Wind data collection began in September 2007 under the direction of UMass Renewable Energy Lab and concluded on August 31, 2009. Four anemometers and two wind directional devices were mounted on the U.S. Cellular tower on Stockbridge Hill. Wind data was measured at heights of 130 and 165 feet to gauge optimal site locations and measure available wind energy. The Swan’s Island Electric Cooperative is grateful to U.S. Cellular for donating temporary space on their tower for our wind assessment instruments for the duration of the study.
The average annual wind speed on Swan’s Island is approximately 5.8 meters per second, or about 13 miles per hour. The wind comes predominantly out of the southwest during the warmer months of the year, but can shift to the northwest during the coldest months. The chart below illustrates the greater strength of the wind during the fall and winter months as well as how an increase in the tower height of a turbine can magnify the power that can be derived from our wind resource.
Swan's Island wind speed data
The vertical axes on the charts below are calibrated in 100,000 Kilowatt-hour increments. So, for example, in January, the turbine would produce just over 600,000 kilowatt-hours, while Islands' demand would total 275,000 kilowatt-hours
The charts above demonstrate that a single utility-scale turbine can generate enough power to satisfy the Islands' demand in every month except August. During all the other months – particularly from mid-fall until mid-spring, Swan’s Island can expect to be a strong net-exporter of clean renewable electric power to the mainland at wholesale prices. In August, when wind speeds are low and the island population swells to its traditional high level, the Islands' electricity demand will be met from power generated from our own turbine and power purchased from the mainland. Every kilowatt hour produced and consumed on the Islands is a unit of power which does not have to be purchased on the mainland and transmitted under the ocean to our Island grid. These are dollars saved. Likewise, every kilowatt hour which is produced in excess of the Island’s needs can be transmitted across our cable to the mainland and sold on the wholesale power market. These dollars earned in sales, added to the savings realized from the generation of our own power, are the principal means by which the Electric Cooperative can begin to lower and stabilize electric rates.
Every Day – a buyer and a seller of electric power
This site was made possible by a grant from Island Institute.