How Much Storage is Needed?
Question: how much power storage does a society need to have, dependent on the degree of penetration of renewable electricity? Back-of-the-envelope/rule of thumb answers:
1. Australian study: up to 30-40% you do not need to worry about storage at all.
2. US study: up to 55%, 8 hours of electricity production from storage suffice.
3. German study: for a 100% renewable energy base you need 41% storage on a renewable electricity production of twice the current electricity production level, to cover for everything, including space heating and transport.
1. [deepresource] – “Don’t Worry About Intermittency Under 30-40% Renewable Energy Share”
2. [nrel.gov] – Timescales of Energy Storage Needed for Reducing Renewable Energy Curtailment
Overall, our results suggest that relatively short-duration energy storage might offer an effective path to reduce VG (variable generation) curtailments at penetrations up to 55%. Across all the mixes of wind and solar resources analyzed, at least half of the potential avoided-curtailment benefits are realized with 8 hours of storage, and the first 4 hours provide the largest benefit. At VG penetrations up to 55%, there appears to be little incremental benefit in deploying very-long-duration or seasonal storage.
3. [deepresource] – Blueprint 100% Renewable Energy Base for Germany
Current German annual electricity consumption 514 TWh. To replace the entire German energy consumption with renewable energy, according to the Fraunhofer Institute, you need 924 TWh/year, almost double the current electricity consumption. Note, this includes space heating and transport. Accompanying storage: hydrogen 179 TWh, thermal solar 68+62 TWh, biomass 50 TWh, battery 9 TWh, pumped hydro 7 TWh. Total: 375 TWh or 41%. Apart from huge numbers of solar panels, solar collectors and wind turbines, this includes sourcing all space heating from heat pumps, hydrogen electrolysers and thorough insulation, reducing heating energy with 2/3.
It is not going to be cheap (not initially), but smeared out over 3 decades it is not astronomical either, but doable. Early, most likely European, adopters are going to be rewarded with the ownership of huge profitable renewable energy industries, skills and patents that can service the rest of the world for decades to come.
Not included in this analysis is the possibility of huge energy saving by adopting the shared autonomous driving car, eliminating the necessity of private car ownership, especially suited for densely populated NW-Europe.