The ultimate guide to wind turbines and how they work
By Matt Mostyn Friday 16 October 2020
You’ve probably noticed wind turbines popping up with more and more regularity across the UK. Right now there are now around 8,600 of them on land, and 2,300 dotted around our seas – and in 2019 they generated nearly 20% of our electricity1.
There’s no doubt about it – wind turbines are transforming the face of renewable energy just as much as they’re changing our landscape. And whether you admire their futuristic beauty, or you’re rather less of a fan, there’s no denying that they’re an intriguing feat of engineering.
So let’s find out more about these towering propellor-topped giants and their role in creating the sustainable energy system of the future.
So what exactly are wind turbines?
In a nutshell, wind turbines turn energy created from the wind into clean electricity for our homes. It sounds simple, right – yet there are some complex mechanisms at work to turn even a gentle breeze into the power that fuels our lives. But before we get into that, let’s take a look at the main types of wind turbines in use today.
Types of wind turbines
There are 2 major types of wind turbines in operation around the UK. The first is a horizontal-axis wind turbine, and this is the one you’ll see most of. With 3 huge rotor blades that form the turbine, its blades also pivot to face into the wind.
The other type is called a vertical-axis wind turbine, and it comes in several different designs. But what they all have in common is a different blade design from the horizontal axis-type – which often looks a bit like an eggbeater. These turbines are ‘omnidirectional’ – which means that they don’t need to be adjusted to point into the wind.
How do wind turbines work?
Essentially, a wind turbine’s blades turn when the wind blows, driving a turbine which then generates electricity. To help catch the breeze, turbines also have a sensor, which detects the direction of the strongest wind.
The giant blades can measure as much as 230 feet in diameter – and they have a distinctive curved shape, which is specially designed to catch the wind.
The spinning motion turns a shaft in the box-like structure (called the ‘nacelle’) at the top of the turbine. Inside the nacelle is a generator, which then converts the kinetic energy of the turning shaft into electrical energy. And voila, that energy passes through a transformer, which converts the voltage before it’s exported for use by the National Grid.
How much electricity can a wind turbine create?
Most onshore wind turbines can produce as much as 6 million kilowatt hours (kwh) of electricity every year – which is enough to meet the demands of around 1,500 households2.
As a rule of thumb, the more the wind blows, the more electricity can be generated. If the wind blows twice as quickly, there's potentially 8 times as much energy available for a turbine to harvest. It’s why wind farms are generally put in places where there’s a steady, reliable amount of wind all year-round – usually either on top of a hill or by the coast.
On the other hand, if it’s too windy, the turbines will shut themselves down so they’re not damaged.
What if the wind doesn't blow?
The blades of most turbines will turn in wind speeds as slow as just 3-5 meters per second – otherwise known as a gentle breeze!
A wind turbine can also continue to turn even on a calm day. That’s because once it’s turning, it can take several hours to slow back down again. Of course, if there’s no wind at all, that’s a different story – but even a slight breeze can be enough to generate power.
Wind is also relatively predictable several days in advance. And that makes it much easier to plan ahead and still make enough power to meet expected demands.
The electricity generated from wind can also be stored in batteries and used when resources are running low – which makes it even less of an issue on days when wind is in short supply.
Advantages and disadvantages of wind turbines
Making green energy from the wind has all kinds of advantages – and there are also a couple of drawbacks. Here’s our rundown of the main pros and cons:
Advantages of wind turbines
Wind turbines generate green energy with no carbon footprint, which can help fight climate change.
Less burning of fossil fuels is also better for our health.
Wind energy is completely renewable. Unlike fossil fuels, wind will never run out.
It takes only 3-6 months to get back the energy used to build and install each turbine (from construction, operation, and recycling3) . After that, wind turbines can create clean energy for as long as 25 years.
Disadvantages of wind energy
Wind turbines do make some noise as the blades turn, but it’s minimal – and modern designs make far less noise than their older models.
There’s some controversy around whether turbines are a threat to wildlife (for instance, killing birds and bats) – but studies show it’s minimal.
In dead calm conditions (which are rare), wind energy can be intermittent.
How efficient is wind power?
A wind turbine is usually around 30-45% efficient – and that can go as high as 50% when the wind is at peak speed.
That figure may sound low – but it’s based on the fact that it’s impossible to capture 100% of the wind’s potential energy. For that to happen, the wind would completely drop after passing through the turbine. Which sounds as unlikely as it actually is!
UK-based wind turbines are able to produce electricity 70-80% of the time, making them a highly reliable source of power for our windy nation.
Why is the UK particularly well-suited to wind power?
Precisely because we live in a place that’s prone to high winds. In fact, Britain gets as much as 40% of Europe’s total wind – which is enough to power the country several times over.
Scotland is actually the windiest place in the whole of Europe, which is why so many of the UK’s wind farms are located there.
It also tends to be windiest here over winter – which means that wind turbines can produce more power at the time of the year when we’re using more electricity (for things like heating and lights).
How much of the UK’s electricity comes from wind power?
In 2019, just under 20% of the UK’s electricity was generated from wind power4. Yet just 6 years previously, only 7% of our electricity was created by wind5. So it’s no surprise that wind power capacity in the UK is growing fast.
Altogether, the UK’s wind farms currently produce enough power to meet the annual electricity demands of around 12 million homes6.
Wind energy is one of the most affordable sources of renewable energy – and the UK government recently announced the investment of even more in wind production.
It includes £160 million to upgrade ports and infrastructure to hugely increase our offshore wind capacity, as well as new targets for floating offshore wind to deliver 1GW of energy by 2030. That’s over 15 times the current volumes worldwide!
Improving wind energy storage
Because wind power is a fluctuating source of energy, renewable electricity can’t alway be made when it’s needed, or used when it’s made – so it can sometimes go to waste.
But if we can develop new ways of storing electricity produced on windy days for times when there's little or no wind, wind could play an even bigger role in the UK’s energy production.
Batteries are one solution, and developments in this area are currently underway. One such project is the installation of a huge wind-powered battery called BatWind in Scotland. Flywheels , which are low-friction wheels that store energy as they spin, are another potential game-changer.
Using fleets of electric cars as giant collective batteries is another option currently in development. Here at OVO, we work with partners like Kaluza, whose platform uses machine learning and AI to create a more flexible energy system. It can make use of wind-generated electricity by storing excess power in the batteries of electric vehicles – effectively turning them into storage devices.
With technology evolving all the time, new energy storage solutions are likely to make wind power even more effective at supplying our electricity needs.
To find out even more about wind energy, read our handy guide.
Wind power – the energy of the future
In early 2020, renewable energy (much of it from wind) provided almost a third of the UK's entire electricity.
In the future, it’s possible that Britain could become totally dependent on green energy. According to Renewable UK, the UK’s offshore wind capacity alone could give us as much as a third of our electricity by 20307.
With the government’s latest plans to make the UK a world leader in clean wind energy, wind power will likely play an increasingly important role in helping us slash carbon emissions, reduce our carbon footprint, and develop a source of sustainable power we can be proud of.
And it's not only wind power that's forging ahead. Read all about the future of hydroelectricity in our informative guide.
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