The Atlantic Array


In June 2008, the Crown Estate initiated the third round of its leasing programme for delivery of up to 25GW of new offshore wind generation capacity by 2020. RWE npower renewables ("RWE") was awarded the development rights for the Bristol Channel Zone now known as the Atlantic Array.

The Project

A planning application is yet to be submitted for the array. This was due to be submitted in December, but has recently been delayed until the Spring of 2013.

The current proposal is for a £3 billion offshore wind farm with a maximum generating capacity of 1500MW. Assuming this capacity is reached, the Atlantic Array could power around a million UK homes. The array is likely to be positioned 14km (8.5 miles) from the closest point to shore on the North Devon coast; 22.5km (13 miles) from the closest point to shore on the South Wales coast; and 13km (8 miles) from Lundy Island. The location of the array at Stanley Bank is thought to be particularly favourable to offshore wind.

Following a public consultation in 2011, the project was moved further from the south Wales coastline (as above) and the turbine density reduced to minimise visual intrusiveness. The number of turbines in the application will also be reduced to between 188 and 278 allowing for greater spacing between each turbine. Turbine size also remains uncertain and may range from 3.6 MW to 8MW.

Environmental Considerations

The clearest advantages of the Atlantic Array are that it will produce a measurable reduction in CO2 emissions, and it will contribute to security of domestic energy supply.

The array's contribution towards renewable energy infrastructure must be balanced with the uncertain detrimental impacts it may have on other aspects of the environment.

The proposed scheme is located largely within, rather than outside, the 12 nautical mile limit anticipated for sensitive coasts. The landscape along the north and south sides of the Bristol Channel comprises the Exmoor and Pembrokeshire Coast National Parks, the Devon and Gower ANOB, and large sections of Heritage Coast; notably Lundy. It is unclear at this stage whether or not the wind farm will be viewable from all sides of the Channel. It is worth considering that on a perfectly clear day, the human eye can see approximately 12 miles. All that may be surmised at this stage is that Lundy poses the greatest risk for visual intrusion.

The Design Envelope

The planning application will be drafted within a "design envelope". Rather than commit to specific parameters for materials and construction at this stage, the planning application will be technology flexible allowing construction to respond to technological developments. This will ensure that, when built, the wind farm is as advanced and efficient as possible.

The design envelope outlined also carries the risk of uncertainty. RWE has provided only a broad estimate of the number of turbines it intends to construct, and it is unclear which MW output turbine type will be used, or whether a combination of turbine types is proposed. This will directly influence the maximum generating capacity of the wind farm, and therefore its cost/utility ratio. This uncertainty will contribute to unease among local residents and regional stakeholders over the extent of detrimental effects on the local environment.


The general disadvantages of wind power are well publicised. Offshore wind presents further obstacles, including more complex and more costly construction. This contributes to a 40% increase in the cost of construction, broadly comprised in additional transport and installation demands, and sufficiently durable turbine foundations. The increase is partially offset by higher energy yields of as much as 30% more than onshore wind. Additionally, these additional costs are expected to decline as the technology develops and as construction experience is gained.

The Atlantic Array has an estimated lifespan of 25 years. Although the main components may be replaced after this time (subject to a further grant of planning permission), this is only half of the lifespan of a nuclear power station. However, based on estimates, the Atlantic Array will be constructed for one third of the cost of the nuclear alternative.

The Local Economy

The construction process will present opportunities for local economic benefit and employment. RWE aims to maximise use of local and regional businesses and will to run a competitive tender process for each part of the works required. Local suppliers and contractors will have opportunities to win some of those contracts.

One should, however, question the extent of the local economic benefit. The skill and expertise required for the manufacture, transport and construction of a wind farm are specialised. It is therefore worth considering what quantity of these expertise are on offer in the South West, and how much business is likely be sourced from outside the region.

When the project is complete, the wind farm will have considerable ongoing maintenance requirements. These provide the greatest opportunities for long term employment to the economies of towns such as Bideford and Illfracombe.


The Atlantic Array presents an opportunity to generate significant amounts of carbon free energy at a much lower cost than some of the alternatives. The local economy may also benefit from employment opportunities during construction. However, without absolute clarity on the size and scale of the array, the extent of these benefits cannot be measured, and subsequently balanced with the true environmental cost to the surrounding landscape.