Hybrid

July 24, 2009

Plug-in cars could cut vehicle emissions up to 90 per cent in Alberta

Engineers recommend “smart” charging systems to maximize use of wind power and manage electricity demand.

Plug-in hybrid electric vehicles (PHEVs) could release 40 to 90 per cent fewer greenhouse gas emissions in Alberta than conventional passenger vehicles, according to a study by electrical engineers at the University of Calgary’s Schulich School of Engineering. The study (PDF) found the environmental impacts of PHEVs in Alberta would depend on factors such as vehicle battery size, battery charging time and wind production levels.

The research of Mahdi Hajian, left, and Hamid Zareipour shows that smart charging of plug-in electric cars could lead to significant reductions in greenhouse gases.

The research of professors Hamid Zareipour, Bill Rosehart and PhD candidate Mahdi Hajian will be presented next week at an international power engineering conference in Calgary, the Institute of Electrical and Electronics Engineers (IEEE) Power & Energy Society General Meeting.

They say Alberta needs "smart" charging systems to make the most of Alberta's wind resources. Infrastructure would include technology with communication links to allow system operators to distribute electricity to vehicles when wind power production is at its highest, usually at night.

Optimal use of clean energy is especially important in Alberta, the province with the highest amount of thermally generated power in Canada. More than 90 per cent of electricity in Alberta is produced by methods that emit greenhouse gases: burning coal, oil or natural gas.

"Even in a thermal-dominated system like Alberta, we can still benefit significantly in terms of environmental impacts by using plug-in hybrid electric vehicles," explains Zareipour. "If we plan to charge them in a smart way, we can reduce a significant amount of emissions in the transportation system."

Smart charging systems would also help the power system handle the increased demand for electricity resulting from widespread adoption of hybrid cars. Cars would be charged outside of peak demand times to avoid overloading the grid.

Hybrid cars run on batteries but switch over to fuel for long trips. Many use their own fuel to produce the extra power that is stored in batteries. Plug-in hybrid electrical vehicles, which this study looked at, use high-capacity batteries to store electricity from the power grid. Zareipour, Rosehart and Hajian say plug-in vehicles are the best choice for Alberta because they make use of clean wind energy from the grid.

"The whole idea is to consume the wind power in the system as much as possible," says Mahdi Hajian, whose research is partially funded by the Institute for Advanced Policy Research at the U of C. "Unfortunately, the wind is unreliable because it’s not always blowing when we need it. Smart charging systems would help us harness the wind so we can store it in the vehicles' batteries for later use."

This is the first study to look at the need for smart charging systems for electric vehicles in Alberta. The researchers used 2007 wind production levels and assumed 30 per cent of Albertans were driving PHEVs when they considered a number of scenarios: battery charging at night, during the day, randomly through the night and randomly over a 24-hour period. While wind energy production mostly happens at night, all four scenarios point to the need for smart charging systems.

The results of the study are specific to Alberta but the conclusions can be applied elsewhere. Zareipour, Rosehart and Hajian say other provinces should also have smart charging systems, but the need would depend on electrical load patterns and the availability of clean energy sources such as hydro.

A handful of automakers have already introduced hybrid electric vehicles. Earlier this month, the province of Ontario announced a range of incentives—including monetary rebates—for consumers who buy plug-in hybrid and battery electric vehicles starting in July 2010.