Off shore Turbines Could Provide Renewable Energy

By Stephen Prudhomme

Anyone who has visited Tybee Island and watched a kite soar to new
heights or a sailboat churn through the waves can attest to the
strong offshore winds.
They can also provide a renewable source of power, and that’s no
whistling in the wind. Bill Bulpitt, a senior engineer at the Georgia
Institute of Technology (Georgia Tech) in Atlanta, headed up a 2-year
study to harness offshore wind power. Using the Georgia Tech campus
in Pooler as a base of operations, Bulpitt targeted an area 10 miles
off the Tybee coast as a prime testing site. He also measured the
winds off Jekyll Island. At a time when the greenhouse
effect is a stark reality and growing concern, a renewable source of
energy that doesn’t harm the environment holds great appeal. Last
fall, Wind Energy Systems Technology, a Louisiana-based company,
successfully bid for four tracts in the Gulf of Mexico that it plans
to use for wind power sites. The company is already developing a wind
farm eight miles off the coast of Galveston, Texas.
Texas, with its flat terrain and strong prairie winds, has likewise
taken the lead in wind farms on land with a nation-leading 3,352
megawatts of wind-generating capacity installed by last June. In
Europe, England, Ireland, Germany and Denmark have built wind farms,
and Denmark has the largest offshore wind farm in the
world. Seeing that not
everything is rotten in the state of Denmark, Tybee could be on the
leading edge in this country in riding the winds of change.
The Georgia Tech study, done in conjunction with the Southern
Company, one of whose subsidiaries is Georgia Power, found winds off
the Georgia coast averaged 16 to 17 mph., exceeding the minimum 14-
mph winds required to drive the wind turbines.
The turbines, standing 250 feet tall from the ocean’s surface to the
“hub” and featuring 300-foot blades, are anchored to the ocean
floor; tests are also being conducted with turbines placed on
floating structures. The wind drives the turbine blades and creates
energy that powers generators, sending electricity through an
underwater cable and to a “transmission
grid.”
The study found the
water off the Georgia cost is relatively shallow, which makes it
easier to construct the foundations of a wind farm, and Tybee and
Jekyll islands offer the best potential for connecting power from an
offshore wind farm to the transmission grid.
Of these two locations, the study cited Tybee as better suited
because the turbines would be less visible from the beach, the wind
resource is slightly better and it is closer to industrial and
maintenance resources. “Tybee has a good wind resource,” Bulpitt said.
As with most things, the issue is money. Bulpitt notes that the cost
to produce electricity through wind power is 9 cents per kilowatt
hour, roughly the same customers pay for standard electricity. The
difference is the 9 cents for wind-generated electricity is the
wholesale cost; conversely, the wholesale cost to produce standard
electricity is a good bit less, according to Bulpitt. “It’s quite
expensive to generate electricity through wind machines,” Bulpitt
says. “Whatever the cost is to build wind turbines on land, it cost
twice as much to build them in the water. Based on that, I don’t know
if and when something will be built.”
The study found that based on today's prices for wind turbines, the
20-year levelized cost of electricity produced from an offshore wind
farm would exceed current production costs from existing power
generation facilities. Additional costs for offshore wind power
generation include the relatively high cost of purchasing and
installing under sea cable and the costs of construction and
maintenance of a facility in the ocean.
There’s also the issue of aesthetics.
In Cape Cod, notes Bulpitt, a proposal to erect wind turbines within
viewing distance of some million dollar homes has generated a great
deal of controversy. “It depends on what’s your appetite for wind
machines,” Bulpitt says.
Leonard Haynes, Southern Company executive vice president for supply
technologies, renewables and demand-side planning, says that
renewable energy resources, including possibly wind, need to be part
of the company’s energy supply portfolio. He adds that they will
continue to pursue wind and other renewable energy options that allow
them to provide reliable and affordable electricity to their customers.
Ocean waves are another possible source of renewable energy
available off Tybee Island, yet there are a number of factors working
against such a plan. Although he’s not engaged in wave research,
Bulpitt says the tides aren’t large enough off Tybee Island. There’s
also the hazard the wave machines would present to the passing ships
headed to and from the Savannah port. Much smaller in size than wind
turbines, they are harder to spot in the open sea.