Ocean warming is a bigger opportunity. Jabbing a thermal collector into a volcanic vent, rolling it through a sterling engine as a cooling system, with the cold side submerged in the cold ocean.
A lot of new, green tech is ludicrous. People want solar farms in the desert because of all the arid heat and lack of clouds, but discount the fragile ecosystem. Wind farms take up much more space than nuclear plants for the same power output. Hydrogen is difficult to store without supercooling, and is only a storage scheme and not a generation scheme, and only operates at 50%-80% efficiency. Hydroelectric is an environmental disaster.
Direct heat applications from solar-thermal water heating are about the only thing that make sense. Their efficiency is high, and their cost is low. A small, 1.2 square meter collector provides 3000BTU/hr, about 85% of a kW; I can fit over 20 of these on my roof at a sun-receiving angle and spacing, giving over 65,000 BTU/hr average throughout the day. My roof can produce 19kW of heat output, while I only need 3kW to stay warm or cool--the AC breaker is 30A, providing about 3kW of cooling.
A hydronic coil off the water heater, an absorption cooler, or so on can harvest the heat collected by less than $2000 of tubes and a total of $3000 of equipment to provide for about $2500 annual air space and water heating and cooling in my house. Excess generated heat could theoretically drive a sterling engine to produce a small amount of electricity, but the investment for more tubes to generate a useful amount of electricity would be unjustifiable; I can buy 100% solar electricity for 12 cents per kWh.
Thus, in just over a year, I can recover my investment in solar water heating by incorporating space heating and cooling, assuming I was in the market for a new furnace and air conditioner anyway--the furnace would be an air handler with electric back-up, vastly cheaper than a new gas furnace, offsetting the expensive absorption chiller. A $900 pellet stove would serve as a back-up. Overall, the setup would save an immense amount of electricity and natural gas.