Wind

Wind turbines work considerably better than most people give them credit for, huge amounts of electrical energy are collectively generated by the worlds wind turbines on an annual basis. As individuals, we can on a domestic basis add to this production quite easily, the installation process is not as difficult as most people would imagine, or, as outrageously expensive as some people think.

Wind turbines work on the principle that the winds forces will rotate aerodynamic blades, using the embodied kinetic energy to turn a rotor, which will in turn, generate electricity.

Wind, is simply energy in motion, it 's caused by a number of factors, including contours in the earths surface, the suns warming effects, and other climatic conditions. During the day, the air above the land mass heats up much more quickly than air over the world oceans, the warm air over the land expands and rises and the cooler heavier air rushes in to take its place, thus creating winds. At night, the reverse action takes place as the air over the land mass cools more quickly than that over the water.

The sun radiates 1 PW (petawatt), or 1014KWh, of energy every hour, only 3% of this energy is converted into wind energy, and just 3% of this wind energy, if harnessed is capable of meeting the global energy demand today. This highlights a massive untapped energy resource waiting to be utilised for the good of the planet.

Wind energy, is currently one of the fastest expanding growth markets within the renewables industry, like all expanding markets, there are many good products, and some no so good, care must be advocated when choosing a wind turbine, design suitability, must come before cost, not all turbines work in all environments.

Wind resources, are somewhat predictably, best along coastal and hilltop locations, but usable wind resources are still economically available and found in many urban locations. With the use of low speed "urban turbines" this energy can be harvested and utilized for all manner of domestic and commercial applications. Wind energy is somewhat less predictable than solar photovoltaic energy, but it will generally be available most days of the year, and in increasing amounts during Winter when the electricity requirement is greatest.

Wind turbines, cannot just be installed anywhere, they need to be mounted as high as practically possible, as the collection efficiency is seriously reduced by high trees, neighbouring structures, and any type of obstacles that diverts the wind from the turbine. Wind energy, is thus much more site specific than solar Pv installations, and any potential site needs to be professionally surveyed prior to installation.

As wind turbines generate varying degrees of electrical power under differing wind conditions, thus making it difficult to state an exact output, to overcome this, and standardise the outputs all wind turbine outputs are collectively measured in KWp (kilowatt peak), this is the units maximum operational output at peak performance.

Domestic wind turbines, that can be classed as reasonably useful commence at 2.0 KWp upto around 5KWp, these units will generally cope with a buildings electrical base load year around and provide some additional power for space and water heating. There are available smaller units, these tend to be wall mounted high revolution rotor models sold by some of the larger DIY outlets, they unfortunately rarely produce any beneficial performance or financial savings in real terms and tend to be rather noisy due to the high rotor speeds.

Larger semi-commercial wind turbine units rated @ 10, 20, 30, 50 or even 250 kWp are all proven products and extremely cost efficient, however obtaining the relevant planning permission maybe somewhat more of a challenge for the prospective wind crofter.

The average cost of a fully installed 5KWp domestic turbine is in the region of £17,000-£ 21,000 dependant upon site location and site requirements.

The cost effectiveness of installing a wind turbine really depends on two main factors, if the proposed installation is eligible for any form of low energy grant from the government, will any surplus "spillage" electricity be purchased back by the local electricity provider for a reasonable price. In Germany, Italy and even areas of the UK electricity generated by renewables is purchased at a premium rate well in excess of the normal retail cost per KW from the local electricity provider in an effort to assist the installer and offset the costs of initial installation of the turbine.  

If you require any further information please contact us.

Most wind turbines being produced today are of the horizontal-axis type, HAWT's as they are known, have blades much the same as a propeller upon an aircraft. Turbine blades, are very strong and manufactured to high tolerances to allow them to withstand extreme conditions both in terms of wind forces and temperatures.

The turbines are usually mounted well in front of the supporting pole to allow safe clearance and a degree of flexing during operation. Most HAWT's are usually three bladed in design, as this is perceived as the optimum design performance. Some turbines face into the prevailing wind with a tail to guide the rotor blades, while others such as the Proven Energy units have the rotors behind the leading head.

