The complete guide to wind energy

Wind energy is the most widely available and most widely used renewable energy source in Northern Ireland. In this complete guide to wind energy, we’ll explore the basics of wind energy. We’re also going to look at how you can embrace this clean, green and sustainable energy source to make the most of it.

Wind energy explained 

What is wind energy?
Wind energy is when the power of the wind is harnessed to generate electricity. Since wind is a natural source of energy that is available in limitless supply, it creates renewable energy. Wind energy is actually a form of solar energy. When the sun heats the earth's atmosphere unevenly, rotation differences in the earth's surface cause the flow of air that we call wind.

How does wind energy work? 
The power of the wind turns wind turbines. Turbines convert the wind’s kinetic energy into mechanical power. The turbines drive generators, which convert the power into electricity for homes and businesses across Northern Ireland.

Wind energy advantages 
There is a wide range of benefits to using wind energy in Northern Ireland and other countries. Some of the key advantages include:

• Clean source of power - There are no emissions generated from wind energy. No harmful carbon dioxide is released, which means wind power doesn’t contribute to global warming.
• Renewable energy - We’re never short of a gust of wind here in Northern Ireland. Wind energy is exhaustible and totally sustainable.
• Community benefits - Wind energy creates green jobs and helps to develop new business supply chains. Most large wind farms also operate community benefit funds to give back to the local area.

Understanding wind turbines 

What is a wind turbine?
Wind turbines are an updated version of windmills. While traditional windmills used the power of the wind to grind grain, modern wind turbines harness the same power to generate electricity.  Just like windmills, wind turbines have blades that rotate when blown by the wind. The rotating blades drive a shaft running through the nacelle — a box containing a generator, gearbox and other equipment. The rotation powers the generator and creates electricity.

There are two main types of wind turbines in the UK. These are the more commonly seen horizontal wind turbines and newer vertical wind turbines.

1. Horizontal wind turbines - These are the sort of wind turbines that immediately come to mind when you think of a wind turbine. They usually have three blades sitting at the top of a tall tower. The first forerunners of modern horizontal wind turbines were used in Yalta, in the former USSR, in the 1930s.
2. Vertical wind turbines - Vertical wind turbines come in various designs, including the eggbeater-shaped Darrieus wind turbine, named after the man who patented its design in France in 1927. Although not as common, they are becoming more popular — not least because the multidirectional design can harness the power of the wind from all directions.

How do wind turbines work? 
No matter what the design of the turbine, the wind turbine blades are rotated by the power of the wind. The movement of this rotation drives the generator and creates electricity. While vertical wind turbines are usually omnidirectional, horizontal wind turbines have to pivot to the correct wind direction. This makes it important to place them so that the blades face the prevailing wind direction.  

The main components of a horizontal wind turbine are:

1. Foundation - Wind turbine foundations are large underground or underwater structures that support the weight of the turbine.
2. Tower - The tower is a tall vertical structure that increases the height of the turbine to reach stronger winds. Most wind turbine towers are made of steel.
3. Rotor & Hub - The rotor and hub are the rotating parts of a wind turbine. They are usually made up of three blades connected by a central hub.
4. Nacelle - The nacelle is the box that houses the generator and other important components. It is usually immediately behind the hub.
5. Generator - The generator is like an electric motor. It converts the mechanical energy of the rotating blades into electrical energy.

How much energy does a wind turbine produce?
An onshore wind turbine will typically generate 2.5 - 3 megawatts of power every hour. That’s enough electricity to keep 1,000 kettles boiling for an hour. The turbine will produce more than 6 million kWh of electricity every year. For a 3.6 MW offshore wind turbine, all those figures could be doubled. The amount of energy generated by a wind turbine depends on the wind speed, the height of the turbine and the size of the blades.

Wind turbines in Northern Ireland and the UK are around 30-45% efficient, with efficiency reaching 50% in peak wind conditions. Turbines can generate electricity in wind speeds of 6mph up to 55mph, when they need to be shut down to avoid damage. 

Wind farms & wind power plants

What is a wind farm?
A wind farm is a place dedicated to wind energy generation. It usually involves a large number of wind turbines grouped together to create wind power in bulk. Each wind farm is connected to the electric grid to generate power for the network.

What are the different types of wind farms?
There are two main types of wind farms: onshore wind farms and offshore wind farms.

1. Onshore wind farms - Onshore wind farms are located on land. They are usually found at altitude in remote rural and coastal areas. They are built on concrete foundations that are hidden below the ground.
2. Offshore wind farms - Offshore wind farms are located at sea. They are usually found in open sea several miles from the coast. They are built on foundations that are either embedded in or anchored to the sea bed.

Wind farm locations in Northern Ireland
Northern Ireland’s climate and landscape make it perfectly suited to creating wind energy. We’ve got plenty of hilly and mountainous rural locations that are ideal for wind farms. Coupled with the regular — but not overpowering — flow of wind from the Atlantic Ocean, that gives Northern Ireland one of the best wind energy resources in Europe.

Those conditions have led to the development of a large number of wind farms across Ireland by Energia Group, of which we’re part. This includes the Altamuskin, Eshmore & Gortfinbar, Clondermot, Cornavarrow, Glenbuck, Lisglass, Long Mountain, Rathsherry, Slieveglass, Teiges and Thornog wind farms in Northern Ireland.  

While all of the current wind farms in Northern Ireland are onshore, there are plans to build offshore wind farms off our coast from 2030. This will boost the contribution of wind power to Northern Ireland’s energy mix. Wind already generates 41.1% of all electricity used in Northern Ireland, compared with 24.6% across the UK.

Power NI Go Green 

With our Eco Energy tariff, the equivalent of all the energy you use comes from renewable generators. A large proportion of this will be from wind energy. You’ll also enjoy online billing discounts, no fixed-term contract and access to Power NI Perks.

FAQs 

How cost effective are wind turbines? 
Commercial 3 MW turbines typically cost more than £2.5m. Return on investment will vary depending on average wind speeds, how often the turbine is operational and what percentage of the power generated is sold to the grid.

Installing a 6kW pole-mounted domestic wind turbine costs around £31,000 and could save around £610 a year on your electricity bills. It will also save around 1.9 million tonnes of carbon every year.

The carbon footprint of wind power is far lower than that of fossil fuels because they don’t emit carbon. Manufacturing, transporting and constructing turbines is energy-intensive. But a wind turbine will usually offset the carbon emissions created during its production within nine months of being in operation.


What environmental considerations are taken into account when designing wind farms? 
Choosing the location of a wind farm carefully helps to minimise its environmental impact. This includes carrying out detailed ecological surveying to understand the local ecosystem.

Priority habitats, migration routes and design features that might attract bats can then be avoided when planning the location. The wind farm can also include a buffer area between turbines and nearby woodland or bat roosts to provide extra protection for local wildlife.


Do you need planning permission for a wind turbine in Northern Ireland?
Yes, planning permission is needed before you can build a wind turbine in Northern Ireland. The location of nearby buildings, other obstructions and any potential impact on your neighbours from the sound of the blades are among the factors that will be under consideration. 

Depending on the size and number of turbines you want to build, you might also need to complete  an Environmental Impact Assessment (EIA) to get planning permission.