Electric vehicles (EVs) could provide power balancing services to grid operators and utilities on a commercial basis, according to a joint report by National Grid and consulting engineers Ricardo, reducing the need to generate more electricity to meet peak demand.
There are two ways of doing it. The cheaper option is demand-side management, which would simply delay the car’s recharge until the grid’s demand peak had passed. This would be done automatically: the owner would just plug in as normal, and enjoy a modest return of £50 a year as a result. According to the report, Great Britain’s fleet of plug-in EVs could – by 2020 – provide up to 10% of the grid’s energy balancing requirements in the evenings and overnight, and 6% during the day.
The other option, known as vehicle-to-grid (V2G), feeds power from the car’s battery back into power lines at times of peak demand, reducing the need for conventional power generation. Developed by a team at the University of Delaware, the technology allows the battery’s charge to fluctuate in response to the needs of the grid operator.
According to the National Grid report, V2G would generate significantly greater revenue per vehicle, ranging from approximately £600 a year for a system with a capacity of 3kW to £8,000 a year for a 50kW installation. The only downside is that the interface which allows the power to flow back and forth between car and grid would be very expensive. Ricardo reckons that this would only be economic for owners of large EV fleets. – Peter Henshaw
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