Some of the onshore infrastructure is already in place. And California's legislature has passed a law for a renewables portfolio standard (RPS) of 50% by 2030 that is likely to boost demand for wind significantly after 2020 – the law is waiting to be confirmed by the state governor Jerry Brown.
Seattle-based Trident expects the entire offshore project to be online in the "2025 time frame".
But the deep-water plan faces significant hurdles for financing and permitting. Around the time of Trident Winds' founding, in July, a marine sanctuary had been proposed that could stymie a commercial project.
The Morro Bay Offshore project could comprise 100-plus turbines on floating platforms more than 24km west of Point Estero near Morro Bay in central California. The water is deep, at about 460 - 915 metres, and the offshore winds are 7-8metres per second and consistent.
That is a better match with the state's demand profile than California onshore wind or solar, said Alla Weinstein, founder of Trident Winds, who believes that onshore wind and solar alone cannot meet California's market needs post-2020.
Prior to founding Trident Winds, Weinstein had founded Principle Power, a recipient of $47m from the Department of Energy for its 30MW demonstration WindFloat Pacific project off Oregon, also in deep-water off the US west coast.
One of Weinstein's colleagues is Eric Markell, a former senior executive with utility Puget Sound Energy in Washington state and former vice president of the New York State Energy Research & Development Authority.
Principle Power's WindFloat floating platform technology has been tested in shallower waters off Portugal since 2011. A prototype was fitted with a Vestas V80 2MW turbine.
When asked whether the wind project would use WindFloat technology, Weinstein said it is too early to know. Floating foundation technology is likely to be commercial after 2020.
A possible advantage for the Morro Bay offshore wind project is a nearby retired water-cooled natural gas plant, as well as a substation and transmission line owned by utility Pacific Gas & Electric (PG&E). Dynegy's 650MW "Three Fingers" power plant, dating from the 1950s, has a water inlet that Trident believes could contain the project's export cable.
Trident is in discussions with the City of Morro Bay but as of late September had not been able to start talks with Dynegy, which has received Federal Regulatory Energy Commission preliminary permits for a wave power facility in the area.
An exact site for the offshore wind project has yet to be chosen, said Weinstein.
Trident is in talks with fishermen and Native American tribes. "We have to be sure we can live with each other," said Weinstein, adding that a site should be selected within the next few months.
Trident has started discussions too with local environmental groups, the California Independent System Operator — which operates the grid – and PG&E.
A lease application is being filed with the US Bureau of Ocean Energy Management (BOEM) and talks were also to start soon with other stakeholders and regulators, including the California Energy Commission, the California Coastal Commission and State Lands Commission.
However, a local tribal organisation, the Northern Chumash Tribal Council (NCTC), has re-applied for marine sanctuary status for the Morro Bay area. The application is being reviewed. An offshore wind project could thus be prohibited. Conversely, it could be seen as compatible with the sanctuary's designated purpose.
NCTC spokesman Fred Collins said: "The [NCTC] has been looking at all the reviews and information that we have available, and we have not made a determination... we are proposing a marine sanctuary off our coasts, [and] one of the main issue is no oil rigs off our coast, lights, and so forth... we have some very big considerations to look at, so, at this time we have no 'point of view'."
Permitting with BOEM typically takes about two years, although permitting with the coastal and lands commissions is less certain. No offshore commercial structure has been approved off California in over 40 years, when an oil platform was consented off Santa Barbara.
Since then, the California environmental movement has become powerful. "But now, we are not dealing with oil, we are dealing with renewable energy – and there has to be more of it," Weinstein said.
Weinstein added that the "viable" onshore wind sites in California have been developed and importing wind power hundreds of miles from Wyoming or other states would be no cheaper than offshore wind. By the early 2020s, deep-water wind technology will be financeable off California, she said.
Wyoming wind will remain pricey, agreed Amy Grace of Bloomberg New Energy Finance, but, added: "Without a carve-out [in the RPS] specifically for offshore wind, there would be little economic incentive to install offshore over [California-based] onshore wind or solar."
California still has onshore wind development potential, despite some transmission constraints. "[It] will take an act of political will to get sufficient revenue support" for Trident's project even after 2020. "The economics are more likely to kill the project than the permitting," said Grace.