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Quick Fact: OPALCO Tidal Energy Pilot Project

Posted in Quick Fact, Renewables

ABOUT this project:

Given our unique service territory in the San Juan Islands, surrounded by the Salish Sea, people have been asking for years why we haven’t explored tidal energy yet. A combination of a 2021 Department of Commerce grant and a 2024 Department of Energy grant has given us an opportunity to study what a project like this could mean. If this project were to move forward, there are still lots of studies, research, and analysis to be done to make sure this is a viable energy source for this region and that it meets the criteria for success on all fronts.

tidal scale

Through a US DOE TEAMER project, OPALCO and our project partners have explored siting of a ~2MW floating tidal stream Orbital Marine Power turbine. The Rosario Strait, near Blakely Island, WA was identified as a viable site with strong tidal flows in proximity to OPALCO infrastructure for interconnection. For the chosen site the interconnection would be via an existing 18” conduit that was installed in 2004 from OPALCO underground vault on northwest Blakely Island and Southeast of Orcas Island to the sea floor. The interconnection would connect to a substation on Blakely Island where the energy would be transmitted via OPALCO’s 69kV transmission system to subsequent islands. It is estimated that one Orbital tidal turbine would be able to power 400 homes in the OPALCO service territory. Estimated annual production is anticipated to be 4.6 to 5.6 GWh.

WHY are we exploring tidal and other renewables?

We’re seeing an imbalance in supply and demand that can that could greatly affect our region. As an island community, San Juan County is at risk of unreliable electricity, as the vast majority of OPALCO’s power comes from submarine cables from mainland WA state. Because of this, OPALCO is committed to implementing local energy generation resources that strengthen the resilience of infrastructure, increase safety and reliability for the co-op members, and keep rates affordable. We also want to ensure that our future energy supply is carbon free to mitigate the impacts of climate change. This is especially important as the US rushes to decarbonize and has been decommissioning coal power plants. OPALCO is looking to meet the goal of providing reliable and resilient power during a time when existing energy sources are being taken off the grid, while still meeting regulatory clean energy goals.

For more information on the growing supply vs. demand issue in our region, visit the Quick Fact: Why Local Renewable Projects? Mainland Power Demand will Soon Exceed Supply.

THE TECH: Orbital Marine Floating Tidal Turbine

tidal barge

The Orbital Marine Power O2 floating tidal turbine has a 242- foot hull with suspended rotors underneath that can be raised for on-site service. The turbine is anchored to the seafloor with mooring lines (See image to right). Floating approximately 5 feet above the waterline and 7.5 feet below, the unit houses two turbines with a combined output of ~2 MW. The device is 197 feet wide including the span of the blades when raised above water. This technology has been deployed since 2021 in the Orkney Islands, Scotland. It is the third grid connected device that Orbital has installed. The Orkney Islands has a similar marine environment to San Juan Islands including pods of Orca Whales. There has been consistent monitoring and no Orca interaction with the device to date. While lessons from the Orkney pilot are informative and will be applied to OPALCO’s project, the Rosario Strait project will undergo its own scientific monitoring and mitigation requirements (as identified in the Draft License Application), ensuring locally relevant data informs every stage of design, construction, and operation. Projects like this turbine would be built and sourced in the USA.

THE DETAILS: Grants and studies completed

In 2018 OPALCO began investigations of multiple tidal device types and deployment logistics in the San Juan Islands. OPALCO found the floating turbine technology to have the most promise considering the service ability, marine traffic and environmental parameters.

Below are details about the work done from 2019-2021, including the Department of Commerce grant.

