Information Sheet
Regulation of Tidal and Wave Energy Projects

Revised: March 2018         Contact: (207) 287-7688     


Tidal energy projects use tidal action (tidal amplitude or currents) to generate power while wave energy projects use wave action (wind-driven water level oscillations) to generate power. Historically, there were a number of small dams along the coast of Maine that used tidal action to operate a gristmill or sawmill using mechanical power until electricity became available locally. Construction was actually started on a large-scale tidal power project proposed for Passamaquoddy Bay in the 1930's, but the project was later abandoned for economic reasons. Despite the fact that designs for tidal energy systems have been patented since the 1800s, there are no commercial-scale tidal or wave energy projects in operation in the United States today and only a handful in operation world-wide.

There is currently a renewed interest in using the ocean to generate electricity, using both traditional hydropower technologies and new hydrokinetic technologies. This interest is being spurred by recent federal legislation promoting development of cleaner domestic energy sources and diversification of energy supplies through use of alternative and renewable sources and by recent studies of wave and tidal power technologies and potential sites, including sites for tidal and wave energy projects in Maine. Interest is also being spurred by the development of new composite construction materials and computer-added design improvements that may overcome some of the technical problems inherent in earlier designs.

Tidal energy projects hold the promise of producing indigenous, renewable, predictable electricity without greenhouse gas emissions and with higher power densities (power output per unit area) than either solar photo-voltaic or wind projects. Tidal energy projects also may be useful in filling in the gaps in generation from other intermittent energy sources, such as wind projects. However, much of the required technology is still in the research and development stage, and the economic viability and environmental impacts of these technologies are largely unknown.

The Governor’s Task Force on Ocean Energy was created in November 2008 to recommend a strategy for moving forward as expeditiously as practical with the development of the ocean energy resources of the Gulf of Maine. The Task Force submitted its final report in December 2009. As a result, the Maine Legislature passed emergency legislation designed to encourage ocean energy development in an environmentally responsible manner.

This information sheet describes the current status of tidal and wave energy technology and how tidal energy projects are regulated in Maine.

Tidal Power Technology

Existing commercial-scale tidal energy projects all use traditional tidal dam (barrage) technology, in which electricity is generated using the head created by holding tidal water back behind a barrier and then passing that water through a turbine when on-going tidal action creates a sufficient difference in water levels on the two sides of the barrier to power an electric generator. Combinations of two or more dams and/or reversible turbines can be used to generate power on both the incoming and outgoing tides. While a tried-and-true technology, tidal barrages have high capitol costs and potentially significant environmental impacts. Also, the number of sites with sufficient tidal range and channel width characteristics to be economically viable is limited.

The nearest tidal barrage is the 20 megawatt Annapolis Royale Project in Nova Scotia, Canada, that takes advantage of the enormous tides in the Bay of Fundy.

New tidal in-stream energy conversion technologies (commonly referred to as hydrokinetic technologies) seek to use tidal currents to generate electricity without the need for a dam or barrage. There are two primary types of in-stream hydrokinetic devices, horizontal axis turbines and vertical axis turbines. Turbine designs include helical or cross-flow units (similar in design to the blades on a hand-powered lawnmower) and axial flow (propeller-type) units of varying diameters that are either open or closed (ducted) and that have either fixed or variable-pitch blades. Deployment configurations include single, dual or multiple units utilizing bottom foundations (either pilings or weighted platforms), monopole foundations (underwater windmills), or anchoring systems for units positioned in the water column. Hydrokinetic tidal systems may use conventional generator technology (wire-wound rotors and stators) or may employ permanent magnet generators, either submerged or located above the water surface.

Maine has significant tidal power potential, especially in downeast areas with a large tidal range and in high-velocity narrows. Various tidal energy devices are currently being tested in Maine and other coastal states, including New York and Ala ska . The diagram below shows the Ocean Energy Power Company proprietary turbine-generator unit (TGU), which utilizes a horizontal cross-flow turbine design with an integral permanent magnet generator, and is currently being tested in Cobscook Bay in Eastport.

