As we transition into a world powered by renewables, there’s one thing you’re going to be hearing a lot more about over the coming decade: batteries.
Why? Because, as solar panels and wind turbines become more and more important in creating electricity for our homes in the UK, we need a reliable way to store the energy they capture.
Right now, our grid delivers power that was generated just moments before. But unfortunately, natural elements like the weather are unpredictable – as we well know, here in the UK! Until wind and solar farms have storage systems that can hold the energy they generate for later use, we’ll sometimes still have to depend on coal and natural gas to meet demand when everyone’s switching their kettles on at the same time.
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How can batteries support a greener grid?
Earlier this year, we saw the effects of this problem when the National Grid warned of potential power cuts, due to a combination of generator outages and low winds. A few weeks later, they issued two more electricity margin notices, caused by low supply from wind farms.
The timing of these warnings, right after Boris Johnson backed plans to massively expand the UK’s offshore wind farms, was pounced on by those sceptical of renewable energy. No matter what your views on the future of renewables, it does raise a valid concern: how can we store the energy generated in times of high winds, to use when there’s demand for it? As Jonathan Marshall, of the Energy and Climate Intelligence Unit, put it to The Times, “the rapid transition in Britain’s electricity system is outpacing the changes in governance and regulation needed” in order to get batteries and other storage systems in place. Our dependent relationship with coal, says Marshall, “needn’t be the case”.
The truth is, we have more than enough power to go around from wind farms. For much of this year, the National Grid has been struggling with having too much power during times of low demand. It’s even paid wind farms to switch off at certain points, to help regulate the grid.
If we had a way to store this energy during the busy periods, we’d have enough energy to go around during quieter weeks. Batteries are the key to the mass roll-out of renewables. So what’s the latest in terms of their development?
Lithium-ion batteries: from camcorders to wind farms
Lithium-ion is the type of battery you’re most likely to be familiar with. They were first introduced commercially by Sony in the 1990s, who used them to power handheld camcorders. These days, they’re inside everything from your phone to your electric vehicle. And in some places around the world, they’re also being used to store back-up energy for electricity grids: like in California, where the 250mWh Gateway Energy Storage project uses the world’s biggest Lithium-ion battery. (Tesla is working on an even bigger one, due to arrive in 2021.)
The primary reason these batteries aren’t already supporting grids everywhere is simple: they’re too expensive. However, the price of Lithium-ion batteries has fallen, and they’re expected to keep getting cheaper, as the number of Lithium mines is projected to double.
This makes them a more serious prospect for large-scale energy storage – but there are other problems with Lithium. Some are concerned that it’s not the most environmentally-friendly choice, because it’s a finite resource. As much as 70% of it could be lost to battery production by 2025. There are also worries about the environmental impact of Lithium mining in Tibet and Bolivia.
Plus, they’re a fire risk: Li-ion batteries have been known to explode, due to the volatile flammable chemicals inside them.
What are the alternatives to Lithium-ion?
Scientists are hard at work looking for battery storage options that don’t use Lithium-ion – and the good news is that there’s been plenty of innovation and discovery in this space in recent years.
One option is flow batteries, which pump electrolytes back and forth between two tanks. These are already being used in some places, to support the electricity grid (China is building the world’s biggest) – but there are a few negatives. They’re less efficient than Lithium-ion, and they depend on the use of vanadium, a rare and expensive metal.
Pumped hydro storage is a more environmentally-friendly option, as it uses water and gravity to store huge amounts of energy. However, hydro batteries take up a lot of space, and so they’re just not feasible in many places.
Scientists at RMIT in Melbourne announced in 2018 that they had discovered a super-green option: proton batteries. These run on carbon and water instead of any precious metals, and have the potential to revolutionise battery energy storage if they can be scaled up to meet demand. Stanford researchers have also come up with a water-based solution: a saltwater battery prototype that stores electrons in the form of hydrogen gas.
Energy can also be stored as heat, in just the same way a hot water tank in traditional home heating systems. Read more about this technology in OVO’s guide to thermal energy storage.
How batteries could help power your eco-friendly home
The role of batteries in the future of renewables isn’t just supporting the grid – they’re set to become a staple feature of eco-conscious homes, too. The International Renewable Energy Agency (IRENA) predicts that the use of home batteries is set to hugely increase by 2030.
Having battery energy storage in your home can help you reduce your carbon footprint in two ways. Firstly, if you’re on an Economy 7 tariff, it can charge up during off-peak times, helping you to avoid contributing to surges of power during the busier hours.
Secondly, it could provide support to your very own built-in renewable energy system. Thinking of getting solar panels on the roof? Install a home battery, and you can make sure you’re storing all the energy you capture on the sunniest days (so you don’t have to depend on coal when the clouds roll in). As JMP Securities’ Joe Osha recently told CNBC, “residential batteries have gone from being a curiosity to an increasingly common part of a new residential solar installation.”
A century ago, it would have seemed an unthinkable curiosity that batteries could power laptops, cars, and all the technology that we use them for today. As we steer towards a greener future, it’s clear that in 10 years’ time, it will no longer seem so odd to think they could be powering our homes, too.
OVO Energy are currently trialing home battery storage technology with some of their members in Lincolnshire. Find out more about how OVO are unlocking the amazing potential of home batteries for solar energy storage.