Electrical switchgear engineers NOJA Power today highlights the need to introduce smart grid technologies to improve the flexibility of the electricity distribution network and ease the connection of diversified, renewable energy resources and help utilities meet the future demand from electric vehicles (EV).
EVs use electric motors for propulsion powered by on-board batteries that are recharged by plugging in to the electricity supply. In the four years since 2008, 27,000 EVs have been sold in the U.S., and since 2009, 29,000 in Japan and 27,800 in China. These fleets include popular cars such as the Nissan Leaf, Tesla Model S and Mitsubishi i-MiEV. EV fleets will continue to grow as range increases and prices fall. In 2011 U.S. President Barack Obama expressed an ambitious goal of putting one million EVs on the roads in the U.S. by 2015. The U.K. is aiming for 1.7 million EVs by 2020 to meet its carbon emission-reduction targets, and industry experts predict one million EVs on Australian highways by 2022.
In 2010, Australian utilities generated 227 TWh of electricity, or around 622 GWh per day. A fleet of one million EVs would require about an additional 5 percent on top of this daily total to recharge its batteries. Like many national systems, the Australian grid has very little spare capacity at times of peak demand such as hot summer days when consumers all turn on their air conditioning at the same time.
Smart grids are a new, more intelligent way of supplying electricity combining computerisation, digital communications, sensing and metering of the electricity network to create a bidirectional, interactive grid that encourages greater use of renewable energy sources. Smart grids equipped with automatic circuit reclosers (ACRs) allow the connection of renewable energy sources such as solar, wind, geothermal, wave and tidal. A large installed base of renewable energy sources would be needed to ensure that EVs deliver on their promise of carbon-free motoring.
“I can picture a scenario where on a hot day in Queensland, Australia, in the near future a shopping centre car park is hosting one thousand EVs all looking for a quick recharge before returning home,” explains Neil O’Sullivan, Managing Director of NOJA Power. “Commercial charging points are likely to offer 415 volt/32 amp three-phase power allowing each EV to receive up to 13.2 kilowatts. That’s 13.2 megawatts just for that one car park. And those vehicles could be taking power for perhaps an hour or two.
“There are three million vehicles in Queensland. If, for example, in the near future, ten percent of those are EVs and a quarter of those EVs are simultaneously being quick charged across the state the utilities could see nearly 1000 megawatts of additional demand,” says O’Sullivan. “The peak demand seen in Queensland is around 8900 megawatts, so an additional 1000 megawatts is easily enough to tip the grid over the edge if it occurs at the wrong time. To avoid this scenario, efforts should be made to enhance the network’s capability by investing in smart grid technologies.
“ACRs are fundamental building blocks for smart grids,” continues O’Sullivan. “The ability of reclosers to help utilities closely match supply and demand, rapidly switch in renewable energy sources and protect the grid is essential if the future additional demand from EVs is to met.”
Units from NOJA Power's OSM range of medium-voltage (15, 27 and 38 kV) ACRs (see “About the NOJA Power OSM range” below) have been installed by utilities in over 80 countries around the world. The ACRs have been subjected to full type testing by independent test laboratories, such as KEMA in the Netherlands, to the latest standards. NOJA Power’s ACRs use solid dielectrics, replacing the environmentally unfriendly oil or sulphur hexafluoride (SF6) gas of older products.
NOJA Power has produced a white paper entitled “Using the smart grid to mitigate the impact of electric vehicles on future electricity demand”, which details how ACRs and other distribution automation devices could enable smart grids to cope with the extra demand from a large fleet of EVs. The white paper is available for download from the company’s website, www.nojapower.com.au.
References:1. “One Million Electric Vehicles By 2015 - February 2011 Status Report”, U.S. Department of Energy.2. “IEA Key World Energy Statistics”, 2011.