Scientists in California make a significant step in what could one day be an important solution to the global climate crisis, driven primarily by burning fossil fuels.
Since everyone else gave a joke answer I’ll take a stab in the dark and say the upper limits would be the availability of hydrogen and physical limitations in transforming heat output into electricity. The hydrogen is the most common element but 96% of it is currently produced from fossil fuels. After that, it would be how well you can scale up turbines to efficiently convert heat to electricity.
Since everyone else gave a joke answer I’ll take a stab in the dark and say the upper limits would be the availability of hydrogen and physical limitations in transforming heat output into electricity. The hydrogen is the most common element but 96% of it is currently produced from fossil fuels. After that, it would be how well you can scale up turbines to efficiently convert heat to electricity.
Electrolysis has up to 70% efficiency and needs sulfuric acid. The superheated thing has about 90% efficiency.