Unit 8, Listening 2, Tapping the Energy of the Tides
Tapping the Energy
of the Tides
Speaker: Concerns over global warming have
scientists and engineers looking for cleaner alternative sources of energy. One
of those alternatives gaining momentum[1]
involves harnessing the energy of
the ocean. Renewable energy experts say in theory, energy from tides, currents, and waves could double the
hydropower[2]
output in the US, producing 20 percent of the nation’s electricity. But the
technology to capture this renewable energy is in its infancy. NHPR’s Amy
Quinton reports on the effort in New Hampshire’s seacoast to tap the power of the tides.
Jack Pare: Coming in, it hits this shore pretty heavy;
going out, it hits the Newington shore pretty heavy. Uh, it is a dramatic roar.
It really is.
Quinton: Jack Pare, a retired aerospace systems
engineer, points to the water under the General Sullivan and Little Bay Bridge
in Dover. He says the tides here in the Piscataqua River move quickly, almost
nine feet per second at its maximum. Pare says engineers know how to capture
that free-flowing energy, and it would be a completely renewable source of
power for the state.
Pare: It’s just one of many things that
you have to do, uh, if you want to, quote, “save the planet” or otherwise cut
down our carbon emissions. There’s no single magic bullet; this is, if you will
…there’s no rifle shot, it’s a shotgun effect. So this is one pellet of that
shotgun effect to be able to take the top off the global warming.
Quinton: Some state representatives believe it’s
an idea worth pursuing. State legislators passed a bill that establishes a commission
to study tidal power generation here
under the bridge. Representative Tom Fargo of Dover, the bill’s sponsor, says
unlike wind power, the benefit of tidal power is its reliability[3].
Fargo: The tide will flow until the earth
rotates no more. It’s, it’s, it’s available; we know when it’s coming; we know
from, from day to day and even hour to hour how much energy you’re going to be
able to get from it; it’s very predictable.
Quinton: And water is more than 800 times denser
than air, making it much more powerful. But almost all the various technologies
used to capture tidal power are expensive and experimental. Only one company so
far is producing it in the United States. A little-known start-up called
Verdant Power has six underwater turbines, resembling windmills, in the East
River in New York. So far, Verdant Power founder Trey Taylor says the turbines
power the lights in a supermarket and a parking garage on Roosevelt Island.
Taylor: But also, uh, inside that garage
there are electric vehicles. There’s, there’s hybrid electric buses, but also
there’s little electric vehicles that go up and down Roosevelt Island,
something a little bit bigger than golf carts, and those are all being plugged
into our tidal power, which I think is a pretty cool story in and of itself.
Quinton: But Taylor has much bigger hopes. He
foresees a time when 300 of these underwater turbines will power about 8,000
homes in New York. But Jack Pare points out the turbine technology that works
well in New York’s East River may not be appropriate for the Piscataqua.
Pare: Uh, we have deep-water shipping,
we have harbor seals, and we have stripers and we have lobsters, none of which
are present on that other site. And
so there’s a little bit more to be careful of.
Quinton: Two companies currently hold federal
preliminary permits to study the feasibility of tidal power in the Piscataqua.
Philippe Vauthier is president of one of them, the Underwater Electric Kite
company, based in Annapolis, Maryland. He says his turbine technology won’t
turn fish into fillets.
Vauthier: And, uh, we put a screen in front of the
turbine to protect the fish to reach that point. Absolutely no problem.
Anything bigger than three-quarters of an inch is safe; it will be deflected[4].
Quinton: Vauthier says smaller fish would be able
to glide through unharmed. He predicts his $2.4 million project could produce
40 megawatts, or enough to power about 36,000 New Hampshire homes. The other
company that holds a permit—New Hampshire Tidal Energy Company, owned by Oceana
Energy—is predicting a much larger power output along three stretches of the river. Charles Cooper
is a technical advisor for the project.
Cooper: I’d be surprised if it reached, uh,
more than 100 megawatts at the most, and that would be very optimistic. And
that’s not trivial in the sense that it certainly can supply, um, a number of
end uses, but it’s not going to be the base load for the region.
Quinton: Cooper says Oceana’s prototype looks
like a large wheel about the size of a Ferris wheel, with an open center that allows large marine animals
to swim through. But he adds their technology won’t work everywhere.
Cooper: This is not really deep water. We’re
not dealing with water over 100 feet deep in the Piscataqua. So if Oceana’s
technology turned out to work best in very large-sized units that might be, oh, I don’t know, 60, 80 feet in diameter,
they wouldn’t be appropriate for the Piscataqua site.
Quinton: In that case, Oceana would likely use
another company’s technology at its sites. Both companies say there are a lot
of challenges and unknowns surrounding tidal energy in the Piscataqua. But the
permits give them three years to study the sites. What they learn will also
help the state decide if tidal power is worth pursuing. For NHPR News, I’m Amy
Quinton.
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