By TIM FAULKNER/ecoRI News staff
If all goes as planned, Block Island will be getting power from the Deepwater Wind offshore wind farm in April, just ahead of the summer season when electricity demand quadruples. The Block Island Power Co. (BIPCO) will then be able to turn off its five high-polluting, diesel-fired generators and get electricity from the five turbines — and there should be plenty. The turbines have a capacity of 30 megawatts, enough for 17,000 homes, while the island uses up to 4 megawatts during peak demand for 1,800 customers.
According to National Grid, the power will run from the turbines to the BIPCO distribution system and then to the island’s electricity users. If the Block Island Wind Farm isn't generating adequate energy to meet island demand, power will be delivered to the island via National Grid's 20-mile undersea and overland cable. BIPCO will be charged a transmission fee based on the amount of power being transmitted from the mainland. Even if Block Island is getting electricity from the offshore wind farm, BIPCO isn't buying its power from Deepwater Wind. National Grid is buying 100 percent of the wind-farm output and BIPCO is buying its power on the open market.
There is no device that switches wind-farm power to mainland power. Electricity naturally flows from the point of generation to the point of demand. If the turbines are only meeting partial demand, the undersea cable will make up the difference with mainland power. If there is excess power being generated, it will run to the mainland through the undersea cable.
Of course, the renewable energy produced by the five turbines will have environmental benefits. They will end Block Island’s need for some 1 million gallons of diesel fuel annually — equal to a hundred 10,000-gallon tanker trucks ferried to the island every year.
In all, the switch from diesel to wind power should eliminate about 40,000 tons of carbon emissions annually.