The role of battery storage

Speaking at an Atlantic Council event on Friday, Energy Secretary Dan Brouillette said “Battery storage can help bring more renewables online“. The implication being that the variability of renewables is such that it is not possible to have more wind and solar without it being backed up with batteries.

To examine whether the Secretary’s statement is valid, one needs to look at other jurisdictions, with more wind and solar than the US, and the amount of battery storage that they have.

Europe is that jurisdiction and is particularly useful as the European electricity market is similar in size to the US being only 20% smaller. In 2019, Europe produced 3,222 terawatt hours (TWh) of electricity whereas the corresponding figure in the US was 4,151 TWh. The following chart shows the amount of renewables – consumed in both markets over the period from 2002 to 2019.

The chart shows that renewables usage has grown substantially in both markets over the period but clearly the level has been much higher in Europe where renewables over the period have almost tripled to represent more than a third of total electricity generation. So if the Secretary is correct about battery storage, the higher penetration of renewables in Europe has been possible only because of greater use of battery storage. But is this the case?

The European Associate for the Storage of Energy reports – in their Activity Report 2018 –  that installed electrical storage capacity (excluding pumped hydro) was 3.5 gigawatt hours (GWh) at the end of 2019. In the US, the Q4 2019 ‘US Energy Storage Monitor’, produced by the Energy Storage Association, does not give a a precise number but it is possible to see from a graph that, at the end of 2019, there were about 2 GWh of energy storage capacity (excluding pumped hydro) nationwide.

Wind and solar produced 569,000 and 407,000 GWh respectively of electricity in Europe and the US in 2019. This is equivalent to 1.1 and 0.8 GWh per minute respectively. In other words: the installed 2019 battery storage capacity in Europe and the US represented less than three minutes of electricity production from wind and solar. With batteries providing such a tiny amount of storage – and with Europe already having twice the amount of renewables online as the US – it is hard to see how the Secretary’s statement – about the need for more battery electric storage before we can have more renewables – is justified.