Maine has plenty of energy in its offshore winds, but building the turbines and their platforms for offshore electricity generation presents a number of logistical challenges.

The parts of an offshore wind platform need to be so big they ought to be assembled at the nearest port, and shipped by sea, not transported by rail or highway.

Paul Williamson, director of the Maine Wind Industry Initiative, told a group of people Tuesday, Jan. 25, at the Maine Wind Energy Conference there are three basic kinds of offshore energy platforms. They are described by their supporting parts — spar, tension and barge.

Bill Follett of Cianbro Corp. said, “The spar concept is cheapest, but it’s so deep — you need 200 feet of water.”

The discussion was held during one of several sessions of the two-day Maine Wind Energy Conference at the Augusta Civic Center, the second such gathering organized by the Maine Wind Energy Working Group.

The spar is a vertical floating base to a wind turbine. Follett said one of these platforms is working well in Norway, but he pointed out that Norway’s coastline is unique with its deep-water fjords.

“How many places in the world are there that would accommodate spar technology?” asked Follett.

Currently the only way to assemble spar turbines is to stand them up, in deep water, attach the turbine and float it out through a deep-water channel to its final location.

Such a deep-water channel extends from near Mack Point in Searsport past Vinalhaven Island in a fairly roundabout way to reach the site off Monhegan Island that has been reserved for a University of Maine experimental wind project.

Besides Searsport, Maine’s other deep-water ports are at Eastport and Portland, said Patrick Arnold of the Maine Port Authority. He said 70 acres of land at Mack Point are available for wind-turbine assembly.

Follett explained the design of future offshore wind turbines must be deployable at most ports around the world. “Businesses want to be able to deploy them worldwide. I don’t think we’re going to see a company building a design that can only be deployed at one spot in the world.”

Asked why Maine has to build a wind turbine that can be used around the world, Williamson said, “We’d like to export parts to other parts of the country and the world.”

Williamson said the number of British wind projects has surpassed those in Germany, but Germany developed most of the parts for those turbines and is selling them in Great Britain.

Follett said a typical spar base for an offshore wind turbine is 300 feet long, by 25 to 30 feet in diameter, and it weighs 1,000 pounds.

It was noted that Maine has a strong composite industry and blades for turbines can be manufactured from composites rather than steel.

“Part of what we see as a boon to this industry is the activity that could go to ports …,” said Arnold. “You have to look at the offshore oil drilling industry in the Gulf and what an economic boon that has been.”

Arnold noted that smaller ports, such as Wiscasset and Rockland, could play a role in assembling parts for wind turbines.

“Shipping parts by sea is going to be very important,” said Williamson.

Ultimately, said Williamson, when permanent wind turbines are installed off the coast of Maine, they will probably be more than 10 to 25 miles out to sea. “The wind is stronger there and there is less problem with the public viewing them (and having a negative reaction),” Williamson said.

Besides the question of how to build, transport and assemble the parts of the turbines, the question of how to transmit the electricity that is generated is a looming one. “Transmission is the enigma, how the turbines are connected to the grid,” said Arnold.

Matt Nixon of the Maine State Planning Office said three sites have been chosen for experimental wind turbines — near Monhegan Island (University of Maine site); near Boon Island off York; and near Damariscove Island, off Boothbay Harbor.

Sue Jones, coordinator of the Maine Wind Working Group, said $1.4 billion has been invested in wind energy projects now working on land in Maine. She said another $4 to $5 billion will be spent on wind energy in Maine, if the state continues its course of encouraging wind energy development.

Maine’s wind energy is “very diverse” and has “tremendous potential,” said Jones. “Offshore energy is on the horizon,” she said. “We’re a growing industry in its economic potential for the state of Maine. We’re poised for growth. Maine has done its homework to really develop a strong and vibrant industry.”