency Drive (VFD). VFDs reduce electric use by adjusting the pump motor’s speed to better match the required pumping output. With improved sprinkler systems, some pumping plants are currently oversized, and do not require nameplate head or flow. Head requirements may also vary throughout the growing season for ground water systems. VFDs reduce electric use by adjusting the pump motor’s speed to match the required load and alleviate the need for less efficient methods of regulating flow rates, such as throttling values or return flows (i.e. “pump and dump”). This protocol specifies minimum acceptable data collection requirements and the method by which these data are to be used in computing savings. For some data elements, alternative sources of data, considered to be of superior quality, are also defined and are allowed. Savings are computed using the methods within the Excel workbook that accompanies this document to ensure standardized application of the savings estimation methods. This protocol also specifies a best practice method of estimating savings. Both the best practice and provisional methods should be used. When sufficient data has been collected from the use of both methods, the RTF may consider changing the category of this standard protocol from provisional to proven. 2. SUNSET DATE This provisional protocol is approved for use until April 30, 2016. 3. DEFINITION OF KEY TERMS Project. A VFD installed to control one turbine pump. The baseline control mechanism (e.g., throttling valve, pressure reducing valve, bypass valve) is either disabled and set to the appropriate condition or removed. Baseline. This modifier refers to the period prior to the upgrade. Post. This modifier refers to the period after the pump unit VFD upgrade is installed and fully commissioned. Operational. A VFD is determined to be operational if it is energized, set to the automatic motor speed adjustment setting, and is capable of providing power to the motor at a frequency of less than 60 Hz. 4. ELIGIBLE PROJECTS Following criteria define the eligible pump upgrade projects: Regional Technical Forum 1 Standard Protocol - Agricultural Irrigation Pump Motor VFD Pumps must be vertical, submersible or line shaft turbine pumps used for agricultural irrigation purposes. Centrifugal and positive displacement pumps are not eligible under this protocol. Pump motors must have a horsepower (HP) rating between 20 and 500 HP. Pump motors must be single speed motors. Pump motors must not be subject to a local energy code requirement for variable speed drive. The baseline control strategy must rely on throttling valves, with or without recirculation. Pump must have a variation in flow requirements of 20% or more, or a reduction in pressure requirements of 10% or more. All throttling valves and recirculation devices must be removed or rendered non-operational as part of the measure installation. The baseline pump load must be disaggregated from the available metered data. The upgraded pump can share a circuit with the following equipment: Electric motors of much smaller capacity than the upgrade equipment, such as center pivot drive motors. Additional pumps that are being upgraded simultaneously. Additional pumps and other equipment that the operator of can estimate the annual hours of operation for. Three years of metered annual kWh consumption must be available. If the computed estimate of baseline annual hours of operation is greater than 2,500 hours, then the practitioner must verify that the computed hours of operation is consistent with the operator’s estimate of hours of operation. The estimate of hours of operation should be computed from the following equation: Hours of Operation = [Baseline Average Annual kWh] / { [Pump Motor HP] x [0.746 kW/HP] x [Motor Loading Factor]} , where the Motor Load Factor is equal to 1.0. 5. REQUIRED KNOWLEDGE AND SKILLS OF PRACTITIONER The practitioner who has lead responsibility for applying this protocol to a pump unit must have at a full understanding of the following: Appropriate safety procedures for collecting pump system specifications, including pump nameplate data and baseline control specifications. This protocol and the accompanying savings calculator. The practitioner must also be able to successfully perform the following tasks: Interview the pump operator to understand the need for VFD and the variation in flow or pressure requirements 2 Regional Technical Forum Standard Protocol - Agricultural Irrigation Pump Motor VFD Identify, by inspection, the pump type and control strategy. Collect necessary pump system specifications and billing or other metered energy consumption data. 6. DELIVERY VERIFICATION This protocol may only be used for pump units that pass the following delivery verification tests: The baseline control mechanism is