The end of the road for thermos-electrics for wearables & vehicles?

Guest author of this feature is Dr Harry Zervos, Principal Analyst, IDTechEx

After several years of excitement, investment and growing interest in thermoelectrics and their potential in energy harvesting applications, it’s now time to clearly look at what’s hype and what’s reality, and the technology developers in the field know that well

In the last few years, companies have filed for bankruptcy, or moved away from the energy harvesting and power generation space to other markets. Others have seen identified applications turn out to be more difficult to commercialize than initially hoped and realizing the hard times ahead, are trying to identify low hanging fruit and applications that can see them through the hardship. Those best prepared for these conditions will survive and be able to enjoy a market that could reach almost 1.5 Billion by 2027, according to IDTechEx Research’s latest report on the topic, Thermoelectric Energy Harvesting 2018-2028.

The end of thermoelectric generators in automotive waste heat recovery
It might come as a surprise to some but for those who have been reading the signs for the last few years, it’s probably not so unexpected. Regardless, in one of the more shocking forecasts within this report is the bad news about waste heat recovery in vehicles: According to IDTechEx, it’s not expected that we will ever see the deployment of thermoelectric generators in vehicles. The excitement of previous years and the investment of almost USD 250 million dollars in projects led by automotive OEMs who each partnered with a thermos-electrics company did not continue after 2014. Grants came to an end, project deliverables delivered and revealed mechanical robustness problems and material systems development requirements that would still take a few more years until they were “deployment ready”. No follow-up work was announced, and reduced press releases and marketing from automotive OEMs followed.

The expected 3-5 % reduction in fuel consumption with the power generated potentially reaching 1200W, became a fleeting dream that ended with the advent of vehicle electrification. Although electric vehicles would not entirely substitute internal combustion engine vehicles in the immediate future, the announcement from Volvo in 2017 of its intention to provide electric and hybrid versions of all of its models starting from 2019 onwards indicate that there’s already timelines in place for full replacement of ICEs. And that would make investing in developing thermoelectric generators counter-productive as the exhaust of the ICE is really the ideal location for generator due to the high temperature difference between it and the ambient, a difference that doesn’t exist at all in an electric vehicle.

For these reasons, IDTechEx feels that further work in this space will eventually cease, with the focus shifting towards industrial applications, with stationary high temperature processes in such settings providing a segment with less stringent robustness requirements for the harvesters.

What about thermos-electrics in wearables?
As for the news from the wearables front, they don’t seem much rosier: Thermoelectric energy harvesting in consumer electronic devices is still the market that most developers would like to address but it is largely at the conceptual stage. The idea here is that the temperature difference between ambient air and the human body will generate enough power for some electronic devices: in order to perform a sensing measurement and transmit the data for instance. The small temperature difference and the resulting imposed power output limit of about 30 W/cm is a hindering mechanism though, and so is the necessity to utilize heat sinks to dissipate heat so as to maintain as high a temperature difference as possible, which adds bulk to the final product. These imposed limitations point to some fitness trackers and wearables with low power consumption (i.e. reduced functionalities) as potential applications, where powering low-power wireless sensor nodes and radios becomes viable. Matrix Industries is launching its crowdfunded smart watch next month, with 10000 or so unit reaching the supporters of their vision with a few months delay than initially expected, but the difficulties that Matrix had to deal with in order to make this smart watch happen only verify how tough this market is to address.