First published July 22, 2019.
keithjardine/iStock
Between January and June 2019, Scotland's wind farms generated 9,831,320 megawatt-hours of electricity, a record for a half-year. According to WeatherEnergy data highlighted by WWF Scotland, that was enough to cover the electricity use of about 4.47 million average homes over the same six months. Scotland has roughly 2.5 million households, so wind alone produced about 1.8 times what Scottish homes consumed, with the surplus equal to a large share of the homes in northern England.
Headlines at the time said Scotland could "power two Scotlands". That makes a nice slogan, but it is not quite what the figures say. Here is what the record meant, what it did not mean, and how the story has developed since.
What the 2019 numbers actually show
The analysis compared the total electricity generated by Scottish wind farms over six months with the typical consumption of a household in the same period. Dividing one by the other gives the "homes powered" figure. WWF Scotland's Robin Parker called the results "amazing figures" and said they showed how much onshore wind could deliver.
Three caveats matter:
- Homes are only part of demand. Households use roughly a third of the electricity in Britain. Offices, factories, hospitals, railways and street lights use the rest. Wind generated far more than domestic demand, but less than everything the country consumed.
- It is a total, not a guarantee every hour. On still days output falls sharply, and the grid has to draw on other sources and on imports through the British network.
- It says nothing about land area. "Enough for a country twice its size" is a misreading. The comparison is about household electricity use, not territory.
Megawatt-hours versus megawatts
Energy stories often mix up two units. A megawatt (MW) measures power, the rate at which a turbine or wind farm can produce electricity at a given moment. A megawatt-hour (MWh) measures energy, the amount actually generated over time. A 1 MW turbine running flat out for one hour produces 1 MWh.
At the end of 2018 Scotland had about 8.4 gigawatts (8,423 MW) of onshore and offshore wind capacity. Turbines rarely run at full power, because the wind varies, so the ratio between what they produce and what they could produce, the capacity factor, is typically 25–40% onshore and higher offshore. Windy months such as the winter and early spring of 2019 push that figure up, which is one reason the first half of the year set a record.
A single month gives a sense of scale: in October 2018, WWF Scotland reported that wind generated the equivalent of 98% of Scotland's entire electricity demand, and on 16 of that month's 31 days wind output exceeded demand.
Why Scotland is so suited to wind
Scotland sits on the path of Atlantic weather systems and has some of the strongest, most consistent winds in Europe. It also has large areas of upland and a long, shallow coastline, both good locations for turbines. Whitelee, south of Glasgow, is the UK's largest onshore wind farm, with 215 turbines and a capacity of 539 MW.
Scotland has also pioneered new technology. Hywind Scotland, off Peterhead, became the world's first floating offshore wind farm when it started generating in October 2017. Floating turbines are anchored to the seabed by cables rather than fixed foundations, which opens up deeper waters. Since 2019 several very large offshore projects have come online, including Beatrice (588 MW), Moray East (950 MW) and Seagreen (1,075 MW).
A coal-free week for Britain
Scotland's record arrived during a broader shift across the UK grid. In May 2019 Britain ran without any coal-fired electricity for about a week, around 167 consecutive hours, according to the National Grid. It was the longest coal-free stretch since the 1880s, made possible by gas, nuclear, wind, solar and imports.
At the time the UK government aimed to close all coal power by 2025. It got there early: Ratcliffe-on-Soar in Nottinghamshire, the last coal-fired power station in the UK, stopped generating on 30 September 2024, ending more than 140 years of coal-powered electricity. Scotland's own last coal plant, Longannet, had already closed in 2016.
Did Scotland hit its 100% renewables target?
Some articles in 2019 claimed Scotland would soon get "all of its energy" from renewables. The real target was narrower: renewable sources should generate the equivalent of 100% of Scotland's gross electricity consumption in 2020. Heating and transport, which make up most of the energy a country uses, were not included.
Renewables reached 97.4% of Scotland's electricity consumption in 2020, just short of the goal, with wind supplying most of it. By 2022 renewable generation equalled about 113% of consumption, and wind alone made up around 55% of all electricity generated in Scotland. The Scottish Government has since set further goals, including 11 GW of offshore wind by 2030.
Common myths about wind power
- "When the wind stops, the lights go out." Grids balance many sources and interconnectors. Variability is a real engineering challenge, and grid operators plan for it with reserve plants, storage, demand response and links to other countries.
- "Turbines never pay back the energy used to build them." Life-cycle studies generally find a modern wind turbine repays the energy used in its manufacture and installation within months to about a year of operation.
- "Exporting power means Scotland doesn't need it." Surplus electricity flows into the wider British grid, and on calm days power flows back. Grid constraints sometimes force turbines to switch off, which is why new transmission lines are being built.
The 2019 record was a milestone rather than a finish line. It showed that wind could do far more than its critics expected, and the years since have turned that early half-year headline into a lasting change in how Scotland makes its electricity.
Sources: Yale Environment 360, July 2019; World Economic Forum, July 2019; edie, November 2018: wind delivered 98% of Scotland's electricity demand; Wikipedia: Wind power in Scotland; Wikipedia: Ratcliffe-on-Soar power station; data: WeatherEnergy and WWF Scotland; photo: keithjardine/iStock.
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