Around the world, utilities and government regulators are watching very closely the first mass energy storage device to be tied to a windfarm - VRB Power Systems flow batteries and Sorne Hill in the Republic of Ireland.

If you want to know why Ireland is the first country in the world to pioneer energy storage by wind farms this seriously, I reckon there are three reasons;

i) They have pretty much (except possibly New Zealand) the best sites in the world for windfarms - where windspeeds are so high, load factors of 35% are commonplace. So wind is cheaper in Ireland than almost anywhere else, incentivising developers to build more of it.

ii) A few years ago, TSO, who were in charge of Ireland's national grid (they are now called Eirgrid Plc), demanded a moratorium on new grid connections to wind farms at 775 MW to overcome the technical challenges of integrating large amounts of unpredictable power. So in order to progress, energy storage started to loom far larger in the minds of irish developers than in other nations, where it has clearly not actually happened at all.

iii) Ireland has grown by on average 7.5% per annum for each of the last 10 years and they need lots more power, which as island they can't easily import from abroad. Dell's Computers European headquarters are run out of Ireland and the country has been a magnet for foreign investment, requiring even more power.

So there you have it - if Sorne Hill's energy storage is seen to work, I can well imagine regulators around the world will be tempted to start mandating some degree of energy storage for future wind farms.

And it's hard not to see VRB Power Systems doing well out of that.

Active Power, a maker of flywheels, has just opened a Tokyo office in order to serve the burgeoning Asia-Pacific markets.

I'm sure there are good reasons for being in Tokyo, but by far and away the greatest growth in electricity consumption is going to be in China, which plans a 6 fold increase in electrification by 2020. Still, many high-tech firms - including I would guess, Active Power - remain nervous of locating in China. They worry that their intellectual property will not be protected, either by the business culture and especially by the courts. A quick glance at the internet suggests there are more than a few companies in China that are engaged with flywheel technology who wouldn't mind getting together with AP or for that matter Beacon Power.

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.