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Energy storage and management

Energy storage and management

Virtual lab, real-world challenges

31 Oct 2018 Margaret Harris
This article first appeared in the 2018 Physics World Focus on Energy Technologies

Physicist Peter Littlewood is the founding chair of the Faraday Institution, which was set up in 2017 as the UK’s “virtual national laboratory” for energy storage science and technology. He speaks to Physics World about the new institution and its approach

What are the key challenges in energy storage research?

It depends what the energy storage is for. One application is electric vehicles, and I’d say we’ve reached a tipping point where nobody would start a car company based on the internal combustion engine anymore. But even so, when you buy an electric car, about half of the cost of it is the battery. There’s a need to push down that cost, and that’s happening already – it’s happening with the evolution of current technologies such as lithium-ion batteries, and it could potentially happen with breakthroughs in next-generation batteries. Lithium-ion batteries are not a single technology but a family of technologies, and at some point – probably in the next few years – they will evolve into something that might be called a solid-state battery, which will be safer, lighter and a bit more efficient.

Then you come to the harder things, and curiously these aren’t energy-storage problems per se – they’re about integrating renewables into the electrical grid. With wind and solar, there will be long periods where you’re not generating much energy, and there will also be substantial periods when you’re generating more than you can use. In the summer of 2018, for example, the weather in the UK was very hot, very dry and not very windy – good for solar, not so good for hydro or wind. For short periods, batteries are reasonable systems for storing renewable energy, but if you’re interested in large-scale storage, battery technologies are not ready, and they may never be. Sources of stored hydropower are now largely used up, and other, similarly mechanical, technologies have inherent efficiencies, so we’re almost certainly going to move into electrochemical storage. A beneficial side effect is that the chemicals you use, such as ammonia, are useful in their own right. That allows you to begin to decarbonize some heavy industry, which represents the third of the economy that will be most difficult to electrify.

Why is it so important to meet these challenges? You mentioned the recent heatwave.

I wouldn’t like to say that the heatwave was necessarily associated with climate change, but fundamentally we have to move to a more sustainable economy. The last time we had a sustainable economy was probably in the 15th or 16th century, when everyone was travelling by horse and cart. I think electrical storage is key to enabling us to use modern technologies in a sustainable way. Our capacity for generating power through renewable sources – solar, wind – is growing rapidly but the storage technologies need to keep up if we want to make the transition. Otherwise, we’ll stall. We’ve already seen that in Germany, where they put lots of renewables onto the grid and then had to back them
up with coal.

What will be the Faraday Institution’s role?

Our goal is to propel the development and take-off of energy-storage technology, and there are three ways we’re trying to do that. One is to put together substantial mission-driven research programmes. We’ve focused on issues that we think are likely to be important in the next few years, and we’re trying to bring together large groups of people to work on them in an organized way. Another focus is training and education. The world is going to need many more people who understand batteries, and I don’t just mean PhD electrochemists – it has to be a very broad group, extending to technicians, mechanics, first responders and others. We also need to make an impact on how these technologies are perceived in terms of education and diversity to make sure we get the right people coming into the field.

The third thing we do is to give policy advice with numbers in it. We can help explain the consequences of technologies, and explain the policy implications of making different choices. That’s important because a lot of what you need to do to get technology to market isn’t just a matter of inventing things, but also making sure you have the correct regulatory framework and the right policies in place.

You were instrumental in setting up another organization with a similar mission, the Joint Center for Energy Storage Research (JCESR) at Argonne National Laboratory in the US. How is the Faraday Institution different?

The JCESR’s research programme is probably at the more fundamental end of the spectrum, but it is based on a similar idea: take a thorny problem, bring in a large group of people to work on it and push hard. The key difference is that with the Faraday Institution we are essentially trying to build a virtual national laboratory. In the US you have energy labs like Argonne, Oak Ridge and Berkeley, and they have a mission that is driven by the public good as defined by the federal government. In the UK, the government has a strategy for industrial R&D, but it doesn’t have a straightforward mechanism of engaging the community in that. Of course, it can put out calls for proposals through the research councils, but these, by definition, are relatively small-scale. There’s no central organization around energy research in the UK like there is in the US.

The vision for the Faraday Institution is to become that national laboratory, but we didn’t want to construct lots of bricks and mortar because the research capability in the UK is largely in universities and in industry, not in government-run institutions. The model we have – and this is the really experimental part – is to try to bring together a community that operates as a national laboratory would, but without everyone being in the same building. We want to get people to think like that – to collaborate internally, work effectively, share ideas, challenge each other, and generally build relationships across the rather fragmented state of research in the UK’s university system. That’s a little bit like JCESR, because JCESR is a so-called “hub”, with research distributed across five national labs and five or six universities, with several companies as partners. We’ve simply scaled that up.

You mentioned bringing people together. A lot of the work in energy storage is being done by material scientists, chemists and engineers. What do you think physicists bring to the table?

Physicists love doing back-of-the-envelope calculations and looking into the fundamentals of things, but I think the main thing that physicists can do in this field is to be integrated. Here’s a personal example. I worked on oxide materials for superconductivity and magnetism for a long time, and it turns out that those same classes of materials are actually battery cathodes. But the electrochemistry community that works on battery cathodes and the materials-science community that works on superconductivity don’t communicate. There is knowledge of different kinds across that spectrum, from electrochemistry to materials science, but it needs to be integrated.

