RE: Additional opportunities with Eskom2 Jul 2019 11:31
faramog - the point about renewables is that the cost is pure capex there is no fuel cost and minimal maintenance, and no CO2 of course. Electrolysis is surprisingly inefficient - something like 25% of the energy is immediately lost. Then you have the problem of storing and transporting the hydrogen gas, which even if it can be done safely leads to another 25% loss of energy. Even if you use a fuel cell to convert the hydrogen back to electricity you suffer another 50% efficiency hit. So overall you put 100kWh of energy in and only maybe get 25 kWh back out - a really bad battery and not at all just a 'bit' more capital.
( https://www.greenoptimistic.com/hydrogen-cars-efficiency/ )
Many people have looked at this and the conclusion is genuinely that it is more cost effective to have a little wasted energy than try like crazy to store every single joule for use later. I know it seems wasteful. I know the green radicals would object. However it IS the most economical way to do things. Like making more food than we actually need, or having more hospital beds than we need when everyone is abroad on their holidays. Blame the tilt of the earth, but it is also what means there is life existing here.