Electrical switchgear engineers NOJA Power Switchgear believes that smart grid technologies need to be introduced to meet the future demand from electric vehicles (EV).
Electric vehicle recharging will place additional load on an electricity distribution grid that is already struggling to meet peak demands. Investing in smart grid technologies will enable power providers to meet these future requirements by improving network flexibility and easing the connection of renewable energy resources.
EVs use electric motors for propulsion powered by on-board batteries that are recharged by plugging in to the electricity supply. The EV population in the US, Japan and China is already substantial and the fleets will continue to grow as the range increases and prices fall along with support from government policy.
US President Barack Obama in 2011 expressed an ambitious goal of putting one million EVs on the roads in the US by 2015. The UK 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.
Given the ambitious targets of various countries to put EVs running into millions on the road, the load on electricity distribution grids will be tremendous.
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% on top of this daily total to recharge its batteries, which may be difficult for the Australian grid to spare especially at times of peak demand such as hot summer days.
Smart grids are a newer and 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.
Neil O’Sullivan, Managing Director of NOJA Power visualises 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. Commercial charging points are likely to offer 415 volt/32 amp three-phase power allowing each EV to receive up to 13.2 kilowatts, creating a requirement of 13.2 megawatts just for that one car park.
Giving another example, O’Sullivan says that if even 10% of the three million vehicles in Queensland are EVs (in the near future) and a quarter of those EVs are simultaneously being quick charged across the state the utilities could see nearly 1000 megawatts of additional demand. The peak demand seen in Queensland is around 8900 megawatts, so an additional 1000 megawatts is enough to tip the grid over the edge if it occurs at the wrong time. Investing in smart grid technologies to enhance the network’s capability can help avoid this scenario.
According to O’Sullivan, ACRs are fundamental building blocks for smart grids, given the ability of the reclosers to help utilities closely match supply and demand, rapidly switch in renewable energy sources and protect the grid while meeting the future additional demand from EVs.
Units from NOJA Power's OSM range of medium-voltage (15, 27 and 38 kV) ACRs 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 automatic circuit reclosers use solid dielectrics, replacing the environmentally unfriendly oil or sulphur hexafluoride (SF6) gas of older products.
A white paper by NOJA Power, ‘Using the smart grid to mitigate the impact of electric vehicles on future electricity demand’ is available for download from the company’s website.