Power Grids and Electric Cars vs Reality

My last blog on electric cars received a few comments from readers, which are always welcome. (It is nice to know that people actually read these blogs!) One reader suggested doing an analysis of whether the adoption of electric cars has an overall benefit in reducing emissions. Their view is that most of the North American (and global) electrical grids still rely heavily on coal and natural gas for base load power generation. Therefore, charging a so-called ‘zero emissions’ electric car on the grid doesn’t actually reduce emissions and simply shifts the source from the exhaust of the vehicle to the smokestack of a power plant somewhere else. It is a nice thought that every electric car will only consume the electrons that come from renewable sources, but unless they are charged exclusively from the owner’s personal rooftop solar array or some other purely ‘green’ source of power, this isn’t the case. The reader made a valid point, so I was curious to find out the answer and crunch the numbers and see what the real-world benefit is and how it stacks up compared to the hype.

I recently visited the Google/Alphabet campus in Mountain View, California for a photo-op of their ‘Android’ sculpture garden (and visit to the merchandise store, of course). In the parking lot next to the visitors centre, I noticed a dozen parking spots had solar arrays covering each spot. Parked and charging each parking spot was an electric vehicle used by the onsite security to patrol the sprawling corporate headquarters. In an ideal world (and sunny California climate) this type of arrangement probably works quite well to charge a fleet of vehicles for this purpose and likely results in a zero-emissions fleet of vehicles.

The photo below shows the set-up:

However, not everyone lives in California or has installed a personal rooftop solar array for their exclusive for charging their electric car. The Google campus is obviously a very specific use case and doesn’t reflect reality for most drivers or homeowners. Taken a step further, even if a rooftop solar array is installed on a home, it is most likely that the vehicle needs to be used during the day and wouldn’t be parked in the garage during the day hours. Most people use their vehicles to get to work or drive kids around and then park at home overnight. To re-create the ideal ‘Google’ scenario would require a secondary battery that is at least as large as the electric vehicle’s battery to store the power during the day and then transfer it to the vehicle at night for charging. This may be the case for some green minded owners, but it is likely that most drivers will simply opt to charge from the existing electrical grid.

If we assume that most electric cars sold will be charged from the local electrical grid, is there really a benefit to driving an electric car?

Well, it depends on where you live and charge the vehicle. Simply using the overall power grid for Canada is one approach, but as I noted above, it is not accurate to think that the electrons that are consumed in Alberta would be sourced from Hydro-electric projects in Quebec.

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Questions and feedback are always welcome!