He calculated that it wasn't economically viable: tons of wattage, but for such brief timespans, that it doesn't actually amount to that much on a comparative scale. The cost of building the collectors and transporting the electricity (from ocean platforms) was much higher than the cost of using other energy sources. Iirc. It wasn't exactly a serious investigation by a team of engineers, but I basically trust his conclusion.

Maybe it will be more attractive in the future after we stop using hydrocarbons?