FAQs

Where will offshore wind farms be built?

Currently, there are two projects along the East Coast of the United States that are vying to be America’s first offshore wind farm. One is in Nantucket Sound, off the southern coast of Cape Cod and the other is off the southern coast of Long Island. There is great potential for wind power in many places along the East Coast from Maine to Georgia.

How far out to sea will they be? And how deep?

In the near future offshore wind turbines will generally be built in water less than 100 feet deep. This determines how far off the coast that they are likely to be sited. In some parts of the country this could be much further out than in others.
 
For example, the Cape Cod wind project will be between six - nine miles from the shore and the closest area of the Long Island wind farm will be a little less than four miles out to sea.  The sites being studied in Georgia, however, are 10 to 20 miles offshore.

Another factor is the cost of getting the electricity to shore and the practicality and cost of building and maintaining turbines further out to sea.  For example, the cables needed to plug the electricity into the grid onshore become longer and more expensive the further offshore the wind farm is located. 

Nevertheless there are advantages further offshore. Wind speeds tend to be higher and the wind is steadier. This means that turbines built further offshore should capture more energy. As a result many hope that the challenges will be overcome and that in the future offshore wind farms will be built much further offshore, perhaps even on floating platforms. 

Will they interfere with shipping?

Wind turbines at sea will be spaced between about 1,500-3,000 feet apart so the physical barriers for all but the largest vessels will be minimal. Nonetheless at certain sites developers may want to restrict navigation within the site for safety reasons.

Any restriction of shipping would be done in accordance with domestic and international laws.  Developers expend significant effort and financial resource on ship surveys to ensure that wind farms are sited where the will have minimum impact on recognized shipping lanes as well as on pleasure boats.

Will they interfere with fishing?

Given the relatively small area of sea-bed that is required there is no evidence to suggest that total fish catch will decline as a result of wind farm developments; if anything the opposite is more likely to be the case.  

Offshore wind terminals can serve as artificial reefs, creating new habitat and attracting fish and invertebrates. In many cases, introducing hard substrate and geometric complexity in otherwise sandy, uniform habitat can lead to increased biomass at the site. Wind farms can also provide a localized refuge from intensive fisheries activity, potentially allowing fish stocks to rebuild and seed adjacent areas.  In addition, as wind farms move further offshore the fishing grounds occupied by the farm will occupy a smaller portion of the total fishing area available to the larger deep water fisheries vessels that could theoretically fish in them.

In any event the wind industry in Europe is working actively with the fishing industry to ensure that fishing is not disadvantaged by the growth of offshore wind farms. Several offshore wind farm developers have also developed good relationships with local fishermen, and have employed them to help with the surveying of sites and the preparation of work for wind farm installation.

How big will they look from the shore?

It obviously depends on how close the turbines are to the shore, and on weather conditions. Most offshore wind farms are barely visible from shore. But visibility may even be a benefit as communities in Europe with offshore wind proposals near them, such as the Norfolk/Suffolk regions of Great Britain, are now planning tourism around the expected desire of people to see and visit the farms.

What if there's a storm at sea?

As with onshore turbines, offshore turbines are built to withstand extreme wind and weather conditions. In the event of severe weather, the blades turn out of the wind and will slow down for safety reasons when wind speeds become gale strength (i.e. 50 miles per hour and above.)

Will they disturb the seabed and cause coastal erosion?

Any proposal will undergo extensive biological and geological reviews prior to construction as part of the required Environmental Impact Statement process. In addition, some offshore projects have been given consent to go ahead on the condition that they also monitor the effects on coastal processes during and after construction.

However, the turbine structures and distance offshore are such that it is very unlikely they would affect the sea bed or wave patterns - indeed there is no evidence from the Danish experience of offshore wind farms of any detrimental effects on coastal processes.

The coastal erosion effects of higher sea levels and more extreme weather patterns due to global warming are already scientifically recognized, and these far outweigh the potential effects of offshore wind farms.

Will they affect marine life?

There are three significant stages of a wind farm from the point of view of marine life: construction, operation and decommissioning. Construction and decommissioning have the potential to generate the most amount of disturbance, and the wind industry, as well as several marine conservation groups, is currently investigating these impacts on marine life.

However it is important that such impacts are considered in the context of all the other marine activities such as global warming, fishing, shipping, oil and gas, etc. In addition, it is also of note that the duration of the construction and decommissioning will only be about six months. For the 20-year operational period there are no known impacts on marine life. Nonetheless the industry is actively investigating potential effects.  Efforts will be taken to minimize the impacts on marine animals prior to and during construction; the area of tower placement will be subjected to harmless sonic “pings” to clear the area before installation begins along with other mitigation efforts. 

It has been suggested that the noise from the turbines travels underwater and would disturb sea life. But studies carried out on the impact of noise from existing offshore turbines note that the noise is very low frequency, and many species are actually unable to hear it.

As with any other local impact issues these concerns must and would be addressed by the project Environmental Impact Statement.

Will the wind turbines use oil?

The wind farms will use a small amount of mineral oil in the project’s transformer. This is more like the oil you use around your house than it is the oil you put in your car. In the example of the Cape Cod project, the oil will be stationary, there won’t be ships coming and going to replace it and it will be triple protected against spill.