  • Established relationship via MOU with Orbital Marine Power in Q1 2021 with informal exchange of information having previously started in mid-2019.
  • PNNL and Orbital awarded US DOE TEAMER Grant (PNNL-32302, Environmental Information for Siting and Operation of Floating Tidal Turbines in U.S. Waters) Site assessment study completed Q4 2021.
  • University of Washington and Orbital awarded US DOE TEAMER Grant (Orbital Marine Power, San Juan Islands Tidal Energy Characterization, Facility: University of Washington and Pacific Northwest National Laboratory).
  • OPALCO awarded WA DOC CEF4 Grid Modernization Grant in Q4 2021 for preliminary design and permitting of floating tidal generation in Rosario Strait.
  • Pacific Northwest National Labs siting study evaluated five different locations around the San Juan Islands and Rosario Strait was chosen for a variety of factors including less marine mammal traffic and close to existing infrastructure.map

The 2024 DOE grant is for feasibility only and is competitive. This grant is only phase one of multiple grant funding phases that would be necessary in order for the project to be successful, if it were to move forward. The 12 month grant period officially started in June 2024. The feasibility study for this grant, which evaluates whether or not this project would be successful, includes:

  • Environmental site study for physical and biological data that includes mapping the sea floor, assessing tidal flow, monitoring tagged fish going through the area, and measuring underwater noise levels
  • Environmental risk register using a third-party objective analysis that evaluates key issues the project will face
  • Draft License Application to Federal Energy Regulatory Commission (FERC)
  • Community Outreach

OPALCO has had ongoing engagement with:

  • Local, state, and federal agencies
  • Tribal Sovereign Nations
  • Local Stakeholders
  • OPALCO members

TRIBAL ENGAGEMENT:

Engagement and collaboration with the Tribal Nations is a key aspect of project development. OPALCO recognizes that the Tribal Nations with ancestral lands in the San Juan Islands have strong spiritual and cultural ties to salmon and other aquatic species in the region that includes thousands of years of access and use for religious/cultural ceremonies, subsistence, and for commercial purposes. The proposed project would be in the Usual and Accustomed (U&A) fishing area for the region’s Tribal Nations who were signatory to the Treaty of Point Elliott, which is a key aspect of why OPALCO started outreach to the Tribal Nations at the inception of the feasibility study. OPALCO began outreach and hosting meetings with Tribal Nations in 2022. OPALCO continued engagement through meetings and correspondence at key milestones throughout the duration of the Department of Energy Phase 1 grant process to share information about the potential project and collaborate to assess the feasibility. OPALCO worked collaboratively with Tribal Nations to identify priority topics requiring study to inform the FERC Draft License Agreement (DLA) application process. In March 2025, OPALCO filed the DLA application with the Federal Regulatory Commission (FERC). Government-to-government consultation with the Tribal Nations will occur between FERC and the Tribal Nations.

Since 2022, OPALCO has been meeting with the Tribal Nations to engage them on this project and to obtain their early input to help shape the project. OPALCO had 92 “touch points” with the Tribal Nations during this time. OPALCO values these long-standing tribal partnerships and appreciates the meaningful input and collaboration that have been received so far, including collaboration on kelp restoration efforts in the vicinity of the project, valuable information on the importance of tribal treaty fishing rights, and tribal perspectives on renewable projects in general.

OPALCO appreciated that the Swinomish Tribe let us know that they submitted a formal objection to the project with FERC on September 30 (additionally two other tribes filed objections). The objections raise concerns about the impacts the project will have on the Usual & Accustomed Fishing Rights and the sensitive marine environment. The Tribe also stated some of the bigger regional issues with old docks and other marine equipment that lingers in the waters will need to be addressed before adding in more infrastructure. The OPALCO Team takes feedback from the Tribal Nations seriously and appreciates the time they took to provide input. OPALCO knows that the success of this project or projects like this in the future will rely on the support and collaboration with the Tribal Nations.

OPALCO will heavily consider any tribal objection as they weigh out the potential of this project. The Department of Energy, who is the current funder of the project, is deciding which tidal energy project will receive future funding and will let OPALCO know later this year the decision of the down select process. At that time the Board will consider all the factors of what makes this project viable or not.