Beyond that, though, I think battery research has got to an interesting stage. For a long time, it has been largely empirical, driven by sets of principles that electrochemists understand, but there’s been very little development in terms of getting a microscopic understanding of what’s going on. We’re now at a point where it’s actually worth making an investment in understanding how a battery works. That might seem like an odd thing to say, but let me remind you that although semiconductor technology came in with the transistor in the 1950s, and integrated circuits turned up 15 years after that, it wasn’t until the 1980s that the fractional quantum Hall effect was discovered. The ability to study that problem only came about because of the vast investment in semiconductor engineering. And that’s often what happens: the really sharp, hard science only gets done after the technology has matured in some way, because then there is the need, the ability and the money around to invest in really understanding it properly. If you look at what’s happening now with battery technology, there are lots of physics tools being applied, and it’s a very interesting field for physicists because you’re forced to think about a problem that isn’t a traditional physics one. The goals are different.

What technologies has the Faraday Institution focused on in the first year of operations?

We’re running four major projects at the moment, three of which are directly related to current technology. One of these involves recycling. We’re among the first institutions to establish a substantial research programme in battery recycling, and it has to be a sprawling programme because the problem incorporates more than just the technology of recycling – it also involves everything from life-cycle analysis to policy. The other two current-technology projects are quite closely related. One goes by the name of “degradation,” which is associated with battery lifetime. In parallel with that, there’s a project on battery system modelling where the goal is to improve the models we have for the performance of batteries and battery systems. You can do that by bottom-up or physics-based modelling, or you can use top-down modelling, which is very data-driven: because we now have a lot of batteries on the market, we can collect data from them and begin to understand their performance using data-mining tools.

The last project we have is aimed at developing new technologies around solid-state batteries. There are some obvious materials science, physics and chemistry questions about how to transition from a graphite anode to a lithium-metal anode; how to replace the liquid electrolyte by a solid electrolyte with a high mobility; and how to make a “softer” cathode material that doesn’t fracture, so that a large amount of charge can pass from one to another. We’re not alone in pursuing these questions, of course; there’s quite a lot of people working on ideas for solid-state batteries.

You mentioned both technology and policy as being important. Where do you think the biggest sticking points are?

I think the technology challenge is the standard one: can you actually do it? We know there are no rules against building batteries that are five or six times more energy-dense than what we have now, so it should be just a matter of fighting our way through that space. The intersection with policy, though, is very important. As an example, let’s look at recycling. The world, globally, plans to have about two-thirds of its vehicles electrified by either 2035 or 2040, so around that time we would need to be producing on the order of 10 million tonnes of batteries and battery materials every year. To put that in perspective, global production of silicon is 8 million tonnes, and aluminium is 63 million tonnes, so unless battery technology changes rapidly, we’ll be using a substantial fraction of the world’s nickel just for automobiles.

That clearly has huge ramifications in everything from geopolitics to recycling, and it’s quite clear that if you fail to get that stuff right, you will stall. At the moment, we’re struggling because battery manufacturers are sourcing cobalt from mines in the Congo and this is simply not acceptable. There’s cobalt elsewhere, and we need to get it from elsewhere and/or reduce the amount of cobalt being used in batteries. That’s a technology change, and it could be done, but it’s also a perfect example of how you could go wrong if you fail to consider things on a global scale.

There’s also a strong intersection of technology with local policy. In urbanized countries like the UK, people worry about charging electric cars; there’s a complaint that even fast charging takes 30 minutes and that’s much longer than fuelling up your car at a petrol station. But charging isn’t very difficult, and if you talk to people who own electric vehicles, they’ll tell you that the number of times they fast-charge tends to be very small. Consequently, they get used to the idea that they never visit a petrol station, and they find the fact that they used to have to go and fill up a tank every week kind of annoying.

There is, however, an infrastructure issue associated with integrating vehicles onto the electrical grid, and in the UK there’s also talk of adding another 30 GW of offshore wind to generation capacity. That will be a pretty straightforward thing to do; at least in principle, we know how to do that. The problem is that is if you’re getting 50 or 60% of the UK’s electricity coming from wind, you need to change the storage integration to make it worthwhile. At the moment, the way we incentivize wind producers to produce wind energy is by paying them even if they’ve got their turbines turned off, rather than giving them an incentive to generate more energy and store the extra electrons. So there’s many aspects where policy and regulation will need to play together with the technologies, and it’s important to ensure that those who make the decisions are getting the right kind of advice – by which I mean advice on what the system is going to look like in the long term, not just the next few years.

When will we see the impact of the Faraday Institution’s research in the commercial sphere?

We’re really targeting impacts on the five- to ten-year time scale, especially for new technologies like solid-state batteries. Even if you were to have a prototype now that you believed you could scale up, it would be several years before it could be in a vehicle. But I think other things might have a subtle impact much earlier. Better battery-management systems, for example, could make an impact just by helping your battery last 10% longer. I also think we’ll have a major impact in terms of people. We really want to train a new generation of scientists and engineers – electrochemists, electrical engineers, material scientists, physicists, mathematicians and computer scientists. We need people who have some understanding across that whole space, while also having sharp experience in one area. There’s a global shortage of battery scientists right at the moment, so anybody reading this should go check job ads.

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