With storage, the system can make use of periods of time when there is too much renewable electricity to make up for electricity shortfalls later in time – for example, from a sunny day to a very cloudy day. In this module we look at the different options to do so and the different time scales over which storage might be required.

Key takeaways:

• Batteries are already used and likely to be most economically attractive option for shorter-term storage
• Hydrogen may play a role in storage at seasonal time scales, even though its round-trip efficiency is low
• There is still considerable uncertainty about the storage technology mix a decade or two from now – but a range of technological options are available