From a windswept sea wall on England’s north Kent coast, Marie King points to miles of empty swampy farmland where there will soon be thousands of solar panels and one of the largest battery installations in the country.
One kilometer from the Norman Church in the village of Graveney, hundreds of shipping containers filled with battery cells will help power the UK grid. It will provide an essential service for manage the increasing use of wind and solar energy, whose offer varies depending on the weather, and up to politicians ” the promises of a greener future.
“It’s the magnitude of this project that concerns me,” says Ms King, a retiree who worked in financial services in London. “We’re not against renewables – we just think they need to be in the right place.”
Such battery factories should become a familiar sight in the UK and elsewhere. Renewable energies such as wind and solar are increasingly cheaper than fossil fuels in most parts of the world, but they need storage to be a viable and stable source of energy. British Prime Minister Boris Johnson last week sworn to install enough wind turbines to power every home by 2030, but it will require solutions to manage the intermittent supply of energy.
This is where batteries come in – devices that store electricity in the form of chemical energy. Lithium ion batteries, used in Tesla mobile phones and electric cars, are currently the dominant storage technology and are installed from California to Australia, and most likely Kent, to help power grids manage growing renewable energy supplies. Elon Musk, chief executive of Tesla, said he expected the company’s energy activities, including supply of solar batteries and huge lithium-ion batteries for the grid – be as large as its automotive business over the long term.
But with lithium-ion batteries, cheaper, longer-lasting storage technologies – most of which are not yet cost-effective – will be required to completely replace fossil-fueled power plants and allow 100% use of energy. renewable energy. Currently, gas-fired power plants are closing the gap to renewables to provide stable energy supplies for longer than current batteries.
Part of the British government green industrial revolution launched last week, a £ 1 billion energy innovation fund to help bring new low-carbon technologies to market. These include a liquid air battery being built by Highview Power outside of Manchester.
Without storage, it will be more difficult for countries to dramatically reduce their use of gas and coal-fired power plants and lessen the adverse effects of climate change, from sea level rise to extreme weather conditions.
From battery technologies that use abundant raw materials to volcanic rocks, to reservoirs filled with liquid air and systems that reduce the weight of abandoned mine shafts, companies are fighting to develop the next breakthrough that will unlock the large-scale renewable energy by mid-century. It’s a quest supported by several top business leaders, including Microsoft founder Bill Gates and SoftBank’s Masayoshi Son.
“If we want complete decarbonization, all of these technologies will be needed,” says Rory McCarthy, analyst at energy consultancy Wood Mackenzie. “But the scale of the investment you need to breach anything is billions of dollars.”
A supply chain “without inventory”
Every day, power grids have to constantly match supply and demand – a feat that becomes much more difficult when you take out the coal and gas-fired plants that provide a reliable and steady supply of energy. Donald Sadoway, Canadian professor of chemistry at the Massachusetts Institute of Technology, likens the grid to “the world’s largest supply chain, with no inventory.”
In the first quarter, renewable energies provided a record 47% British electricity. Yet that success created a problem weeks later, when energy demand fell 20% after the coronavirus first nationwide lockdown in March. The job of the National Grid becomes more difficult when production of electricity from renewable energies reaches about 50 percent of the total – it needs the help of large rotating turbines from fossil fuel power plants to moderate the volatility of the system.
With the drop in demand, the share of renewables in the energy mix rose above half and engineers at the National Grid control center were forced to perform a delicate balance, part of which involved increased storage usage – justifying, proponents say, the expansion of the technology.
This has turned out to be a test for what the grid will look like in the future, when there will be a greater share of renewable energy, says Peter Kavanagh, managing director of Harmony Energy, which feeds the grid from of six Tesla lithium-ion batteries. in Poole on the south coast of England.
“Solar and wind are the cheapest form of generation in several countries, but you need this storage to keep it running once you reach a certain size of your energy mix in renewables, like us. saw it during Covid, ”he says. “Covid did it. . . has proven the business case [for battery storage] five years in advance. ”
Over 97% of the world’s energy storage is currently done by using electricity to pump water to an elevated reservoir and then releasing it, which drives a turbine to produce even more electricity, which is called “pumped hydroelectricity”. The water reservoir acts as a means of storing energy. But these systems are challenged by geography and could be constrained by increasing water scarcity in the future.
