NOTE: This interview is also available as a video

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Please introduce ‘repowering?’

Power stations are capital-intensive investments, and they've been reused before. They've been reused often to convert to gas. They've been converted for energy for waste and for biomass, and what we're saying is: add a few more ideas.

Add nuclear, add advanced geothermal, add thermal storage, and suddenly these assets have lots of options, lots of outs, lots of pathways forward. What we're doing s adding more options.

The problem is it's a question of speed, and we need to transition as fast as possible to avoid tipping points. If you reuse infrastructure rather than rebuild it from scratch, you're going to save time and you're going to save money.

Where did the repowering idea come from?

This came out of my interest in nuclear power, where I sat down with an old friend and we were talking about high-temperature reactors. And he said, “I remember, a high-temperature reactor has a special attribute that it can meet the steam temperature that coal stations need.” They're like a drop-in solution, which is an overly simplistic way of looking at it.

 But that was the original idea – “Is it the case that you could engineer a reactor to be exactly the right attributes of a coal boiler?”  Then the idea that you can just literally plug and play and replace is possible. In the journey we've been on since then, obviously, it's a lot more complicated. But it's still true that in the 1950sin the UK, when we were working on our AGRs, our gas-cooled reactors, they were engineered to be the same size and same spec as the coal units, because back then, the UK engineers believed that they would switch out coal for nuclear. Even in the 1950s that was being thought about. This is a modern take on that question.

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How has repowering developed?

So clearly energy is such an underpinning force for development. For humans to thrive, we need access to energy. We've done that in various ways over the centuries. Our current way is through fossil fuels. The problem with that, of course, is it has lots of environmental issues associated with it, whether it's local air quality or climate change. Finding a way to get beyond fossil fuels and stop burning things is one of the biggest challenges that we face. It's probably going to take the best part of a century to achieve.

The question is, can we do it in time to stave off something like a tipping point that makes it really hard for humans to thrive? And so, speed matters. When it comes to thinking about the transition, what we've been doing so far is putting new cleaner forms of energy into the system, but it hasn't quite worked in terms of getting the existing sources of energy to turn off.

There's still a huge amount of reliance on fossil fuels to create electricity around the world, particularly in Asia, where they built their stations later and have many of them operating today. The repowering concept is to say, what could we do at the site of those thermal power stations that would help speed up the transition to clean energy? 

The original animating idea was, "What about nuclear?", because essentially, nuclear has a lot of the same characteristics as coal. The unit sizes are similar, they produce steam, which turns a turbine, provides power. What if you could take the coal boilers away and put nuclear reactors in place? That was the first thought we had, and we started with that idea. Since then, we've realized that actually there's many ways in which this could be done, and perhaps the biggest difference from just building renewables is that this is going to involve and engage the current owners of these assets. Instead of them feeling like the transition is something that's happening to them, that they should stop and try and hold back or delay, they're part of the transition. You're turning a coal asset owner into someone who feels like they have a future, that they can contribute to this transition, and by giving them technologies they can integrate into their plants to pull down the coal burn and clean up their operations, that's at the essence of repowering.

That involves also the reusing of lots of assets, including the transport infrastructure, the grid infrastructure, the licensing, and the workforce. All of that can be reused, and reusing is always a good thing.

What have you discovered through this journey?

So I think one of the things I've realized perhaps as we've gone on this journey is that there's a huge role to play with storage and the ability to take electrons and turn them, hold them, and store them, whether it's in the form of batteries, but actually now in the form of heat. Once you have a heat store on your power station, it becomes a much more flexible option.

It's a bit technical, but essentially what you're saying is instead of just spinning and generating, without being able to store your electricity, you're starting to build storage into your power station as a feature of the plant. That helps your operator to accommodate more variable renewables, but it also means that you have got the potential to add extra sources of power in to your station.

What has Repower achieved that you are the most proud of?

I'm really proud of the fact that we've assembled a really great team of partners. We've found really great academic partners in different parts of the world.

 We've seen actual policy changes in Indonesia, for example. We've got fantastic research partners in China. The work we've done in Poland has become adopted as government policy, which has probably gone beyond all of our hopes and expectations.

 I'm really pleased that just from that first question of “Could this be done and why is no one doing it?”, we've now got this ecosystem of people - and it wasn't a new idea when we first asked this question. What's been lovely is we've just been bringing people together who are all thinking similarly, and now they're doing it together rather than individually.

