PTI

The power stored in electric cars could be sent back to the grid - thereby supporting the grid and acting as a potential storage for clean energy - but it will only be economically viable if we upgrade the system first.

In a study, published in the journal Energy Policy, two scientists showed how their seemingly contradictory findings actually point to the same outcome and recommendations: that pumping energy back into the grid using today's technology can damage car batteries.

But with improvements in the system, it has the potential to provide valuable clean energy.

Electric cars store excess energy when they are idle. Vehicle-to-grid (V2G) technology makes it possible to transfer that energy back to the grid when the car is not being used.

This energy could help regulate the frequency of the electricity supply, reduce the amount of electricity purchased at peak times and increase the power output of the system. Two recent studies, one by Kotub Uddin at the University of Warwick in the UK and the other by Matthieu Dubarry at the Hawaii Natural Energy Institute in the US, seem contradictory, with one suggesting that V2G degrades car batteries and the other that it improves battery life.

But the two scientists worked together to look at how their studies overlap, showing that they actually come to the same conclusion.

"Although both our papers seem contradictory, they are actually complementary," said Dubarry. "V2G is not going to be easy, but, if done properly, it has a chance to make a difference for both utilities and electric vehicle owners. We need more research to understand the process better and benefit from the technology," said Dubarry.

The two authors agreed that in order to be economically viable, V2G has to be optimised between the requirements of the car owner, the utilities and the capability of the grid.

In other words, the needs of the different people and systems involved have to be balanced. The question then became 'can this technology be profitable?' The previous studies had different approaches to answering this question.

Dubarry showed that using today's V2G technology can be detrimental to the car battery, while Uddin found a smarter grid would make the process economically viable, and even improve the battery.

With improvements to the system, V2G could actually improve electric car battery life and be profitable for everyone involved.