Green Services Direct

Will wind work for you? Or are they expensive follies?

Chances are wind is already powering your home, at least some of the time. For the first three months of 2023, wind was the biggest source of electricity in Britain. Wind power, from both onshore and offshore turbines, generated 33% of Britain’s electricity in that quarter – compared to gas-fired plants (31%), according to data from Drax Electric Insights. Wind overtaking gas is a major milestone to decarbonise Britain’s electricity.

The UK has been described as “the Saudi Arabia of wind energy.” Breezy conditions are enough to generate clean electricity to power millions of homes. “And the great thing is wind won’t run out. It will vary but it won’t run out as long as the sun keeps shining,” said Dave Vince of Ecocity.

But what if you want to cut out the middleman and install a turbine in your own home?  Will a tiny turbine reduce energy bills and help combat global warming? Or are mini windmills faddish eyesores only capable of powering a kettle or toaster, but not both at the same time?

How do wind turbines work?

When the wind blows, even just a gentle breeze, the blades spin, creating kinetic energy. This turns a shaft inside the turbine, which drives a generator and converts the kinetic energy of the spinning motion into electricity. The stronger the wind blows, the more electricity is produced.

Wind is a low carbon, renewable source of energy. Unlike solar energy, wind can be generated day and night. However, it is completely dependent upon the weather which is changeable. As a result, the government has said the UK will continue to use gas and nuclear to provide a more constant supply. This issue - common to all renewable technologies – can, however, also be tackled by battery storage.

Suitable locations

Before you install a wind turbine, you need to make sure it’s a suitable site with enough wind. The best starting point is to check out a wind speed database, such as www.rensmart.com/maps. Enter the postcode of the location you wish to site a wind turbine.

Wind turbines will generally operate between 7mph and 56mph, according to the National Grid. “The efficiency is usually maximised at about 18mph and they will reach maximum output at 27mph,” it advises. FuturEnergy, which installs domestic turbines, reckons wind speed above 5.5m per second at 10 metres is the minimum. A lower wind speed won’t generate enough electricity to justify the cost of installation.

Wind needs a clear path to the turbine. Obstacles such as trees and high buildings can cause turbulence and affect turbine performance. This means turbines won’t work in the average urban back garden. Wind turbines are only recommended for “rural, extra blustery areas with lots of unobstructed space,” says Ovo Energy. This is why solar panels remain the more popular choice for homeowners who want to go green, adds the energy supplier.

Roof-mounted or standalone turbines

Generally, there are two main types of domestic wind turbine:

• Roof mounted – these small wind turbines sit on your roof as solar panels would. Installing them on top of the building gives the best height advantage to harness any wind. These have a vertical axis and rotate in a horizontal plane. They’re generally smaller and cheaper to install than standalone turbines. But as they’re not as big, they tend to be less powerful, usually around 1-2kW in size.
• Pole mounted or standalone – these are the typical freestanding ‘windmill’ and by far the most common. They work best in a massive field, such as a windy hilltop or breezy coastline. These standalone turbines are bigger as they don’t need to fit on a rooftop. Generally, they’re around 5-6kW in size. They are also more expensive, but have a  better chance of powering your entire house than a roof-mounted system.

Will a turbine supply enough electricity?

The average UK household uses about 3,731kWh of electricity per year.  This could be produced by a 2kW turbine with good wind speed of 12m/s (12 metres per second), according to Tim Pullen, an expert in sustainable building methods and home energy. Writing in Homebuilding and Renovation, he said: “The maximum output of a 2kW turbine is – as the name suggests – 2kW, which is enough to run a kettle or toaster but not both, at the same time. And then only when the wind is blowing,” So, while a 2kW turbine can produce enough electricity to meet total annual consumption, it won’t be capable of supplying all the household demand at any one time. This can be partly overcome by a battery storage solution, but there will still be windless days when grid electricity is required, said Pullen.

What does a turbine cost?

The cost will vary depending on which type of turbine you buy, how big it is and who installs it. Expect to pay between £5,00o to £7,00o for an average 2kW turbine, including installation and connection to the grid. A battery storage system is likely to double the price.

Meanwhile a free-standing 5kW turbine may cost up to £25,000. But don’t forget you may also have to cover the cost of hiring planning consultants and environmental experts to obtain planning permission. This could bump up the bill to £30,00-plus.

At present, there are no national grants for wind turbines. There are some regional grants, but they tend to be for community schemes rather than single turbine projects.

Can I get paid for exporting energy from my wind turbine to the grid?

The Feed-in-Tariff scheme – which paid people with home energy generators -  unfortunately closed in 2018 to new entrants. But the government replaced this with the Smart Export Guarantee of SEG.  This rewards people for exporting any energy from renewable sources back to the National Grid. If you’re eligible you could get payments four times a year. To qualify, your system must be installed by a Microgeneration Certificate Scheme (MCS) registered installer. All energy companies with more than 150,000 customers are obliged to offer a SEG tariff, though rates vary.  Currently, Octopus Energy offers the best rate in the UK, paying 24p for every kWh you produce from wind or solar (prices correct June 2023).

Is planning permission needed for a single turbine?

Planning consent is likely to be needed. Rules vary throughout the UK. In England, planning permission may not be required for a roof-mounted turbine, if it meets a list of criteria, including:

• You have a detached house
• You’re only installing one turbine
• You don’t already have an air source heat pump installed. Otherwise, you need to seek planning permission.
• No part of the turbine, including blades, should be more than 3m above the height of your chimney or 15m above the ground
• The installation meets MCS standards
• A minimum of 5m needs to be between your turbine and the boundary of the property.

You might also be able to install a pole-mounted or standalone turbine if it meets the rules, including:

• The highest point of the wind turbine is no more than 11m tall
• You’re only installing one turbine
• It must adhere to MCS standards
• You don’t already have an air source heat pump installed  

All this comes under permitted development, but interpretation of the rules varies from area to area, so it’s essential to check with your local planning authority. If your house is a listed building or you live in a conservation area or heritage site, permitted development rights are limited.

Full government planning guidance for renewable technologies in England can be found here https://www.legislation.gov.uk/uksi/2011/2056/made

In Scotland, building-mounted turbines always need planning permission although a standalone may not. If it’s the only mast on the site, not on a heritage site or near a listed building and at least 100m from a neighbouring property, then it may not need planning consent.

In Wales and Northern Ireland, the rules are simpler: planning permission is always needed.

So, are domestic wind turbines worth it?

Wind power in the UK is a fantastic resource and the fastest growing clean energy. But installing your own wind turbine isn’t cheap or easy. Planning consent is likely to be needed, neighbours will probably object and you will need deep pockets. Before you take the plunge, the first crucial step is to establish whether you have a suitable site with good wind speed and free from obstructions. Only then is it worth investigating further.