Cousins Island is an island in Casco Bay

Casco Bay

Casco Bay is an inlet of the Gulf of Maine on the southern coast of Maine, New England, United States. Its easternmost approach is Cape Small and its westernmost approach is Two Lights in Cape Elizabeth...

. It is connected to mainland Maine by a bridge. It is also connected to Chebeague Island

Chebeague Island, Maine

Chebeague Island is an island town in Cumberland County, Maine, United States, located in Casco Bay, 10 miles from Portland. These islands are sometimes referred to as an older, now archaic term "The Calendar Islands" because there was once a belief that the approx. number of islands was about 365....

 by a 15-minute ferry ride on the Chebeague Transportation Company's ferry, the Islander. It is part of Yarmouth, Maine

Yarmouth, Maine

Yarmouth is a town in Cumberland County, Maine, United States, located approximately ten to fifteen miles north of Portland. Its population was 8,349 at the 2010 census....

.

The island's southwestern peninsula is the site of the Wyman Energy Center, an oil-fired electric power plant capable of producing up to 823 megawatts of electricity. Wyman is a peaking power plant

Peaking power plant

Peaking power plants, also known as peaker plants, and occasionally just "peakers," are power plants that generally run only when there is a high demand, known as peak demand, for electricity.-Peak hours:...

, which means it is only fired up to operate during times of high electricity demand in the region, such as hot summer days.