Harnessing Kinetic Energy from Footfalls Harnessing Kinetic Energy from Footfalls Scope e-Knowledge Center Pvt Ltd May 2014 Harnessing Kinetic Energy from Footfalls Table of Contents 1. 2. 3. 4. 5. 6. 7. 8. Energy Harvesting from Human Footfalls.............................................. 2 Footfall Energy Harvesting Floor – A Brief ............................................ 3 Experiments with Energy Harvesting Floors ......................................... 4 The Technology behind the Energy Floors ............................................ 5 Piezoelectric - The Preferred ................................................................... 6 Market Analysis ........................................................................................ 7 IP Perspective ........................................................................................... 8 Conclusion.............................................................................................. 10 Harnessing Kinetic Energy from Footfalls 1. Energy Harvesting from Human Footfalls With the electronic devices becoming integral part of day-to-day life, both in personal and industrial environments, the demand for energy is tremendously increasing across the globe. In the effort to find alternative sources to supplement the conventional energy sources, the energy industry has found the feasibility in fossil fuels, nuclear, thermal, hydro, solar etc. The researchers’ quest for eco way of generating energy has found a destination at the feet of fellow human beings. Human body generates a lot of energy while doing the most-common activity - walking. Every foot fall causes pressure when the foot hits the floor, which goes untapped. With the ground surface engineered to harvest the energy, power can be generated from the human footfalls, stored and used as a power source or even fed to the power grid. For instance, a person dancing on an energy harvesting floor can generate 5-10 watts; in a packed dance club, the production can meet up to 60% of the total energy required for the club. Page # 2 Harnessing Kinetic Energy from Footfalls 2. Footfall Energy Harvesting Floor – A Brief Sustainable energy is the buzz word in the energy industry, and an emerging technology in the industry is the footfall energy harvesting floor, which generates energy from the routine human activities, such as walking, running, jumping, dancing etc. The technology works on the basic principle of converting kinetic energy, obtained from the pressure applied on the floor surface, into electrical energy. The “footfall energy harvesting floor” comprises a floor covering that encloses a transducer mechanism for converting the applied pressure into electrical energy and a means for transmitting the electrical energy for storage or load consumption. Among the other technologies that promote sustainable energy, energy harvesting floor is considered to be the most productive as it does not depend on any of the natural resources, such as wind, water or sun that are not consistently available. Energy harvesting floors, which take input from human footsteps without affecting pedestrians’ normal life, are easy to install, environment friendly, and are truly sustainable. Page # 3 Harnessing Kinetic Energy from Footfalls 3. Experiments with Energy Harvesting Floors Over these years, researches and developers have experimented on footfall energy harvesting floors to study their feasibility, reliability and effectiveness. Constant experiments have been carried out in the East Japan railway stations, streets of Toulouse and West Ham underground station over a period of varying durations, ranging from several weeks to few years. These experiments have provided evidences that energy harvesting tiles are robust, practical and can be used as an alternative source of producing energy. Post the initial success, improvements are being made and tested for enhanced power generation performance and capacity, along with advancements in material durability. The energy thus captured can be used to power streetlights, pedestrian crossing lights, bus stop displays, traffic signals, automatic ticket gates in stations, information displays etc. Dance clubs around the globe have piloted the footfall energy harvesting floors belonging to the prototype concept - "Crowd Farm", in which energy from footfalls of clubbers dancing on the floors is collected and used to power LED lights and, in the long-term plan, fed into the club's power grid. Page # 4 Harnessing Kinetic Energy from Footfalls 4. The Technology behind the Energy Floors With this method energy harvesting proving its feasibility, developers of energy harvesting floors concentrating their efforts find the most-efficient way of harvesting energy from footfalls. As a result, several inventions are in the prototype stage. However, some industry players, with the aim to popularize and establish this technology among varied consumer segment, have already initiated marketing of their products, which has been well received by environmental activists. Based on the mechanism used for converting the kinetic energy into electrical energy, footfall energy harvesting floors can be broadly classified into the following categories: A piezoelectric element like PZT, PVDF, etc., is used as transducer means to convert the kinetic energy into electrical energy upon stepping on the floor tile. Deformation of the Piezoelectric piezoelectric element caused by the load acting the tile induces charges which can be siphoned off. Page # 5 Magnetic Transducer means comprises a magnetic element and a conductive element, wherein one of the elements is movably coupled to the floor surface. When a pressure is applied on the floor surface, the conductive element cuts the magnetic flux and so current is induced in the conductive element. Generator A mechanical arrangement viz. hydraulic, pneumatic and spring is coupled to the floor surface, such that a rotor of a micro-generator arranged in the floor tile is driven by the mechanical arrangement when a force acts on the floor surface. Static A capacitor is formed in the floor tile by using two charging layers uniformly separated by a small gap, wherein one layer is coupled to the tile surface through springs. By pressing the tile surface, the gap between the layers is altered and so charges are induced in the layers. These charges can be extracted by suitably connecting