It’s a familiar story and one that industry has long struggled to rewrite. The performance of a battery degrades over time and, at some point, will no longer hold enough charge to operate – for example, an electric bus (such as the Wrightbus Streetdeck Electroliner, pictured above), which has high power requirements. While many such batteries will have been disposed of, the focus is increasingly shifting towards giving them a ‘second life’, particularly where static applications are concerned – for example, storing energy from renewables, such as solar panels. And with an estimated 6.7 million pure electric vehicles (EVs) operational worldwide and 34.7 million predicted by 2030, the potential for battery reuse is, according to second life battery energy storage firm Connected Energy, ‘vast’.
Following a recent announcement by carmaker Toyota that it will be exploring how to make batteries easier to recycle, more attention should also be paid to giving used EV batteries that ‘second life,’ argues Connected Energy CEO Matthew Lumsden. “Toyota recently announced a bold plan to develop ‘green batteries’ – batteries that are low-carbon, low in cost and easy to recycle. Some simple changes at the design stage of batteries could add significantly to their reusability before end of life,” he states. “It is our assessment that up to 30% of vehicle batteries can be re-used in second life energy storage systems. Second-life applications must become ubiquitous across the world, if an unacceptable waste of resources through premature end-of-life battery recycling is to be avoided. Vehicle manufacturers can help.”
Connected Energy utilises its control systems, stacked together in bespoke containers, so the batteries are used exactly as they are in vehicles. “This approach capitalises on all the R&D and safety systems invested in them by OEMs,” adds Lumsden. Moreover, the process could be made dramatically easier and universally considered with a few design changes. “A first basic would be to ensure that batteries are regular cuboids and stackable. Removing odd shapes or additional sections that protrude sounds simple, but would no doubt have some complications. However, these need to be designed out. Adding fixing holes and channelling into the external casing of the batteries could transform the ease with which they can be cost-effectively installed and connected once outside a vehicle.”
To incorporate these changes into battery design, however, requires a real commitment to second-life use, whilst designing for the first life. But here’s the payoff. Over its lifetime in operation, a second-life BESS (battery energy storage system) could save an additional 450t/MWh of CO2 equivalent, compared to using first-life batteries, he calculates, “so we must ensure the use of second-life batteries in energy storage systems. This will not just save carbon and use the embedded carbon better, but reduce competition for raw materials.”
SKYE-HIGH THINKING
Meanwhile, a scheme looking to improve the resilience of electricity supplies in remote and rural areas – using battery storage and local energy resources to maintain power in isolated areas – is progressing to a pilot phase on the Isle of Skye. The Resilience as a Service (RaaS) project is funded through Ofgem’s Network Innovation Competition (NIC) and brings together E.ON, Scottish and Southern Electricity Networks (SSEN) Distribution and Costain to develop a new, market-based solution that could be applied at suitable sites across Great Britain to improve security of supply for local communities.
The RaaS project has a strong research and development focus, so it is important to consider other technologies that could deliver the service, says Dan Jerwood, battery and flexibility project lead at E.ON. “While the primary solution the project will implement is a single new battery, incorporating electric vehicles and other sites with flexible demand or generation have been considered as able to support and extend the service. E.ON and its customers are open to many considerations, in terms of the technology they operate, including second-life batteries. At present, all batteries in our optimisation platform are new, and we are confident that our control technology and methodologies will work equally well with new and second-life assets.”
The choice to take a second-life battery is therefore commercial. “Like a second-hand car, these assets will be cheaper than buying new, but the costs to transfer the modules into a static application, higher rates of degradation, lack of manufacturer’s warranty and increased operations and maintenance costs should be taken into account,” adds Jerwood.
The intermittency of electricity in rural areas is often caused by a single connection to the wider grid and, if this fails, there is no alternative route of supply, so the area will black out. The simple option would be to add another connection to the zone, he says. However, this would come at a significant cost and require installation of the new services in some of the most picturesque parts of the country.
“The RaaS battery solution will automatically detect a network outage and communicate this to the battery. The battery will then instantaneously trigger all the necessary network protection before going into load-following mode. When the solution detects restoration of the supply from grid, it will transfer seamlessly back. No outage – lower costs for the DNO [Distribution Network Operator] – less resource-intensive areas to manage – no diesel back-up.
“We should not forget that a battery holds only a finite amount of energy, so in the case of the long outages that were experienced during the storms of winter 2021, the stored energy would eventually deplete,” Jerwood concludes. “However, this would also address the challenge the DNOs have in identifying where multiple faults exist by keeping the network alive. This in itself would promote faster fault repair and accelerate the return of customers to supply.”
SURGE OF INVESTMENT
Climate change and the rapidly rising price of fossil fuels have, of course, prompted a surge of investment in new renewable energy production. But while new solar panels and wind turbines can be quickly added to national grids, the big question is about intermittency – how do you keep the lights on when the sun doesn’t shine and the wind doesn’t blow? Adding more renewables to the electricity grid also means you need to boost other energy sources to balance the network, as too much or too little power can cause it to collapse.
In the town of Kankaanpää, Finland, a team of young engineers has completed the first commercial installation of a battery made from sand they believe can solve the storage problem in a low-cost, low-impact way. “Whenever there’s a high surge of available green electricity, we want to be able to get it into the storage really quickly,” says Markku Ylönen, one of the two founders of Polar Night Energy, which has developed the product.
The device has been installed in the Vatajankoski power plant, which runs the district heating system. Low-cost electricity warms the sand up to 500°C by resistive heating (the same process that makes electric fires work). This generates hot air, which is circulated in the sand by means of a heat exchanger. With sand being a very effective medium for storing heat and losing little over time, the developers say their device could keep it at that temperature for several months. “So, when energy prices are higher, the battery discharges the hot air, which warms water for the district heating system, which is then pumped around homes,” adds Ylönen.
BOX: REACTIVE POWER
Zenobē is building the first battery in the world to absorb reactive power direct from a transmission network. Rated at 100MW, it is also claimed to be the largest transmission connected battery in Europe when it is commissioned.The demand for reactive power services to help manage voltage levels is growing due to the rapid uptake of renewable power generation. As part of its Pathfinder programme, National Grid, the UK’s Electricity System Operator (ESO), conducted a tender for the provision of reactive power in the Mersey region of the UK. This gave an opportunity for bidders to demonstrate how their solutions deliver better outcomes than traditional providers.
Zenobe’s specialist high voltage engineering team worked with supply chain partners to optimise not only the absorption of reactive power but also active power services that run concurrently. This innovative design, which included a direct connection on to the 275kV bay, has enable the stacking of multiple active power, capacity and voltage services.
Zenobe won a nine-year contract to deliver 40MVar of reactive power services in May 2020. This was the first time a battery has delivered this type of service anywhere in the world.
Later, the company was the first to use the revision to England’s planning regime for generation assets to build a 100MW facility, which is also Europe’s largest transmission connected battery when it is commissioned in 2022.
BOX: EV POWER BANK
In April 2022, an energy storage system from Batteryloop fitted with second-use batteries was installed at the headquarters of metals recycling company Stena Metall Group in Gothenburg, Sweden.
The BLESS I (BatteryLoop energy storage system) consists of 800 Toyota Material Handling forklift truck battery modules of 150Ah each, offering a power capacity of 155kW.
It is connected to 55 electric vehicle chargers, of which four of them offers semi-fast charging of 22kW.
The system offers peak shaving, which cuts the property’s power peaks and thereby reduces the power cost of the electricity network subscription. It also enables users to sell back electricity to the grid during times when Peak Shave is not used. Micropower Group is the battery producer.