McCrone Report: Why is Scotland so energy rich in renewables?

But what’s the science behind that?

Why is Scotland such a rich location for green energy, particularly in comparison to the rest of the UK? The National spoke to engineering and energy expert Professor Gareth Harrison from the University of Edinburgh to dig into why Scotland is a “sweet spot” for renewables.

When asked how he would describe Scotland’s renewable potential in one word, Professor Gareth Harrison came straight out with “enormous”.

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“We have more than we could possibly use if we are prepared to exploit it and there’s been more political will up here [than in the rest of the UK] I think, to get on with it [renewables] and accept facts,” he said.

The deputy head of the school of engineering at the University of Edinburgh explained it all comes down to the country being in a perfect location geographically, with its wet and windy weather and a great variety of terrain creating the ideal conditions for renewable energy to thrive.

Scotland sits in the middle of the storm track across the Atlantic, and Harrison explained why this gives the country great promise in green energy.

“Virtually every single storm that comes out of the Western Atlantic comes screaming over Scotland,” said the professor, who was involved in a report produced by the Royal Society of Edinburgh in 2019 documenting where Scotland was at with different energy technologies.

“This drives virtually everything. I think it’s reasonable to say Scotland is the windiest country in Europe and has among the biggest waves.

“You get storms that originate in the West Atlantic which come across and get hit by strong winds from the north, south or often the south-west. It’s the balance of those and the speed that determines how windy, wet or sunny it is, and that drives most of the renewable potential.

“It shares a lot of that [weather conditions] with Ireland but Scotland is sufficiently far north that it’s in the sweet spot for getting the right sort of weather for renewables.”

Wind

A large part of Scotland’s potential lies in wind energy and Harrison explained that, as well as being a significantly windier country than England, the country’s population density and range of terrain mean it lends itself hugely well to renewables.

“Some of Scotland is very hilly and these are not great places for building wind farms but quite a lot is rolling hills which is pretty good for wind farms. Some of Scotland is pretty flat, and these places are excellent for them,” said Harrison, who is also the university’s Bert Whittington Chair of Electrical Power Engineering.

“Then if you’ve got sea there, it’s an incredible place to build wind farms as long as you’re not behind a mountain.

Beatrice Offshore Wind Farm in the Moray Firth (Image: -)

“Scotland’s territorial waters are large so you’ve got a sparsely populated country and a lot of resources. That’s the main reason why it’s good because, compared to how many people live here, it has a vast amount of resources.

“The reason people started building wind farms in Scotland and not in London is that its resources are better. For the same wind turbine, you get more energy [in Scotland], so actually it costs less. The wind is stronger here and in many respects there are fewer obstacles. Scotland is a relatively smooth and flowing place.

“As you go further north and west across the UK, it generally gets windier. England does get good wind but it’s much larger. Per head of population, there’s less wind.”

Wave

Strong winds in Scotland mean big waves. Wave energy is one of the more tricky forms of renewable energy to manage, but Harrison said if any country has the resources for it, it’s Scotland. Some of the largest waves in the North Atlantic come crashing on to the Scottish coast and Harrison said he hopes Scotland can find ways to use that potential.

He said: “The fact the continental shelf is relatively close to land means you get quite big waves coming fairly close to land before they get tripped up. We have a very significant proportion of Europe’s wave potential.

“The reason you don’t see many wave devices out is that it’s a good bit behind wind. There were a lot of political shenanigans with developing the wave programme in the 1970s and 80s. It’s difficult to manage because wave is enormously powerful.

"If you imagine a metre’s worth of wave coming to you, it can have 1MW of power, the equivalent of about 400 kettles boiling. So you’ve got to design things that can cope and not get washed away in some of the big waves. But if anywhere is going to do it and has the resources to do wave, it’s here, Scotland just has to persist with it.”

Tidal

Scotland also has large potential for using tidal stream energy – where electrical generators are installed directly into the tidal stream with no requirement for a wall to obstruct the flow, like a barrage.

Harrison explained: “If you think about a map of Scotland, you’ve got the North Atlantic on the west and the North Sea on the east and a relatively narrow bit towards the top. Basically, if you imagine the tide as a very long wave coming round, one of the things that happens with waves is they get tripped up, and you end up with big differences in timing between the west and the east and when you get that timing difference, you get very large flows of water.

Turbines off the uninhabited island of Stroma is the world’s largest tidal energy farm (Image: -)

"So places where you’ve got obstructions, or channels or headlands, you tend to get fast flows of water. So, for example, the Pentland Firth – my late colleague Iain Brydon called it the Saudi Arabia of marine energy.

“You get that constriction there that forces the water through the narrow channel and it means the speeds of the water go up. A big advantage of tidal energy is that it’s predictable.”

Hydro

Scotland has made use of hydro power since the turn of the 20th century, with several schemes operating across the country. It played a vital role in connecting vast swathes of rural Scotland to the grid.

Harrison explained a combination of the storms that come over Scotland and the country’s hills make certain spots perfect for this energy source. “To produce hydro power, you need water dropping from a height,” he said.

Pitlochry hydro station and dam (Image: -)

“These storms bring rain and the structure of Scotland means you’ve got big hills in the middle and you get a significant rain shadow effect. You get very warm, moist air coming in, it goes up, it cools, forms clouds and then buckets and most of that lands over the hills. Some of it goes to the west and some to the east, and that’s why you have a lot of hydro power built in areas north of Perth.

“It comes back to geography. You have a lot of water being dumped and the right sort of hills in the right place. Scotland is pretty fortunate. And one of the things about hydro is it is controllable. If you’ve got a dam with a valve, you can control it.”

Solar

Scotland is not famous for sun but that doesn’t mean it has no potential for solar energy. Harrison highlighted how Scotland’s cloudy and mild weather is actually beneficial to solar and is an important part of the renewable mix, given it often provides power when other sources are unavailable.

He added: “Although it is cloudy here, we do get some days which are crystal clear and that’s very good for solar, and it’s not too hot generally.

“When a panel gets very warm, its efficiency drops, so if you compared a panel in the same sunlight here [Scotland] to the south of England, you’ll find we’re more efficient, so that’s an advantage. If it’s light cloud, solar performs quite well. It’s a good part of the mix.”