Electric cars which you can use for electricity storage

Sometimes you need vision to identify a solution to a problem and the hardest thing is to think laterally to solve the problem. Storing electricity is hard to do, especially in large quantities. In the home you store heat in your radiators and in your hot water cylinders and tanks but you do not usually store electricity save in the batteries of a few hand held devices. 

If we could easily store electricity we could save a great deal of energy. Electricity power stations operate most efficiently when they run at constant rates, but the demand fluctuates greatly. So we waste a lot of fossil fuel is generating electricity that no one uses and which we cannot store. If we could store it we would generate less of the stuff, thereby emitting fewer pollutants and less carbon dioxide. 

To store electricity on a large scale is very hard. You can build highly inefficient large batteries but these have their own environmental problems. You can build a dam and create a lake below the dam. When you have surplus electricity you wish to store, you can pump the water up to the dam. When you want to use the electricity you can let it flow back to the lake through generators which feed current back into the grid. There is actually one of these storage sites in North Wales, but they use land, a scarce resource close to urban areas, and flooding land has several bad environmental effects including the release of carbon dioxide and methane from rotting vegetation. 

There  might be other ways of storing electricity but no one could think of them until eleven years ago when Willett Kempton of the University of Delaware and Steven Letendre of Green Mountain College thought about electric cars.  They reasoned (eleven years ago), before a single electric car was available for sale, that if every car in the United States was powered by electricity the battery storage capacity of all those cars would have much greater capacity than all the US  electricity generating utilities.

They also knew that all cars spend much more time idle and not being driven than they spend being used. In fact cars spend 95% of their time doing nothing with their engines turned off. Why not use the massive batteries in electric car for storing grid electricity when the cars are not working and draw out the power if necessary when the cars are idle? The critical part of this thinking was to recognise that electric vehicles are not just a load but also offer storage possibilities. They also recognised that instead of renewable electricity export to the grid (which often is inefficient and often happens when the grid does not need the current) the batteries of electric cars can be used to store domestically produced renewable electricity from your PV system or your local wind turbine. 

In 1997 there were no commercially produced electric car and the computer software and hard ware industry was a lot less sophisticated and a lot more expensive than it is today. There was no broadband. Now in 2008 researchers at the University of Delaware (Willett Kempton again) have found a way to use electric cars and hybrid cars as an intermediate store of electricity. A prototype has even been produced by a Californian company, A C Propulsion, whose car has an inboard computer using broadband over the plug in electric cable that connects the car to the mains.  

When you have several thousand vehicles so connected there is a critical mass which can store electricity generated when no one wants it, and put back the current in peak times, provided the car is not being used. It saves a lot of wasted electricity, and prevents carbon emissions and enables generating stations to operate more efficiently with lower baseloads. 

If we can get past the prototype stage and if we can get broadband sent over electricity cables with sockets created specially for electric cars all over London, we can significantly reduce emissions using fleets of electric cars. I should say “might” because we have to understand the down side (there are always down sides); we have to factor in the environmental cost of batteries, for example.  

If it works it might well help transport be significantly less carbon intensive and in the very long term reduce the need for so many fossil fuel or nuclear power stations. 

To prevent catastrophic climate change we must to use all available technologies appropriately and devices, modify behaviour, act imaginatively and think laterally. I have never been convinced of the environmental benefits of the electric car, which I fear simply moves emissions from city centres to power stations. If we can use electric cars as electricity stores then the argument in their favour is compelling.

2 Responses

  1. I’m astounded at how silly is this idea of “borrowing” a driver’s car battery. Storing and then removing electricity from a driver’s car battery degrades and wears out the battery. Duh! No driver will allow that
    without just compensation. So if the utility is forced to pay what the storage actually costs, then why in the world would a utility be so incredibly stupid as to pay all that money for the V2G network and suffer all the inconveniences and problems of trying to coordinate their needs and those of the drivers (who are forced to
    let the utility know all their plans and all changes to those plans for their driving – a horrible encumbrance)
    when they could much more easilt simply buy the batteries themselves, have total control over their placement and their use? Anyone want to explain why they now think this V2G idea makes any sense?

  2. Kent,

    I don’t think you’ve quite got the point; the storage would only work when there was a critical mass of cars connected – probably around 2000 electric propelled cars. Each car would need a small computer to connect to the utilities’ network and that would help manage the storage.I guess the “compensation” would be the free charging of the car?

    There would be no need for drivers to let the utility know what they are doing – they just carry on as normal – I guess the critcal mass takes care of that too.

    You raise a good point about degradation and I don’t know the answer; it’s one of those things that have to be looked at.

    Certainly in savings of capital costs the idea, if it works, would save the utilities plenty, but as I said in my post, you have to look at the down side very carefully.


    Robert Kyriakides

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