Emerging Issues: Tidal Energy
With demand for energy on the rise and the threat of climate change looming just over the horizon, there is an urgent need for new, clean, and renewable sources of energy. In November 2006, Washington's voters passed Initiative 937, which required the state's 17 largest utilities to obtain 15 percent of their electricity from renewable sources by 2020. And Congress is currently debating HR 969, which would create a national renewable portfolio standard and compel utilities nationwide to generate or buy 20 percent of their electricity from renewable sources by 2020.
Since passage of I-937, Washington state utilities have renewed their focus on seeking new and viable ways to generate renewable power. Washington has a long history of hydropower, and the environmental headaches associated with operation of large dams. And recently wind power has made inroads with 6 wind projects and 660 turbines completed in Eastern WA since 2001. But new growth in hydropower will be difficult and wind cannot meet all of the region's growing demand. Because of this, utility companies and PUDs have begun to investigate the feasibility of power derived from the Puget Sound's strong tidal currents. See HB 3216 - 2007-08 developing wave and tidal energy technologies in Washington.
In the spring of 2007 the Snohomish County Public Utility District received preliminary permits from the Federal Energy Regulatory Commission to study seven sites in Puget Sound for tidal energy at Admiralty Inlet, Agate Pass, Deception Pass, Guemes Channel, Rich Pass, San Juan Channel and Spieden Channel. In addition, Tacoma Power has received a preliminary permit to study the feasibility of tidal energy in the Tacoma Narrows.
These permits reserve a project location for the permit holder and allow up to three years for feasibility and environmental studies. At the end of three years, the permit holder must re-file their license application or lose priority for that area. Construction is not allowed under a preliminary permit. To begin construction a developer must obtain a hydropower operating license from the Federal Energy Regulatory Commission (FERC) or be granted an exemption. Obtaining a license can be up to a seven year process and require significant analysis and consultation with federal, state, and tribal entities.
Tidal energy holds the promise of abundant clean power located near the State's major population centers. Tidal energy can be harnessed in a number of ways to fit the needs of the community and the site being considered. Because tides are regular and highly predictable, tidal energy does not carry the same risks of uncertain production common to solar and wind.
Preliminary testing by Snohomish County PUD has revealed that tidal currents in Puget Sound's Admiralty Inlet are stronger than expected with a power potential two or three times greater than initial estimates. Snohomish County''s initial aim is to one day produce 100 megawatts of electricity from the tides of northern Puget Sound, enough energy to power 60,000 homes (for comparison, by the end of 2007, WA will have 948 megawatts of energy produced by wind power). Such output would require as many as 1,500 turbines in the seven sites currently under study.
More research is needed to determine the effects of tidal energy development on marine life and the physical structure of benthic habitat in Puget Sound. Turbine blades could strike marine mammals or migrating fish, a project's structural footprint may displace benthic organisms, and drawing energy out of the tide could have unknown effects on circulation patterns and sedimentation in Puget Sound.
It will be important to analyze tidal energy projects in the light of our efforts to address recovery of Puget Sound Southern Resident Orca whales, Puget Sound Chinook salmon, Hood Canal Southern chum, and depressed bottomfish populations. It will also be important to analyze tidal energy in comparison with other options for meeting growing energy demand. All energy production carries a cost—be it global warming from fossil fuel combustion or depleted salmon runs from hydropower. At this point, the true costs of tidal energy are unclear.