The Northland Age

Can grid cope with electric transport?


As electric cars appear more and more on our roads there are a flurry of articles casting doubt on whether the electricit­y grid can cope with the extra load. Having read quite a few of them it is clear the authors had never driven an electric car and they are treating the whole scenario as you would a petrol or diesel vehicle, whereas the method of driving and refuelling the vehicle is completely different.

Having used an electric car for five years, and just recently lost my home-charging facility, I have a better understand­ing as to how the whole user experience works.

The first thing to understand is that over half of all car journeys are less that 10km and a passenger car would typically spend 23 out of the 24 hours in a day parked.

This means even though a modern electric car would have a battery of 50 amp hours to 100AH, if the car is plugged in at home or at work, it would only have to recharge five to 10AH at a time.

It is very important to use an electric car in this way as sitting in a charging station for half an hour at a time is a real pain. It is envisaged that supermarke­ts would have charging stations so that drivers can plug their cars in and go do their shopping and, with a huge roof, a supermarke­t could be making electricit­y from solar panels and selling it at a good price.

People tend to forget that the whole of NZ is already wired for electricit­y and you can tricklecha­rge an electric car from the normal electric system in a house, with probably a special wire about the same size as used for a water heater or electric cooker.

Parts of the grid will have to be beefed up, but an important factor is that renewable energy is not centralise­d, as with a coal-fired power station, but is but spread right round the country. As an example of this, Northland is already self sufficient in renewable geothermal electricit­y and this paragraph from the Transpower plan, “In Northland, based on current connection enquiries, there is potentiall­y up to 2GW of new renewable generation that could be built – enough renewable electricit­y to power up to 375,000 households”, shows power lines will have to be installed to export power, not import it.

Alsso, electric transport does not require a very big rise in the total amount of power needed, possibly only about a 10 per cent increase, and production of electric cars is starting slowly and it will take 20 years to convert the existing fleet of fossil-fuel-powered cars.

There is plenty of time to strengthen the grid and electric vehicles should bring down the cost of personal transport considerab­ly but it might be a bumpy ride.

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