The advantage of lithium-ion batteries is that they can be placed anywhere and can deliver power to the grid very quickly, just as they do in electric cars. They can respond in milliseconds and typically provide up to four hours of storage, helping grids cope with sudden power outages, but are less profitable in the long run. In the UK, the majority of large-scale lithium-ion batteries provide power for 30 to 90 minutes.
And local residents like Ms King are concerned for their safety, after a spate of battery fires in recent years. There were 33 fires at facilities in South Korea between 2017 and 2018 alone, and there have been more recent incidents in the UK and the US.
A patchwork of technologies
Alternative technologies could allow safer storage of large amounts of energy for longer periods of time, which would allow for even greater integration of wind and solar energy. But they need to be scaled up quickly to meet growing demand and become cost competitive.
In January, the California Energy Commission, the US state’s leading energy planning and policy agency, called for long-term energy storage – defined as providing energy for more than 10 hours – enough to store a day’s solar energy for nighttime use.
One of the winners of the tender was Invinity Energy Systems, a company that uses large batteries based on vanadium, a raw material used by the steel industry to increase the strength of metal. These so-called Redox flow batteries – first developed by NASA in the 1970s – use large reservoirs of separately charged electrolytes to store energy, making it easier to increase capacity than conventional batteries. .
Matt Harper, chief operating officer of the company, says vanadium batteries can store eight to 10 hours of renewable energy during the day and deploy it during peak demand, or overnight, helping to reduce the price of electricity. They are also “more likely to put out a fire than to start one,” he says, because they use a water-based electrolyte. They also last longer than lithium-ion cells – and can last 30 years.
In the center of Dalian, in northeast China, Rongke Power is building the world’s largest vanadium battery. At 800 megawatt hours, that would be more than three times the size of the world’s largest lithium-ion battery facility in California. This would help Liaoning Province’s power grid to better integrate wind power.
“We wouldn’t be allowed to install a large-scale lithium-ion battery in the city center, [due to safety concerns]”Says Li Bin, Marketing Director of Rongke. “The safety concerns of lithium-ion batteries have not been resolved.”
Still, vanadium prices are highly volatile and jumped to $ 127 per kilogram in November 2018 before dropping to $ 25 per kg today, which could impact the cost of production.
MIT’s Professor Sadoway believes the technologies should be based on metals that are more abundant than those used in lithium-ion and vanadium batteries like aluminum, sulfur, calcium and antimony. In 2005, he helped develop a liquid metal battery that uses calcium and antimony and a molten salt electrolyte. The company that developed it, Ambri, has been supported from the start by Mr. Gates, who invested in the program after watching Dr. Sadoway’s chemistry lectures online.
Ambri’s battery aims to store energy for more than six hours and Mr. Sadoway estimates its cost can drop below $ 150 per kilowatt hour when deployed on a large scale, which would make it cheaper than current lithium-ion systems. “We want to reduce lithium-ion,” he says.
The company has yet to find a large commercial customer and Mr. Sadoway warns of the long lead-time in the development of new battery chemistries: “It’s a difficult technology, it’s a heavy industry, it’s not. not like writing code, ”he says. “It’s really difficult.”
Thought in the Stone Age
Others looking for storage options avoid batteries altogether and try natural and physical solutions similar to hydro-pumping – which can store energy for up to 20 hours – but without the need for natural reservoirs. .
Outside the German city of Hamburg, a large windowless gray concrete building has the words “Welcome to the New Stone Age” written on the front in purple letters. The factory is run by Siemens Gamesa, the world’s second-largest manufacturer of wind turbines, and uses 1,000 tonnes of volcanic rock from Norway to store 130 MWh of energy in the form of heat, providing enough power for around 3,000 German households, or around 750 electric cars.
