Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall.
At the beach, we’re supposed to watch out for strong tides. Our oceans are powerful places. Could they also be power sources?
Here to tell us more are Charlie Adams and Kolya Shields from our Possibly Team.
Charlie Adams: Hi, Megan!
Kolya Shields: Hello!
Megan Hall: So how exactly could we use tides as a power source?
Charlie Adams: One method gaining some momentum is tidal turbines.
Rob Cavagnaro “From a physics perspective, it’s the same as a wind turbine. It’s fluid flowing past the blade that generates torque, that spins the rotor that turns the generator”
Kolya Shields: That’s Rob Cavagnaro, a mechanical engineer studying marine energy at the Pacific Northwest National Labs.
Megan Hall: How do they install these turbines?
Charlie Adams: They either float on the surface of the ocean or get anchored to the sea floor. And they generate power when water flows through them as the tide goes in and out.
Megan Hall: How much electricity are we talking here?
Kolya Shields: The Department of Energy estimates that all forms of tidal power could power more than 20 million homes in the US
Megan Hall: That sounds pretty good!
Charlie Adams: It’s something, but that’s still only about 5.4% of the electricity we currently use. And that’s before we all electrify our cars and home heating.
Megan Hall: So, don’t count on tidal power to be our main source of renewable energy’?
Kolya Shields: No, but there’s something tidal power offers that could make it a useful part of our energy grid- it’s extremely predictable.
Charlie Adams: To learn more, we spoke with Dr. Andrea Copping, a Senior Manager at the Pacific Northwest National Laboratory.
Dr. Andrea Copping: We know the tides come and go most places twice a day…we can predict what a tide will look like two and 300 years in the future.”
Kolya Shields: In other words, tidal energy is reliable.
Megan Hall: So, why don’t we have more of these tidal turbines?
Charlie Adams: First, there are a lot of places with small tides, and of course, in the middle of the country there are no tides at all.
Kolya Shields: And right now, these projects are pretty expensive to install and maintain.
Charlie Adams: There have been some successful demonstrations in New York, New Hampshire, and Maine, but no commercial-scale ones in the US, yet.
Kolya Shields: But Andrea says it doesn’t have to stay that way.
Dr. Andrea Copping: the US has several large sites of really big tidal power: Cook Inlet in Alaska, Puget Sound in Washington, coastal Maine, those are the big ones. But there’s a lot of smaller areas…They’re not megawatts and gigawatts but they could very well serve many of those communities.”
Megan Hall: Ok. But, the idea of these tidal turbines makes me a little nervous. Won’t marine life get chopped up in those big blades?
Dr. Andrea Copping: Whale sushi, I hear it all the time, and it’s absolutely not correct.
Charlie Adams: Andrea says that’s a common fear- that these really fast blades will hurt fish and other sea creatures.
Kolya Shields: In reality, the turbines spin very slowly. Andrea says she hasn’t seen a single case of lethal collision with marine mammals.
Charlie Adams: Researchers have also monitored how tidal turbines contribute to underwater noise and electromagnetic radiation and have found, so far, they fall within appropriate levels.
Megan Hall: Ok, but back to the cost of these projects- are they worth the investment?
Kolya Shields: They’re not going to meet all of our needs for renewable energy, but they do have a role to play.
Charlie Adams: For example, when one village in Alaska installed a tidal turbine, they reduced their use of diesel fuel by 90%. Other remote coastal communities and island nations could do something similar.
Kolya Shields: Also, out at sea, Andrea says tidal power could be used for remote data collection, weather buoys, and even offshore aquaculture.
Megan Hall: So what does the future look like for tidal turbines?
Charlie Adams: In short, it’s likely to be a small, local solution that can be very effective in some places. And, with more research and development, it could play a bigger role in the future of renewable energy.
Megan Hall: Great. Thanks, Charlie and Kolya.
That’s it for today. For more information, or to ask a question about the way your choices affect our planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts.
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Possibly is a co-production of The Public’s Radio, Brown University’s Institute for Environment and Society, and Brown’s Climate Solutions Initiative.
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