Wave Power Technology

Other hydrokinetic technologies seek to generate electricity from the motion of ocean waves. Many of these technologies use hydraulics to convert water level oscillations into electricity. Others employ compressed air or direct mechanical drive. Some ride on the ocean's surface (so-called sea snakes), while others are submerged. Some produce electricity at the device, while others pump pressurized water to on-shore generators. Finally, some are designed for shallow, near-shore locations, while others are designed for deep-water, off-shore locations.

While other states have better wave regimes than Maine , it is likely that at least some of the emerging wave technologies will be tested here, possibly in association with off-shore wind energy plants (where there is wind, there are waves).

Federal Regulation

Non-federal hydroelectric power projects, including tidal and wave energy projects that are interconnected with the interstate electric transmission grid, are subject to licensing by the Federal Energy Regulatory Commission (FERC). Traditionally, FERC has only issued 30-50 year licenses for commercial-scale projects. However, in light of the need for developers to be able to deploy projects on a short-term basis to evaluate the economic and technical feasibility and the environmental effects of various technologies, FERC has created a stream-lined pilot project licensing process to allow the licensing of demonstration hydrokinetic projects for testing purposes. Pilot projects must be small; short-term; avoid sensitive locations; subject to modification or shut-down if unforeseen impacts occur; subject to plans for monitoring and safeguarding public safety and environmental resources; and removed, with the site restored, at the end of the license term unless a commercial license is issued (more information on the licensing of hydrokinetic pilot projects is available on the FERC website).

All tidal and wave energy projects, whether interconnected with the electric grid or not, are subject to permitting by the U.S. Army Corps of Engineers (COE) under Section 404 of the Clean Water Act (regulating the discharge of dredged or fill materials into waters of the United St ates ) and/or Section 10 of the Rivers and Harbors Act (regulating construction and other work in navigable waters) (for more information, go to the COE website).

State Regulation

Tidal and wave energy projects are subject to permitting by the Department of Environmental Protection (DEP) under the Maine Waterway Development and Conservation Act (MWDCA), the State's one-stop hydropower permitting law. The MWDCA requires an evaluation of the full range of potential economic and environmental impacts of a project, including impacts on public safety, wetlands, water quality, fish and wildlife resources, historic and archaeological sites, public access, and energy generation. DEP has permitting jurisdiction over all tidal and wave energy projects located in State waters (those waters within 3 miles of the mainland and any island that is part of Maine).

Tidal and wave energy projects are also subject to review under Section 401 of the Clean Water Act, which requires that any applicant for a federal license or permit for an activity that may result in a discharge to navigable waters obtain a certification from the State that the activity will not violate applicable state water quality standards. These standards consist of designated uses and numeric and narrative criteria designed to ensure that Maine 's waters satisfy the swimmable-fishable goals of the Clean Water Act. These standards also include an antidegradation policy requiring that existing in-stream uses be maintained and protected. DEP has certification authority over all tidal and wave energy projects located in State waters.

For a summary of state and federal regulatory processes for tidal and wave energy projects, see the December 2009 U.S. Department of Energy report: Siting Methodologies for Hydrokinetics.

Federal-State Coordination

In August of 2009, Maine became the first state on the east coast, and only the third state in the country, to sign a Memorandum of Understanding (MOU) with FERC to coordinate procedures and schedules for review of tidal energy projects in State waters or in federal waters (beyond the 3-mile state territorial limit) where the projects affect resources or uses in Maine's coastal zone.

Ocean Energy Legislation

In 2009, the Maine Legislature passed and the Governor signed into law An Act To Facilitate Testing and Demonstration of Renewable Ocean Energy Technology . This law was enacted to streamline and coordinate State permitting and submerged lands leasing requirements for renewable ocean energy demonstration projects so that the State of Maine can become an international proving ground for testing new technologies in specific locations along the coast in an environmentally responsible manner.