either removed or disable and set to the maximum flow condition. The practitioner must verify the VFD has been installed and is operational. The practitioner can determine if the VFD is operational through inspection of the VFD display during operation. If the system is in auto-mode and the driving frequency is 60 Hz, then the practitioner should have the operator temporarily reduce the pumping requirements of the system; the practitioner can then observe the system being driven at a frequency less than 60 Hz. 7. DATA COLLECTION REQUIREMENTS The following data must be collected and entered into the savings calculator. The minimum acceptable procedure for obtaining the data is specified. In some cases, alternative procedures are allowed which would provide data of higher quality. 7.1. Pump and Pump Motor Specifications Pump type. Determined by inspection. The pumps must be vertical, submersible or line shaft turbine pumps. Baseline Control Strategy. Baseline system motor controls must be on/off, with or without pump pressure or flow control devices that do not adjust motor speed. 7.2. Specifications for Additional Equipment on the Metered Circuit An inventory of equipment on the circuit must be compiled, that includes: The type of equipment The rated load of the equipment For all equipment with a rated load greater than or equal to two percent of the rated load of the pump, the following data must be collected. Estimated annual hours of operation. Collected from the system operator. Regional Technical Forum 3 Standard Protocol - Agricultural Irrigation Pump Motor VFD 7.3. Specifications for Additional Program Measures Affecting the Metered Circuit For any energy efficiency measures that were implemented on the metered circuit during the three year pre-installation period, or during the same year as the VFD installation, the following information must be provided: Name of the measure Date of the measure installation Estimated measure savings. If there is an RTF approved estimate of savings for this measure, then the RTF approved value should be used. Otherwise, the value estimated by the measure practioner should be used. 7.4. Baseline Electricity Consumption Three years of baseline annual electricity consumption must be collected. Acceptable data sources are: Utility metered data of a circuit that a pump is the only power-consuming equipment on. Utility metered data of a circuit that the other equipment loads have been subtracted from. Sub-metered data from a true RMS power meter. 7.5. Inputs for Cost-Effectiveness Analysis The following data need to be gathered to support the cost/benefit analysis feature of the calculator. Entries will be limited by the calculator to a restricted set of options. Certain entries are completely predetermined. Project completion date. Measure cost. The initial cost of installing the measure, including all materials and labor costs. This is the full cost of the VFD installation. This value must be supported by invoices or other documentation. The following values are used in the cost-effectiveness calculation, but are pre-set in the calculator. Electric shape. The calculator assigns an appropriate electric shape for Northwest regional irrigation pumping loads. Periodic costs or savings. Any non-annual periodic costs associated with the measure, and the associated time period. These are incremental costs of the efficient option over the costs of the baseline. For a fan VFD, the calculator restricts this value to be zero. 4 Regional Technical Forum Standard Protocol - Agricultural Irrigation Pump Motor VFD O&M costs or savings. Annual O&M costs or savings associated with the measure. These are costs or savings which occur with the efficient option that would not occur with the baseline option, i.e. the costs associated with VFD maintenance. The calculator restricts this value to be zero. Non-energy benefits. Annual non-energy related costs or savings associated with the measure. The calculator restricts this value to be zero. Measure life. Number of years the measure is expected to be in effect. For a pump VFD, the calculator restricts this value to be 10 years. 