Scientists study how an offshore wind farm may impact California wildlife 

SANTA CRUZ >> Scientists are studying how a planned wind farm off the California Central Coast may affect marine wildlife.

The proposed project, called Castle Wind Offshore, would include roughly 100 turbines floating more than 35 miles northwest of Morro Bay, outside the bounds of the Monterey Bay National Marine Sanctuary. The companies working on the project plan to make the wind farm operational by 2025. This is in line with Gov. Jerry Brown’s plan to get more than half of California’s energy from renewable sources by 2030.

“We need all the renewable energy sources we can find to reduce our dependence on fossil fuels,” said Alla Weinstein, CEO of Trident Winds, one of the companies that plans to build Castle Wind Offshore.

There are several wind farms off of coasts in Europe and Asia, but the U.S. is a little late to the game. The only commercial offshore wind farm in the U.S. so far is one in Rhode Island that began operating in 2016. Several more are in planning stages along both the East and West Coasts, including another, smaller California project in Humboldt County.

OUR FLYING NEIGHBORS

Researchers have found that existing offshore wind farms affect wildlife in many ways. Construction noise can disturb marine mammals, for example, and some underwater turbine foundations have transformed into artificial reefs that house mollusks and small fish.

The wildlife effects of offshore wind farms in California will probably differ from effects of wind farms elsewhere. According to Emily Kelsey, a United States Geological Survey researcher who studies seabirds in California, water deepens quickly off the West Coast. Because of this, offshore turbines in California would need to be on floating platforms anchored to the seabed rather than on columns drilled into the seafloor like the turbines in Rhode Island. Kelsey says the coastal area’s depth affects what wildlife call the coast home as well, so effects on individual species may be different compared with other wind farm sites.

Kelsey, a Santa Cruz-based wildlife biologist, has been studying how an offshore wind farm in California might affect marine birds. She and her colleagues combined data about the population sizes and behaviors of 81 bird species to estimate how vulnerable each might be to an offshore wind farm. The team reported its findings in an issue of the Journal of Environmental Management earlier this month.

The most salient effects vary from bird to bird, Kelsey found. Loons and grebes, which are more likely to avoid areas with large structures, could be discouraged from foraging in their natural habitats if turbines are nearby. Pelicans and gulls, on the other hand, run the risk of colliding with turbines because they often fly at turbine-blade heights.

And the level of risk varies with the turbines’ distance from shore – many species will be less affected if the turbines are farther from the coast.

“The ocean isn’t a uniform landscape and some areas are more valuable to birds than others,” Kelsey said.

TESTING THE WATERS

To start probing how a floating offshore wind farm might affect a wide range of California wildlife, the Bureau of Ocean Energy Management, a federal agency, contracted environmental consultants to put together a risk assessment. Eventually, any company that wants to build an offshore wind farm in California will need to submit detailed plans for testing how appropriate a site might be – such as surveying the local wildlife – to the bureau.

The environmental consultants scoured research papers to compile a list of factors that might affect wildlife – including collisions with turbines, oil spills and artificial light – and find what animals are affected by each. Impacts vary from one kind of animal to another, they found. Whales, for example, might be most affected by noise from construction of the turbines or collisions with ships approaching the turbines for maintenance. For seabirds, the dangers might be collisions with turbines or displacement from their natural habitats.

Environmental consultant Alicia Morandi, who led the Bureau of Ocean Energy Management-funded risk assessment, says the report was just a starting point. Companies would still need to evaluate the environmental impacts specific to their projects, and this risk assessment would help do that.

“It can help lay out which species we thought might be more vulnerable,” Morandi said. “This could help industries get a sense of what may be an issue and what some of the mitigation processes are.”