How can you compare offshore and onshore wind turbines?

1 Location and wind conditions

The first and most obvious difference between offshore and onshore wind turbines is their location. Offshore turbines are installed in the sea, usually several kilometers from the coast, while onshore turbines are built on land, often on hills or plains. The location affects the wind conditions that the turbines face, such as speed, direction, turbulence, and variability. Generally, offshore wind is stronger, more consistent, and less turbulent than onshore wind, which means that offshore turbines can produce more energy and operate more efficiently. However, offshore wind can also be more unpredictable and extreme, which can pose challenges for the turbine design and maintenance.

2 Size and capacity

Another difference between offshore and onshore wind turbines is their size and capacity. Offshore turbines tend to be larger and more powerful than onshore turbines, because they have more space available and less restrictions on height and noise. For example, the average offshore turbine has a rotor diameter of about 150 meters and a capacity of 6 megawatts (MW), while the average onshore turbine has a rotor diameter of about 100 meters and a capacity of 2 MW. Larger and more powerful turbines can capture more wind energy and generate more electricity, but they also require more materials, infrastructure, and transportation.

3 Cost and profitability

The third difference between offshore and onshore wind turbines is their cost and profitability. Offshore turbines are more expensive to install and operate than onshore turbines, because they involve more complex engineering, logistics, and environmental challenges. For instance, offshore turbines need special foundations, cables, substations, vessels, and offshore workers, which can increase the capital and operational costs significantly. On the other hand, offshore turbines can also be more profitable than onshore turbines, because they have higher capacity factors, lower grid connection costs, and higher market prices. The profitability of offshore and onshore wind projects depends on many factors, such as the wind resource, the distance from the shore, the policy support, and the competition.

4 Environmental and social impacts

The fourth difference between offshore and onshore wind turbines is their environmental and social impacts. Offshore turbines have less visual and acoustic impacts than onshore turbines, because they are farther away from the population and the landscape. This can reduce the public opposition and the legal barriers that often hinder onshore wind development. However, offshore turbines can also have negative impacts on the marine ecosystem, such as the disturbance of wildlife, the alteration of habitats, and the collision of birds and bats. Both offshore and onshore wind turbines need to comply with environmental regulations and conduct impact assessments to minimize their ecological footprint.

5 Technology and innovation

The fifth difference between offshore and onshore wind turbines is their technology and innovation. Offshore turbines are relatively newer and less mature than onshore turbines, which means that they have more room for improvement and optimization. Offshore wind technology is evolving rapidly, with new concepts such as floating turbines, hybrid platforms, and digital solutions emerging in the market. Offshore wind also offers more opportunities for collaboration and integration with other sectors, such as oil and gas, maritime, and hydrogen. Onshore wind technology, on the other hand, is more established and standardized, which means that it has less potential for cost reduction and performance enhancement. Onshore wind still benefits from innovation, but at a slower pace and smaller scale than offshore wind.

6 Reliability and availability

The sixth difference between offshore and onshore wind turbines is their reliability and availability. Offshore turbines are more exposed to harsh weather conditions and saltwater corrosion than onshore turbines, which can affect their durability and performance. Offshore turbines also have more difficulties in accessing and repairing than onshore turbines, because they require specialized equipment and personnel. These factors can reduce the availability and reliability of offshore wind farms, and increase the risk of failures and downtime. Onshore turbines, on the other hand, are more protected and accessible than offshore turbines, which can improve their availability and reliability. Onshore turbines also have more experience and data to support their operation and maintenance.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?