Frequently Asked Questions

The UK has been blessed with a wealth of energy resources but many of those resources are now dwindling, including fossil fuels such as coal and oil, particularly in the North Sea. That, combined with an ever-growing demand for energy throughout the world, means we need to find new ways of generating power. Exploiting ‘home-grown’ renewable resources like wind will help us make the UK less reliant on other countries and on fluctuations in global fuel prices.

The Government is committed to increasing the amount of energy we use from renewable sources not only to give the UK a safe, reliable, sustainable supply of energy, but also to create jobs in new industries and technologies that could help boost the economy and make Britain a world leader in renewables.

With our long coastlines and great wind resources, the UK is uniquely placed to generate renewable energy from offshore wind. In fact, we are the windiest country in Europe. Not surprisingly, the Government’s 2010 National Renewable Energy Action Plan sees offshore wind as a key area for development and believes it will play a major role in helping the UK meet its target of producing 15% of its energy from renewable sources by 2020. At the moment, offshore wind is one of the leading renewable energy technologies capable of achieving the Government’s targets for generating renewable energy and lowering carbon dioxide (CO2) emissions, as it can be deployed on a scale to match many conventional power stations. Offshore wind also offers the benefit of higher average wind speeds and less turbulence compared to onshore wind, so it can produce more energy.

A turbine consists of three components - the tower, the nacelle and the rotor (including blades). The nacelle houses the electro-mechanical components (e.g. gearbox and generator) and the rotor blades are set in motion by wind, rotating the main shaft which in turn, through a gearbox, generates energy in a generator. The generator that produces the electricity is connected to the turbine’s electrical control system. The energy output is led through a high-voltage transformer (this transforms the electricity to the required voltage) and is fed into the National Grid network via an offshore substation and an underwater export cable.

The turbine blades will normally start to turn at wind speeds of approximately 4 metres per second (9 miles per hour). Maximum electrical output will be reached when the wind speed is above 12 to 15 metres per second (24 to 37 miles per hour). The blades will stop turning when the wind speed is excessively high, typically around 26 metres per second (58 miles per hour) or higher (above gale force), in order to prevent damage to the internal machinery.

When the wind stops blowing, there will be an automatic increase in electricity into the National Grid from alternate sources of energy generation including coal, gas and nuclear.

A modern wind turbine produces electricity 80%- 85% of the time but it generates different outputs dependent on wind speed. Over the course of a year, it will generate about 32% of the theoretical maximum output, although this is generally higher offshore than onshore. This is known as its load factor. Over the next few years, National Grid will look at ways to expand the grid in order to deal with increased electricity supply from energy developments such as wind farms, so it is able to accommodate more electricity capacity.

Are the UK’s targets to meet 15% of its total energy consumption by 2020 costing me money? Yes, some of the money you spend on energy bills will go towards renewable energy developments. According to Ofgem, the correct figure is no more than 9% on your average domestic bill. In fact, Ofgem’s Energy and Gas Supply Market Report stated that wholesale electricity and gas costs were by far the biggest factor in the rise in energy bills, accounting for 45% of current fuel bills, and not ‘Green Taxes’.

Rising wholesale gas prices market - where companies buy and sell their gas and electricity to provide to their customers - accounted for a £170 rise in the average UK gas bill in 2011. In contrast, renewable energy subsidies cost energy bill payers approximately £20 a year - of which both offshore and onshore wind accounts for about £10.

The UK Renewable Energy Roadmap published by DECC stated that "Securing renewable sources of energy is a key pillar of the UK Government’s strategy for a diverse, low carbon energy system alongside nuclear, cleaner coal and gas, and energy efficiency. However, as a relatively new, emerging set of technologies, renewables tend to be more expensive than existing fossil fuel generation." Properly designed and targeted subsidies are designed to develop new technologies and bring costs down, thus boosting Britain’s competitiveness.

Companies developing wind farms do not get given subsidies during the planning and construction stages of the development and only receives subsidy for each unit of energy it actually generates. All renewable energy developments rely, to a greater or lesser extent, on public subsidies, not just wind farms. It is highly likely that the subsidies for wind farms will decrease as wind energy becomes more competitive with traditional fossil fuels such as coal and gas. Subsidies for wind power account for just £10 of the average annual household energy bill in the UK and the Government plans to cut subsidies for offshore wind over the next few years.

The cost of generating energy from wind farms is reducing toward a point where it becomes comparable with conventional generation technologies, such as gas fired generation. We believe that the costs of wind energy will continue to fall as the next generation of technology becomes available, such as the latest turbine components and control systems that improve efficiency. As scale increases, the cost of offshore wind is expected to fall substantially and the Offshore Wind Cost Reduction Task Force Report (June, 2012), and The Crown Estate cost reduction pathways study, both set out that 30-40% cost reductions are achievable. The average onshore wind farm in the UK will pay back the energy used in its manufacture and construction within six to eight months. This compares favourably with coal or nuclear power stations, which deliver only a third of the total energy used in construction and fuel supply over that period. Offshore wind farms will take longer than this but still less time than time taken by coal or nuclear power stations.

