Solar power surpasses 10% of global electricity… batteries usher in ‘solar at night’

At noon, solar power supplies more than 25% of global electricity demand. But between 8 p.m. and 5 a.m., it falls to virtually zero. Energy storage systems (ESS)—batteries that store electricity and release it when needed—are bridging this gap between day and night and shaping solar power’s next phase. Ember said solar power accounted for 10% of global electricity generation for the first time in the first half of this year.

The growth is already evident in the pace of expansion. Global solar generation rose from 769TWh in the first half of last year to 1564TWh in the first half of this year, while the growth rate of solar generation was seven times faster than the increase in total global generation over the same period. In Chile, solar power accounted for 71% of generation at noon; in the Netherlands, 58% at 1 p.m.; and in Germany, 55% at noon. By 9 p.m., however, solar power had almost disappeared in all three countries.

Batteries shift this electricity across time. Driven in part by the spread of lithium iron phosphate (LFP) batteries, the average installation cost of battery storage systems worldwide fell 95%, from $2,634 per kWh in 2010 to $140 last year. Ember said falling prices, along with improvements in performance, safety and lifespan, have made batteries an economically viable way to shift cheap solar power from daytime to nighttime.

There are already examples of this on power grids. In California, solar power and batteries supplied more than a quarter of average daily electricity demand between 7 and 9 p.m. in the first half of this year. In Bulgaria, they supplied 24% of demand during the same period and an average of 10% from 7 p.m. to 7 a.m. the following day. Chile is also meeting more than 10% of evening electricity demand with solar power through batteries.

The change is therefore clear. Instead of curtailing or selling cheaply the electricity generated during the solar-heavy middle of the day, grids can connect it to evening demand, creating room to address the curtailment and negative electricity price problems that have grown with the expansion of solar power. However, the forecast is based on the assumption that all 459GWh of new battery installations this year will be used to shift solar power across time; the potential presented by Ember does not represent actual operating results in every region.