Wind energy, both onshore and offshore, plays a key role in the transition to a carbon-free energy system. The technology used in onshore and offshore wind turbines is similar, but the differences are in location, size, scale and how the generated energy is transmitted.
Onshore wind energy is obtained from turbines placed on land, most often in rural areas where buildings do not obstruct air movement. Onshore wind farms are more economical and easier to maintain than offshore wind farms. Their construction generates lower costs, as well as lower emissions compared to other energy sources. However, the efficiency of these turbines is lower due to variable wind conditions.
Offshore wind energy uses turbines located in offshore waters, where wind speeds are higher and more stable. This makes offshore farms more efficient, but also more expensive to build and maintain. The location of these farms away from the coast minimizes their impact on local communities, but also makes them more difficult to maintain. They require advanced infrastructure and large investments, which often means corporate financing for these projects.
Both forms of wind energy have their advantages and disadvantages, but in combination they can effectively support sustainable energy development.
What is onshore wind energy?
Onshore wind energy is derived from turbines located on land, where air movement drives the turbine blades. These installations are often located in rural or sparsely populated areas, where buildings and other obstructions do not interfere with airflow. There are more than 1,500 operational onshore wind farms worldwide, generating a total of more than 12 gigawatt hours of electricity.
Onshore wind energy has relatively low production and operating costs, making it one of the cheapest forms of renewable energy sources. Construction of these farms is faster and maintenance is easier than for offshore installations. There is also the advantage of lower environmental impact, as emissions of carbon dioxide and other pollutants are minimal.
The main challenge for onshore wind power is fluctuating wind speeds, which can affect the regularity of energy production. Onshore wind turbines tend to have a lower height than their offshore counterparts, which affects their efficiency. In addition, the location of onshore wind farms can be controversial due to the impact on the landscape and the possible threat to birds.
Advantages of onshore wind energy:
- Reduced environmental impact. The construction and operation of an onshore wind farm generates far fewer emissions than other energy sources, and the land on which they are located can continue to be used for agricultural purposes.
- Cost-effective. It is one of the cheapest forms of renewable energy (along with photovoltaics) and far cheaper than offshore wind power. With cheaper infrastructure and lower operating costs, onshore wind farms can help lower electricity bills.
- Faster installation and easier maintenance. Onshore wind farms can be built in a matter of months on a large scale, and are relatively cheap and cost-effective to maintain compared to offshore farms.
Disadvantages of onshore wind energy:
- Variable wind speed. The constancy of electricity production from wind farms can be disrupted by fluctuating wind speeds and changes in wind direction.
- Lack of wind or intermittent production. When wind is unstable (or absent), electricity cannot be generated using wind power. Various solutions will be needed to meet our energy needs, including other sources of renewable energy, as well as the provision of clean energy through interconnectors and better management of energy demand.
- Impact on people and nature. Some people complain about the appearance of wind farms in the landscape and noise. There are also concerns that onshore wind turbines may pose a threat to birds (see our article “How does a wind turbine work?” for more on this).
- Lower energy production. Onshore wind farms produce less energy than their offshore counterparts (known as the “capacity factor”) because onshore development plans often limit the height of turbines, which is not the case for offshore turbines. The average onshore wind turbine produces about 2.5 to 3 megawatts (MW), compared to an offshore average of 3.6 MW.
What is offshore wind energy?
Offshore wind energy involves turbines installed in offshore waters, where air movement is stronger and more stable than on land. Offshore turbines are larger and can produce more energy due to more favorable wind conditions. The lack of terrain obstacles and higher wind speeds at sea promote more efficient use of energy potential.
One of the main advantages of offshore wind energy is the ability to build farms on a larger scale, which enables the production of significant amounts of electricity. The location of the farms away from the coast minimizes their impact on local communities and the landscape. Such a location also promotes the protection of marine ecosystems, which can be protected due to limited access to turbine sites.
The disadvantage of offshore wind energy is the higher cost of building and maintaining the infrastructure. More difficult operating conditions, such as high winds and waves, and distance from shore make maintenance and repairs difficult. Offshore farms require significant investment, which means they are usually financed by large corporations, limiting the participation of local communities in their operation.
Advantages of offshore wind energy:
- Offshore wind turbines are more efficient. Higher wind speeds and greater consistency mean that offshore installations need fewer turbines to produce the same amount of energy as onshore wind farms.
- Reduced environmental impact. Being many miles from the coast, offshore turbines are distant from the local population. Limited access to their location can even help protect surrounding marine ecosystems.
- More space for construction. The oceans provide ideal conditions for building wind farms in terms of scale and open space. Building more wind farms means producing more clean and sustainable energy.
Disadvantages of offshore wind energy:
- Higher cost. Offshore wind farms require more complex infrastructure, making them more expensive to build.
- Maintenance and repairs. Higher wind speeds, strong tides and accessibility issues make maintenance of offshore wind farms more challenging.
- Less local participation. While onshore wind turbines can be owned or managed by local cooperatives or even individuals, offshore wind turbines require significant investment, meaning they are typically owned by corporations. Nevertheless, they provide important jobs during the construction and operation of a wind farm.
Onshore and offshore wind power differ mainly in location, cost and efficiency. Onshore installations are cheaper to build and maintain, but produce less energy due to variable wind conditions. Offshore turbines, on the other hand, located in the waters, generate more energy due to stronger and more stable winds, although their construction and maintenance are much more expensive and complicated. Offshore farms are also less disruptive to people, but require large corporate investments. Both technologies are essential to achieving clean energy goals.
Used information from:
https://en.wikipedia.org/wiki/Offshore_wind_power
https://en.wikipedia.org/wiki/Wind_power