Office buildings could soon be partially powered by employees’ cars, thanks to a new cost-saving vehicle-to-grid programme from Nissan. The ‘Vehicle-to-Building’ scheme – which recently completed a successful pilot test – uses staff cars as a temporary power supply, minimising the building’s dependence on the electric grid during peak energy hours.
Six of Nissan’s all-electric LEAF cars are connected to the building’s power distribution board, with charging of the cars’ batteries varying throughout the day. During peak hours, when grid electricity is the most expensive, the building can draw stored power from the vehicles, lowering electricity costs. But when grid electricity is cheaper power flows the other way, ensuring the cars are fully charged for the workers’ commute home.
The scheme has been has been running at the Nissan Advanced Technology Center, in Japan’s Atsugi City, since July 2013. According to Nissan, “the facility [has] benefited from a reduction of 25.6kW during peak summer periods … with no impact on the workers' daily commute, or their vehicles.” The reduction in electrical power usage – reported at 2.5% during peak times – is predicted to result in a total saving for the Nissan Advanced Technology Centre of almost 500,000 Yen (£2,950) per year.
The office-based scheme has been adapted from Nissan’s ‘LEAF to Home’ system, which was unveiled in March last year. Working in a similar manner to the ‘Vehicle-to-Building’ concept, the home system uses a power station that encourages charging at more economical times, such as overnight, and returns power to the home in peak-hours to take the edge off of the electricity bill. In addition, the LEAF can also be used as an emergency power source in the event of a power outage.
However, the charging/discharging process could have a detrimental effect on a car battery. “The Vehicle-to-Building [scheme] saves a certain amount of electricity cost, but it would definitely cause wear”, says Sekyung Han, an electric vehicle battery expert from Hanbat National University. He adds that: “Although the energy cost is minimised, the overall cost – including the battery wear cost – could be higher than the saved electricity cost.” Something he feels would need to be assessed in future tests. – Ian Randall
Photo credit: Nissan LEAF