Navigant Research projects that revenues from energy harvesting (EH) technologies will come in at about $268 million globally this year and will reach nearly $375 million in 2020, a compound annual growth rate (CAGR) of 4.9 percent. A recent report from the group analyzed the market for photovoltaic (PV), piezoelectric, electromagnetic, and thermoelectric energy harvesting technologies as employed in industrial and consumer products “that are untethered or need to become disconnected from the electrical outlet.”
Conventionally, such devices are powered by batteries, but energy harvesting represents an option with potentially lower costs, lower maintenance, greater convenience, and lower environmental impact.
Powering the “Internet of Things”?
These technologies have particular application in building automation and “Industrial Internet” applications, and are becoming an important element of the emerging “Internet of Things.” Jeffrey R. Immelt, chairman and CEO of General Electric, has defined this Internet of Things as “an open, global fabric of highly intelligent machines that connect, communicate and cooperate with us.”
This emerging intelligent network employs miniaturized sensors and wireless communication devices embedded into machines to monitor their condition and activity. Embedded devices can automatically control and optimize machines’ functioning, reducing the need for human intervention.
Such machine-to-machine (M2M) communication offers potential environmental benefits, according to a report from the Carbon War Room. The group projects that by 2020, 12.5 billion M2M devices will be operating globally, up from just 1.3 billion today. Such devices will allow companies to save energy, reduce waste, and better integrate renewable energy sources. M2M, combined with related information and communication technologies (ICT), could reduce global greenhouse gas (GHG) emissions by 9.1 gigatons (Gt) carbon dioxide equivalent (CO2e) yearly.
Energy harvesting technologies can fit into this Industrial Internet picture by increasing the self-sufficiency of M2M devices, delivering constant power by pulling in ambient energy from the immediate environment, without the need for grid connections or batteries. M2M devices are becoming increasingly miniaturized, using low-power microprocessors that require very little electricity.
Energy harvesting technology “has reached a tipping point,” according to Dr. Harry Zervos, senior technology analyst for research firm IDTechEx. Zervos wrote recently that “the necessary lower power electronics and more efficient energy gathering and storage are now sufficiently affordable, reliable and longer lived for a huge number of applications to be practicable.” The two most mature EH technologies are solar cells and electrodynamos, said Zervos. However, other technologies are starting to gain market share, including thermoelectrics, which harvest ambient heat and convert it to electricity. The U.S. Department of Energy (DOE) has partnered with automakers BMW and GM to develop devices that harvest waste heat from engines and exhaust systems and use it to help power vehicle electrical systems.
In a report for IDTechEx, Zervos predicted that the global market for energy harvesting devices will reach $2.6 billion by 2024, several times higher than Navigant Research’s projection cited above.
Energy Harvesting for Improved Environmental Performance
German technology firm EnOcean GmbH produces wireless EH technologies for self-powered switches and sensors, along with wireless transmitters and software tools and middleware. EnOcean manufactures energy converters based on motion, heat and solar energy.
Green & Clean Journal asked Laurent Giai-Miniet, CEO of EnOcean, where the company sees the fastest-growing demand for its technologies. He said EnOcean sees fast growth in the commercial-building automation and smart-home markets, especially due to the need for increased energy efficiency and environmental performance. Also, he said, “Manufacturers have recognized the benefits of standard-based, batteryless and maintenance-free solutions,” recognizing that “they not only free the user from a regular battery change, but give the user the freedom of choice to flexibly create and extend an intelligent connected system.”
Giai-Miniet also sees increasing demand in the area of LED control, where wireless sensors and actuators can help achieve greater energy efficiency. He told Green & Green Journal that building automation systems themselves help reduce energy consumption in buildings by 20 to 40 percent. “To illustrate,” he said, “if a sensor detects that a room or area is no longer occupied, lights can be automatically switched off and the HVAC systems automatically set back, saving an average of 30 percent of energy compared to a non-automated system.” Giai-Miniet pointed out that there is a great demand for increased energy efficiency right now in industrial plants. Batteryless technologies are easier and less costly to retrofit on existing facilities, making energy harvesting a useful option for powering sensors and control devices.
Giai-Miniet also asserted that energy harvesting technologies offer environmental benefits beyond reducing energy consumption. For one thing, he said, “the wireless operation saves a lot of raw materials, including copper and PVC.” The technology also “eliminates the need for batteries, which contain heavy metals such as mercury, lead, cadmium, and nickel. At the end of their lifetime, batteries are hazardous waste and need to be carefully and expensively disposed of by the manufacturer or the user.”
Giai-Miniet told Green & Clean Journal that EnOcean components are now in more than 250,000 buildings and, as a result of those installations, “we have saved 15,500 miles of cables, 1,000 tons of copper and 2,500 tons of PVC.” He added that “at a typical expected device lifetime of 25 years, the batteryless solutions installed will save 50 million batteries.”
Harvesting Vibration Energy at Large Scale
In investigating energy harvesting, Green & Clean Journal editors wondered whether energy harvesting could be used for power generation at large scale. Lei Zuo, engineering professor at the State University of New York at Stony Brook, investigated energy harvesting technologies and wrote about his findings in the Journal of Intelligent Material Systems and Structures. He admitted in his article that most applications of EH are in low-power electronics such as sensors. However, Zuo also pointed out that “vibration exists everywhere, such as the vibration of floor and wall, machines, pumps, vehicle chassis, railway train or tracks, and human motions, etc.” and that such ambient energy could become “a good alternative energy source” if workable EH technologies were developed.
Zuo’s paper suggested that technologies available now are not sufficiently developed for large-scale EH applications. Efficiency and vibration control are key obstacles. He wrote that “A fundamental challenge is that large-scale vibration is very irregular at time-varying frequency and at low, alternating velocities, which makes efficient and reliable energy conversion difficult and limits the options for efficient power takeoff technology.”
But those obstacles haven’t prevented a Dutch firm called Energy Floors from investigating ways to transform human foot traffic into electrical power. Primarily known for its energy-generating dance floors, company representatives told Green & Clean Journal that it is now developing a Sustainable Energy Floor and has just entered into a contract with the Russian Railways Research Institute to develop a walkway designed to generate power through passenger footfalls in train stations. The company plans to carry out a test installation next year at one of the railway’s facilities.