Analysis: used EV batteries still have a considerable amount of capacity left and can be repurposed for energy storage applications
By Barry Hayes and İbrahim Şengör, UCC
Electric vehicles are widely seen as the key to decarbonising road transport. Despite recent supply chain issues, global electric sales continue to break records every year. The latest figures from the Irish motor industry show that electric surpassed diesel car sales in Ireland for the first time in the first three months of 2023 and represented more than 24% of all new cars sold. The days of the internal combustion engine car are numbered, with last years' announcement of an EU-wide ban on the sale of new petrol and diesel engine cars by 2035.
But this rapid growth of the electric car market leads to an inevitable question: what will happen to the millions of used electric car batteries in the near future?
From CNBC, where do electric car batteries go when they die?
It is commonly accepted that an electric car battery's "second-life" starts when its performance drops to 70 to 75%. While recycling has been proposed as a solution to dealing with end-of-life batteries, the idea of repurposing these batteries for second-life applications is becoming increasingly attractive.
Second-life batteries are retired electric vehicle batteries that still have a considerable amount of capacity left and can be repurposed for various energy storage applications. The second-life battery market is currently in its infancy, but is set for exponential growth. A new "stationary storage systems" sector is emerging, with second-life batteries providing new local and grid-scale energy storage capabilities.
How can we get the most out of electric car batteries?
One of the most promising applications is in stationary energy storage systems designed to support the integration of renewable energy into the electricity grid. Eurostat figures show that Ireland's renewable energy share in electricity production was 36.4% in 2021, which still lies just below the EU average despite significant progress over the last two decades.
From France24's Down to Earth, what should be done with the batteries used to run electric cars?
As we move towards a target of 80% renewable electricity by 2030, increasing grid energy storage capacity will be key to the reliable integration of wind and solar generation. Energy storage will be essential to reduce the amount of "curtailment" of renewable energy, where the output of renewable generators is deliberately turned down since there is not enough electrical demand, or because the grid cannot accommodate the energy flows due to technical constraints.
Second-life EV batteries can be combined into a large-scale energy storage system, similar to the Tesla Powerpack to store excess renewable energy generated by wind and solar farms. This stored energy can then be released into the grid during peak hours, helping to stabilise the grid and reduce the need for fossil fuel-powered plants.
A good example of this is the Amsterdam Arena in the Netherlands, which uses second-life Nissan LEAF batteries to store energy from solar panels on the roof of the stadium. The second-life batteries also provide a backup power option in the event of a grid outage. Similarly, retired EV batteries could be used in data centres for backup power, replacing some of the diesel generators used by the vast majority of data centres.
From Moteurnature, how second-life Nissan electric batteries are used in the Amsterdam Arena
Second-life EV batteries can also be applied in residential energy storage systems, allowing homeowners to store excess solar energy generated during the day and use it at night. Similar to the "vehicle-to-grid" concept, this can help reduce the reliance on grid-supplied electricity and further promote the use of renewable energy sources.
Another application could be building public EV charging points supported by retired EV batteries. Despite recent growth in EV availability and increasing EV numbers on our roads, we are falling behind the transport electrification targets in the Climate Action Plan. There are numerous reasons for this, but a critical issue is public confidence in EVs due to range anxiety and the lack of charging points.
To overcome this, we urgently need to increase the number and extent of fast EV charging stations. Retired EV batteries could be used to enable the grid connection of new fast charging stations without the need for expensive power network upgrades. This is especially important in rural locations where the grid is weak and the network capacity for new connections is limited. This could help to make EV charging more accessible and affordable for all.
From Tesla, powerpacks in use in Terhills in Belgium
Environmental benefits to reducing demand for new batteries
The repurposing of second-life EV batteries can have significant environmental benefits. By extending the life of EV batteries, the need for new battery production can be reduced, minimising the environmental impact of mining and manufacturing raw materials for new batteries. Furthermore, the repurposing of batteries can help reduce the amount of electronic waste that ends up in landfills.
On the other hand, using retired EV batteries in second-life applications can be challenging due to several factors. These challenges include battery health problems due to degradation, safety concerns, inconsistent quality and availability, compatibility issues, and economic viability. Retired EV batteries may have reduced capacity and performance, contain hazardous materials, and may not be compatible with all applications. Additionally, the availability and quality of retired batteries can vary, making it difficult to ensure a reliable supply.
In conclusion, second-life batteries have the potential to revolutionise the energy storage industry and contribute to the transition to a more sustainable energy system. The repurposing of these batteries can provide a cost-effective and environmentally friendly alternative to new battery production. However, addressing the challenges associated with second-life batteries, such as standardization and battery management, will be critical to unlocking their full potential. As we continue to explore the possibilities of second-life batteries, it is important to recognise their potential as a key component in building a more sustainable future.
Dr Barry Hayes lectures in Power Systems Engineering at UCC and is a funded investigator in the SFI MaREI Centre. He leads a research group focused on the operation and planning of future power systems. Dr. İbrahim Şengör is a Postdoctoral Researcher under the Future Electricity Grids Project at the SFI MaREI Centre at UCC.
The views expressed here are those of the author and do not represent or reflect the views of RTÉ