Wrapping Up the grant cycle: 

On March 27, 2025, OPALCO filed a Draft License Application with the Federal Energy Regulatory Commission (FERC) for a 10-year pilot project license for OPALCO’s proposed Rosario Strait Tidal Energy Project. The Draft License Application compiles the best available science, presents the results of the site characterization studies, and includes a discussion of existing conditions affects analysis but is only the beginning of the analysis needed to get to a Final License application. The work to date is not considered complete but is at a point where key areas will be identified for further study. Based on the government-to-government consultation results and the public comments, FERC will decide on next steps and whether to advance the project to the Final License Application (FLA) for the pilot project.

September 30, 2025 was the last day to make public comments on the Rosario Tidal Energy Project as part of the public process with a pilot Draft License Application (DLA) with the Federal Energy Regulatory Commission (FERC). Future funding is currently dependent on Department of Energy (DOE) and is being determined but is still months away from a decision (as of 9/30/25).

OPALCO remains firmly committed to financial responsibility and environmental stewardship. Local, renewable energy projects need to be technically, environmentally, and fiscally sound. If this project were to move forward, there are still lots of studies, research, and analysis to be done to make sure this is a viable energy source for this region and that it meets the criteria for success on all fronts.

Historically, OPALCO explored a different tidal energy project in the early 1980s. Tidal energy has great potential to supply us with carbon-free energy in this area – especially valuable during the winter and night hours. By providing renewable power locally, the project and projects like this could reduce reliance on carbon-based energy generation and long-distance, dam-generated, energy imports, leading to broader environmental benefits for marine mammals.

Additional Resources:

FAQs

In 2024, OPALCO was awarded a grant from Department of Energy to continue feasibility studies for a tidal generator in Rosario Strait. During this period, it will be determined if a tidal energy project in San Juan County could move to full development. With an earlier grant, OPALCO and project partners explored siting of a ~2 MW floating tidal stream Orbital Marine Power turbine in our area. The Rosario Strait was identified as a viable site with strong tidal flows in proximity to OPALCO infrastructure for interconnection, with minimal environmental impacts.

As impacts of climate change and legislation drive up the costs of green power, OPALCO is committed to exploring local, renewable energy sources. With water being 800 times the density of air, tidal stream energy is to the northwest what solar is to the southwest. While solar is minimal in the winter, tidal power is strong and predictable year-round, but more importantly, it can be firmed with a small fraction of the storage solar or wind would require.

It will provide 5GWh of annual generation serving approximately 400 homes based on annual average usage in San Juan County.

This is a competitive grant through DOE for $3M. Based on the outcomes of the yearlong grant, our project could be selected to receive more grant funds and advance to the next phases.

A feasibility study is a way to evaluate whether or not this project could be successful. For this project it will include:

  • Environmental site study for physical and biological data that includes currents, turbulence, waves, ambient sound, water quality, fish tag receiver, sea spider, stable moor
  • Environmental risk register using a third-party objective analysis that evaluates key issues the project will face
  • Draft License Application to Federal Energy Regulatory Commission
  • Community outreach

The full cost of the project is still being determined. OPALCO only plans to move forward with the project if it is financially feasible and doesn’t affect OPALCO member rates. We would need to get grant funding for this project to move forward.

Orbital Marine is a company out of Scotland that has installed this unit in the Orkney Islands. This is a similar marine environment to the San Juan Islands. They have successfully been generating electricity from their O2 since 2021.

No, if this project were to move forward a unit based on the O2 unit design would be manufactured in the US and installed in the water at that time.

The site environmental study does have monitoring devices that will be submerged in the proposed location. This equipment will be underwater for a limited amount of time and will give us important information on tidal flow and marine wildlife. However, during the feasibility phase there are no plans to install any power generating infrastructure.

A FERC preliminary permit is an initial step, and it lets us have first priority in applying for a license for the project that is being studied. It does not allow for any specific work to be done – it is a step to ensure the study of the project’s feasibility. If the project is found feasible then we can use the data and info gathered to prepare an application for a license and then would need permits to get specific work done.

Here is the link to our Preliminary Permit Docket Number P-15368-000: https://elibrary.ferc.gov/eLibrary/search.

