Jul 14 2013

Visibility of Offshore Wind Energy Structures

Published by under Student blog entries

(Sullivan 2013)

(Sullivan 2013)

Wind is a significant renewable energy found near the coasts of many continents. A factor causing the lack of harnessing coastal wind renewable energy is the dislike, by coastal residents, for visibility of the turbines from the coast. This visibility factor has caused failure of U.S. offshore wind energy projects. As offshore wind turbines have evolved through the years, they have become increasingly larger. The change is turbine sizes causes new offshore wind farms to be increasingly visibly prominent from the shore. A recent 2013 study shows how researchers are taking the first step into fixing this issue.

The Sullivan (2013) study consists of researchers taking preliminary measurements of the visible distances of existing offshore wind turbine factories found in the UK(Sullivan, 2013). The study uses wind farms located in the Irish Sea, North Sea and Thames Estuary. The wind farms ranged from 25-140 turbines of variable sizes and different viewpoint distances from the coast. Researchers took observations from different distances both during the day and night. The data gathered from the observations also took in consideration of the weather, lighting, visibility conditions, and backdrop content/color. A rating system was created by the researchers ranging from visibility ratings 1-6. Visibility rating 1 is described as the least visible and rating 6 is most visible.

(Sullivan 2013)

(Sullivan 2013)

Results from the study seem to illustrate that new larger offshore wind facilities will have to be placed a considerably long distance from the shore to not be visible by coastal residents. Small and moderate sized wind farms were visible to the naked eye at distances exceeding 26 miles. Even at night, due to the aerial hazard lights, the wind turbines were visible from distances greater than 24 miles. The facilities were very noticeable at viewpoints located about 10 miles away from the wind farms. These results should be helpful to the United States’ interests in offshore wind energy projects.

The United States expect over 2,000 MW of offshore wind projects to come online by 2015(Bedard, 2010). Most U.S. projects are placed near the northern and central Atlantic Coast. This is due to the gradual drop off of the continental shelf near these areas. Offshore wind facilities would be easier to build in these shallower waters compared to the deeper areas offshore of the western U.S. Some areas of the Eastern U.S. Continental Shelf extend as far as 300 miles (Pinet, 2003). The extensive length of the Eastern Continental Shelf could make it easy to build offshore wind energy facilities and keep them out of visibility of the coastal residents.

Although the Sullivan study does not conclude the definitive distances offshore wind farms should be from the shore, it takes the first step by finding the distances existing wind farms are visible by coastal residents. Future studies could help build on the Sullivan results and eventually find the distance at which the U.S would need to place these offshore wind energy facilities from the shore, to satisfy the coastal residents and power demands.

References

Sullivan, R.G., Kirchler, L.B., Cothren J., Winters, S.L., 2013, Offshore Wind Turbine Visibility and Visual Impact Threshold Distances, National Association of Environmental Professionals.

Bedard, R., Jacobson, P.T., Previsic, M., Musial, W., Varley, R., 2010, An Overview of Ocean Renewable Energy Technologies, Oceanography, v. 23, p22-31.

Pinet, P.R., 2003, Invitation to Oceanography, Jones and Bartlett Inc, Burlington, MA, p 39.

2 responses so far




2 Responses to “Visibility of Offshore Wind Energy Structures”

  1.   Jonah Keyserlingon 17 Jul 2013 at 1:38 am

    Although it is important for wind companies to attempt to make their wind farms as least visible as they can from eyes on the coast, I do not believe that the distances future farms are placed from the shore should be planned to appease the wealthy beachfront owners. Increasing the distance that wind farms are from the shore has many negative effects that certainly out weigh the aesthetic appeal.
    First of all, the cost of production and maintenance of the wind farms increases greatly the farther and farther they are built from shore. The farther out you go in the ocean the deeper it gets which means the turbines will have to have bigger, stronger foundations, increasing the cost. The power cables that lie under the ocean and bring the electricity from the farm to land will have to be longer which will also increase the cost. Boats will have to travel farther and use more fuel to get to the turbines for maintenance, again increasing cost and it will take more time to build the farms farther out and we all know time is money. Second, the farther out in the ocean you go, the more dangerous it is for the workers to build and the farther away they are from help. Deeper waters cause for more drilling, more pounding, and basically more everything and all of this extra mess only increases the likely hood for workers to get injured. Also, if injuries do occur, it will take longer for the helicopters to get out to the worksite, which will make treatment efforts slower. Third, moving the turbines back also results in more harm to the environment. The bigger turbines lead to more habitat destruction (one could make an argument for floating turbines but they still aren’t used widely) and the longer power cables lead to more electromagnetic radiation they emit. Not to mention, the ships will emit more gas fumes as they will have to travel farther into the ocean for maintenance.
    Not to say that studies like Sullivan 2013 are not important, it just seems a little troubling that a great cause like wind energy has to preform scientific research that will help find answers as to how to keep the cause hidden. Instead the research should be on the location that will make the turbines most efficient, not the most invisible. Speaking of efficiency not all bad would result from having turbines very far out in the ocean. The wind tends to be stronger farther out so the farms would generate more energy. However, when one looks at the grand scheme of things, visibility of the turbines or lack there of and a little stronger winds, really don’t compare to some of the other factors that come into play when building wind farms.
    So beachfront owners should bite the small burden of having these wind turbines in their view because keeping them almost or completely out of sight is just not logical. And if offshore wind farms prove to do well and a solid number of them are built, they may be able to lower the amount of fossil fuels being burned which could lead to cleaner air for the beachfront owners to live in. Getting cleaner air seems like a pretty fair trade off for seeing tiny, spinning specs on the horizon of the ocean or a sound.

  2.   Jonah Keyserlingon 18 Jul 2013 at 1:49 pm

    Mark J. Kaiser and Brian F. Snyder, Off Shore Wind Energy Cost Modeling, Green Energy and Technology, http://books.google.com/books?hl=en&lr=&id=3n5ylusAE0EC&oi=fnd&pg=PR6&dq=determinants+of+deepwater+wind+turbines&ots=ri_ZfDShO_&sig=SCrv4izg52m3Zi4uHTry09JSOMo#v=onepage&q&f=false

    This link provides a paper that discusses all the other factors, other than aesthetic ones, that go into building offshore wind turbines.(also includes aesthetic appeal too)

    I can’t put picture on comments