Re:Nuclear energy is a vital part of solving the climate crisis
by labawi on Sunday November 10, 2019 @02:21PM
(#21499637)
Why not store hydrogen? Estimated round-trip efficiency is approximately 40%. Storage in underground caverns / mines.
If most of the energy consumption is supplied directly, the storage part need not be overly efficient as long as it can cover the slack. 40% seems good enough. Even 20% is workable, if need be, just need to over-provision enough PV / wind and the over-provisioning itself significantly reduces needed storage.
If combined with capacious long-distance electrical grid (e.g. HV DC), load scheduling, high-uptime offshore wind, some PV in deserts, maybe thermo-electric solar, some batteries for rapid load following, etc, we really can supply enough power even with 0 coal, gas and nuclear power plants, and it wouldn't even bankrupt us. All we need is will. The technology is already sufficient and with improvements it won't be even that hard.
Electricity to gas conversion has terrible efficiency. 30-40% for the electrolysis and Sabatier process, and then ~50% efficient for the gas combustion engine. Net efficiency is in the 20-25% range. Hydroelectric storage is geographically dependent. Most of the US is in flat terrain.
California said they would do solar and wind plus storage. Then they realized storage was not possible, and they used fossil fuels instead. Similarly, Germany closed down their nuclear plants, saying they'll build intermittent renewables plus storage. And then they ended up building fossil fuel plants when they realized storage could not fulfill the base load they lost from closing nuclear plants.