There isn’t a single universally agreed-upon percentage of electricity demand that must be met from grid storage in a 100 % renewable electricity system. It may be as high as 20% for some countries, but in situations where there is an overcapacity of wind and solar, it can be potentially < 5 % of annual demand.
New data show that by the end of 2026, grid storage will be a 1.15% share of global electricity demand (up from 0.16% in 2023). Who’s rolling out the most? No surprises for guessing. It’s China. China’s grid storage installations in December 2025 alone (65.4 GWh) exceeded the entire USA’s 2025 total annual installations (46.5 GWh), and the US is the world’s 2nd largest grid storage market.
Who’s also able to build an over-capacity of wind & solar? Once again, China. China is also rapidly electrifying its whole economy & abandoning the combustion engine. Like the famous Hemingway quote about going bankrupt, the Fossil Fuel Age may end “Two ways. Gradually and then suddenly.”
Another thing that’s needed is dynamic pricing to make electricity cheaper when it’s sunny and more expensive when it’s not sunny. This would incentivize consumers (especially big industrial consumers) to shift their power consumption more towards peak electricity production times.