Goldsmiths’ 2013

Visit to Green Park Wind Turbine

Ecotricity is a green energy company based in Stroud, Gloucestershire, England specialising in selling green energy to consumers that it primarily generated from its wind power portfolio. It is built on the principle of heavily reinvesting its profit in building more of its own green energy generation.

The Ecotricity wind turbine, on the outskirts of Reading, is one of the tallest land-based windmills in the UK. It is well known because it can be seen beside the M4, soaring above Junction 11 and offering over 11 million people a year an inspiring view of a cleaner future. It is one of the very few truly urban wind turbines in the country.

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It has been running since November 2005 producing 2MW of electric power at a wind speed of 14 m/s. This equates to 4.5 million units (kWh) of green electricity every year providing enough energy for between 1200 and 1500 average British homes and businesses via the national grid.

The turbine is 120 meters tall with a hub height of 85m and has a mass of nearly 300 tonnes.

The rotor diameter is 70m and each blade is 33m long. The blades can rotate at 6 to 21 rpm depending on wind speed although the power remains constant when it reaches 2MW.

The whole turbine is designed to ‘flex’ in the wind and the blades are rigid but very flexible, being made of Carbon Fibre with wood at the centre. They can be turned 90 degrees on their axis and have sloped sides of 30 degrees against the wind.

The foundation is strong concrete which took a week to pour and a month to set. It is 2m deep with a diameter of 40m. The foundation is circular to reduce pressure. In more modern turbines the foundations are made in a factory.

The whole turbine took 5 days to be built. It was delivered in sections and very few bolts were used. A crane was used to allow welding to take place.


The above picture shows the sections.

The turbine is a German-made Enercon E-70 second generation wind turbine. It is a gearless type comprising a direct drive synchronous generator (there are not many moving parts) with permanent magnets attached each blade. There is also a magnet in the hub, which is rugby ball shaped to reduce turbulence.



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The above picture on the right is of a panel at Green Park that is supposed to give various readings about the electricity generated.



Wind tunnels were used to get an increase in efficiency.

The turbine is capable of facing into the wind, even if the wind changes direction, the turbine turns too! This means that the turbine can generate electricity wherever the wind comes from. An attached wind monitor allows this to be done automatically. The wind monitor measures the wind speed and can stop the turbine if the wind gets too high. 67 mph is the cut-off point. The magnets clamp together to stop the turbine if the wind speed gets too big.

No ice can develop on the blades as they are heated. They are twisted slightly to reduce noise and displace rain properly. This also increases aerodynamic efficiency.

The turbine produces electricity through the wind powering a generator unit. This is direct current and the conversion to ac is done on site. The national grid can only take a certain amount of electricity and some turbines can be altered to accommodate this. Enercon doesn’t do this as much. The idea is to find methods of storing this excess electricity.

The turbine cost £2.5 million to build in 2005 but would cost less now. The payback time for this was eight years. This means that the money made from the quantity of electricity generated in the eight years equalled the cost of building the turbine. Payback for the carbon used/produced in the process was six months. The lifetime of the turbine is 25 – 30 years.

Engineers don’t go up the tower very often (the only access is a very tall ladder). There are computers at the base constantly monitoring the turbine.

There is a light on top of the turbine that can be seen by aircraft and the turbine is painted in anti-glare paint.

Contrary to myth turbines do not kill birds and modern turbines are not noisy. On our visit to the Green Park we were only aware of the traffic on the M4.


The turbine is owned and operated by Ecotricity, an electricity supplier in the UK that builds wind turbines to supply clean energy to its thousands of customers across the country. Ecotricity is dedicated to fighting climate change through building attractive and sensitively sited wind parks. The Green Park turbine demonstrates Ecotricity’s preference to site turbines in commercial locations rather than areas of natural beauty. The Green park site was once a landfill site.

It took five years of planning to get the wind turbine built (now it would be 2-3).

