"Energy Harvesting" Powers Small Wireless Devices

We've been tracking the potential of "energy harvesting" to power devices without conventional batteries or grid connections since 2011. The latest market entrants demonstrate this segment continues to expand to meet the need son the Internet of Things (Iot).

Sol Chip's "Everlasting Solar Battery" "...integrates all the components required — in a single battery unit — to harvest and supply sustainable solar/light energy to low-power applications." Sol Chip was recognized as a 2016 Sustainia 100 solution. The Sustainia citation noted the potential impact on IoT e-waste "...by limiting the need to continuously replace batteries and reducing the associated costs and waste."

Freevolt from Drayson Technologies Limited "...provides power for Low Energy Internet of Things (LE-IoT) devices. Its a...technology that harvests radio frequency (RF) energy from wireless and broadcast networks such as 2G, 3G, 4G, WiFi & Digital TV... Freevolt technology can extend device lifetime by constantly trickle charging the battery and removing the need for battery swaps or plug-in charging." Freevolt was also recognized as a 2016 Sustainia 100 solution. The Sustainia citation noted the technology's potential for ICT4D. "Freevolt enables the cable-free installation of connected devices in hard-to-reach or dangerous location, bringing off-grid charging to rural markets."

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2013 research shows the "Ambient Energy Harvesters" (AEH) market now growing at a CAGR of 17%. Some wearable tech incorporates AEH and AEH can mitigate the environmental impact of the Internet of Things (IoT). These applications, which could significantly reduce IoT's battery e-waste stream, will likely accelerate the market.

We described this technology in September 2011 by quoting a manufacturer. "[Marlow Industries has announced] a complete range of thermoelectric-based energy harvesting devices, offering customers a low-cost, zero-maintenance power solution for wireless sensor applications…By converting small degrees of temperature difference into milliwatts of electrical power [they] can perpetually power wireless sensors for the lifetime of the application. This green innovation offers a solid-state, reliable energy source for sensors, actuators, valve solenoids and other small devices by recycling wasted heat…With new building codes requiring sophisticated lighting, heating, ventilation and air-conditioning systems (HVAC), 'smart' designs are key to moderating usage…builders will have a cost-effective and green alternative that will relieve resources spent powering these devices."

In addition to thermoelectric (heat-to-electricity), AEH includes about half-a-dozen other technologies. IDTechEX forecasts thermoelectric and electrodynamic (mechanical-to-electricity) to be the two main commercial technologies by 2016.

GBI Research characterizes the industry in 2013 this way: "For many decades people have searched for ways to store and channel the energy from heat and vibrations, and one driving force behind the search for new energy harvesting devices is the desire to power Wireless Sensor Networks (WSNs) and mobile devices without the use of batteries. Furthermore, the need to address the problem of climate change is also fueling interest in this area. Ambient Energy Harvesters (AEHs) are power supplies that are capable of harvesting energy from the environment and could potentially replace batteries altogether in the future as they are coupled with an ultra-low-power embedded processor…In addition, energy harvesting will create opportunities for designers to delimit application areas, because unlike current batteries less space is required and there are no accessibility issues related to maintenance. Due to these advantages, the AEHs market is expected to grow at a compound annual growth rate (CAGR) of 17.1% from 2012-2016…energy harvesting is expected to gain popularity among business and consumers because of the environmental friendliness and other benefits that it offers."

A 2011 report from IDTechEx put the energy harvesting market at $0.7 billion in 2011 and foretasted $4 billion for 2021, although the company appears to have appeared to scale back its forecast in September 2013 to $2.6 billion in 2024.

Manufacturers where talking about milliwatts in 2011; by November 2013 they were talking microwatts. GBI quotes a Linear Technology Corporation, "With entire wireless sensor nodes now capable of operating at microwatt average power levels, it is feasible to power them from non-traditional sources. This has led to energy harvesting, which provides the power to charge, supplement or replace batteries in systems where battery use is inconvenient, impractical, expensive or dangerous. It can also eliminate the need for wires to carry power or to transmit data. In addition, otherwise wasted energy from industrial processes, solar panels, or internal combustion engines, can be harvested for useful purposes."

Duke University (USA) reported in November 2013 that their researchers, "...have designed a power-harvesting device with efficiency similar to that of modern solar panels.The device wirelessly converts the microwave signal to direct current voltage capable of recharging a cell phone battery or other small electronic device...this versatile energy harvester could be tuned to harvest the signal from other energy sources, including satellite signals, sound signals or Wi-Fi signals...They used a series of five fiberglass and copper energy conductors wired together on a circuit board to convert microwaves into 7.3V of electricity. By comparison, Universal Serial Bus (USB) chargers for small electronic devices provide about 5V." (Published paper.)

The Guardian (UK) reported back in 2009 that Nokia is working on a prototype phone charger "able to power itself on nothing more than ambient radiowaves – the weak TV, radio and mobile phone signals that permanently surround us. The power harvested is small but it is almost enough to power a mobile in standby mode indefinitely without ever needing to plug it into the mains...Individually the energy available in each of these signals is miniscule. But by harvesting radiowaves across a wide range of frequencies it all adds up...Wireless charging is not intended as a sole energy source, but rather to be used in conjunction with other energy harvesting technologies, such as handset casings embedded with solar cell materials." This technique seems dependent on a high density of signals, limiting its potential to urban areas in developed counties.

When the story broke in 2009, the MIT Technology Review quoted a Nokia researcher as saying, “I would say it is possible to put this into a product within three to four years." Four years later, we could find no recent updates. Yet the original story seems to have enjoyed new life in August 2013 on social media, with all citations tracing back to the 2009 stories. There are cautionary tales here about both the promise of cutting edge technology and the acuity of social media.

Click on the 'FutureTech' tag, above, to see more Green ICT technologies still under development or just emerging commercially.