Thanks to Scottish Renewables for inviting me to speak at the Net Zero Conference yesterday as part of the grid integration session. My topic was the importance of flexibility to integrating clean resources into the electricity grid.
It was a chance for me to get out my ‘where is energy stored in our energy system’ graphic again and start slightly off-topic with a wider whole energy system context.
We talk lots about the importance of batteries, pumped storage hydro, and other forms of flexibility directly linked to the electricity system. However, I am still surprised at the scale of fossil fuel based energy storage that we rely on across the system and that we need to either do without or replace in order to deliver net zero.
Energy storage, and other forms of flexibility, provide many benefits: improved efficiency in operation of the energy system, resilience against unexpected events, and support for integrating less flexible components including variable renewables. System-wide, the vast majority of energy storage has historically come from stocks of petroleum, gas and coal.
The energy stored in these fossil fuel reserves has been falling over the last decade. For example coal stocks in 2019 were less than a third of their level in 2014, reflecting the reduced use of coal overall.
But that reduced level of fossil fuel storage hasn’t been replaced.
An agile energy system can reduce our reliance on energy storage, but it can’t remove it. We need storage to manage intermittent renewables, to maintain an operable electricity system (which itself forms an increasing fraction of our overall energy system), and to maintain secure supplies of energy for heat, transport, industry and electricity.
Whilst we have a growing awareness of the importance of low carbon flexibility and storage linked to electricity, we also need to keep the big system-wide picture in mind as well: we have a long way to go and we need to think beyond just electricity for truly whole system solutions to energy storage and flexibility.
Back on the topic of grid integration I really enjoyed the discussion with the other panel members Kate Mulvany, David Boyland and Lynne Bryceland who brough perspectives from Cornwall Insight, SSE plc Transmission and SP Energy Networks on what is needed to support net zero in Scotland. And we were fantastically chaired by Morag Watson. It was a great session to be part of, hope it was interesting to listen to!