In 2010, the Maine Legislature passed and the Governor signed into law An Act To Implement the Recommendations of the Governor's Ocean Energy Task Force. This law was enacted to overcome economic, technical and regulatory obstacles and to provide economic incentives for vigorous and efficient development of promising indigenous, renewable ocean energy resources in ways that recognize the concurrent need to sustain the ongoing biological integrity of the State's waters, the vitality and productivity of ocean harvests and the differing needs and uses of the seas and other natural resources and to ensure the provision of these benefits to the people of the State by careful use of such public resources for renewable ocean energy production.

Encouragement of Tidal and Wave Power Development

The 2010 law amended the MWDCA to provide that it is the policy of the State to encourage the attraction of appropriately sited development related to tidal and wave energy, including any additional transmission and other energy infrastructure needed to transport such energy to market, consistent with all state environmental standards; the permitting and siting of tidal and ave energy projects; and the siting, permitting, financing and construction of tidal and wave energy research and manufacturing facilities. Thus, all applications for tidal and wave energy projects must be processed in keeping with this policy.

The 2010 law also sought to encourage tidal and wave energy development by:

  • Requiring that the Public Utilities Commission take into account the state's renewable energy generation goals in determining the public need for proposed transmission lines;
  • Directing the Public Utilities Commission to solicit proposals for long-term contracts to supply installed capacity and associated renewable energy and renewable energy credits from one or more tidal energy demonstration projects;
  • Directing the Governor's Office of Energy Ind ependence and Security to make recommendations to the Legislature regarding terms and conditions for long-term contracts to supply installed capacity and associated renewable energy and renewable energy credits from renewable ocean energy projects; and
  • Directing the Maine Port Authority to assess existing port facilities and make recommendations to the Legislature regarding acquisition of real estate needed to facilitate renewable ocean energy development opportunities.
  • Directing the Bureau of Revenue Services to report to the Legislature regarding whether and under what circumstances ocean energy-generating equipment in transit within the State on April 1 is exempt from personal property tax.
  • Establishing a Renewable Ocean Energy Trust fund to to protect and enhance the integrity of public trust-related resources and related human uses of the State's submerged lands.

General Permits for Tidal and Offshore Wind Energy Demonstration Projects

The 2009 law amended the MWDCA to establish a new general permit process for tidal energy demonstration projects. To qualify for a general permit as a tidal energy demonstration project, a project must use tidal action as a source of electrical power; must have a total installed generating capacity of 5 megawatts or less; and must be proposed for the primary purpose of testing tidal energy generation technology, including mooring or anchoring systems and transmission lines, and collecting and assessing information on the environmental and other effects of the technology.

The general permit process for tidal energy demonstration projects is designed to dovetail with FERC's pilot project licensing procedures for hydrokinetic technologies. In applying for a general permit, an applicant must submit: (A) a copy of a pilot project license application, as filed with FERC, along with all information required by FERC; (B) proof of general liability insurance for the project; (C) demonstration of financial and technical capacity to construct and operate the project; (D) a copy of an environmental assessment for the project issued by FERC under the National Environmental Policy Act (NEPA) that includes a finding of no significant environmental impact (FONSI); and (E) an acknowledgement that the DEP may require the applicant to take remedial action under the law, including the cessation of operations and removal of project facilities, in order to protect natural resources and/or public safety.

Once all the required information has been filed, the DEP must act within 60 days on an application for a general permit and water quality certification for a tidal energy demonstration project.

Unless surrendered by the applicant or terminated by the DEP, a general permit for a tidal energy demonstration project is valid for the term of the pilot project license issued by FERC for the project. The DEP may grant one or more extensions of the general permit term to coincide with any approved extension(s) of the pilot project license or any related annual license issued by FERC.

The 2009 law also amended the Natural Resources Protection Act (NRPA) to establish a new general permit process for offshore wind energy demonstration projects, including wave energy test projects. To qualify for this general permit, a wave energy test project must use ocean wave energy to produce electricity; be proposed as part of an offshore wind energy demonstration project and be designed and sited to test production of electricity from wave energy in conjunction with and in a manner that complements electricity produced by an offshore wind energy turbine; employ up to 2 wave energy converters, each of which may use different technology, not already in use in the Gulf of Maine for commercial energy production, for the primary purpose of testing and validating the overall design of the converter and related systems; and may include a mooring or anchoring system and an ocean sensor package.

