Tapping the Mighty Mississippi
and Coastal Tides with Underwater Turbine
The turbines work by capturing
the energy of flowing water, which they pick up
from waves, tides and currents
Feb 27, 2011 - Joey Peters - ClimateWire - ScientificAmerican.com
Experts at the Federal Energy Regulatory Commission
are taking a cautious look at 123 applicants who
want to generate renewable energy underwater, using
a relatively untested technology.
The technology in question is called hydrokinetic.
Like the turbines in dams, hydrokinetic turbines
generate power from the movement of water. But
these turbines don't need dams and don't present
some of the challenges and expenses that come with
them, explained Ed Lovelace, executive vice president
of engineering at Free Flow Power, based in Gloucester,
The turbines work by capturing the energy of flowing
water, which they pick up from waves, tides and
currents. Because water has greater density than
air and flows are more constant than wind, underwater
turbines can deliver much more energy than wind
In the past few years, more than 100 proposals
for hydrokinetic projects have been filed with
FERC. On average, the projects include clusters
of 20 or more turbines. Free Flow Power is behind
88 of them, which are slated for the Mississippi
River Basin between St. Louis and Gulf of Mexico.
Proposed locations from other companies include
ocean coasts, where turbines can capture tidal
This rush to development is prompted by hydrokinetic's
potential to produce renewable energy on a large
scale in places where it can easily connect to
the nation's power grid, Lovelace said. The Mississippi
River offers a massive resource, drawing water
from a drainage area that covers about 40 percent
the total area of the lower 48 states in the United
But placing a mechanism that is similar to a wind
turbine in the water could have its consequences.
Turbines can be insulated well so they do not leak
electricity, but they still generate small electromagnetic
fields around them. They also may be loud, and
noise travels farther and faster underwater and
could impair wildlife.
Drawn-out licensing procedure
FERC has kept most of these projects at a slow
pace by requiring that companies go through multiple
stages of scrutiny before getting a green light.
Before FERC can grant a license, companies have
to apply for permits that give them priority over
a site. Once granted, the permits give the company
in question priority over a site for up to three
years. This period lets the companies study the
site for feasibility of the technology. They also
have to prove the projects will minimize harm.
If the company likes the site, it can next apply
for a license through FERC that would allow power
production on it.
For each permit proposal, FERC does an environmental
review and takes in public opinion. The regulatory
agency also grants shorter "pilot" licenses
as an alternative to streamline the process. While
FERC's conventional hydropower licenses can last
40 to 50 years, pilot licenses cut that down to
five years. Part of this is because regulators
want to be cautious with relatively untested technology.
"FERC has to be convinced these can generate
electricity in safe matter," said Glenn Cada,
a researcher at the Oak Ridge National Laboratory. "The
licenses have a provision in them that if something
unexpected happens, FERC can remove [the turbines]."
In the years since applications started hitting
the agency, it has granted only one license to
a project that would have generated power from
waves on the coast of Washington state. That was
back in December of 2007, and the company behind
it, Finavera Wind Energy, has since surrendered
its license, said FERC spokeswoman Celeste Miller.
In 2008, FERC also allowed Hydro Energy Green,
a company based in Hastings, Minn., to put two
35-kilowatt turbines in the Mississippi River.
At the time, the city of Hastings had already had
a conventional hydroelectric FERC license. Hastings
asked FERC to allow the hydrokinetic turbines to
operate by adding them as an amendment to its conventional
license. FERC allowed it, and the Hydro Energy
initiative became the first in the country. To
date, they're the only hydrokine