Will E-cars work out?

There may be an e-car in space but how will it work roadster in spacefor you and me? An electric car needs about 1kWhr of charge for every 7km of travel. To fully recharge at one of the “Fast Charge” stations takes 30min to 45mins depending on the range of the car and could be longer if you have to wait for a spot. With such a slow turnover, these stations will  have to be heavily subsidised or levy high prices close to the cost of fuel.

It would be much more convenient to just plug in at home and recharge overnight. This works out at less than half the cost of fuel for a normal car but adds power demand on the grid equivalent to an extra home. This could create problems with peak load on your local transformer as well as the grid as a whole.

You could install a special Off Peak circuit to recharge your e-car. This might cost around $1000 depending on the situation but would halve the recharge cost and reduce loads on the grid and local transformers. Unfortunately, most off peak power is from fossil fuel generators. While fossil fuel generators are being phased out even a small increase in Off Peak demand could push up off peak tariffs sharply. These higher prices could extend the use of fossil fuel power while causing big problems for other off peak power users like sewage plants, factories, food storage, warehouses etc.

People who own their own home and who do not work full time could install an extra $3500 of solar to recharge their e-car at home. Of course you would have to keep the car parked around the middle of the day to get the best charge. To recharge with your own solar power at night would mean adding about $5000 of battery storage. Of course this assumes you have the suitable roof space and don’t mind having to replace the extra batteries after 8 years.

What is needed is options to cheaply recharge during the day wherever you are parked. Unfortunately this is not economically attractive to most employers, shopping centres or councils without big financial subsidies or some other means to offset costs. One possible offset is that people value sheltered parking and may be prepared to pay a modest rate especially if it was covered with solar that would also recharge their e-car. The twin value streams of sheltered parking and solar power could make this option economically viable even while the numbers of e-cars are relatively few.

Add you comments below and help out by taking a short, 9 question, survey at https://www.surveymonkey.com/r/C7CSV57

AEMO commissioned a study on the impact of e-cars on the grid but made three flawed assumptions. Firstly they assumed that plenty of coal power would be around to charge e-cars overnight even as climate change impacts increase. Then they assumed that long hall trucks would not be involved but Elon Musk has begun production of his electric prime movers. Lastly they assumed that all e-car owners owned a free standing home and would install special off-peak recharging circuits that AEMO could control. Correcting these assumptions it is easy to see that demand will increase in evening peaks and for overnight off peak power. As a result, costs will rise steeply for local grid infrastructure along with prices for diminishing off peak power. This will have serious economic consequences, slow e-car adoption and hamstring further reductions in GHG emissions.

We need to plan for e-cars and that means providing convenient recharge options with renewable energy where people park during the day.




  1. I did the survey but the answers need more choices. I would be happy to plug in at a shopping centre etc if I knew the power was coming from renewable energy but not if it was coal fired power.

    • The idea is that the parking would be covered in solar and generating power either to recharge e-cars or to offset power use at the shopping centre. However the setup cost means it is not attractive unless there is a parking fee.

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