Wind farms are supported by the National Grid which supplies power from a variety of energy sources, such as renewables and nuclear, and not just coal and gas power stations. The Grid is used to dealing with fluctuations in supply and demand as power requirement changes during the course of the day.

At present Navitus Bay only intends to develop the area within the boundary announced in February 2014. Whilst Navitus Bay has the right to development within the whole zone up to 2020, there are no plans at this stage to do so.

The boundary of the northernmost part of the wind park – the ‘top triangle’ has been removed. As a result, the size of the wind park will be approximately 153 square kilometres, where previously it was 175 square kilometres. Navitus Bay Wind Park will now provide up to 970MW of capacity. This will generate enough low carbon electricity to power around 700,000 homes every year and will offset approximately 1,290,000 tonnes of CO2 emissions each year.

Yes, the boundary change will reduce visual impact in different ways from all viewpoints along the coast in Dorset, Hampshire and the Isle of Wight. In the case of the Isle of Wight, New Forest National Park, Lymington, Christchurch and Bournemouth, the change will increase the distance of the nearest turbine from the shore; in the case of Swanage and Durleston Head, the change will reduce the horizontal spread of turbines on the horizon. The change will also open up a clear gap between the turbines and the Isle of Wight.

We changed the boundary of the proposed wind park in response to feedback from statutory consultees and local residents that we received during our last and final round of public consultation. Feedback showed there were a range of concerns about the wind park, which we believe the boundary change addresses.

The visual representations of the proposed wind park have been prepared by independent landscape architects and have complied fully with both recognised guidance and industry best practice.

We are aware that consultation has recently been carried out by Scottish Natural Heritage (SNH) on visualisation guidance and that this may result in new guidance being adopted in the future.

In order to maintain our on-going commitment to open and transparent communication, we have provided, for information, an additional visualisation produced according to the consultation draft, which was issued for consultation by SNH in May 2013, for comparison with our current visuals. Both visuals are prepared in an identical manner; the only difference is in the way in which they are displayed.

Any future adopted changes to visualisation guidance would have no bearing on the outcomes of our seascape, landscape and visual impact assessment.

Modern wind turbines are designed to operate for more than 20 years. At the end of the lifetime of the wind park, Navitus Bay will either decommission the park and remove all of the turbines from the Development Area or apply to repower the development.

There is no peer reviewed evidence suggesting that impacts from collisions with wind turbines are causing increases to bird mortality rates that are unsustainable on any populations of birds. There are over 15 operational offshore wind farms of over 25 turbines (and 3,400 onshore wind turbines across the UK at 324 different sites). Two years of bird surveys have been undertaken to determine the importance of the project site and its cable route to birds throughout their breeding, wintering and migration periods. To find out more, please read our wildlife and environment section

Renewable energy accounts for less than 4% of the UK’s total energy needs at present and Navitus Bay is supportive of any efforts to decarbonise our economy through the promotion and development of renewable energy. It believes that wind, wave and tidal, amongst other technologies, all have a role to play in helping the UK meet its 2020 renewable energy targets. The long timeframes for the commercial development of large-scale wave and tidal schemes mean that they do not represent a genuine alternative to offshore wind. Even when such schemes are available for commercial deployment, they will complement offshore wind rather than displace it.

Any natural or manmade feature will have some impact on the surrounding climate. As a result of the wind turbines extracting energy from the wind there will be a local reduction in wind speed immediately behind the turbine. This impact will quickly disperse and for the wind reaching the coast this effect will be imperceptible. For sailing boats passing immediately behind the turbines the impact will be similar to passing by a small island and the impact on sailing is anticipated to be minimal.

There is a perception that wind farms can generate sea fog, but there is no evidence to suggest this. Independent analysis of weather and temperature data has shown that sea fog is a natural process and will occur with or without the wind park. Further independent studies have indicated that the Navitus Bay wind farm will have no additional impacts on the climate of the local coast in terms of wind, temperature, rainfall or sunshine.

Navitus Bay has been liaising with local commercial shipping operators and statutory authorities, such as the Maritime and Coastguard Agency, Trinity House and others, throughout the design and development process. It has undertaken marine traffic surveys to monitor the movement of vessels in and around the proposed offshore development area as well as collision risk modelling. Commercial shipping will be able to sail around the wind park both during construction and when it is operating. The turbines will also have a clearance of at least 22m from the highest mean tide to allow the majority of yachts and recreational boats to pass underneath safely.

Meteorological masts (met masts) are used to gather information on the climate and the speed and direction of the wind. Navitus Bay currently has consent for the installation of a met mast located outside the development area. It is considering applying for a location within the development area. Only one met mast will be built and it has yet to be constructed.

As a very important heritage asset and tourist attraction, Navitus Bay understands the concerns raised about any potential impact of the wind park development on the Jurassic Coast World Heritage Site. It is not anticipated that the project will impact on the outstanding geology for which the Jurassic Coast is designated; however, this matter, and the potential impact on its setting and other cultural and natural elements, will be captured in the Environmental Statement. Navitus Bay continues to engage with the World Heritage Site Steering Group and other key stakeholders to ensure that any potential impacts on the area are fully accessed and communicated at the appropriate time.

Operational noise from the wind park will be assessed as part of the EIA but will not be discernible onshore.