By Roy L Hales
Though there are a couple of operational projects along the United States eastern seaboard,1 tidal energy is still an infant technology. The Puget Sound is one of the most promising locations on the West Coast. In 2014 developers aborted a proposed project in Admiralty Inlet, between the Olympic Peninsula and Whidbey Island, because of ballooning costs. More recently, a University of Washington poll finds Washington residents support tidal energy.
Washington Residents Support Tidal Energy
The researchers mailed out 3000 surveys, choosing an equal number of recipients from the Puget Sound and else where in the state. A total of 661 were completed and mailed back.2
“We measured support for tidal energy as an average of multiple questions, on a scale of 1 to 5. Residents who lived within 15 miles of the Puget Sound coast had an average support score of 3.82, whereas non-coastal residents (more than 15 miles from Puget Sound coast) had an average support score of 3.67, a statistically significant difference,” explained the resulting paper‘s lead author Stacia Dreyer, a postdoctoral researcher at the UW’s School of Marine and Environmental Affairs and adjunct faculty at Arizona State University’s School for the Future of Innovation in Society.
She added, “For perceived benefits – having a local source of energy that will benefit current and future generations was the most highly rated at a score of 4.02 on a 1-5 scale. When we split the residents by coastal vs non coastal, we do not see a change in how they rated this benefit – it is the highest for both, and not statistically different.”
” … We do find a difference between a pilot project that is producing electricity and is grid connected, vs a pilot project that is not producing electricity and is not grid-connected. Mean score of 3.77 vs 3.31 on scale 1-5, therefore, residents are more likely to support a grid connected pilot project compared to a non-grid connected.”3
Researchers telephoned a random sample of non-respondents. The opinions of the 21 who agreed to be interviewed were not noticeably different from the respondents who completed the questionnaire.4
How Much Could Tidal Energy Generate?
Tidal energy could become an important component of Washington’s clean energy mix.
“The numerical simulation I used in my thesis suggested that the theoretical resource limit for a plant in Admiralty Inlet is about 1000 MW — that’s about 2/3 (depending on how you do the math) of the average power consumption of the city of Seattle. Harnessing more than 50% of the theoretical limit is unlikely, in my opinion. So, I would not describe tidal energy as a silver bullet for our regional energy needs, but it could, ultimately, be an important contributor to our regional energy mix. I haven’t seen anyone put together an updated number for Puget Sound since that time. An array spanning the Strait of Juan de Fuca would probably have a somewhat higher power output,” explained Brian Polagye, Co-Director, Northwest National Marine Renewable Energy Center.5
“Levels of support differ depending upon the stage of development. We know that perceived benefits and risks play an important role in predicting support. When a project moves into the water, perceived risks may become more salient. For example, we found that the largest perceived risk was that marine mammals would be injured – which is a risk specific to turbines in the water.”6
The two strongest concerns mentioned by respondents were that the moving blades (3.18), or noise produced by a tidal turbine (3.0), might injure marine mammals.7
“The technology would need to be more societally compatible than it is today and we’d need to continue to see limited environmental effects from build out at much larger scales than we deploy today,” said Polagye.
In their paper, the researchers concluded:
This is the first study to measure public views towards tidal energy in Washington State and reveals that overall the Washington State public is positive towards tidal energy, as indicated by high levels of acceptability and support. We found that higher levels of perceived benefits and climate change beliefs are associated with increased acceptability and support of tidal energy whereas greater perceived risks are associated with decreased acceptability and support.8
Top Photo Credit: Admiralty Inlet, Washington State. Credit: Doug Helton/ NOAA’s National Oceans Survey photostream via Flickr (CC BY SA,2.0 License)
- “In the United States, Verdant Power first piloted an array of small turbines in the East River of New York as part of the Roosevelt Island Tidal Energy (RITE) project and was the world’s first grid-connected tidal array demonstration. The Maine Tidal Energy Project, led by developer Ocean Renewable Power Company (ORPC) featured one grid-connected turbine in Cobscook Bay, ME” – Stacia J. Dreyer et al, Changing Tides: Acceptability, support, and perceptions of tidal energy in the United States, ScienceDirect, Volume 29, July 2017, p 74 ↩
- Ibid, p 76 ↩
- email from Stacia Dreyer, lead author of Changing Tides: Acceptability, support, and perceptions of tidal energy in the United States. ↩
- Dreyer et al, Changing Tides p 77 ↩
- emailed response from Brian Polagye, Co-Director, Northwest National Marine Renewable Energy Center ↩
- email from Stacia Dreyer ↩
- Table 1: Perceived Benefit and Risk Items With Mean (SD), Changing Tides: Acceptability, support, and perceptions of tidal energy in the United States ↩
- Ibid, p 81 ↩