Long-duration energy storage: The missing piece of the power sector puzzle for net zero
Loch Lochy, site of the Coire Glas project | Credit: SSE
Jim Smith, Managing Director for SSE Renewables explains why projects like the Coire Glas pumped hydro storage scheme are needed to help the UK achieve its goal of net zero greenhouse gas emissions by 2050.
In the not too distant future wind and solar will be generating most of the power the country needs, but the big question is what will be the balance of other technologies needed to ensure security of supply.
In the UK today, we mainly rely on gas-fired power stations to balance the grid, ensuring supply meets demand, but that has carbon emissions associated with it. We also know there are already periods during the year when renewables are providing more electricity than the country needs at that moment and whilst we can store very small amounts and export some; increasing levels are going to waste. Just last year, enough renewable power to supply a million homes for an entire year was wasted.
A big part of the solution is energy storage, which comes in many forms. There are of course lithium-ion batteries which are great for rapid, short-term system response but are not cost-effective for longer durations.
Long-duration storage can help reduce the cost of meeting the UK’s net zero target by storing excess renewable energy for longer periods of time, for several hours or days, to deal with extended periods of low wind or solar output.
While innovative forms of storage like hydrogen and compressed air may well play an important role in the future, today there is already a tried and tested long-duration storage technology which has been around for decades and is experiencing a global renaissance – pumped hydro storage.
Pumped hydro storage is the world’s largest, most proven, cost-efficient, and mature electricity storage technology and is deployed heavily across China, Japan, the United States and Europe to support the integration of increasing levels of variable renewables.
At Coire Glas in Scotland’s Great Glen, SSE has a pumped storage project ready to go. If built, it would have capacity to generate up to 1500MW of electricity with 30GWh of storage - enough to power around 3 million UK homes for up to 24 hours non-stop.
Research commissioned by SSE, by flexibility modelling experts at Imperial College London found that just 4.5GW of new, long-duration pumped hydro storage, with 90GWh of storage could save up to £690m per year in energy system costs by 2050. That is the equivalent to 3 Coire Glas projects.
The study found that most of the savings to the energy system would be from the avoided capital expenditure in higher cost electricity generation technologies, such as new nuclear that would otherwise be needed to meet net zero by 2050 whilst also meeting security of supply.
Importantly, the report highlighted that despite all of the benefits which new long-duration pumped hydro storage projects would bring, the current policy and market framework is unlikely to unlock the investment needed. This is because the long-duration and low carbon capability of technologies like pumped storage are not sufficiently valued.
In the coming weeks, BEIS and Ofgem will publish an update to their Smart Systems and Flexibility Plan which is an opportunity to set out an overarching framework and accompanying actions to support the deployment of these vital technologies.
It’s time to put in place the missing piece of the power sector puzzle to reach net zero.
Find out more at coireglas.com
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