How flexible battery technology could help the switch to green energy

Dr Vladimir YufitAs the world becomes more reliant on renewable energy, power systems will need to cope with the variability of wind and solar power, and balance this with the peaks and troughs in energy demand.

“The peak in solar energy generation is midday,” explains Dr Vladimir Yufit, a Research Fellow in Imperial’s Department of Earth Science & Engineering. “But energy needs are low at that time because people are at work. At 6pm, when people are returning home and turning on the oven or TV, the sun is going down. If we can store energy and deliver it when it’s needed, we can mitigate the problem.

We can already store energy in batteries but Dr Yufit says they lack the flexibility and durability to meet our growing demands. “Power from wind and sun is intermittent – it might be too low or too high. Our current electricity grid can cope with it and absorb up to about 30 per cent of renewable energy, but beyond that its operation can be significantly destabilised.

“Without adequate storage capacities, excess of renewable energy generation must be curtailed. Or in the case of a shortage of renewable energy generation, additional means like gas-powered turbines must be engaged. Otherwise we may find ourselves experiencing frequent blackouts.”

Dr Yufit has 20 years’ experience in energy storage, including the last ten at Imperial. When he joined the College he began working on an idea for a new type of “flow battery”.

“Think about the normal type of battery in the back of your phone,” says Dr Vladimir Yufit. “It’s a black box – static with no moving parts. You can’t add anything to it.”

Unlike a standard battery, a flow battery has separate compartments or tanks where electroactive chemicals can be stored. These chemicals can reversibly change their state in a reactor to either deliver or store energy. Making the tanks bigger means more energy can be stored. By increasing the number of cells more power can also be generated. Controlling the flow of chemicals into and from the reactor controls the maximum power, making the battery even more flexible.

“A flow battery can store energy for long periods and offer more energy when it’s needed. It’s possible to recharge this type of battery much faster. It’s also possible to add more tanks, giving you the potential for storing more energy.”

Dr Yufit says that standard batteries also degrade too quickly: “They change – either through an irreversible chemical reaction or a structural change – and that affects their performance. This doesn’t happen in the same manner with this new kind of battery which means they can last for 15 or 20 years.”

Dr Vladimir YufitDr Yufit had already secured two patents for the battery technology and published several academic papers before he joined the Techcelerate programme. He says he applied in the hopes of learning about entrepreneurship, establishing links with potential customers and developing a company.

“I’m a scientist with a scientist’s mindset. I know much less about business. The Techcelerate programme took me out of my comfort zone and changed my mental attitude. It made me realise how important it is to engage with potential customers, focusing not only on the technology, but also on whether the technology is needed and where.”

“During the programme, I spoke to some big names in industry including Shell, Saudi Aramco, Repsol, BP and EDF. I met with project leaders, senior engineers, some five or six people in each company. I asked them about energy storage issues – what are the problems, how can we solve them?”

The process helped Dr Yufit understand customer needs and gave him the opportunity to discuss his battery technology and how the product could meet those needs. “The process didn’t necessarily change our road to market,” he explains. “But it did change the way I viewed the technology – as a system that is flexible and can be tailored to the customer.”

Thanks to the programme, and the grants that have followed, he has now spun-out a company – RFC Power Limited. At the same time he continues to work on prototypes and on refining the chemicals used in the battery. He adds: “Techcelerate gave me a way to communicate with potential customers and investors. The programme has finished but I’ll continue to communicate with those people and establish new links. And, of course, I will continue to ask questions.”