The first ever offshore wind farm was in Denmark in 1991 and has been decommissioned in 2017. It was commissioned by Ørsted and had 11 wind turbines. With increased global warming, the need for harvesting renewable resources for electricity generation became necessary. And today there are 18 countries in the world with projects of more than 57 GW. But while taking care of our future we were somewhere neglecting the present. Yes, this is what we will talk about, the pros and cons of offshore wind farms. Including this, we will get to know the environmental impact of offshore wind farms: positive or negative.
What is a Wind Farm and its Types?
A place where wind power generation takes place is known as a wind farm. With a group of wind generators ranging from 600 kW to 5 MW, turbines are spread over a vast area to take maximum advantage of the wind. On the basis of the location of these wind farms, they are categorized into 3, namely on shore, offshore, and near-shore wind farms.
1. Onshore wind farms are located 3 kilometers inland from the coast and are the most common type of wind farm.
2. Offshore wind farms are located in the open sea or a lake many miles from the shore. These are less frequent and are mostly built where there is no infringement upon pre-existing business, and it is neither an important sailing route.
3. Nearshore wind farms are located less than 3 kilometers from the coast.
What are the Pros and Cons of Offshore Wind Farms?
Offshore wind farms are located far from shore within the lakes and ocean. Though they are less frequently built, they have their set of pros and cons.
Pros of Offshore Wind Farms
1) Generates More Energy
On average, an offshore wind farm has the potential to produce more than 1 MW of power in comparison to onshore wind farms. The height of turbines for onshore wind farms is height-restricted whereas offshore turbines can be as large as required. Their turbine blades being scaled much larger can generate more energy. Also, wind speeds are generally high at sea in comparison to land, which allows offshore wind farms to generate more power.
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2) Less Intrusive
Being located in a region within a sea or lake, offshore wind farms are not intrusive like onshore wind farms. No farming, grazing, or any other piece of private land is invaded by the construction of wind turbines. Offshore wind farms do not interfere with neighboring countries or buildings or create obstacles in their way. Offshore wind farms are built in larger areas per square mile as they have a less physical impact on the environment.
3) More Efficient
Due to their capability of generating more electricity offshore wind farms are more efficient than other types of wind farms. Suppose a certain amount of energy is generated from 11 onshore wind farms. That very same amount or even more energy can be generated by 4-5 wind turbines in an offshore wind farm. The reason for them being more efficient is the more consistent direction of the winds at higher speeds at sea than on land.
Note: The number of turbines mentioned here is solely an estimate to explain things better.
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Cons of Offshore Wind Farms
1) Less Local Involvement
In the list of pros and cons of offshore wind farms, let us begin with the cons now. Onshore wind farms are owned by local businesses, but that is not the case with offshore wind farms. With more investment involved, it makes it difficult for local businesses and organizations to play their part. Only big corporations own offshore wind farms. Despite the fact that offshore wind farms provide job opportunities, they are not necessarily benefiting a particular local community. So, with this, they do not offer the same economic opportunities as onshore wind farms.
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2) Maintenance Challenges
Yes, offshore wind turbines are more capable and produce more power due to high-speed winds. Still, they are more susceptible to damage from these high-speed winds. With unpredictable weather conditions and storms often rambling the wind turbines, they are damaged often. Thus, offshore wind farms require repairs and maintenance quite often. Talking about repairs and maintenance, they surely are expensive, and often expenses done on repairs make offshore wind farms an expensive initiative to handle. Also, if cost is not an issue here then lack of accessibility is also a challenge to maintenance. Yes, located far away from shore their maintenance is challenging, and it consequently often takes longer to repair.
3) More Expensive
Building structures offshore is not as easy as it is on land. We can get machines and other equipment to make our work easy and finish things quickly. But in water things are more complicated in terms of transportation of heavy machinery. Due to the complexity of construction and installation, especially in deep waters, offshore wind farms require huge investments. Thus, they are more expensive but with a decrease in the availability of land for onshore wind farms, energy companies are opting for offshore wind farms. Now, let’s unravel what are the problems with offshore wind farms.
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What are the Problems with Offshore Wind Farms?
