My recent post on Wind Turbines attracted an interesting comment from a reader by the name of "nommo". In summary, nommo's view is:

• [T]he way we run the [national power] grid at the moment is wrong
• It is incredably [sic] inefficient to have a centralised power supply.
• [A] nation of electric cars would actually be a great energy storage buffer.
• Then there is the concept of compressed air storage...
• [W]ould you rather have a nuclear power station less than 20 miles from your home (and temporary storage of waste) or some windmills?
• [N]uclear plants are built by foreigners (I'm paraphrasing this one as I didn't quite understand it. I'd recommend you read it yourself)

I hear these sort of sentiments a lot from the green movement, and in general my main response to those who say that we're doing electricity distribution wrong is to point out that we are not the ones doing it.

I used to work for the National Grid Company - boring IT support as opposed to proper engineering - and from my position under the desk fiddling with network cables I was able to gain some appreciation of the enormous complexity of the task of generating and distributing electrical power on a national scale. The people involved, from the mad bastards in the line engineering team who swing about on pylons to the analysts trying to match supply to demand, are not just punching the clock and kicking back for the day. It's a constant physical and intellectual battle to keep the system going and the electrons flowing.

And the system is pretty damn efficient, by which I mean there are no compelling alternatives to current methods of electricity distribution, regardless of how much money you've got to spend, that offer a better energy conversion efficiency. Such alternatives will probably be developed; but they're not here yet. But if you want to take the initiative, and move back to the fields to live next to a windmill today, then be my guest.

The core point I made about Wind Turbines - not my original work - was that the output of said generators is unpredictable, because the wind doesn't always blow, and thus they aren't much cop for national power generation which depends on stability of supply. I'd reiterate what I said to local Green Party councillor, Charlie Bolton , and throw it open to everyone: if you can come up with a better technology then please do!

As a means of stabilising that supply, Compressed Air Energy Storage (CAES) is certainly worth a look. It's not a new technology - the first CAES plant was built in 1978 - and is in use in several countries around the world. Alabama's Power South Energy Cooperative was apparently an early adopter, although there doesn't seem to be anything on the web-site about it.

A 2,700 MW CAES is planned for Ohio, using old limestone mines to store the compressed air. The designers' web-site looks pretty compelling.

Cars as Portable Batteries

One interesting idea raised by "nommo" was that electric vehicles could be used as portable batteries to store energy from unpredictable wind generators and thus smooth out national supply by releasing their energy on demand when plugged in at home in the garage, a load-levelling function performed in the current UK grid by Pumped Storage Hydroelectricity .

According to the DVLA, there are around 28,000,000 cars on the road in the UK, and 33,000,000 vehicles in total. These statistics are a bit old, so let's keep the numbers simple and say there are 35,000,000 vehicles driving around in 2008. Let's say that all of these vehicles were converted overnight into Plug-in hybrids (by some fantastical effort herewith undefined) so that each contained a 4 kWh battery. (For comparison, a standard hybrid car like the Prius contains a 1 kWh battery). And let's say that no one drives these cars, and they just stay in the garage. And that the batteries are constructed using a technology with no constraints on discharge/recharge cycle. And while we're at it, let's also say that they convert power at 100% efficiency. And that they cure cancer.

This would give us a total "garaged" energy storage capability of 140,000 MegaWatt-Hours. Reminding ourselves via a table of Orders of Magnitude for power that a MegaWatt is ten to the power of six watts, and a Terawatt is ten to the power of twelve watts we can compare this garaged value to the UK's daily requirements.

• UK Daily power requirements (TWh): 0.96
• Hypothecated "Garaged" Power Storage (TWh): 0.0144

The latter figure is 1.46% of the former. Now this does actually compare pretty well to the UK's current energy storage systems. The largest hydro pumped storage facility in the UK - Dinorwig - can generate 288MW from each of its six generators for 5 hours - a total of 1,440 MWh. Adding in the older four 90 MW generators at Ffestiniog (we'll assume they can manage five hours as well), that gives us a total UK energy store of 0.002 TWh, or 0.2% of daily national power requirements.

So this idea could be a goer. In about thirty years, when there are sufficient batteries installed in cars, of sufficient capacity, with a technology that supports fast and frequent discharge/recharge cycles. But if you think you can do it now, there are plenty of venture capital firms out there to whom you can speak. Just remember, that UK local authorities flush with cash collected from council tax payers do not count as a legitimate source of VC funding.

Counterpoint

Plenty of people disagree with me about the viability of wind power. Have a look at the British Wind Energy Association for another take on the same data. Their contention is that the UK's small number of large power stations is the problem for which a large number of small power stations is the solution; a concept for which they use the technical term "lumpiness".

They're protestations would be more compelling if they were able to run their industry without massive lobbying efforts and state subsidies - ironically the same critique that is often made of traditional power companies.

The Nuclear Option

I'm hesitant to legitimise a false dichotomy - wind or nuclear - but I will say one thing. I would be totally relaxed about living 20 miles away from a nuclear power plant, because just like all Bristolians I already do. I'm referring of course to Oldbury Nuclear Power Station , which is sadly due to cease operations this year. In my case, this is exactly a 19.2 mile drive from my front door.

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For more information about why Nuclear power isn't the bogeyman that many people think, have a look at this book. (It's even got lots of stuff about carbon footprints and global warming if you're into that sort of thing):