Every year, 50 percent of the energy produced worldwide from coal, oil, natural gas, nuclear, and renewable energy sources is lost as heat. This untapped resource could be a promising additional source of useful energy, and for decades, scientists have worked to develop efficient systems to convert waste heat to electric power.
In a recent study, Berkeley Lab researchers developed a techno-economic model to predict the economic viability of different waste-heat conversion technologies. Their model will help guide future research by steering scientists toward novel designs and technologies that are more likely to enable cost-effective and efficient waste-heat conversion.
Up until now, most of the research centered around waste-heat conversion technologies has been focused on the physics behind waste-heat conversion engines, such as thermoelectric generators that recover exhaust heat in internal combustion engines. Berkeley Lab’s techno-economic model enables researchers to have a more system-wide approach, which focuses on technological requirements for commercial viability, such as the temperature of the waste heat source, the cost of heat exchangers, or the minimum capacity factor — the fraction of the time the waste heat source is available.
“Although more than 60 percent of the waste heat is available below 100 °C, our analysis shows the waste heat conversion is only economical above 150 °C,” said Ravi Prasher, associate lab director at Berkeley Lab. “This finding is very important in prioritizing research and development for waste heat conversion heat engines.”