April 2020 | SMITHSONIAN 51feet into two tanks atop the Cape
Split headland. The stored water
ran down a tube to a conventional
hydroelectric turbine at the base of
the cliff s. The scheme attracted in-
vestors, but in 1920 a fi re destroyed
all of Clarkson’s equipment. The
project never recovered.
Not long after that, Dexter Cooper,
a hydraulic engineer in Maine, drew
up plans for three dams, spanning
a total of more than 7,000 feet, that
would trap high tides in Passama-
quoddy Bay, creating an upper pool
that spread over 100 square miles.
Upon release into the lower pool
of Cobscook Bay, which covered
another 41 square miles, the water
would generate 345,000 kilowatts
of power. With the encouragement
of President Franklin D. Roosevelt,
Cooper’s summertime neighbor on
Campobello Island, and over the
objections of fi shermen, who feared
that turbines would turn the bay to
bouillabaisse, the Public Works Ad-
ministration in 1935 began building
two dams, plus worker housing,
near Eastport, Maine. But fur-
ther studies revealed there wasn’t
enough local demand for the power
after all, and steam and convention-
al hydropower plants could generate
electricity far more cheaply. By 1936 the project ground to a
halt. It revived, zombielike, for another look under Dwight D.
Eisenhower, and again under John F. Kennedy. Every study
reached the same conclusion: DOA.
In 1980, Nova Scotia Power began to convert a causeway
spanning the tidal Annapolis River into North America’s fi rst
grid-connected tidal dam, or barrage. A hybrid of ancient tid-
al mill and modern hydroelectric plant, the barrage featured a
four-bladed turbine 25 feet in diameter. On an outgoing tide,
the device generated up to 20 megawatts. It operated for 35
years—but not without controversy. The barrage blocked fi sh
migration and killed some salmon and mackerel, trapped ma-
rine mammals, interfered with nutrient and sediment fl ows,
and contributed to erosion. In January 2019, a mechanical
problem shuttered the Annapolis tidal barrage, succeeding
where decades of environmental opposition had failed.
WHEN SUSTAINABLE MARINE ENERGY fi rst formed, in Scot-
land in 2012, it focused on providing power at utility scale, of-
ten defi ned as delivering at least a megawatt into the existing
grid. “That was the big prize,” Hayman says. But when Britain
decreased its subsidies for tidal power, SME began looking for
other markets. “Our ‘aha’ moment was realizing that no one
had done a simple thing well,” Hayman continues. “There were
hundreds of island communities
running on imported diesel” that
were blessed with sheltered coastal
sites, high tides and fast currents.
Appropriately scaled tidal power,
he fi gured, could help them kick
their expensive fossil fuel habit, re-
duce the environmental risk of fuel
spills and make them more resilient
in the face of extreme events, like
tsunamis or hurricanes.
SME fi rst tested the Plat-I in west-
ern Scotland’s Connel Sound, then
eventually shipped the parts to Nova
Scotia, which supported tidal energy
projects. The company chose Grand
Passage for its New World debut be-
cause the channel’s bathymetry is
known, the water runs fast and clear,
and the site is easily accessed. But
Brier Island, population 168, also
aligns with Hayman’s broader aim of
servicing remote islands and other
coastal areas. “The Faroe Islands are
a prime candidate for fl oating tidal,”
Hayman says aboard SMEagol. “The
Philippines have great currents,
British Columbia’s Discovery Pas-
sage, the Channel Islands, villages
in Indonesia and Korea...” Hayman’s
mental globe-spinning may seem
grandiose. But wind and solar power
also seemed fringy and, to many, a
little absurd just two generations ago. Now those technologies are
downright mainstream, providing almost a tenth of U.S. power, at
competitive prices, and growing fast.
In Grand Passage, SME has demonstrated that a fl oating
platform has major advantages over tidal power’s other main
design option—a turbine anchored to the seafl oor. Platforms
are far cheaper to build and install than bottom-mounted de-
vices (and remove, should things go wrong). And a technician
can perform routine maintenance on a platform-mounted
turbine during slack tide. “A visit from a lobster boat will do,”
Hayman says. Attending to devices on the sea bottom, in com-
parison, may require a submersible vehicle or a heavy barge
with a lifting rig.
With my eye on the yellow fairings that smooth the fl ow
rushing past the Plat-I’s tri-bladed rotors, I ask Hayman if his
multimillion-dollar equipment might be in harm’s way. No,
he says: Dangerously high currents, ice chunks and debris
kick the turbines up and out of the water. And because SME
designed the rotors to swing up independently, maintenance
can be performed without taking the whole device offl ine, so it
continues to generate revenue.SEE MORE of Greta Rybus’ photographs of the Plat-I and the
Bay of Fundy at Smithsonianmag.com/tidalNovember 19 73 : Breezin’
Green energy
still seemed a bit fl aky when Smithsonian
began covering the subject. 1971’s “How to
harness sunpower and avoid pollution” looked
to the sun, saying as “the real energy crisis
dawns on an electricity-hungry world, solar
energy has begun to appear practicable.”
Two years later, the magazine leaned into
wind power (above), noting that windmills may
appear “silly” to some folks, but “when you
compare the wind to a pile of dead plants,
which seems more reliable?” A 2018 article
marked the mainstreaming of “alternative”
energy. It profi led the largest U.S. city powered
entirely by renewable sources—conservative
Georgetown, Texas, deep in the heart of oil
country. Not that all our forecasts have been
on the money: In 1973, we reported that the
outlook for natural gas reserves was bleak:
“Domestic production is expected to peak in
the mid-Seventies and decline thereafter.”05550
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