Building of the week: the Tehachapi battery

Renewable energy technology is moving fast. The price of solar PV has plunged in recent years, and the cost of wind turbines is falling too. Grid parity beckons, but the more renewable energy there is in the grid, the more balancing there will need to be to cope with intermittency. The output from solar panels and wind turbines depends on the weather, and at the moment, we still need coal power stations to take up the slack.

To sceptics, intermittency is an excuse to write off renewable energy as impractical. But that’s a bit like seeing the first generation of mobile phones in the 1980s, and declaring that they’ll never catch on because they don’t fit in a pocket. Just as miniaturisation has made mobile phones ubiquitous, advances in energy storage are leveling out the output of renewable energy and making it more dependable. I’ve detailed some of these technologies before, and I really ought to go back and update the post given how many different solutions have emerged in the last two years.

There are tidal schemes, pumped water storage, molten salt heat storage for solar plants, or schemes to haul railway trucks uphill and let them roll back down at times of peak demand. Until recently, the most obvious solution has proved elusive – the battery.

But then in September, this non-descript looking warehouse opened for business.

Inside, it houses the world’s largest battery bank.

It’s at Tehachapi in California, where some 5,000 wind turbines are expected to be generating a grand 4,500 MW by the end of 2015. The Tehachapi Wind Energy Storage Project will be able to store 32 megawatt hours of that, moderating the region’s contribution to the grid.

Now this is a pilot project and it doesn’t come cheap – this is a $55 million facility. You get a lot of lithium ion batteries for that money. Over 600,ooo in fact, but 32MWh is not a huge amount of power. Still, even a couple of years ago, it wouldn’t have made economic sense to attempt an experiment like this one.

And two years from now, it might be much more affordable. The price of electric car batteries (for that is what these essentially are) has halved since 2010. Tesla’s multi-billion dollar ‘gigafactory’ aims to drive the price of batteries down even further and make electric cars a mass market proposition. Elon Musk believes an electric car battery could cost $100 in a decade, down from several thousand today. His claims would sound arrogant if we weren’t seeing just that sort of advance in other areas of technology.

Bringing the price of batteries down isn’t a sustainability revolution in itself. We’ll want a ramping up of battery recycling and cleaner methods of creating lithium too. But there’s no doubt that affordable battery storage would be a huge advantage in the renewable energy revolution.