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Ecotricity / Building supply and demand for renewable power

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Ecotricity is a fast-growing installer of wind turbines in the UK.

There is considerable demand for renewable electricity in the UK, driven both by electricity supply companies that want to meet their statutory renewable requirements, and by customers who want to buy less environmentally damaging energy.

By 2006, Ecotricity had 27 MW of installed wind in 11 wind farms.

Customers in 2007 included over 30,000 homes and 1,000 businesses.

Avoids 25,000 tonnes/year CO2 emissions at average UK grid replacement.

"Climate change is a global issue which is affecting the poorest communities all over the world. But we can all make a difference. Many solutions exist on an individual level and one is choosing Ecotricity, as we have done, to help tackle climate change."

Oxfam, Ecotricity customer


There is a strong demand for renewable electricity in the UK, which exceeds current supply. Demand is driven both by electricity supply companies wanting to meet their statutory renewable requirements, and by customers who want to buy less environmentally damaging energy.

Wind turbines are a mature sustainable energy technology. They have high levels of public acceptance both at national level in the UK and around sites where they have been installed, although a minority of vocal opponents often block planning permission for wind developments. Developments with small numbers of turbines, away from areas of particular scenic beauty, are the most acceptable to the public. This is the market sector that Ecotricity has pioneered and developed.

Ecotricity wind turbine, Green park, Reading.

The organisation

Ecotricity grew out of the commitment of Dale Vince to develop the use of wind power, which he began in 1991. His initial work was in masts for wind monitoring. The income from these enabled him to finance the construction of his first wind turbine, near Stroud in Gloucestershire, in 1996. The company is still based in Stroud, and in 2007 had over 100 staff and an annual turnover of about £18 million.

The technology

How does it work?

The hub of a wind turbine is rotated by the force of the wind on the blades that are attached to it, which drives an electrical generator. The hub is mounted on a tall tower in order to capture high wind speeds (since the speed of the wind increases with height above the ground) and so that the blades are clear of anything on the ground. For grid-connected machines, the electrical output from the generator goes through power conversion and safety systems.

Many of the turbines are linked directly to the national grid, usually at the transmission voltage of 11 or 33KV. Ecotricity also runs the ‘Merchant Wind Power’ scheme, whereby turbines are installed to supply electricity directly to the distribution network of a business. By receiving power directly, the losses and costs associated with grid transmission are avoided, and any excess can still be sold. The result is that the turbines can be economic at sites with a lower wind speed than is usually viable, and the Merchant Wind Power customers can buy electricity at a lower price than conventional mains supply.

The installation of the wind turbines will see the Dundee site join Ecotricity as a pioneer in the ongoing promotion of alternative, cleaner energy sources for heavy industry.

Trevor Haynes, Michelin – Ecotricity Merchant Wind customer

How much does it cost and how do users pay?

Wind installations typically cost £800 – £1,000 per installed kW. Since 1995, Ecotricity has been a registered electricity supplier and funds the installation of new wind turbines using the profits from electricity sales, supplemented by commercial loans. Ecotricity sells customers the electricity generated by its wind farms, supplemented by conventional ’brown‘ electricity,which it buys from the wholesale electricity markets.

Because the percentage of renewable electricity in the Ecotricity mix exceeds the amount required under the UK Renewables Obligation, Ecotricity is able to sell the excess Renewable Obligation Certificates (ROCs) to other suppliers who are not meeting the required percentage. This is a significant component of the income stream of all new Ecotricity wind energy projects.

Merchant Wind Power customers purchase electricity at below market rate, in return for providing turbine sites. Other customers pay no more than the normal electricity price in their area, even though the electricity mix from Ecotricity has a higher contribution from renewable energy. Profits from electricity sales are invested in new wind installations, and all turbines are owned and operated by Ecotricity.

How is it maintained?

Ecotricity is responsible for operation and maintenance of the wind turbines. The performance of all turbines is monitored remotely, so that electricity output is known accurately. Monitoring allows the fine-tuning of turbines to deliver the maximum energy output, with any problems identified as soon as they occur. The physical lifetime of the turbines is 25 to 30 years.

Ecotricity wind turbine, Green park, Reading.


By 2007, Ecotricity had 27 MW of turbines in operation in 11 wind farms, of which 9 MW came from the Merchant Wind Power scheme. Turbines had a rated power of between 500 kW and 2 MW. Ecotricity customers included over 30,000 homes and 1,000 businesses.

Environmental benefits

During 2006, the wind turbines operated by Ecotricity delivered 46 GWh of electricity. The average carbon dioxide emission for UK grid electricity generation is about 0.55 kg CO2 per kWh, so on this basis Ecotricity turbines prevented the emission of 25,000 tonnes/year of CO2.

However, the real carbon reduction is probably higher, because wind electricity tends to displace coal-fired generation, rather than the less carbon-intensive base load from nuclear and gas fired power stations. The Parliamentary Office of Science and Technology and the Select Committee on Environmental Audit suggest that wind energy should be regarded as replacing coal fired generation at 1.0 kg CO2 per kWh. On this basis, Ecotricity turbines prevented the emission of 46,000 tonnes/year of CO2.

Community engagement

Although opinion surveys show an overwhelming support for wind energy, both in the UK in general and in the locality of wind farms, there is a minority of vocal opponents to wind energy. Ecotricity often chooses industrial and commercial land without great scenic value as potential sites for small wind farms, sites which might not be considered viable by larger wind developers. The company consults fully with local communities before and during the planning process, and has achieved a high success rate with planning applications.

You don’t really have to give anything up, you just use a different supplier. You do feel better about it when you know that it’s not actually polluting the planet every time you use an electrical appliance.

Molly Scott-Cato, Ecotricity domestic customer

Ecotricity has helped the whole wind sector in the UK by showing many people that having a local wind turbine can be a positive experience. The Enercon turbines are generally liked because of their slow rotation and aesthetic blade design. At several sites, the first turbine proved so popular that a second has been installed. For instance, at Swaffham, Norfok, local residents lobbied the council to get a second turbine.

The ‘Merchant Wind Power’ programme has engaged businesses that might not otherwise have considered renewable electricity. It has brought them financial savings and a positive image, with good feedback from employees and local media about the wind energy ’in the back garden‘. The very visible use of wind turbines by some of the best-known names in UK business has added significant credibility to wind as an electricity source. Customers – both domestic and business – like buying electricity from a supplier that invests all its profits in installing more wind capacity.

Update: what happened next?

Ecotricity has experienced significant growth since 2007. The Ashden Award fund was used to promote the Merchant Wind Power scheme with businesses, through developing a dedicated micro-website ( and events. Seven wind parks are operating under the Merchant Wind Power scheme, with another two under construction.

By early 2011, a total of 55 MW capacity had been installed in 16 wind parks, with a further 31 MW under construction and over 140 MW at the planning stage. Ecotricity wind turbines are generating about 136 GWh/year, avoiding the emission of 75,000 tonnes/year CO2 at average grid replacement (or 136,000 tonnes/year if displacing coal). In 2010, Ecotricity had over 41,000 domestic customers and 4,200 business customers, and provided 41% of the electricity it supplied from renewable sources.

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