Many of the wind turbine manufacturers are based in Scandinavia or Holland, where the governments actively support and encourage investment in renewable technologies. This factor, coupled with the lack of access to cheap fossil fuels,and high electricity prices, along with a passionate belief in utilising renewable energy' have driven the market forward at an incredible rate. Some say that these countries are now the world leaders in wind turbine design and construction.

The latest generation of three bladed horizontal wind turbines have incredibly high tip speeds of up to six times the wind speed, high efficiency, and low torque ripple, which contributes to high reliability. This design of wind turbine is the favoured option for all medium to large scale wind turbines, and all of the commercial wind farms use this style of unit.

A typical horizontal wind turbine located on a wind farm would have a height similar to a 25 storey building and have three blades that span 60 metres across, it alone could provide power for a entire town.

For domestic purposes, it is more common to have wind turbine units that stand between 9 and 12 metres in height, and have blades 6 metres across. Units such as the WES5 Tulip, are of high quality, and fit more easily into the local environment. They are easily installed by trained engineers and can produce a significant amount of electricity at low wind speeds.

The complete package of design and installation for a good quality wind turbine installation that will provide a meaningful amount of power and cover the annual base load of your building is surprisingly affordable, prices range from between £17,000 to £24,000 installed, commissioned and working.

Any surplus "spillage" power generated but not consumed can be fed back into the local grid and sold back to the power provider, the rates received are dependant upon your local providers terms and conditions.

To extract the absolute maximum benefit from home generation installation, we at The Low Carbon Company advocate it be coupled with heat pump technology. When used in conjunction with wind power or photovoltaic electricity, the benefits are considerable. Rather than simply using the generated power to provide light and small power, if used to heat or cool the building through a GSHP or ASHP significant cost savings upon the total energy consumption of the building will be achieved.

Whether, it be the highly efficient ground source geothermal heat-pump that can offer both heating and or cooling simultaneously, or the more basic air source heat pump a COP (coefficient of performance) of between 5.03 to 2.8 respectively, can be expected. Thus every Kilowatt (Kw) of home produced electrical energy, provided by the wind turbine and used by the heat pumps can generate between 3 and 5 times worth of usable heat. Therefore a 5Kwp wind turbine supplying home generated power could be capable of running a 23kw GSHP.

If you would like more information please contact us.

Vertical-axis wind turbines, (VAWT's) are less common than the horizontal versions and are generally relegated to the small domestic end of the market place at predominantly less than 4kwp outputs. However, they are efficient and relativity quiet in operation and arguably  visually more attractive.

The VAWT as its name implies has its main rotor shaft running vertically, rather like a spinning corkscrew in appearance. Vertical-axis wind turbines have blades that go from the top to the bottom and are usually wrapped around the central mast. The Turby VAWT from Holland has a distinctive design and has gained favour with many commercial institutions and local governments commissioning installations of units on top of office buildings and factories.

To attain maximum performance from the VAWT it must be mounted as high as possible, low level installations below 20 metres do-not perform efficiently due to the lower wind speeds nearer the ground and turbulence that often occurs from surrounding trees, buildings and other geographical elements.

The advantage of a VAWT is that the generator and its gearbox are located at ground level which make the structure much lighter and less costly as the pole does not have to support this additional weight or stress factors in stormy high wind conditions. The VAWT being multi bladed can catch wind from any direction which is of great advantage when there is no predominant or predictable wind direction. Also the huge energy losses often attributed to horizontal turbines "hunting" for the wind are removed.

At the the top end of the market for vertical axis wind turbines, the British manufacturer "Quiet Revolution" produce a very highly engineered unit which is almost "art", unfortunately, its high capital cost and lower output, are set against the true beauty of the engineering.

If you would like more information or a site survey to assess the possibilities of installing a wind turbine at your site please contact us.

At present we have no completed local wind turbine installations, we have one application currently in planning in Jersey and two installations in the design stage.

Unfortunately our last application for a turbine in St Martin, Jersey Channel Islands was refused by the planning department.