After learning about all the pros and cons of offshore wind farms, here is a list of what are the problems with offshore wind farms in certain situations.
- Building turbines and installing them is an expensive and complex process. But at the same time production and installation of power cables under the seafloor for electricity transmission to land can also be very expensive.
- In deeper water, building secure and robust wind farms is a difficult task. In water more than 60 meters (200 feet) deep things started getting problematic to handle.
- Offshore wind farms are built up to 26 miles offshore depending on viewing conditions. But some residents may find this unpleasing and may affect tourism and property values too.
- Wind turbines are susceptible to getting damaged from wave action too.
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What are Negative Effects of Offshore Wind Farms on Public Health and Community?
Two main effects on public health and community offshore wind farms are sound and visual impact. Mostly wind farms produce an aerodynamic sound that is caused by the movement of turbine blades by air. But there is also a mechanical sound generated by turbines. Turbine design and the speed of wind are two main factors affecting sound levels.
There have been complaints by residents living in the areas nearby regarding sound and vibrations. According to Industry and government-sponsored studies in Canada and Australia, sound and vibrations from offshore wind farms have no adverse effect on the health of the people.
Also, an effect known as shadow flicker can be annoying to some people. This happens under certain lighting conditions and can be minimized primarily by proper and careful citing. Then by installing window awnings, planting trees, or curtailing wind turbine operations during certain lighting conditions.
Since offshore wind turbines are taller and wider, they can be problematic for aviation. Thus, the Federal Aviation Administration (FAA) laid the requirements, large wind turbines or other structures with a height of more than 200 feet have red or white light. These lights needed to be turned on at night for aviation safety. After learning about the pros and cons of offshore wind farms, you now also know about the negative effects of offshore wind farms on public health and the community.
What is the Environmental Impact of Offshore Wind Farms?
Offshore wind farms have vast potential and are highly efficient. But despite all these, there are a number of environmental impact of offshore wind farms. These issues need immediate recognition and efforts should be taken to mitigate the impact.
1. Large Space Requirements
Offshore wind farms require more space because they have bigger turbines and blades. Depending on their location, offshore wind farms are competing with other oceanic activities like fishing, sand & gravel/oil & gas extraction, recreational activities, aquaculture, and navigation.
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2. Life Cycle Global Warming Emissions
Yes, wind farms are used to reduce carbon emissions as they do not produce harmful emissions during operations, thus reducing global warming. But little do we know that during the life cycle of a wind turbine, some emissions are associated. They include emissions during materials production, transportation, on-site construction, and assembly. Other stages like maintenance, decommissioning, and dismantling also include emissions.
Estimates of total global warming emissions by wind turbines depend on different factors like wind speed, the material composition of wind turbines, and the percentage of time the wind blows. Mostly, 0.02 and 0.04 pounds of CO2 equal to kilowatt per hour is an estimated wind turbine life cycle global warming emission.
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There is no reported impact on water from the operation of offshore wind turbines. Though some water is used in all manufacturing processes, to manufacture cement and steel for wind turbines, this does not count as a negative impact of offshore wind turbines on water.
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Mostly bats and birds are harmed by wind turbines. As per a review by the National Wind Coordinating Committee (NWCC), there is evidence of birds and bats dying after colliding with a wind turbine. The spinning of wind turbines changes air pressure and disrupts the path of the birds. However, the committee concluded that these impacts are relatively low and do not pose the danger of extinction to any bird or bat species.
Offshore wind turbines have a similar impact on seabirds, but the number of deaths recorded is minimal. However, marine animals are also affected at large but at the same time, some studies suggest that offshore wind farms act as artificial reefs which can increase the fish population. The impact is location-based and can vary on the same basis. Still, proper research and monitoring systems are required for understanding the in-depth impact of offshore wind farms on marine ecosystems.
So, today you learned about the pros and cons of offshore wind farms. Even though wind farms help us in reducing carbon footprint, they still have some inevitable drawbacks. However, with proper planning and better investments, it is possible to reduce the negative effects of offshore wind farms on the public, community, and environment. What are your views regarding this, and do you consider them harmful too?
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