There’s also another heat -> electricity conversion method used by nuclear fission reactors, though it could presumably be used for anything in place of a steam turbine: thermocouples. Usually people think of them as electrical sensors for heat, but they can also scale up to produce a lot of electricity from a lot of heat. It’s not very new technology either; Voyager spacecrafts use it in their RTGs. No idea about how that scales though.
There’s also another heat -> electricity conversion method used by nuclear fission reactors, though it could presumably be used for anything in place of a steam turbine: thermocouples. Usually people think of them as electrical sensors for heat, but they can also scale up to produce a lot of electricity from a lot of heat. It’s not very new technology either; Voyager spacecrafts use it in their RTGs. No idea about how that scales though.