Electric cars can help the power grid – New Scientist

The batteries of electric cars could be used to keep the electricity grid stable. From 2030, the mobile batteries can offer solace.

Solar and wind energy are sustainable energy sources that are also becoming cheaper. But they have a drawback. Changes in the weather cause variations in yield.

‘We need short-term storage in the grid to absorb these variations,’ says a climate researcher Paul Behrens from Leiden University. This is necessary to store a temporary surplus of electricity for those times when the wind is not blowing and the sun is not shining.

Chengjian Xuwho obtained his PhD at Leiden University in December, showed with Behrens and other colleagues on how electric car batteries can contribute to this short-term storage.

Old battery

Electric car batteries can be used in two different life phases. You can plug your car into the grid for short-term storage when you’re not using it. Or you can use old batteries that are no longer suitable for driving vehicles.

These old batteries are often still usable and have a capacity of 70 to 80 percent. This makes them suitable for stationary, longer-term energy storage. This application does require an infrastructure in which old batteries are collected, tested and, if necessary, repaired. You can then merge them into a centralized storage system.

“People are already doing this with some of Nissan Leaf’s first-generation batteries to provide energy storage in off-grid places,” says Behrens.

Car batteries

Behrens says about the use of batteries that also serve in cars: ‘Cars spend a large part of their time parked. We only use them 10 percent of the time, or less. The rest of the time the batteries can be used as storage.’

If you have an electric car that is stationary a lot, you cannot yet register for short-term storage. After all, this first requires technical adjustments to both the cars and the grid. For example, it must be possible to discharge on demand from the electricity grid. And an operating system is needed that regulates charging and discharging. There are various projects worldwide to investigate such technical solutions.

If successful, electric car batteries could meet the demand for short-term energy storage in most areas as early as 2030, the researchers write. To this end, they created a predictive model that takes into account, among other things, the expected number of electric cars in 2030, how often people drive, and how quickly the capacity of the battery decreases.

Better for your battery

For a valuable contribution to the grid, it is not necessary for everyone to offer their electric car. Worldwide, only 12 to 43 percent of owners need to participate, the researchers calculate. That could drop to less than 10 percent if we start using half of second-hand batteries for stationary storage.

If you are afraid that this will leave you with an empty battery, or that it will shorten the life of the battery, don’t worry. When using the batteries, capacity is reserved for car trips. And the degradation model used by the researchers shows that using the battery in this way could even improve its lifespan.

This is because battery life is also determined by usage and conditions, such as temperature and speed, of charging and discharging. By connecting the electric car to the grid, you can use the battery smartly, which can reduce degradation.