This morning I was reading the usual batch of letters to my local paper on how terrible renewable energy is, how global warming is a myth, blah blah blah – the usual reheated zombie arguments. And this morning the old myth that renewables need 100% backup from fossil fuels reared its ugly head once again.

After reading The Solar Economy during the summer, I’ve become fascinated with how a solar powered economy would work in practice. I got an hint of how this works when I visited EAE Ltd this summer. They use power from their wind turbine directly by day and then at night use it to charge their electric forklift truck. This is a very simple form of energy management that spreads the peak of consumption across 24 hours – using the forklift battery to capture renewable energy when it is available for use during the day.

A smart grid would do this on a much larger scale. The grid would link lots of generators, large and small, using a range of generation technology – microhydro, solar PV, wind, biomass CHP etc – with lots of users – commercial, residential and electric vehicle owners. Some of those users would also have storage facilities – most notably electric vehicle owners. The smart bit of the grid would control the balance between generation, storage and use and manage the flow of money between them. When supply exceeded demand, the price per unit would drop and the storage facilities would charge up. When demand exceeded supply, those owners of storage facilities could opt to sell energy back to the grid at a premium. This optimisation of supply and demand would lower peak demand, so any backup required would only have to cover a much lower essential demand.

There are interesting proposals for how this could work in practice. You could be driving your electric car and the energy management system would advise you to charge up in the next hour at a certain charging point (identified by GPS) as prices were low. Later you could be sat at your desk at work and receive a text from your car outside advising you to sell some of its stored energy while prices were high, leaving enough charge to get home. Some estimate that, by selling such services to the grid, electric vehicles could become a source of income rather than a drain on your resources.

Smart!