As we aim to become more reliant on renewable energy sources, consideration must be given to how we can keep the lights on during periods of low production. Diversification of production methods will help, but notes in The Guardian that the International Energy Agency has forecast a storage boom over the next decade.

It is expected that the majority of storage will be by way of lithium-ion batteries. However, lithium is itself a finite resource, toxic chemicals are used to process lithium and there is the question of where these batteries will go when they reach the end of their useful lives. In addition, their capacity is limited.

has set out four potential alternatives for storing renewable energy:

  • Gravity Storage - using excess energy to pump water upwards into a reservoir and then, when required, releasing the water to run over generating turbines to generate electricity. Using a mineral-rich fluid with a higher density than water could allow this technology to be used more widely as the slopes would not need to be as high to generate the same amount of electricity. There is, therefore, potential for this type of storage to be incorporated within some solar development sites in place of the more common battery storage.
  • Heat Storage - excess energy is used to heat molten salt or silicone. The salt or silicone is able to maintain the temperature until the heat is used to generate a steam turbine to create electricity.
  • Green Hydrogen - using excess energy to run electrolysers and create green hydrogen, which can then be used to run power plants, factories and heavy vehicles.
  • 'Cryogenic' Batteries - excess energy is used to clean, compress and cool air which is then stored as a liquid. When additional power is needed, the air is heated, expanded and used to power a turbine to generate electricity.

We will likely begin to see more and more renewable energy developments incorporating on-site battery storage. There is also potential for on-site gravity storage and green hydrogen production. However, in order to create longer term storage solutions, the future may hold larger scale stand alone storage facilities which separately connect into the grid. Developers will need to make strategic decisions about whether to include battery storage within their projects now, or to wait to see how these other storage technologies evolve.

https://www.theguardian.com/business/2022/jan/10/heres-how-to-solve-the-uk-energy-crisis-for-the-long-term-store-more-power