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Electricity is first used to heat volcanic rocks to at least 600 ° C. Energy can be stored for up to a week, but the goal is to distribute electricity overnight. The system can be installed in coal-fired power plants that shut down and use their turbines, according to Hasan Oezdem, head of innovation projects at Siemens Gamesa.
“You can turn them into giant storage facilities,” he says. “Bigger utilities are desperate for a second life option because you can’t sell them – no one buys coal-fired power plants. We propose to continue to operate with an ecological objective. “
On the outskirts of Manchester, a similar project is taking shape at the site of a disused power station – using vessels of liquid air rather than volcanic rock. Highview Power inaugurated its 250 MWh plant at Trafford Energy Park in November after winning a £ 10million grant from the UK Department for Business, Energy and Industrial Strategy.
“Lithium-ion is a great technology, but it’s too small for the challenges the network faces,” says Javier Cavada, CEO of the company. “The long-term economic model [storage] is to ensure that all wind and solar generation is used.
Lithium-ion: in the driver’s seat
Despite their various advantages, these technologies will struggle to beat the lithium-ion manufacturing scale, which has been driven by the surge in investment in electric car during the last decade. The price of lithium-ion batteries fell 87% in real terms between 2010 and last year, to around $ 156 / kWh, according to Bloomberg New Energy Finance.
This price is likely to fall further. Globally, network storage battery installations are expected to reach 741 gigawatt hours by 2030, mostly lithium-ion, led by the United States and China, according to Wood Mackenzie. A GWh is enough to power 1 m of houses for an hour.
In addition, hydrogen, produced by electrolysis of water using electricity, could emerge as a competitive solution for energy storage for longer periods. Hydrogen can be stored in underground caverns or in depleted oil and gas fields.
Hive Energy, which is planning the Cleve Hill solar and storage site near Graveney, is deciding what technology to use for its battery, but will likely opt for lithium-ion, said company chief executive Hugh Brennan.
“It’s like trying not to buy an iPhone,” he says. “It is also more cost effective to provide short-term energy storage to take advantage of differences in electricity prices.” The company plans to install at least 200 MWh of batteries, he says.
In Graveney, however, there are signs outside the church and along the road with images of gas masks and the slogan “No solar power plant!” Ms King and other residents say they’re not against expanding renewables, but they are hopeful that alternative storage technology will be used for the site.
“Despite all the risks, that doesn’t give them a huge capacity to store energy,” says Ms. King. “If there was a different technology that was more secure, we would clearly appreciate it.”
Additional reporting by Nathalie Thomas in Edinburgh
Beyond lithium-ion: energy storage technologies
Storing renewable energy requires low-cost technologies that have a long lifespan – where they can be charged and discharged multiple times – are safe and can store enough energy cost-effectively to meet demand.
Vanadium redox flow batteries use two reservoirs containing positively and negatively charged liquid vanadium electrolytes that are pumped through a membrane into a cell. Batteries have less degradation than lithium-ion and a longer lifespan.
Liquid air is cooled to minus 196C, after which it is stored in tanks. It is then heated, which drives a turbine to generate power. An alternative uses heated compressed air to store energy in purpose-built caverns.
Gravity storage involves lifting and lowering heavy blocks of abandoned mine shafts as a means of storing and generating energy.
Thermal energy storage Matla, a company backed by Bill Gates’ Breakthrough Energy Ventures, stores energy in the form of heat in the form of molten salts. The company says the technology can last for over 20 years and is suitable for over six hours of storage.
Liquid metal batteries uses metals that naturally separate when heated to form a cathode and anode separated by a saline electrolyte. When initially heated, the battery maintains its high operating temperature by generating heat during discharge and charge.
Cheap batteries using cheap raw materials like iron, sulfur and zinc offer alternatives to lithium-ion battery technology. Zinc-based battery developer EOS, for example, claims its battery has the ability to discharge power for three to 12 hours. Form Energy, a startup backed by Bill Gates, says its battery can store energy inexpensively for up to 150 hours
Hydrogen using electricity to produce hydrogen is one way to store energy, but the process results in substantial energy loss, making it less efficient than batteries.