Emily Elias: We usually don’t get the wind included in our weather reports unless it’s, you know, pretty extreme. But, keeping track of our windy days is pretty important for folks who are trying to harness it as a power source. The question of how windy it is becomes very important when you’re about to invest millions and millions into wind farms. So on this episode of the Oxford Sparks Big Questions podcast, we’re asking, what is a wind drought? Hello, I’m Emily Elias, and this is the show where we seek out the brightest minds at the University of Oxford and we ask them the big questions. And for this one we have found a researcher who loves windy days probably more than sunny ones.

Matthew Wright: Hi, I’m Matthew Wright, and I’m a PhD student in the physics department in Oxford. I’m part of the atmospheric physics part of the department looking at weather and climate physics.

Emily: Do you mind if we just kind of start with breaking down some definitions? We’re going to be talking about wind today and wind droughts. What is a drought when it comes to wind?

Matthew: Absolutely. I think when you first hear the term ‘wind drought’, it’s not two words that you expect to see together, but it’s almost what you would expect, I think. So a, wind drought is when you have a prolonged period without very much wind. So we might have very still conditions and it’s not very windy.

Emily: How do you measure the wind?

Matthew: We have a couple of different ways. We have weather stations which are, located all over the country and they have a device which will be blown by the wind and it almost spins round on the little stick and the speed at which that stick spins around tells us the speed of the wind. So that’s the way that we can measure it directly. And a lot of those will be at, places like airports or other weather stations across the country. And the other really important tool that we use, our, weather forecasting models. So we put all the observations into those weather forecasting models and that can help us estimate what the wind might be somewhere where we don’t have a direct observation.

Emily: Can you give me an example of like what a wind drought is?

Matthew: It’s not something that you’ll generally see on the news or in the weather forecast because it doesn’t really impact people’s day to day lives, it impacts people working in the energy sector. So there’s actually, a good example from last year in late November and early December in 2023 where we had a week long wind drought over the UK and what that was really low wind speeds 40% lower than we would expect for that time of year. And that was bad in itself. But at the same time as we had these really low wind speeds, we had a simultaneous cold snap. So the energy demand across the country was 15 to 20% higher than we would’ve expected. So we had this really low wind power, really high energy demand. And if you put those two things together, that’s a big problem for the electricity system. And it resulted in the gas prices increasing quite a lot throughout that period. So that’s one example from last year. And also we have had Quite a still 2024 so far. So SSE, who are one of the major operators of wind farms in this country, released their report for the summer and they’ve produced a third less renewable energy, quite a lot of which is wind power than they expected this year. So that’s an example then of a longer wind drought, which has maybe been over four or five months, with less wind power generated over the summer than we might expect.

Emily: Oh, that’s not good.

Matthew: No. But again, not the kind of thing that you hear about in the news very much, which is quite interesting. And so what we’re trying to do to put this into the public domain a little bit more and at least get people in the weather and climate and energy communities talking about wind droughts and the way in which weather affects the energy sector is along with colleagues from the University of Newcastle and the University of Reading and a wider group of people from across the energy sector, we’ve produced a report which looks back at, last year at 2023, and looks at all the different ways that weather impacted the energy system. So wind droughts are a big part of that. Ah, but we’re also interested in storms, heat waves and other weather conditions that impact the energy system. And that’s being released very soon and hopefully helps people to think about these problems a little bit more, learn from past experiences and, just get people talking about how weather impacts the electricity system a bit more.

Emily: Yeah, because you often hear about, like, sunny days, not sunny days, cloud cover. But wind is something they don’t necessarily think about.

Matthew: And it’s only going to get more and more important as we have these very ambitious targets to build lots of wind farms. It’s only going to get more relevant.

Emily: So is there a way that you’re able to predict what’s going to happen in the future for people who are making these big decisions, like where we’re going to build a wind farm or how much energy we need to balance off with like our wind turbines and all that sort of thing.

