A Big Battery

There are very few genuinely innovative energy products. The problem with energy is that the laws of physics limit what can be done and when it can be done. In the case of electrical energy we have the means of generating electricity from non fuel sources, – wind and light – but until now no really easy means of storing the electricity that we can generate. Attempts to feed solar and wind generated power into a grid fail to be effective in large emission reductions; because of the intermittency of the source of energy we need to have large power stations running on standby by, wasting fuel and creating emissions, to cover the times when the wind does not blow and the sun produces no light. Continue reading

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.