the layers to an external circuit. Harnessing Kinetic Energy from Footfalls 5. Piezoelectric - The Preferred Though various kinds of footfall energy harvesting technologies exist, piezoelectric is the commonly-used technology. It generates energy from external force impulses or vibration in flooring, bridges, roads and structures. The other potential sources of piezoelectric energy harvesting systems are deformable objects such as golf balls. This system can produce energy even with consistent or predictable vibrational frequency. With its ability to leverage any kind of force, stress or strain, it is ideal for different applications, and hence has a widening market potential. The investment on piezoelectric energy harvesting is expected to reach US$145 million by 2018, and thus, by 2022, it will be a US$667 million market. Though, power generated using piezoelectric systems are predominantly in cigar lighters, they have found applications in wireless sensors and various portable electronics. However, the varying or inconsistent vibrational frequency range limits the practicality for certain applications. Page # 6 Harnessing Kinetic Energy from Footfalls 6. Market Analysis Energy harvesting (EH) has become a major area of focus in Europe and North America; Asian organizations too are investing in the various EH technologies. By 2020, the global energy harvesting market is expected to reach $4.4bn. Majority of the sustainable energy technologies calls for a constant monitoring of, the surrounding environment of installation location. Further, the suitable type and specifications of the devices has to be decided based on the survey reports. Parameters such as size of the devices and place of installation also mandate the tedious, time and effort-consuming post-installation monitoring and maintenance tasks. In contrast to other technologies for which locations are decided based on surveys conducted over a prolonged period, energy harvesting floors eliminate any pre-installation analyzing or monitoring to identify the ideal location. The sole criterion to be fulfilled for the installation is that the place should have human movement. Every city around the world has a huge, growing population, and public places like airports, railway stations and commercial complexes receive huge amount of footfalls throughout the day, thus making them suitable for energy harvesting floors Energy harvesting tiles started off as prototypes in the beginning of the last decade; significant developments have given them a capability to produce up to 20 watts per hit and about 10 kilowatt-hours in a week. With the support from environmentalists, these tiles have become a runaway success around the world. Some of the leading international players in the footfall energy harvesting floor technology and technologies used in the products thereof are listed below: Piezoelectric The Facility Architects (UK) Innowattech (Israel) Soundpower Corporation (Japan) Powerleap (US) Piezo Power (US) Energy Automation (Lebanon) Advanced Linear Devices, Inc (US) Generator Page # 7 Sustainable Dance Club (Netherlands) G Pavegen Systems Ltd (UK) KinergyPower (US) The Facility Architects (UK) Harnessing Kinetic Energy from Footfalls 7. IP Perspective th The footfall energy harvesting floor technology came into existence in the mid of 20 century. However, it has received increased attention in the last few years, which is evident from a considerable increase in the number of patent filings in the piezoelectric sector. The traditional lead zirconate titanate PZT ceramic is being replaced with organic alternatives such as polyvinylidene difluoride. In addition to creating piezoelectric systems with enhanced efficiency and temperature performance, companies also lay emphasis on the flexibility of the materials. Companies such as Toyota Boshoku Corp, Pavegen, Seratech, Hong Kong Applied Science and Technology Research Institute Co Ltd are prominent players in energy harvesting floors. Below is a comparative split of patents/publications owned by the players: There is a steep rise in the patent filing trend during 2011-2012, due to increasing focus on the research and innovations in the footfall energy harvesting sector. Companies such as General Electric and East Japan Railway Company are keen in developing their prototypes. A comparative percentage of details about the products and prototypes are given below. Page # 8 Harnessing Kinetic Energy from Footfalls The below table has the list of key players actively involved in both patent filing and manufacturing products related to footfall energy harvesting floor: S. No. Page # 9 Key Player Patent title Product Patent document 1. The Facility Architects Energy harvesting system SmartFloor / using hydraulic circuit Pacesetters GB2471658A 2. Pavegen Systems Energy harvesting Pavegen WO2011138585A1 3. Floor suitable for Sustainable Dance Club generating, converting and/or storing energy Energy Floors EP2201247B1 4. Innowattech Multi-layer piezoelectric generator Pedestrian tiles US8278800B2 5 Soundpower Corporation Electric apparatus provided with power generating function PowerUS20120248937A1 Generating Floor 6 Kinergypower Traffic-actuated electrical generator apparatus KinergyPad US7629698B2 Harnessing Kinetic Energy from Footfalls 8. Conclusion Though being advantageous in several aspects, such as manufacturing, installation, aesthetics, maintenance, availability etc, this technology can only contribute to low power applications. It requires highly-efficient converter mechanism and storage devices and has a less storage lifespan. Besides, the materials used in manufacturing the devices must be highly durable, as they will be operating throughout the year. As of today, this technology is in its nascent stages due to the above stated reasons. Development in the areas of storage and transmission of energy may eliminate all the drawbacks and make this an effective technology for power harvesting. Page # 10 Harnessing Kinetic Energy from Footfalls References http://www2.hull.ac.uk/science/engineering/research/energy,_environ__sustainable/energy_harvesting.as px http://health.heraldtribune.com/2013/03/17/the-body-electric-harnessing-human-energy/ http://www.renesas.com/edge_ol/features/09/index.jsp http://www.greenbusinessguide.co.za/piezoelectric-energy-harvesting-market-to-expand/ http://apps.research.ufl.edu/otl/pdf/marketing/13608.pdf Page # 11