Storing The Change

Cheaper and better batteries are set to revolutionise the concept of energy storage. Here is the tech spark that triggered the illuminating possibility of clean energy.

- Ajay Sukumaran

When Chetan Maini rolled out Reva, India’s first electric car, in 2001, he used 250-kg lead-­acid batteries that ran for about 80 km and took eight hours to charge. Today, the best lithium ion (li-ion) batteries, he says, could take you, for the same weight of batteries, roughly 600 km, last five times longer and charge in less than an hour. “It’s still going to cost a lot more, of course, and yet it’s no small transition. And it’s been getting better every year,” says Bangalore-based Maini. Better, because the cost of li-ion batteries has come down almost eight per cent every year, on an average, in the past 15 years.

The next generation of batteries—and people are looking beyond li-ion—could potentially offer more energy density and possibly fix some of those niggles seen in consumer devices, the fires especially. And, while new battery technology doesn’t exactly roll out into the market as quickly as new mobile phone models do, the pace, from a chemistry point of view, has been dramatic. If it weren’t so, points out one expert, we would still be stuck with nickel-cadmium. And, yes, we wouldn’t be talking about the iPhone X, or smartphones in the first place.

“The fundamental change has been in terms of cost reduction. We were talking about $500 per kilowatt hour (kWh) some years ago; today we talk about $250 per kWh. So the cost has halved in just four or five years,” says Venkat Srinivasan of the Argonne National Laborat­ory in the US, where he heads the Collaborative Centre for Energy Storage Science. “Countries are now talking about having aggressive targets because they feel this is within reach. It doesn’t sound like fusion or something that is always 20 years away.”