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Ecotricity explains: What is battery storage?

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23 Dec 2021

Founded in 1995, Ecotricity was the world’s first green energy company. Throughout our history we’ve been Britain’s green energy pioneers, and today we stand apart from the rest as the country’s greenest energy company.

We’re constantly building and innovating, to do whatever it takes to end fossil fuels in Britain – using the money from our customers’ bills. Our work on biomethane will soon be making sustainable gas out of grass cuttings on an industrial scale, thanks to the country’s first truly green gas mill.

Getting to 100% renewables isn’t only about building more windmills, sun mills and gas mills. Our existing national grid infrastructure is designed and built for fossil fuel power stations, and needs to be dragged into the 21st century so that it can make full use of green energy.

That’s why we’re also building and innovating in the field of energy storage, a key factor in increasing the amount of renewable energy that the national grid can handle.

battery storage
Why do we need battery storage?

The national grid needs to match energy production to consumption, so that the electricity supply is balanced and to prevent voltage anomalies, overloading and drops in availability. With fuel-dependent power stations, more generation can be brought online quickly to match peaks in demand such as people cooking dinner in the early evening.

This is harder with renewables, where the energy they create is more intermittent, for example, depending on the time of day and what the wind is doing. It’s not just that generation drops sometimes, there are also issues when green energy sources produce more electricity than the transmission lines can handle in a local area and clean energy production has to be capped.

To make the most of renewables, we need to smooth out the energy output so that we’re not wasting power – and we need to be able to supply extra electricity at the drop of a hat, to match any sudden increase in demand from homes and businesses.

This is where battery storage comes in, capturing and storing green energy that isn’t needed at the time of generation and saving it until it’s called upon. It’s an important part of a modern national grid and a network of grid-scale batteries is essential for Britain to end its reliance on fossil fuels.

How does battery storage work?

Battery energy storage systems are far bigger and far more advanced than the rechargeable batteries we use in our smartphones and laptops. Nonetheless, when it comes to the fundamentals, they’re very similar indeed. Power goes in, it’s stored in the battery, then flows out again when needed.

Grid-scale batteries use computers to coordinate energy production and energy storage, deciding when to increase the reserve or release energy to the national grid. In this way, green energy generated at times of low consumption is stored for use when demand peaks. Up until now, these peaks have been filled in by firing up extra generation capacity in a fossil fuel or nuclear power station. As more battery storage is installed to match continued increases in green generation, there will be less and less need for fossil power. Batteries can also react at a speed that no rotating mechanical machine can match – making them a really efficient answer to these peaks and troughs in demand.

Ecotricity battery storage

Our first battery project is currently underway at Berkeley in Gloucestershire. It's a 1 megawatt lithium-ion battery, essentially a shipping container with lots of smaller batteries connected together and systems to control it. We’re starting with 1 megawatt because we need to check that the battery will perform properly for us and iron out any kinks – then we can move forward with our 10 megawatt and 50 megawatt battery plans.

When it comes to size, grid-scale batteries are chunky beasts. A standard shipping container can hold a 1-3 megawatt battery, while our 50 megawatt battery will need a site around the size of a quarter of a football pitch. However, compared to other grid-scale infrastructure, they don’t make too many demands in terms of space and they’re not intrusive – batteries are silent in operation.

Innovations in energy storage are crucial in the fight against the climate crisis. But we don’t actually need to wait – today, we have proven technology that can generate and store enough green electricity to supply the entire country from renewables. All we have to do is get on and build the wind and sun parks, along with the batteries to help manage the flow of electricity. And as an important bonus, it’ll make us energy independent as a country, making us less affected by the factors that have driven energy wholesale costs so high since the start of the recent energy crisis.

Ecotricity is a not-for-dividend company and we use all our profits to fund the building of new green-energy projects. Thanks to our customers, we’re able to do get a step closer to a green Britain every day.

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