DeviceGuru

Worried about blackouts and brownouts becoming commonplace as electric vehicles go mainstream? The solution may be coordinated off-peak charging, based on computerized charging stations in concert with off-peak pricing incentives from the electric utilities, a recently released study suggests.

The study, conducted in the U.K., examines the efficiency, costs, and greenhouse gas emissions of current and future electric vehicles, including the impact from EV charging on electricity demand and infrastructure for generation and distribution.

With respect to the issue of overloading the power grid, the study’s executive summary states its conclusion that with coordinated off-peaking charging — even in the case of 100 percent migration to EVs — the U.K.’s current electric generation capacity should be sufficient. Quoting from the study’s executive summary:

“Uncoordinated charging would increase national peak load by 7 percent at 30 percent penetration rate of EV and household peak load by 54 percent, which may exceed the capacity of existing electricity distribution infrastructure. At 30 percent penetration of EV, off-peak charging would result in a 20 percent higher, more stable base load and no additional peak load at the national level and up to 7 percent higher peak load at the household level. Therefore, if off-peak charging is successfully introduced, electric driving need not require additional generation capacity, even in case of 100 percent switch to electric vehicles.”

The study’s executive summary also addresses EV’s environmental impact due to various methods of generating electric power…

“GHG emissions from electric driving depend most on the fuel type (coal or natural gas) used in the generation of electricity for charging, and range between 0 g/km (using renewables) and 155 g/km (using electricity from an old coal-based plant). Based on the generation capacity projected for the Netherlands in 2015, electricity for EV charging would largely be generated using natural gas, emitting 35-77 gCO2 eq/km.”

The study also compares the total cost of ownership (TCO) of EVs, hybrids, and plug-in hybrids (PHEVs). It concludes that EVs currently are uncompetitive with regular cars and hybrids, due to the high cost of batteries. Specifically…

“We find that total cost of ownership (TCO) of current EV are uncompetitive with regular cars and series hybrid cars by more than 800 €/year. TCO of future wheel motor PHEV may become competitive when batteries cost 400 €/kWh, even without tax incentives, as long as one battery pack can last for the lifespan of the vehicle. However, TCO of future battery powered cars is at least 25% higher than of series hybrid or regular cars. This cost gap remains unless cost of batteries drops to 150 €/kWh in the future. Variations in driving cost from charging patterns have negligible influence on TCO.

The study, entitled “Energy use; cost and CO2 emissions of electric cars,” was originally published in Elsevior’s Journal of Power Sources. It’s available as a download for $41.95, from Elsevior’s ScienceDirect site.