Utility Week

10 | MAY 2021 | UTILITY WEEK Countdown to COP Analysis Is storage the next big thing? A lot more storage and flexibility is needed to balance intermittent generation, but the rules must change if investors are to put up the sums needed for large-scale projects, says David Blackman. T he year just gone has provided the UK with an extended sneak preview of the energy system of the future. With the pandemic depressing demand for electricity, we got to see what the system looks like with renewables accounting for a much bigger slice of total generation. One of the things we saw was that peri- odic excesses of renewable energy meant wind farms had to be switched off at par- ticularly gusty times, fuelling a £718 million payout of balancing costs to generators by the Electricity System Operator (ESO) in the second quarter of 2020. The size of this payment illustrates how the UK will need to dramatically increase its capacity to store electricity to help the grid match the greater peaks and troughs in demand and supply that look set to be a fea- ture of an energy system increasingly pow- ered by intermittent generation. "Our system is getting more stressed at times of low demand, which is when renewa- bles need to be curtailed. Storage is valuable because it allows that otherwise curtailed demand overnight to be used," says Bob Hull of consultancy Riverswan Energy Advisory, and previously a senior figure both at Ofgem and National Grid. By 2050 the ESO has calculated that the UK will require 40GW of additional storage capacity, 15GW of which must be delivered by 2030, to support the delivery of the UK's transition to a net-zero grid. "Effective storage is going to be absolutely vital but the current system doesn't really value storage and flexibility in the way it needs to. A lot of the system is done on an hour-long basis and needs to be upgraded for a world where you have big swings in generation," says Josh Buckland, who worked as special advisor to ex-business sec- retary Greg Clark. So what are the policy and regulatory hurdles holding back the development of energy storage facilities and how can they be overcome? Space for all technologies The nature of the barriers will depend on the technologies and the duration of storage they are designed to deliver. "There is space for all technologies but they have different operational and eco- nomic characteristics," says Hull, who was the author of a recently published report for Scottish Renewables on the financing of long-duration storage projects such as hydro power stations. A big source of potential storage will be delivered via the batteries on wheels which are set to flood the motor market as the 2030 ban on sales of internal combustion engine cars and vans approaches. Tariffs already exist that enable house- holds to charge their electric vehicles (EVs) Drax's Cruachan power station, in Argyll and Bute, Scotland, is one of only four pumped-stor- age hydroelectric plants in the UK. The scheme can provide 440MW of power and has a capacity of 7.1GWh and is capable of providing a black start capability to National Grid.

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