Can SMRs remedy our nuclear energy shortfall?

There’s been a flurry of investment recently by US tech giants into small modular reactors, or SMRs, as it becomes apparent solar and wind initiatives aren’t going to be sufficient for the energy hungry AI data centres they’re building.

As the name suggests, SMRs are designed to harness the power of nuclear energy, but in reactors a fraction of the size, meaning they can be constructed at lower cost, in more convenient locations, in a shorter time frame. So, are they the answer to Big Tech’s huge appetite for clean energy? Malcolm Grimston who is a senior research fellow at the Centre for Energy Policy and Technology at Imperial College London. Malcolm is an expert on nuclear power…

Malcolm - He's certainly quite right to note that we haven't got any running examples at the moment. On the other hand, there is an enormous amount of interest right the way across the nuclear world in small modular reactors at the moment. There are research projects going on in China, UK, the US, elsewhere in Europe, and so on. Driven, I think, by a recognition that large scale nuclear still very much has a part to play. When you've got a big grid with central point sources of generation, then 1500 megawatts or whatever the size of a big nuclear reactor still makes a great deal of sense. But there are also circumstances in which you're going to want smaller, more flexible units. Countries whose grids are not as developed as yet, for example. Reactors that are a little bit more able to follow load, to switch on and off - with a big reactor, you can load follow with it, but it's not very economically attractive - with smaller reactors, if you've got a station made up of 5 or 10 separate units, then at times of low demand over the summer in the Northern hemisphere, you can switch them off and so the economics are improved in that sort of way.

Chris - Do you think people will switch them off or will they say, well, this is a bit of a cash cow. It's quite cheap to run, it's got no carbon footprint. I'm just going to run it flat out all the time and make as much money as I can?

Malcolm - It very much depends on what else is going on in your electricity system. If you have a system which is based on dispatchable capacity, so you can switch it on and off as you need it, and we're really talking in the modern world about gas although in many countries coal continues to play that role, then in those circumstances, yes, the fact that nuclear power stations are relatively expensive to build and relatively cheap to run compared to fossil fuels means you would run them all the time. The interesting question, of course, is in those countries which are increasingly dependent on variable renewables. Where the demand, for example, as we've seen in the last few weeks in Europe can vary enormously in those circumstances, you need something that can ratchet its output up and down depending on what's coming out of the renewables at any particular time.

Chris - Some people say, well, look, we know how much nuclear costs, and we know how much we're going to have to invest in a technology we don't have yet. Batteries are here and they're here now and they're getting cheaper all the time and they're getting better all the time. Why don't we spend the money on a battery instead?

Malcolm - Bearing in mind that with batteries you've got two issues. There's the output of the battery, so you need to be able to match megawatt for megawatt, gigawatt for gigawatt, whatever it is that you are trying to replace at any moment. But there's also the capacity. If you have a period of two or three weeks without wind, which we see on a number of occasions in Europe, it's no good having several gigawatts of battery capacity if they've all run flat. You can get somewhere with batteries. The world is nowhere close to battery technology yet. 99% of storage is still done with pumped hydro storage in the world. There's no single silver bullet with this. We're going to see a lot of things working together, but I think imagining that batteries are anywhere close to answering the sort of questions of the intermittency of renewables at the moment is, I think, simply not the case.

Chris - What then is the vision for how we would deploy the next generation of nuclear in the UK?

Malcolm - It may well be a mixture. We have, of course, Hinkley Point C being built at the moment, and the likelihood of other stations. That's 3.3 gigawatts. It's big. On its own, it will generate about 7% of UK electricity. Replacing the large plants that have started to come off to the end of their lives recently, and will be pretty much gone by the early 2030s, that's the main thing. In terms of small modular reactors, you can put them closer to cities, probably, on safety grounds. That means that your distribution network doesn't have to be as big. There'll be a number of industrial processes. It's interesting to the IT industry where there are very large demands of electricity where an SMR would be pretty much ideal on the assumption that they can be built to time and cost, and so there are some developing niche areas of very high demand.

Initially, I think we'll see those sorts of developments. Beyond that, of course, they can end up just fitting into a grid like any other development. We call them SMRs as if these are something magical and new, but actually the Magnox plants in the UK, the first generation nuclear plants, the earlier ones of those, up to about 350 megawatts fit into the bracket that would have them defined as smaller reactors today. The other big point, of course, is that you move away from a system where you build nuclear reactors as a construction project and far more towards assembling nuclear reactors as a manufacturing process, and this should allow far greater economies of scale. The supply chain should settle down without having to make quite significant changes depending on the particular requirements of a reactor site.

Chris - The case sounds quite compelling, but there seems to be enormous inertia somewhere in the system. We've heard industry leaders, we'll hear from Rolls-Royce a bit later who are saying, or have said, that they've got concepts. They want to see progress. Other countries appear to be going ahead. The UK appears to be sitting on its laurels a bit. What's the reason for that? What's dragging things back?

Malcolm - The idea of a merchant nuclear plant, of building a nuclear plant and then hoping that you've got a market at the end of it that's going to make a profit, is really pretty much a non-starter. You need to have very strong guarantees about something along the way, either managing the cost of the project, that risk being shared, or guaranteed markets into the future. Only governments can make that sort of guarantee because a market as a whole tends to be much more focused on the short term. Government involvement is required certainly at the research and development and deployment stage, probably ongoing into the market. The UK has always been rather ambivalent about this. On the one hand it says, this is a competitive market, it's up to industry to decide, but on the other hand it then intervenes in all sorts of ways in that market to push things in the right direction. It is the sort of thing that can often be difficult in a democracy because the benefits of this will probably accrue to the government after, or maybe the government after the government after the one that's actually taking the decision and putting the money up. When that competition is with putting more money into the health service or benefits or whatever it happens to be… That's been a British disease in all infrastructure: that we lost that great ability that the Victorians had of thinking long term and making investments in infrastructure which would then pay off over decades to come. But if people hadn't been doing that for us back in the great days of the railways or the power stations that were built in the 60's or 70's, then we'd be in a much worse state. I think we owe that to the future that we provide for them in the way that previous generations have provided for us.