Matthew: Yes. So the predictability is really important and that’s something that I’ve been working on and lots of other researchers across the UK and across the world are, looking at, at the moment. And I think I would probably break this into two different aspects. The first one is about wind energy now. So that’s predicting how much energy is going to be produced by our wind farms tomorrow, next week, across the next season. And that’s really important for people like the National Grid to make sure that we are supplying enough electricity to meet the electricity demand in this country. So that’s really important. And that uses weather forecasting models that I mentioned previously. And the other aspect is about future planning and where we should build wind farms in the future. And to do this we have to use a, modelling approach. We have to use climate models. And we will look at things like how variable the wind speed might be in a particular location, what the probability of wind droughts is, what we might expect the average wind speed to be, and how we might expect that to change over the, over the next few years. So there’s lots of different aspects and climate models can help with some of those decisions where people should build wind farms.

Emily: There’s probably a lot of stuff that you know about wind and how it’s measured and how it’s being tracked. But what are the things that you don’t know?

Matthew: I think the main drawbacks that we have are to do with how good our models are. So I mentioned that we use observations and these act as the inputs into our weather models and our climate models. And there’s actually not that many observations, right? We have, we have quite a few weather stations. But compare if you think about the whole world that we’re modelling, in our weather and climate models, there’s relatively few observations and they all tend to be at, the ground level and often they’re in urban areas. And so it’s really difficult for us to have a complete picture of what the wind or the weather is doing across the world at any given time. And so a lot of what we try and do is fill in the gaps using our, weather and our climate models. So making sure that the physics that’s in these models is correct, making sure that we have a really good spatial and temporal resolution. So that means making sure that we can give forecasts which are very localized to a specific location and also forecasts which update, very frequently. So maybe every 10 or 15 minutes would be really good for wind farm forecasting. So basically, using those observations and improving our models and finding better ways to use those observations are how we’re trying to fill these gaps. And I think maybe the other thing to mention – our observational record doesn’t go back that far. So in the best cases, we have a few observations that might go back 150 years or something like that. But in a lot of cases, many weather stations have only been operational for 40 or 50 years, maybe. So if we’re thinking about building wind farms which will be operational for 30, 40, 50 or more years, we want to know how variable the wind is in that location. So how likely is it that we have a year where there’s not very much wind at that wind farm? And, because we don’t have data going back very far, it can sometimes be quite difficult to work out how the wind will vary on the decadal timescale over the lifetime of these wind farms.

Emily: Looking at the future, what difference could this make in making sure that we have clean, beautiful wind energy to power our homes and to make a sustainable energy grid?

Matthew: That, for me, is what is the most important part of our research, how we can apply this to make a difference in the future and lead to, clean energy that doesn’t have very high carbon emissions. And I think there’s a few aspects here. So firstly, if we can find out more about the frequency and intensity of these wind droughts, it really helps us plan that energy system of the future. So it can tell us where we should put our wind farms. It can also tell us how much storage, how much energy storage, we might need in our future energy system. So these types of storage might be big batteries, it might be pumped hydro storage, which means pumping water up a hill when we have loads of energy, and then when we need to release that energy, letting the water run down the hill and converting that energy back to electricity. So it can really help us plan the energy system of the future. The second thing that people are working on, and it’s really important to understand, is about the geographical extent of these wind droughts. So we’ve talked a lot about the UK today, but obviously this is something which affects the whole of Europe and increasingly the whole world. As more and more wind farms are built in lots of different countries, it’s a bigger issue. Especially if you think about somewhere like Europe, where all of their electricity grids are connected together, it’s a much bigger issue if a wind drought hits lots of countries at the same time. So understanding where wind droughts might occur together, and then designing the connections between different countries’ electricity grids will be really helpful as well. And I think the key thing, really, is if we can predict these wind droughts and build wind farms in the right places, this means that we can reduce the use of fossil fuels to produce electricity, reducing our CO2 emissions and, leading to this really nice clean energy system.

Emily: Wouldn’t that be just a beautiful thing?

Matthew: Yes, absolutely.

Emily: This podcast was brought to you by Oxford Sparks from the University of Oxford, with music by John Lyons and a special thanks to Matthew Wright. Please tell us what you think about this podcast, or if you have a big question, get in touch. We are, @OxfordSparks. Or check out our website, oxfordsparks.ox.ac.uk. I’m Emily Elias. Bye for now.