The nice thing about hanging out with engineers is that they usually rise to a challenge.

They like a challenge because it forces them to think through and solve problems, and there's no bigger problem than how do we expand our access to affordable, secure energy? That's the challenge and not to cause environmental damage in the process. All these engineers are really engaged, and it's fantastic because just keeping something ticking over is not fun. Reinventing something is really fun. That's why you find all this energy and these great people that help you have hope.

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What motivates you to do what you do?

When I was working in wildlife conservation in the 1990s, we were writing new laws to protect species and ecosystems. One of the scientists we were engaging with in the government said, oh, well, we can protect all these things, but climate change is going to change everything, and this will mean that none of this works. I thought then, well, that seems curious.

If that's the case, I should probably look into climate change. From that point on, I realized that everything I cared about, not just nature, but humanity was imperiled, was at risk from this threat, that hardly enough attention was being paid to it. It was seen as a quirky thing that maybe we should care about, but not really.

Back then, it felt quite lonely, but now what's happened is it's become accepted and it's mainstream almost. But there's always something new to work on, there's always something new to discover. Because it's such a big challenge to get us off of our addiction to fossil fuels, there's always more you can learn. I like being on a steep learning curve.

I like always discovering new things. I like finding new solutions. This has been a really rich seam to mine in that sense of meeting fantastic people with great solutions.

What partnerships or innovations are needed to make repowering more common? 

So I think the biggest thing that we need to do is work with asset owners, and whether that's utilities or privately-owned merchant plant, to understand, to give them this new insight that their assets could have a future, and then work out with them what's going to work for them. I feel like for a long time we've been talking about the transition in terms of: “Switch off coal and they'll just go away”. But they're not going away.

 They're still here. They've been here for decades, and they're going to be here for decades more unless we engage in a conversation. So for me, asset owners are the big piece of the jigsaw puzzle that we need to engage with.

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What role do governments and policies play in making repowering projects successful?

One of the things that's been perhaps absent in a lot of liberalized markets is governments having an idea about what to do with their existing grid infrastructure and their existing assets. It's been very much left to the market. 

The developers come forward. They have their projects. They try and connect to the grid, and it's not been done with a top-down strategy of how could we do this most efficiently and what could we do with our existing assets? Governments are now slowly realizing that a purely market-driven thing might give you short-term answers that make sense, but in the long run it might be actually more inefficient. Governments need to still continue to have a strategy for energy.

Yes, liberalized markets are quite good at allocating capital, but they're not going to make decisions that perhaps are in the best interest of the country in the long term. We need a little bit more government thought about what's the most cost-efficient way of doing this so that the public is not paying more than it needs to for its transition. 

What kind of incentives or subsidies exist to support repowering efforts? 

The reason this hasn't perhaps become more common is because this concept is not often found in the models that are used to think about energy system transition. The government policies don't really see this. It's not visible. There might be public subsidy for renewables. There might be capacity market payments for existing plant, but this combination of siting clean sources on the site of existing assets hasn't been given a particular policy lift. It hasn't really taken off in the way that it might have done.

If it has happened, it's been because of enlightened asset owners realizing they wanted to make use of their site. I would say that it's suffering from not being thought of, not being included in the modelling, and it needs more attention.

What else should be known about repowering?

One of the features of a modern energy system is that grids are really important. We have a situation in many countries where we have grid systems that work, but we're going to need a lot more grid. If we throw away the existing grid system and start everything from scratch, it's going to slow everything down and be very expensive.

Reusing our grid infrastructure and making sure that we don't waste what we have is fundamental to keeping costs low and keeping the thing happening faster than it would otherwise. For me, one of the most important things I've taken from this is that “reuse your grid infrastructure” is a good message. 

What is your message to the world?

There's always hope.

 This is a century-long transition. We're maybe 30, 40 years into it? We still have a long way to go, and it's a complex system. We don't know how badly we've upset the system. We don't know quite what the risk is, but the only way forward is to keep moving and to keep improving the situation, which is what is happening. We haven't bent the curve in emissions yet, but we can see a way to doing that. If we can get coal off the system faster, replace it with clean, reuse the infrastructure we can, we'll get there faster.

Ultimately, it's a pro-humanity message that we have inventiveness. We're naturally inquisitive. We take the world, and we shape it. That's what we've always done. We can't unravel that. We cannot go back. We can only go forward. We need to go forward with new insights, more information about what we're doing, and our ingenuity will find solutions.

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