OPALCO has been working with local, state, and federal agencies for permitting and environmental requirements. The team is meeting with Tribal Nations to get feedback and share information throughout the project.

We are doing feasibility studies to determine the environmental impacts.

Engagement and collaboration with the Tribal Nations will be a key aspect of project development. The Tribal Nations with ancestral lands in the San Juan Islands have strong spiritual and cultural ties to salmon and other aquatic species in the region that includes thousands of years of access and use for religious/cultural ceremonies, subsistence, and for commercial purposes. The proposed project would be in the Usual and Accustomed (U&A) fishing area for the region’s Tribal Nations who were signatory to the Treaty of Point Elliott. The team is meeting with these Tribal Nations to get feedback and share information throughout the project. We started these meetings years ago (2002) and are continuing with these throughout the duration of the DOE/FERC process. There will be other opportunities through FERC for the Tribal Nations to give official comment on the project.

We started our outreach to Tribal Nations over 2 years ago. It started with initial outreach to the Tribal Chairpersons from the Tribes we regularly consult based on our state, local, and federal agency recommendations. We have expanded our outreach to include the fisheries, environmental, and cultural departments and preservation officers as recommended by the Tribal Nations.  We have strived for early engagement and an inclusive approach based on working with each Tribal Nation to determine how best to engage them throughout this process. To date we have had 10 meetings with the Tribal Nations and additional meetings are scheduled over the next month.

We are not at a stage where Tribal Nations have formally commented or expressed their support. Since we are still in the feasibility phase of the project, we are still gathering and sharing information and helping define what should be studied. To date, the Tribal Nations have been responsive and engaged and have been great to work with. We will be sharing all information that is studied with the Tribal Nations.

This is part of what is being studied during the feasibility stage. This aspect of the project will be looked at from various perspectives and we will be seeking input from Tribal Nations and the regulatory agencies involved with recreation and commercial fisheries and navigation.

The energy world is changing dramatically due to climate impacts, carbon reduction legislation, and the transition toward renewable power. The goal of our state and nation is to transition away from fossil fuels and heat our homes and fuel our cars, trucks and ferries using electricity. This lofty goal is proving to be highly challenging. Given our remote location, our best bet for clean and affordable firm power is to build renewable generation projects locally. OPALCO wants to explore power options that can offer power when the sun isn’t shining, and the wind isn’t blowing. Tidal power has a much more consistent flow of energy and can offer power in the winter months when we use the most.

The device will be visible from shore. There are always trade-offs for every power generation source, and we will need to weigh out the costs and benefits including visual impact.

Orbital Marine out of Scotland has had the floating stream O2 device in the water in the Orkney Islands. You can find pictures of the location with the technology at https://www.orbitalmarine.com/. They have been successfully harvesting power since 2021.

The FERC pilot license OPALCO is applying for is good for 10 years. The unit lifespan is 20 years. If it makes sense, there is potential for continuing with a full commercial license to use the unit for its full license.

The fine details of who would do what have yet to be determined. The current plan is that Orbital and OPALCO would split maintenance of the unit. Orbital would monitor and deal with most major things. OPALCO would do some of the more routine maintenance. This current grant will help determine some of these details.

This project is outside of the shipping channel based on AIS frequency maps.

Unknown. This is part of what will be determined during this study. Breaking even will be dependent on future regional power costs.

We won’t know until analysis is done. If it’s not about saving money the likelihood of going forward is small.

This is a grant funded project with the goal being nominal costs to OPALCO members. Regional power costs are going up so OPALCO is exploring ways to have some local, renewable generation that will be more cost effective that mainland power.

We have done initial engagement with the National Marine Fishery Service. This is the group we are required to work with because Orca Whales are in the area. They will dictate what studies we need to do and who we will need to consult. This is all mandated by the Marine Mammal Protection Act and the Endangered Species Act. We chose this location based on a study by PNNL that stated there was less marine mammal traffic than some of the other local locations.

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