As I wrote recently here in Power Engineer Magazine . . .

"A breakthrough in multi-megawatt class energy storage is at least a possibility in the next 10 years. At the moment, only a few megawatts can be stored using various energy storage technologies, and at great cost. Wind power would make a huge contribution if perhaps 1000MW could be stored overnight (when it is almost worthless) and sold back into the spot market during the day – when prices are at their highest."

So I was very taken to learn of Sorne Hill windfarm in Ireland, which will shortly have 12 megawatt hours of vanadium flow battery storage, courtesy of VRB Power Systems. Just view all the technical detail here in this January07 piece in New Scientist.

If I've got my doubts still though, there is as yet absolutely no mention of cost for this technology - hard figures like cost per installed watt. The plan for this windfarm seems to be to sell back into the spot market, which would make sense if the technology was expensive and the spot prices were high. And I'm just trying to imagine how big these vanadium flow batteries are. If - as per the article - 70,000 litres of vanadium sulphate solution delivers 800 kilowatt hours, that means 87,500 litres gives you 1 megawatt hour. 12 megawatt hours then requires 1,050,000 litres - or (assuming a similar volumetric density to water) 1,050 cubic metres of space or 37,500 cubic feet of space needed to hold the batteries. That seems like a lot of space, but it is certainly much less than the total surface area required for a 12 megawatt windfarm.

If all goes well at Sorne Hill windfarm, I think we'll see a vast increase in this kind of energy storage. Selling into a spot market with supply shortfalls has to be the most cost-effective way to make this technology pay. So I'm wondering when this will take off in California . . . if it had been around in 2001 in scale, I'm sure that enron traders could not have made anything like the profits they did.

VRB is definitely a company to watch - it has an energy technology that can actually bring prices down.