Thermal photovoltaic efficiency of 40%! Scientists have developed a new thermal photovoltaic cell!

A research team from MIT and the National Renewable Energy Laboratory (NREL) has successfully developed and demonstrated a thermophotovoltaic (TPV) cell capable of converting heat into electricity more efficiently than conventional steam turbines.

Thermophotovoltaic (TPV) converts light at infrared wavelengths into electricity mainly through the photovoltaic effect, and can realize a method of energy storage and conversion.

90% of the world's electricity is generated by heat sources such as natural gas, coal and concentrated solar power. For a century, the conversion of this thermal energy into electricity has relied primarily on steam turbines.

On average, steam turbines can only reliably convert about 35 percent of their heat source into electricity. Even the most efficient heat engine ever built has a peak efficiency of around 60%. To make matters worse, steam turbines rely on moving parts that must operate at certain temperature thresholds.

And this new design is designed to capture higher-energy photons from higher-temperature sources, thanks to its use of higher-bandgap materials and multiple junctions. In tests between 1900 degrees Celsius and 2400 degrees Celsius, the new TPV cells maintained about 40 percent efficiency. Early TPV cells averaged around 20 percent efficiency, with the previous record for highest efficiency at 32 percent.

Asegun Henry, the Robert N. Noyce Career Development Professor in MIT's Department of Mechanical Engineering and one of the researchers on the project, said: "Thermal photovoltaic cells are the final critical step in proving that thermal batteries are a viable concept. An absolutely critical step on the road to fully decarbonizing the grid."