Guide written by:
Albert, Manager of a gardening service, Leicester
Interest in domestic wind turbines in the UK increases year after year. Ideal for a countryside home, but trickier to set up in a city, wind turbines can be a great way to get into renewable energy and off-grid energy production. Read on to find out more about installing a wind turbine for more sustainable living.
- Legislation and standards
- Electricity production
- Required wind power
- Horizontal or vertical axis
Why choose wind energy?
There's no better time to start doing your bit for the planet and producing your own energy. Making your own electricity allows you to save money and protect the environment at the same time. Wind energy isa great renewable energy source and producing your own fits in perfectly with government initiatives to transition towards greener energy sources. As such, you might even be eligible to apply for a grant to get your wind energy system up and running.
Renewable energy is, of course, natural, clean and, most importantly, it doesn't run out. However, if you want to harvest wind energy, you will need to live in an area with a lot of wind. Before you get too deep into planning, you need to ensure that the area in which you live has enough regular wind speed to make your investment worthwhile.
Windpower Feasibility Study
There are a few different ways to find out if your property is eligible for a wind turbine. Firstly, you can carry out your own wind study. Self-assessment is the first step in finding out if your home is a suitable location for a wind energy system. You'll need to measure the wind speed in your intended location for at least three months but ideally over the course of a full year.
Next,you'll need to order a more comprehensive Windpower Feasibility Study to be carried out by professional technicians. This involves not only measuring wind speed, but also giving you an idea of the physical and planning constraints or technical issues that could affect your project. The finished study will be able to provide you with an estimate of initial costs as well as what kind of return you can expect on your investment.
You might also be able to get an idea of whether or not your property is suitable by simply looking around your home. Are there already wind turbines in the area? If so, there's a good chance you will be able to set up one of your own.
It's worth nothing that wind turbines are best suited to countryside use as there are fewer buildings to obstruct wind flow. Cities experience a lot of wind turbulence which will lower the efficiency of your wind energy system; wind turbines in urban environments usually have to be set up much higher up which comes with its own disadvantages.
Wind turbine regulation
Another important point to consider is planning restrictions. If you're thinking of installing a wind turbine, you will have to apply to your local council to let them know of your plans. While most councils will encourage the installation of a renewable energy system, you may have to put in an application for permission and consult your neighbours. Whatever the case may be, you will always have to contact your local authority and this is a great opportunity to ask about any financial aid that may be available to you.
How to choose a wind energy system
In order to be an efficient energy harvesting system, wind turbines have to be able to meet your needs. With this in mind, you'll have to start by really thinking about exactly what you want from your wind turbine. If you only aim to power a few household appliances, you will easily find a model to fulfil your needs (depending on the appliances, of course).
Wind turbines intended for domestic use can be fairly small. In fact, compact micro wind turbines are becoming more and more popular. Small turbines can be installed at different heights but remember that the higher they are, the less they will be affected by air turbulence from city streets. Wind turbines in the countryside can generally be installed at lower heights as they won't have to withstand the same level of directional air shifts.
Wind turbine height regulations
In England, the highest part of the wind turbine blade must not exceed 11.1 metres. If you are installing on top of a building no part of the turbine should protrude more than 3 metres above the highest point of the chimney. While all wind turbines in England, Wales and Northern Ireland must comply with planning standards, you don't necessarily need planning permission to install a standalone turbine in Scotland (as long as your land is not protected, your turbine installed at least 100 metres from your neighbours and you only install one). It is imperative, however, that the lowest part of a standalone wind turbine blade is at least five metres above ground level.
Excess energy production
If you produce more energy than you can use – which is unlikely with a small turbine but possible with a full-sized model – you can sell excess energy back to the grid. This is done through a scheme called the Smart Export Guarantee (SEG) which replaced the Feed-in Tariff in 2019.
If you plan to sell your excess energy you will have to install an export meter. Bear in mind that the electricity grid is reaching its peak in some parts of the country (such as the south coast of England) meaning you won't be able to sell back energy in these areas. If you already have solar panels, your wind energy can be combined with your solar power. Hoping to install solar panels? You'll have to call in the professionals and be sure to have your equipment checked on a yearly basis.
Wind turbine power
To work out how much power your wind turbine will provide it's important to be aware of a few factors.
