Large scale electricity storage

The increasing implementation of renewable electricity generation in the form of solar power and wind power leads to increasing intermittence of the electricity generation. In the European Union the CO2 emission is to be reduced by 80% in 2050 (with respect to 1990), while in the Netherlands a more strict goal of 95% reduction is planned; which means a massive implementation of renewables  and CO2 neutral technologies. It can be shown that the renewables implementation results in systematic daily and seasonal variation of renewable power. Solar power and wind power both peak at daytime and diminish at night. Solar power in the Netherlands is 6 times stronger in summer than in winter while wind power is about 2 times stronger in winter than in summer.

The combined generation of solar and wind power on an extended electricity grid needs to be matched by the total demand and intermediate electricity storage.  Storage on both daily and seasonal timescales are necessary to match supply and demand 24h/365d of the year. Typical scales are up to EJ for short term storage worldwide and many tens of EJ for long term storage by 2050.

Green: possible output of solar and wind power on a large scale grid with ~30% renewable energy use. Blue: possible electricity use pattern in a progressively electrified society. Black: short term day/night storage. Red: long term seasonal storage. Info in J. Renewable Sustainable Energy 6, 033105 (2014)

Large scale solutions for electricity storage

  • Ammonia (NH3) as energy storage, energy density: 6.5 kWh/kg.
  • Hydrogen generation and storage.
  • High energy density Li and Na-ion batteries, energy density: 100 – 400 Wh/kg.
  • Hydrogen based batteries: light metal hydrides for Ni-MH batteries, Ni-Fe batteries with very long lifetime.