Procedural Changes

The 2010 law also made several procedural changes in existing law to streamline the review process for tidal and wave energy projects. Under these changes:

  • The DEP has original jurisdiction over any tidal or wave energy general permit application, while the Board of Environmental Protection only has authority to hear any administrative appeal of the Commissioner's decision;
  • Any judicial appeal of a DEP or BEP decision on a tidal or wave energy general permit must be made directly to the Maine Supreme Court, instead of going first to Superior Court;
  • The DEP may enter into an agreement for outside review of an application for a tidal or wave energy project without requiring that the applicant consent to the outside review and agree to pay all costs associated with the review; and
  • Tidal and wave energy projects are not required to be consistent with Land Use Regulation Commission zoning, even if located in an unorganized territory.

Other statutory changes are discussed below.

State Submerged Lands Lease

A lease is required for the use of state-owned submerged lands in connection with the placement of any tidal or wave energy project in State waters, including any mooring or anchoring system and transmission line. Both the 2009 and 2010 laws amended the provisions of the State's submerged lands leasing program governing tidal and wave energy projects.

With respect to tidal and wave energy demonstration projects:

  • Within 15 days of receiving a copy of a general permit application for a tidal or wave energy demonstration project, the Director of Public Lands shall, if requested, provide the applicant a lease option for use of state-owned submerged lands needed for the project.
  • Within 30 days of receiving a copy of a general permit for a tidal or wave energy demonstration project, the Director of Public Lands shall issue a submerged lands lease for the project. The term of the lease must be consistent with that of the general permit, including any extension(s) of the permit, and the period of time needed to fully implement the approved project removal plan. The lease may include reasonable conditions, but these conditions may not impose any condition more stringent than those on the general permit and may not frustrate achievement o the purpose of the project.
  • The annual rental fee for a tidal energy demonstration project for which a general permit has been issued shall be $100 per acre of submerged lands occupied by the project, up to a maximum fee of $10,000.

With respect to commercial tidal and wave projects:

  • Within 30 days prior to filing an application for an MWDCA permit and water quality certification, an applicant for a submerged lands lease for a commercial tidal or wave energy project must participate in a joint interagency pre-application meeting with DEP and the Department of Marine Resources.
  • The applicant must certify that a completed DEP permit/certification application has been or is concurrently being filed at the time of filing its submerged lands lease application.
  • The Director of Public Land s shall provide notice of the lease application to the Marine Resources Advisory Council and any established lobster management policy council whose designated lobster management zone is within 3 miles of the proposed project.
  • In making findings on a submerged lands lease application for a commercial tidal or wave energy project, the Director of Public Lands shall adopt all pertinent findings and conclusions in any permit issued for the project by the DEP, and may condition any lease on receipt of a DEP permit and other conditions the Director considers reasonable.
  • The annual rental fee for a commercial tidal or wave energy project shall be in accordance with a fee schedule, to be established by rule, that balances state goals of assurance of fair compensation for use and mitigation of potential adverse effects on or conflict with existing uses of state-owned submerged lands that are held in trust for the people of the State with state renewable ocean energy-related goals.
  • A lease for a commercial tidal or wave energy project may be issued for a term of up to 50 years (this term cannot exceed the term of any FERC license issued for the project).

Local Review

The 2009 law provides that a municipality may not enact or enforce any requirement for a tidal energy demonstration project located within the municipality that is stricter than the requirements of the general permit process, and the municipality has the burden of proving that the project is located within its municipal boundaries.

The 2010 law provides that a municipality may not enact or enforce any ordinance that prohibits the siting of a tidal or wave energy project, including associated facilities, within that municipality, and may only regulate a project or part of a project located within its boundaries.

Additional Sources

State regulatory process and for DEP application forms

FERC hydrokinetic pilot project licensing process

Public Law 270, An Act To Facilitate Testing and Demonstration of Renewable Ocean Energy Technology, effective June 4, 2009.

Public Law 615, An Act To Implement the Recommendations of the Governor's Ocean Energy Task Force, effective April 7, 2010.

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