@corlin Skeptical, for numerous reasons.

One notable example: they keep saying supplying a reliable source of high-grade heat to heavy industry without the use of fossil fuels is "a problem without a solution" - it's not. Electric arc furnaces have existed since 1888, and they can be run off hydropower or nuclear; nuclear reactors can also be built to directly supply extremely high temperatures (even some *1960s* HTGRs were capable of supplying 950C), and are exceptionally reliable.

@corlin Additionally, keeping those fancy thermophotovoltaics from getting fried by the high temperatures would be quite the achievement, given semiconductors are quite heat-sensitive and generally have short lifespans at elevated temperatures. When they fail... $$$$$.

A more robust solution would likely be to use mature steam technology - use the heat from the thermal battery to make high-pressure steam, then use the steam to spin a turbine (which also stabilizes the grid thanks to inertia).

@IrelandTorin
One the new and special photovoltaic system has been proved to be robust and long lasting at 2,000°.

Two they do use steam, and other heat carrying fluids to run turbines.

@corlin As far as I'm aware, there is no known way to build semiconductor devices that can function - let alone *survive for extended periods* - at those kinds of temperatures (ie ~2000 Celsius).

My understanding of physics suggests that should not even be possible; those temperatures are high enough that the dopant atoms should become mobile and start diffusing through the bulk semiconductor, quickly destroying the p-n junction & rendering the device useless.

Are you sure they're not lying?

@IrelandTorin
I am saying they have a working pilot plant. And I don’t believe the photovoltaic is based on silicon.

I have no idea of the composition.

@corlin Graphite's thermal properties have been well-known for a very long time, and the idea of using it for high-temp thermal energy storage is not new either. It could even have been done with 1800s technology.

The only real "special sauce" that company appears to have is the use of thermo-photovoltaics, however even if they do resolve the longevity and cost issues... you still have the problem of needing absolutely monstrous, complex, expensive inverter systems to convert to usable AC pwr.