Thermoelectric Harvesting Finding its Place at Last?

Dr Peter Harrop
Thermoelectric Harvesting Finding its Place at Last?
The new IDTechEx report, "Thermoelectric Energy Harvesting and Sensing 2020-2030" scopes a multi-billion dollar opportunity. Raghu Das, IDTechEx CEO and co-author of the report enthuses, "The future is electric. 60% of the world's primary energy is wasted as heat. Turn that heat into electricity and the benefits are huge. The Internet of Things is nowhere near reaching the predicted billions of nodes yearly monitoring everything from oil spills to forest fires and earthquakes. This is because batteries cannot be changed or charged in such deployments, so you need to make the electricity at the node, typically in the dark. Thermoelectric harvesting from heat differences is often a strong candidate. Another problem is smart watches expiring in hours. They have inadequate area for solar alone so how about electricity from heat, now there is progress in viably exploiting small temperature differences?"
So far, thermoelectric energy generators (TEGs) are a small business because of cost and poor performance. Thermoelectrics is a poor third in energy harvester sales, well behind electrodynamics (wind and water turbines etc.) and photovoltaics on everything. Nonetheless, 2019 was a bumper year for TEG research and new approaches to thermoelectrics and to thermeoelectric sensing became active areas. For example, quantum and spin thermoelectrics now promise ten times the efficiency.
Yes, progress is poor in finding more efficient materials for conventional thermoelectrics at the temperatures where almost all the demand lies - up to 300C. However, taking a cue from other forms of energy harvesting, less efficient options with much more acceptable formats and costs are looking good. Welcome to wide area, stretchable, and biocompatible TEGs employing polymers and composites.
The Executive Summary and Conclusions of the report are sufficient for those in a hurry. Its new infograms explain the huge opportunities, impediments, patents, new materials, inventions and new approaches. There are ten year forecasts for different applications of thermoelectrics and wearables. The Introduction explains the basics, traditional manufacturing and formats, and the trends. Go to Chapter 3 for New Principles: Quantum Dot and Spin-Driven. Chapter 4 closely examines Low Power: Flexible and Stretchable Thermoelectrics - the technology, new inventions, healthcare and wearables opportunities. Here is good news about viably harvesting electricity from small temperature differences with many examples. High power thermoelectric harvesting is very rare but Chapter 5 Status of High Power TEG examines latest approaches.
Chapter 6 assesses new manufacturing technologies, including the new polymer formulations, CNT, printing. The new Applications of Chapter 7 include building facades, roads, implants, wearables, internet of things, radiative cooling at night, gas turbines and military. The New Materials analysed in Chapter 8 include many polymers, silicon including within silicon chips and new heat sources. Chapter 9 Thermoelectric Sensing deals with using the Seebeck effect to do the actual sensing, a smaller market but now a vibrant one with fabrics, and flow, radiation and gas sensing involved. Indeed, the thermoelectric self-powered sensor using both effects is described. Finally, Chapter 10 profiles relevant activity of 32 organisations.
Will market growth in thermoelectric energy harvesting primarily come from low or high power opportunities? Which researchers and manufacturers have the products with the most potential? Forecasts by industry? Significance of latest advances? Most active countries? It is all here in the new IDTechEx report, "Thermoelectric Energy Harvesting and Sensing 2020-2030"