8. PROVISIONAL DATA REQUIREMENTS During the period that the RTF classifies this protocol as Provisional, the following data requirements will be in force: Post-installation Annual Electricity Consumption. One year of post-installation annual electricity consumption must be collected. Acceptable data sources are: Utility metered data of a circuit that a pump is the only power-consuming equipment on. Utility metered data of a circuit that the other equipment loads have been subtracted from. Sub-metered data from a true RMS power meter. Acres Irrigated. The number of acres irrigated by the irrigation system that the VFD is a part of during each of the three pre-installation years and during the year immediately following the installation. Crop Type. The type of crop grown on the field(s) irrigated by the irrigation system during each of the three pre-installation years and during the year immediately following the installation. The following data should be collected if available: Measured Flow Rate. The measured flow rate produced by the pump. Irrigation System Type. {Gravity system / Sprinkler system / Drip, trickle, or low-flow micro sprinklers / Subirrigation } 9. SAVINGS ESTIMATION STEPS Savings are estimated using the savings calculator that accompanies this protocol. Savings are estimated as follows. Regional Technical Forum 5 Standard Protocol - Agricultural Irrigation Pump Motor VFD 9.1. Determine Average Annual Baseline Consumption for the Pump Annual Baseline Pump kWh. For each of the three years, the following electricity consumption amounts should be subtracted from the measured electricity consumption: Estimated Consumption Of Additional Equipment. The estimated annual energy consumption of each additional piece of equipment on the circuit, excluding equipment with rated loads less than 2% of the pump rated load. Annual energy consumption for other equipment is determined by multiplying the rated load by the operator’s estimate of annual hours of operation. Estimated Savings From Other Measures. For any additional incented energy efficiency measures as described in section 7.3, the estimated other measure savings should be subtracted from the metered data for all years prior to the installation. For example, if a VFD were installed in the fall of 2013, and irrigation hardware measures had been implemented in the fall of 2012, then the estimated savings from the irrigation hardware measure would be subtracted from the 2011 and 2012 metered electricity consumption. If the VFD and irrigation hardware were both installed in fall 2013, then the estimated savings from the irrigation hardware measure would be subtracted from the 2011, 2012, and 2013 metered electricity consumption. Average Annual Baseline kWh. Compute the average annual baseline kWh. This is the sum of Annual Baseline Pump kWh divided by three. 9.2. Compute Savings Using the Simplest Reliable Method Estimated Annual kWh Savings. Multiply the Average Annual Baseline kWh by Average Measure Savings Percentage. The Average Measure Savings Percentage is 25%. 9.3. Compute Savings Using the Best Practice Method The status of this standard protocol is provisional. Therefore, in addition to the savings estimation method described in sections 9.2 and Error! Reference source not found., the best practice method must also be used to compute savings. Annual Post-installation Pump kWh. This is the measured electricity consumption for the one year immediately following the VFD installation, minus: Estimated consumption of additional equipment. As described in section 9.1. Estimated Annual kWh Savings. This is the Average Annual Baseline kWh minus the Annual Post- installation Pump kWh. 6 Regional Technical Forum Standard Protocol - Agricultural Irrigation Pump Motor VFD Note that while the Acres Irrigated and Crop Type are provisional data collection requirements, they are not used in the best practice savings estimation method. When sufficient data has been collected under this provisional standard protocol, the RTF may use this information to inform either the Average Measure Savings Percentage value or the savings estimation method for a standard protocol with “proven” status. 9.4. Life Cycle Costs and Benefits The calculator contains results of the ProCost model, which computes life cycle costs and benefits. Inputs to the model include the estimates of first year savings described in sections 9.2, Error! Reference source not found., Error! Reference source not found., and Error! Reference source not found. and the cost-effectiveness input data described in section 7.5. ProCost computes life cycle costs and benefits from the economic perspectives of the end user, utility, and region. The ProCost model for this measure is available on the RTF website. 10. SAMPLING PROCEDURE No sampling is permitted by this protocol. Data collection and savings estimation is required for each upgraded pump unit regardless of the number of such units that may be upgraded at a facility. 