Initially the MOD, CPRE and Radar service for airports were against it. IN the Thames Valley energy region 75% of people initially didn’t want it. After it was built 65% liked it.

The Renewables Obligation (RO) is designed to encourage generation of electricity from eligible renewable sources in the United Kingdom. It was introduced in England and Wales and in a different form (the Renewables Obligation (Scotland)) in Scotland in April 2002 and in Northern Ireland in April 2005, replacing the Non-Fossil Fuel Obligation which operated from 1990.

A ROC is the green certificate issued for eligible renewable electricity generated within the United Kingdom and supplied to customers in the United Kingdom by a licensed supplier. ROCs are issued by Ofgem to accredited renewable generators (or in the case of generating stations subject to a NFFO (non-fossil fuels obligation). This enables the Green Park wind turbine to earn 70p for each KWh of electricity with a feed-in tariff.

A feed-in tariff (FIT, standard offer contract advanced renewable tariff or renewable energy payments) is a policy mechanism designed to accelerate investment in renewable energy technologies.

Under a feed-in tariff, eligible renewable electricity generators are paid a cost-based price for the renewable electricity they supply to the grid.




The above left picture show Kate, our guide for the visit, with the wind turbine behind her. The above right picture shows Dr Stephen Flower, the organiser of the Goldsmiths’ course, with the turbine behind him. You can see the “lovely” green anti-reflecting green paint and the fact that it is touched up regularly (by hand !!!!).

Visits to the Green Park visitor Centre are by appointment only. School and community group visits can be arranged through Ian Gough on Tel 07792 158530 or at Ian also runs a series of lectures aimed at local businesses and occupiers on the benefits of responsible, sustainable development.

Ecotricity also had an electric car charging point near the wind turbine.


Wind power elsewhere

The windiest country in Europe is the UK and it sis the third biggest wind generator.

There are about 2000 onshore wind turbines in the UK.

The first wind farm was built in Cornwall in 1991.


The above pie chart show that over 70% of our electricity generation still depends on fossil fuels and that nuclear is used for a further 20%. EDF want to increase our dependence on nuclear by building another 8 nuclear power stations. But there is a genuine push to increase the use of renewable resources. Scotland wants to be carbon neutral by 2050 and the Isle of White is aiming for this too.

‘RenewableUK’, formerly known as the ‘British Wind Energy Association’ (BWEA), is the trade association for wind power, wave power and tidal power industries in the United Kingdom. RenewableUK has over 660 corporate members, from wind, wave and tidal stream power generation and associated industries.

The UK is one of the leaders in offshore wind electricity generation as it is surrounded by 33% of Europe’s seas.

The London Array is an off-shore wind farm in the Thames Estuary in the United Kingdom. With a nameplate capacity of 1,000 megawatts (MW), it is the world’s largest offshore wind farm. The site is more than 20 kilometres (12 mi) off the North Foreland on the Kent coast in the area of Long Sand and Kentish Knock, between Margate in Kent and Clacton in Essex. The first foundation was installed in March 2011 and phase I, consisting of 175 turbines delivering a capacity of 630 MW, was confirmed fully operational on 8 April 2013. It was formally inaugurated by the British Prime Minister David Cameron on 4 July 2013. The wind farm is named the London Array because it supplies electric power to parts of Greater London.


Off shore wind farms need a great deal of planning due to the possible effect on wildlife and the placing of cables.

There are around 350 hydropower schemes currently licensed by the Environment Agency in England and Wales. There are not enough suitable sites in the UK to accommodate many more large-scale hydroelectric power stations and even if all these potential schemes were installed, at significant distribution cost, they would still only represent between 850,000 and 1.55 million kilowatts (kW) of new electrical generating capacity – about 1–2% of the UK’s currently installed capacity. However it is better than nothing.

China is the country that is making and using wind turbines the most and it is also leading the world in hydroelectric and solar energy.

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