California’s coming offshore wind boom faces big engineering hurdles

California’s coming offshore wind boom faces big engineering hurdles thumbnail

This week, dozens will compete for the right of California to lease the first commercial wind power site off the coast of California in an federal online auction . This could help kick-start California’s next clean energy boom.

Collectively, the winners will pay at least tens of millions of dollars for exclusive rights to submit plans to the Bureau of Ocean Energy Management for wind turbines at five sites that stretch across more than 370,000 acres of the Pacific. Three of the areas are clustered near Morro Bay along the central coast, starting about 20 miles due west from the picturesque seaside town of Cambria. Two more are located in the north of Humboldt County.

Annual average wind speeds around the Morro Bay sites reach 8 to 10 meters per second, exceeding those around some large offshore wind farms already developed in the North Sea. Towering turbines at the locations available for lease could deliver approximately 4.5 gigawatts clean electricity to California’s grid. This is enough to power over 1.5 million homes.

The state has an even more ambitious goal: building 25 gigawatts of offshore wind by 2045. That’s equivalent to nearly a third of the state’s total generating capacity today, or enough to power 25 million homes.

But the ambitious plans for offshore wind face a daunting geoological challenge. The continental shelf drops steeply a few miles from the California coast. It is therefore prohibitively costly to build standard offshore wind turbines. These are built on top of fixed structures that reach the seafloor. The turbines built near Morro Bay and off Humboldt, where water depths reach up to 1,300 meters (around 4,300 feet), will need to be placed on floating platforms, a speculative and very costly technology. Some companies have started using such platforms. They are tied to the sea bottom by moorings in places like the coasts of Scotland and Portugal. These sites still produce very little power. California will need to quickly develop large fleets of floating wind turbines in order to meet its ambitious plans.

The hope is that the state, a large consumer of electricity, will be a huge early market for the technology, helping it to scale up, push down costs, and drive innovation in the emerging sector. This would help the US develop offshore wind power, an alternative energy sector that has long lagged behind countries like China and the UK. If the floating industry proves to be viable, it will unlock vast amounts of renewable resources that have been largely untapped.

But there are many engineering and regulatory challenges ahead. California’s goals could be achieved by creating or upgrading ports, building new vessels, streamlining permitting processes and building up a West Coast manufacturing sector. It could also require shifting to new types and platforms that are easier to deliver and install. All of this would need to happen at a rapid pace.

David Hochschild is the chair of the California Energy Commission. He readily admits that there are looming problems, but he insists that the state is committed in overcoming them.

“This technology is ready and ripe,” he said. “We’re all in.”

High hopes

The appeal of floating wind is obvious. Somewhere around 60 meters deep (nearly 200 feet) it becomes impractical for developers to build what are called fixed wind foundations. The winds that blow over deep waters off the coast are often strong and consistent.

Off Morro Bay, and other potential California locations, the winds drop at midday, but rise in the evening. This is almost in perfect sync to consumer demand, and in a much different pattern than the electricity generated from solar farms.

Those characteristics will help the state’s grid operators draw more of their electricity from carbon-free sources through the evening, which will serve an increasingly crucial function as the California power sector moves off fossil fuels, says Alla Weinstein, chief executive of Trident Winds, which is a partner in the Castle Wind joint venture, which is bidding in the auction this week.

The state’s climate laws will require 90% of its electricity to come from such resources by 2035. That same year, California will mandate that all new passenger vehicles sold in the state must be zero-emissions, placing growing demands on the grid.

Hochschild believes that California’s floating wind boom will also spur economic development. This includes the creation of a state-based manufacturing industry near ports that could supply turbine blades and towers. He believes offshore wind development could bring in tens to billions of dollars in investment over the next quarter century.

Companies participating in the auction will earn credits if they commit to investing in workforce training, supporting the development of domestic supply chains, and engaging with indigenous tribes and underserved communities. These credits will be taken into account when deciding the winner.

But California is placing a lot of hope on an industry that barely exists today.

a floating wind turbine


Only a handful of mostly small demonstration projects have been developed so far, totalling around 125 megawatts, according to a Department of Energy report published earlier this year. The largest floating farm in the world so far is the nearly 50-megawatt Kincardine project off the shores of Scotland. The report also notes that small projects are being developed in China, Japan and France, as well as Norway, Norway, and Portugal.

There are big plans to build more globally. The total capacity of projects in the pipeline–including large sites in Australia, Brazil, South Korea, and the United Kingdom–doubled in 2021, to more than 60 gigawatts.

