OPALCO proposes to harness tidal power for San Juans

||| FROM TOBY COOPER for SALISH SEA CURRENT |||

Orcas Power and Light Cooperative (OPALCO) has quietly launched an ambitious five-year campaign to bring tidal-power-generating capabilities to San Juan County waters. 

Foster Hildreth, OPALCO’s managing director, seeks to explore “all possible technologies to build reliable, sustainable, and carbon-free resources to meet the energy needs of San Juan County.” 

His enthusiasm for tidal power emerged in 2018 when he set OPALCO on an international quest to harness the daily tidal flows of Rosario Strait.

In 2021, OPALCO formed a strategic alliance with Orbital Marine Energy, Ltd., of Edinburgh, Scotland; one of only a handful of marine energy companies worldwide. 

Orbital identifies itself as a “renewable energy company focused on the deployment of its pioneering floating tidal turbine,” is working as a “technology partner” with OPALCO to develop a proposed site off Blakely Island in Rosario Strait.

The preferred site for the Orbital 2 tidal generation unit is just east of Blakely Island where tidal currents are strong. (OPALCO)

OPALCO declined to answer questions about project details or its timing, saying that it is too early to comment on specifics. 

Krista Bouchey,  spokesperson for OPALCO, said that plans to provide comprehensive updates regarding the Phase 1 Funding opportunity would be provided “once discussions with key stakeholders are finalized, likely sometime this summer.”

Orbital did not respond to inquiries.

Studying feasibility

OPALCO’s web postings describe that feasibility studies have been conducted under a grant from the Department of Commerce’s Clean Energy Fund and the 2021 signing of a memorandum of understanding with Orbital.

Orbital’s website postings describe the OPALCO-Orbital partnership as one of two proposed marine projects competing for a $6 million U.S. Department of Energy (DOE) grant for the development of a “tidal energy research, development and demonstration pilot site.”

DOE has announced that the competing project is located in Maine, as detailed in “Environmental Information for Siting and Operation of Floating Tidal Turbines in U.S. Waters,” in the Pacific Northwest National Laboratory publication Tethys.

Only one of the two proposals will be selected to move forward with development of a full project.

Project design

OPALCO indicated in 2022 that it was seeking to install one floating tidal turbine in Rosario Strait off Blakely Island or Orcas Island, connecting to grid power via an existing 18-inch conduit installed in 2004 on the sea floor between Blakely and Orcas. From a substation, the energy would be transmitted via OPALCO’s system throughout the service area.

OPALCO estimates that the tidal turbine would have a maximum generating capacity of approximately 2 megawatts with an annual output of 4.6–5.6 gigawatt hours annually — able to power 400 homes.

As part of the permitting process, OPALCO anticipates state and federal interagency engagement with the U.S. Army Corps of Engineers, the National Marine Fisheries Service, the U.S. Fish and Wildlife Service, the Washington Department of Fish and Wildlife, the Washington Department of Ecology, the Washington Department of Natural Resources and the Federal Energy Regulatory Commission.

Once the necessary environmental studies have been completed, permitting the deployment of this system is expected to take approximately 24 months, according to OPALCO.

Large-scale installation

In partnership with Orbital Marine Energy, OPALCO seeks to bring to local waters an industrial device of unprecedented scale.

OPALCO proposes to deploy a 242-foot floating tidal energy turbine on a trial basis in San Juan County’s waters, aiming to provide local power and help steer the region to a clean-energy future. (Orbital Marine Energy, Ltd.)

At 242 feet in length, the Orbital O2 unit would nearly stretch goal line to goal line of a regulation NFL field. Each 66-foot wing holding a hydrogenating rotor would nearly reach sideline to sideline. 

Each rotor, while spinning during power generation, covers an area nearly the size of an NBA basketball court.

With the articulating, hydraulic “legs” raised for maintenance, the O2 resembles an airliner on the surface of the sea. For normal operations, the legs are lowered deep below while the narrow body remains afloat.

Orbital estimates that the mooring cables that hold the O2 in position could lift 20 double-decker buses.

Approximately a dozen tidal power stations using turbine or other technologies are reported in operation worldwide, including the O2 currently deployed in Scotland’s Orkney Islands.

Orbital claims that their O2 technology has solved issues such as high costs, dangers to marine mammals and fish, heavy physical loads of fast-moving seawater, and the corrosive effects of the marine environment — issues that are cited as factors inhibiting the growth of tidal power generation. 

The company has plans to site three additional devices in the waters around the British Isles. 

Orbital declined to say why they would be willing to send their only operating unit to San Juan County. However, the company has posted a description of a next-generation composite floating device that promises to include tidal generation, wind generation, battery storage and “green hydrogen production,” all ultimately integrated into a regional power grid.

OPALCO and Orbital are awaiting DOE’s decision on the pilot grant, according to Bouchey. As their plans take shape, Salish Current will be reporting further.

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