There is so much news on offshore wind and its benefits, but how does the installation of wind turbines in water affect the marine environment?

What are offshore wind farms?

Offshore wind farms are wind turbines installed in open water. They are one of the newest forms of renewable energy and their deployment has been expanding rapidly recently as climate change continues to be a pressing global issue. Offshore wind has been successful because of steady ocean winds and extra space that has not been used.

Why should we invest in them?

Compared to onshore wind turbines, offshore wind turbines produce more electricity on average, thanks to steady offshore breezes. However, the initial cost of installing offshore wind farms is more expensive than installing onshore wind farms. 

Environmental Effects of Offshore Wind Farms 

Surveying needs to be conducted to assess the impact of offshore wind farms on nearby marine habitats and ecosystems before construction. 

During the construction, underwater noise can disturb marine life. For example, dolphins and whales use echolocation to communicate. With the intense underwater noise from the installation construction, the noise can damage the marine mammal’s hearing and echolocation or even kill them. The construction process could also release harmful contaminants into the ocean which could also cause affect the marine life.

Noise Effects and Protection

Research on noise reduction methods has helped address and mitigate such impacts. Secondary noise reduction techniques include bubble curtains, isolation casings, hydro sound dampers, dewatered cofferdams, and double piles/mandrel piles. Not only are these secondary noise reduction methods necessary, but there needs to be constant monitoring during the construction process to protect marine animals. Monitoring can include Marine Mammal Observation (MMO) boats that watch marine mammals in the area. Temporary hydrophones are also used to measure the decibels (dB) coming from the construction. 

Ecosystem Effects and Benefits

After the installation of offshore wind turbines, the marine ecosystem can also be affected. The cables carrying the generated energy back to the shore that lies on the seafloor create electromagnetic fields that can impact navigation, predator detection, and communication of certain species of fish and shellfish. The foundation bases of the turbines can also change the natural hydrodynamic flows of the ocean, which can drastically alter existing habitats and ecosystems. This disruption of wave flow can affect some organisms’ life cycle stages, especially larval dispersal and spawning which could also lead to changes in species composition, abundance, distribution, and survival rates in certain ecosystems.

All these factors need to be taken into account when corporations are planning to install an offshore wind farm so that marine life isn’t too greatly affected. However, on the bright side, some offshore wind turbine installations plan and incorporate marine habitats into the foundation bases so that they could provide habitat spaces for marine organisms to live in. 

Environmental Protection Policies

Because of the complex nature of installing offshore wind farms, there are policies in place to make sure that marine habitats and ecosystems are protected. For example, in the US, policies like the Marine Mammal Protection Act, Endangered Species Act, Magnuson-Stevens Act, Fish & Wildlife Coordination Act, and National Environmental Policy Act are set up to protect marine wildlife. The Bureau of Ocean Energy Management (BOEM) and other organizations such as NOAA Fisheries help enforce these regulations to make sure that offshore wind development reduces the environmental impacts on marine life and also give recommendations on how to approach the installation process with the least amount of negative impacts.

Why do we need offshore wind farms?

With global temperatures increasing past the safe range scientists have determined (1.5 degrees Celsius increase),  the transition to renewable energy is vital to reduce the environmental changes future generations would have to experience. Aside from the minor challenges with the cost of installations and approval process, offshore wind is a great option to consider and transition the world’s energy generation towards. Current policies require several rounds of approval for an offshore wind farm to be installed, but many governments including the US are working on changing policies to make the transition to offshore wind more smooth.