That's a smart argument, but I think what it's missing is that the cost of gasoline is much higher than the cost of its energy equivalent on the electricity mar

That's a smart argument, but I think what it's missing is that the cost of gasoline is much higher than the cost of its energy equivalent on the electricity market. I.e, the cost of 1 Joule of energy != the cost of 1 joule of gasoline. Because gasoline is a premium energy source, if we can produce it from photovoltaic sources, we can effectively mark-up photovoltaic electricity. In the long-term, that would make it economical to greatly expand our photovoltaic capacity. The cost equivalence Prometheus is aiming for is: Market price of 1 gallon of gasoline > cost to produce 1 gallon of gasoline using renewable energy. Another factor is that Prometheus production works in remote areas where transmission losses for electricity are high (i.e., remote hydroelectric plants).