11. RELATIONSHIP TO OTHER PROTOCOLS AND GUIDELINES The relationship between this protocol and other relevant protocols and guidelines is as follows: International Performance Measurement and Verification Protocol – 2007 (IPMVP), Efficiency Valuation Organization. This protocol is consistent with Option A - Retrofit Isolation: Key Parameter Measurement described in the IPMVP, as the key parameter is measured (baseline pump annual energy consumption) and the additional parameter required for computing savings, percentage savings, is estimated based on historical data. M&V Guidelines: Measurement and Verification for Federal Energy Projects Version 3.0, U.S. Department of Energy Federal Energy Management Program. The relevant part of this guideline is Section 11.4 Variable Speed Motors. This guideline requires both baseline and post measurements, which is not consistent with this protocol. Verification by Equipment or End-Use Metering Protocol, 2011, Bonneville Power Administration. This BPA guideline, based on ASHRAE Guideline 14-2002, in general requires both baseline and post metering. The protocol described herein is based on baseline-only metering, although its provisional form calls for pre- and post- metering. Sampling Reference Guide, BPA. It is unlikely that more than 20 pump units would be upgraded as part of any one project. It is difficult to obtain reliable sample estimates from populations this small, Regional Technical Forum 7 Standard Protocol - Agricultural Irrigation Pump Motor VFD especially given the likely variation in savings between units. Therefore no sampling is allowed. This is consistent with the BPA guide. 12. TYPICAL COST OF APPLYING THIS PROTOCOL Shown below is an estimate of typical cost of applying this protocol for a single pump unit. Projects that involve more than one pump unit at the same facility are likely to see lower cost per unit. Expenses for alternative measurements, allowed by this protocol, are not included in this estimate of typical cost. Item Quantity $ / Hour Rental Total Cost Labor Utility or Trade Ally Practitioner Travel 1 50 50 Scheduling 1 50 50 Facility Operator Interview 2 50 100 0.5 50 25 1 50 VFD Inspection Savings Estimate Total 50 $275 13. USER’S GUIDE TO THE SAVINGS CALCULATOR The Agricultural Irrigation Pump VFD Savings Tool calculated the annual energy savings following the steps outlined in Section 9 of this protocol. Step 1: Project level information. Enter the following information in the highlighted fields: Date of VFD installation: in the format MM/DD/YYYY Pump motor size: in HP, can be between 20 and 500 Acres irrigated by this system Project cost Measured flow rate: in gpm, if available Step 2: Annual information. Enter the following information for each of the three years prior to the VFD installation and the year following the installation in the highlighted fields: 8 Metered kWh: the annual electricity consumption on the metered circuit, obtained from billing history or sub-metering equipment Crops grown on irrigated acreage: the type and variety of crop(s) grown in each year. Regional Technical Forum Standard Protocol - Agricultural Irrigation Pump Motor VFD Irrigation system type: the irrigation system type, if available, selected from the pull-down menu. This information is collected in each year to capture any changes to the irrigation system during the metered period. Step 3: Additional equipment on the metered circuit: Enter the following information for all additional electricity consuming equipment on the circuit being metered. Equipment: a brief description of the equipment. For example, “center pivot drive motor”, or “secondary pump”. Rated load: the rated load of the equipment, in HP or kW Units of rated load: select either “HP” or “kW” from the pull-down menu. Estimated annual hours of operation: for all equipment exceeding 2% of the pump rated capacity, enter the estimated annual hours of operation of the equipment, as reported by the customer. Step 4: Additional measures on the same irrigation system: Enter the following information for all incented energy efficiency measures implemented on the irrigation system during the time of the pre and post data collection. Name of measure: This should be descriptive. If it is an RTF approved measure, the RTF measure name should be used. Date of installation: in the format MM/DD/YYYY Estimated annual measure savings (kWh): If this is an RTF approved measure, the RTF UES or standard protocol should be used to estimate savings. First metered year that measure impacted: select from the pull-down menu. A measure is assumed to impact annual metered data if it is installed for at least half of the growing season months in the year (April through October). Step 5: Results: The following results are shown below the entered data: The adjusted annual kWh: for each of the three years prior to the VFD installation and the year following the VFD installation. Estimated hours of operation: based on the average annual baseline kWh and the pump motor size. Annual kWh savings: shown for both the simplest reliable method and the best practice method. Percent saving: Annual kWh savings, shown as a percentage of baseline annual kWh Cost effectiveness: the total resource cost test benefit/cost ratio, as determined by ProCost. Regional Technical Forum 9