This new renewables capacity — which will total more than 140GW up from 33GW today — will drive a need for up to 30GW of short-duration storage and more than 20GW of longer-duration firm backup capacity to balance the grid, Aurora Energy Research calculated.
They added that 20GW of new nuclear and 3GW of carbon capture and storage (CCS) would also be needed by mid-century.
Aurora noted that while many low-carbon forms of flexibility have been proven, they are not currently viable at the scale required under current market conditions, and so policy and market interventions are needed.
"Balancing a net-zero power system will require low-carbon forms of flexibility that are not yet commercially viable to be delivered at a large scale," said Richard Howard, research director at Aurora Energy Research.
"Government will need to intervene to bring these options to fruition — through carbon pricing, and technology-agnostic flexibility markets to drive competition and innovation."
Increasing the amount of wind and solar on the grid means matching demand with supply will become harder, Aurora explained.
This will create a greater need for short-duration storage technologies such as batteries and pumped hydro.
Even with increased storage capacity, there would still be ‘excess’ power that cannot be balanced over hours and days, Aurora added. This could reach 185TWh per year by mid-century.
Rather than curtailing this output, it could be used for hydrogen production to decarbonise other sectors, the analysts suggested.
They added that currently, swings in residual demand — total power demand minus output from renewables and nuclear — are up to 5.4GW in 30 minutes. But as renewables penetration increases, this could rise to 8.5GW by mid-century.
Aurora also warned with a system more dependent on wind power, the UK could become vulnerable to prolonged, cold, windless spells — which can happen for about two weeks a year.
The analysts said technologies such as flow batteries, compressed or liquid air storage, hydrogen storage, or gas with CCS, could help in this scenario.
However, most of these options have been technically proven, they are not yet commercially viable, according to Aurora.
Policy and market interventions needed to help deliver a net-zero power system could include:
- A carbon tax or trading system to reduce carbon emissions;
- Government, energy regulator Ofgem and system operator National Grid should define the operability challenges of increasing variable renewables and removing thermal generation.
- Pursuing technology-agnostic policies and regulations based on system demands would help to create an environment to allow the market to provide the cheapest solutions.
The UK set a target of net-zero greenhouse gas emissions by 2050 in June.
There is currently just over 13GW of onshore wind operational in the UK. However, the technology is excluded from the country’s contract for differences (CfD) support scheme, despite developers being increasingly able to compete in the market.