Wind power is determined by the following equation:
P= 0.5 x ρ x A x Cp x V3 x Ng x Nb
In this formula ρ represents air density which sits at approximately 1.2 kg/m3. 'A' represents the rotor swept area which refers to the area of the rotor in square feet. This is important as the rotor is the part of the turbine that captures the energy; the larger the rotor, the more power it will harvest.
Cp stands for coefficient of performance and Ng refers to generator efficiency. Finally, V = wind velocity (m/s).
Before you get too deep in calculations, it's worth noting that your wind turbine manufacturer can help you estimate the energy you can expect to generate. If you keep just one thing in mind, remember that wind power is directly proportional to rotor area so the bigger your rotor, the more power you'll have.
It's important to bear in mind that using a formula will only provide you with a theoretical number. In fact, there are lots of factors that will modify this value starting with any gaps in power as the rotor starts up and its cut-out speed which is a safety feature that cuts off the turbine when wind speed gets too high. You'll also have to think about the efficiency of your specific rotor and generator.
The Betz's limit states that the maximum power extracted from the wind is limited to 16/27 x 100, meaning no wind turbine can capture more than about 59.26% of the kinetic energy of the wind.
The overall efficiency of a wind turbine – excluding the factors noted above – takes into account power losses linked to the performance of the rotor and generator. As it goes, the various parts of a wind turbine will never work at full capacity at the same time.
It's estimated that wind turbines are around 25 to 55% effective. The following table provides power output estimations based on a standard wind turbine with a 1.9 m rotor diameter.
Nominal wind speed
Electric appliances powered
5 LED lamps, a TV, laptop, hair dryer and mobile phone charger
Please note that these figures are estimations. Of course, when there is no wind, no power will be produced. In this case, additional batteries can make up for a lack of production. The capacity of a wind turbine is usually indicated by the diameter of the rotor blades and their mechanical performance. Here are a couple of examples of specifications you might see:
- rotor diameter: 60 cm to 3 m (120 W to 1.5 kW);
- rotor diameter: 3 m to 10 m (1.5 kW to 30 kW).
Vertical axis vs. horizontal axis wind turbines
Wind turbines come in two basic types: vertical axis wind turbines (or VAWT) and horizontal axis wind turbines (HAWT). Wind turbines that rotate on a horizontal axis are cheaper than vertical axis wind turbines. This type of wind turbine harnesses the kinetic force of the wind, meaning the rotor blades are directly affected by wind speed. While these wind turbines can only process wind that comes in at a certain angle they are more productive when conditions are right.
Vertical axis wind turbines are a more recent addition to the market and are therefore more expensive to purchase. These wind turbines are able to change direction with the wind and are therefore able to capture wind coming from all 360 degrees. This makes them a better option for areas with unreliable wind..
Wind turbine regulations
It's important to note that wind turbine regulations differ across the country. While setting up a renewable energy source is generally encouraged, you might find it trickier than you thought to get permission as applications are often blocked by neighbours.
You will also never be allowed to set up a wind turbine in a Conservation Area, World Heritage site, or in the grounds of a listed building. If you do manage to get permission, financial grants may be available to help you out. Once everything is on paper, you can proceed to picking the right standalone, building-mounted or micro wind turbine for your property.
Finally, remember that installing a wind turbine does not come cheap. Wind turbines can cost up to £30,000 so be sure you've got the budget to back up your plans!
Guide written by:
Albert, Manager of a gardening service, Leicester, 53 guides
For several years I have been running a garden service with a clientele of both individuals and companies. I manage a team of gardeners and ensure the creation and maintenance of green spaces. At the same time, I bring my expertise to my clients in terms of the maintenance and improvement of their gardens. In fact, as a trainee and working in the hospitality industry at the beginning of my career, I focused on landscaping in a local community where I acquired solid technical skills through in-house training and the follow-up of major projects in a rapidly changing town. On a personal level, I am equally oriented towards the art of gardening. With my wife, I created our garden from start to finish and I maintain it carefully, the same goes for the vegetable garden. As for DIYing, it’s not to be outdone. Yes, gardening is also tinkering: pergola, hut, pavement, fence, and so on...There is always something to do in a garden. After working well together, my wife and I are proud of the result and delighted to be able to take full advantage of a friendly and warm environment. So, let us give you advice and help you in your choice of tools, maintenance, or improvement of your garden, nothing could be simpler.