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A few people home charging at the same time can blow out the grid

Mon Apr 24, 2017 9:16 pm

In the UK it is as little as 6 cars on the same block charging at the same time can blow out the grid and in Canada the predicted number is 10. There are a few factors that lend a big hand in this like time of day charging is done but as we see EV's with longer ranges come to the road the concern for grid capacity becomes an issue. The bigger the battery the bigger the demand on the grid
POWER CUT Charging just SIX electric cars at once on the same road could lead to local power outages across the UK
Britain is facing a major energy crisis, as the growing use of electric cars could see large power cuts across the country. BRITAIN will need a massive overhaul of its energy network if it’s to support the increase of electric vehicles on our roads, a report has claimed.

It suggests that local areas could see large power shortages as a result of just six electric cars charging at the same time on a single street.... ... ss-the-uk/

The supply of electricity isn't the main issue. Hydro-Québec says the electricity consumed by one million electric vehicles is equivalent to less than two per cent of the electricity sales in Québec in 2009. Similarly, even in winter when electricity demand is highest, B.C. has the unused capacity on its grid to charge nearly 2.4 million light duty vehicles — almost all the 2.5 million registered vehicles in B.C., a study by the University of Victoria's Pacific Institute for Climate Solutions reports.

But that doesn't mean utilities can ignore the coming wave of plug-in cars.

"Say 10 houses on the same street are plugged in at the same time — that could be an issue," says Nick Beck, director of transportation energy technology at Natural Resources Canada.

A power cable is seen attached to an electric vehicle in downtown Vancouver. Researchers expect a higher concentration of the cars in certain neighbourhoods, putting stress on the electrical system in that area. ((Jonathan Hayward/Canadian Press))

The scenario isn't as unlikely as it might sound. Hybrid-electric cars already tend to cluster within certain neighbourhoods. Plug-in electric cars are expected to do the same as neighbours see each other getting new cars, talk about the benefits of not having to fill up with expensive gas as the pumps, and sell each other on the idea of electric transport.

The problem is that the neighbourhood transformers that convert electricity to the right voltage before it enters people's homes aren't designed for the kind of load created by a number of cars all drawing large amounts of power from the grid at the same time, and they may fail, causing neighbourhood power outages. To accommodate electric cars, those transformers may need to be upgraded, Beck says.

Another problem is human behaviour.

A report by University of California in Davis found plug-in electric car users don't naturally think about what's best for the grid if they pay a constant rate for electricity, and they often plugged their cars in during the hours of peak electrical demand. But most of the extra capacity within the grid is available late at night and very early in the morning. That means that to minimize the load, people would have to be persuaded to charge cars at night, not during the day or the high-demand evening hours when they've just driven home from work.

Beck thinks that problem will be easily solved through electricity pricing. Already, utilities are installing smart meters in homes that allow them to impose higher billing rates during peak times to encourage people to switch their electricity use to off-peak hours. Beck predicts "smart chargers" that communicate with the smart meter will soon be available. Such chargers would automatically switch on when the electricity price drops to a certain threshold, making it simple for users to charge at off-peak times, Beck says: "The controller's doing the thinking for you."

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