The Biden administration has set a US goal of developing 15 gigawatts of floating wind by 2035 and established a program designed to cut the cost of the technology by 70% over that time. (It’s also aiming to build 30 gigawatts of all types of offshore wind by 2030. )

High costs

For now, however, floating wind power remains hugely expensive.

It’s hard to put precise figures on the technology today, given the small pool of projects across different regions, but the levelized cost is roughly $200 per megawatt-hour, according to the DOE report. The average cost of energy over a project’s life, including the costs of building it and maintaining it, is called the levelized cost of energy. )

Standard offshore wind, land-based wind projects, and large-scale solar farms run around $80, $30 and $35 per megawatt-hour, respectively, according to the US National Renewable Energy Laboratory. This wide gap will discourage grid operators signing long-term power purchase contracts unless they are incentivized by policies or regulators.

California’s climate laws might do exactly that, requiring grid operators to source more electricity from carbon-free sources over more hours of the day, even though it may initially be more expensive.

Floating wind developments in the United States will have to deal with many regulations and high costs. Under a century-old law, any ship delivering goods or people from one US site to another must be built, owned, and primarily crewed by American citizens. According to Carl Valenstein, an attorney who specializes in maritime industries at Morgan Lewis & Bockius, past findings and precedents indicate that floating wind sites will be subject to these restrictions.

The problem is that there are only a few compliant ships that can tow and plant the floating turbines. Some of the work could be done on-site by foreign-flag vessels, and certain US ships could be retrofitted for some of these tasks. It’s clear that the US ship-building industry must move quickly if it hopes to meet both fixed and floating offshore wind targets.

“At some point in the next year, people are going to have to ask the question: Where are we going to get the ships to implement these plans along the current timelines?” Valenstein says. These capacity constraints will be felt if there are a lot of these projects. And you can’t get these ships built in an hour California faces even more challenges. Many of California’s ports are too small and too low to support the massive towers, turbines and platforms.

It could also cost tens to billions to build the electricity transmission capacity necessary to plug all the offshore wind turbines into a grid. California’s Independent System Operator, which manages the state’s main electricity network, found that just accommodating four gigawatts of electricity from the sites near Humboldt County could cost between $5 and $8 billion.

Last, we have to consider permitting.

Winning the federal auction is just the beginning. Every winning developer will still need to work through lengthy environmental review and approval processes with a variety of federal, state, and local agencies, ultimately securing no fewer than 30 permits. Weinstein estimates it could take between five and seven years.

And Californians have a well-earned reputation for blocking and stalling major developments. They are particularly touchy about coastal projects–whether they can see them or not.

Catching the wind

Despite the challenges, fans of floating wind remain optimistic.

Walt Musial is the leader of the research efforts at the National Renewable Energy Laboratory on offshore wind. He predicts that the industry will move beyond pilot scale and developers will gain more experience building larger floating wind facilities.

Research groups estimate that the costs could fall from around $200 per megawatt-hour to between $58 and $120 by 2030. Floating offshore wind would be more expensive than onshore and solar, but it could still play an important part in an overall energy portfolio.

The technology is also improving. The turbines themselves are getting taller, which means that they generate more electricity and revenue from each site. Some research groups and companies are also developing new types of floating platforms and delivery mechanisms that could make it easier to work within the constraints of ports and bridges.

The Denmark-based company Stiesdal has developed a modular, floating platform with a keel that doesn’t drop into place until it’s in the deep ocean, enabling it to be towed out from relatively shallow ports.

Meanwhile, San Francisco startup Aikido Technologies is developing a way of shipping turbines horizontally and then upending them in the deep ocean, enabling the structures to duck under bridges en route. The company believes its designs provide enough clearance for developers to access any US port. Some 80% of these ports have height limits owing to bridges or airport restrictions. A variety of federal, state and local organizations are evaluating California and other US ports to determine which ports are best positioned to service floating wind projects. They also assess what upgrades may be necessary.

Government policies across the US, China, the European Union, and elsewhere offer incentives to develop offshore wind farms, domestic manufacturing, as well as supporting infrastructure. That includes the Inflation Reduction Act that Biden signed into law this summer.

Finally, as for California’s permitting challenges, Hochschild notes that the same 2021 law requiring the state’s energy commision to set offshore wind goals also requires it to undertake the long-term planning necessary to meet them. This includes preparing a strategy to streamline the approval process.

Despite floating wind’s promise, it is clear that to make sure it is cost-competitive, and achieve the goals set, the state will need to make huge investments in infrastructure, manufacturing and other areas, and build large projects at a rate that the state hasn’t been able to in the past. California could be a leader in a new sector of clean energy, harnessing its vast coastline resources to achieve its ambitious climate goals.

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