Solar Electric Power
The most prominent example of solar power in use is at the newly constructed Visitor Center on Spectacle Island. The building is oriented with a roofline facing south so a solar electric (photovoltaic) system could be installed with maximum solar gain. These photovoltaic panels produce enough energy to keep a small fleet of electric vehicles operational on the island as well as to send clean electricity to the electric utility company's power grid for use throughout the area.

There are several smaller photovoltaic installations on a few other islands. These are called "remote" or "stand alone" systems because they are not connected to the grid and have battery packs that store the electricity produced from the sun. Peddocks Island has had one of these systems since the mid-1990s.

The harbor islands are an excellent location for solar power because the low tree cover and flat areas between the islands allow for maximum duration of direct sunlight without shading. Several additional locations have been studied for photovoltaic systems that could be connected to the electric power grid. If these get installed they would produce enough energy to supply electricity to approximately 500 homes per year.

Wind Turbines
Depending on which island you visit, you may be able to see a wind turbine on the mainland at Wind Mill (Pemberton) Point in Hull. This single turbine produces power for all the streetlights in town, the equivalent of about 200 homes each year. This elegant machine has been so successful that a second, larger turbine is being planned for another part of town. That machine will produce enough energy to offset the electricity use of about 500 homes per year.

The area of the harbor along the coast has high average wind speeds, making it a prime location for wind power. Like the photovoltaic system, potential sites for additional wind turbines have been studied and are in the early planning stages.

Hydroturbines
On a boat ride out of the inner harbor you might notice the large egg-shaped containers of the Massachusetts Water Resource Authority (MWRA) wastewater treatment plant on Deer Island. This facility, the second largest in the United States, uses the same amount of electricity as more than 2,000 homes each year. Using a hydroturbine, however, the facility produces 10 percent of its electricity from renewable energy. The hydroturbine is installed in the outfall tunnel where large quantities of treated wastewater are discharged into the ocean. It turns as water is pushed out, generating electricity.

Bioenergy
In addition to natural resources such as the sun and wind, organic materials including human-generated waste are also sources of renewable energy. The Deer Island facility uses methane, a byproduct of the treatment process, to power a steam turbine generator. This digester gas is burned to heat water into steam. The steam is funneled through a turbine, which turns the generator and produces electricity. This produces enough electricity to power over 1,000 homes each year, about half of the electricity used at the facility. The steam also produces heat, which is piped throughout the facility, eliminating the need for additional heating for all but about two months of the year. The steam turbine generator and hydroturbine save the MWRA - and ratepayers - over $6 million annually in electricity and fuel costs.

Planning Guide for Renewable Energy
A 2005 study discusses possible renewable energy installations on the Boston Harbor Islands and what it will take to make them occur.

» Boston Harbor Islands Renewables Planning Guide (Submitted by Urban Harbors Institute University of Massachusetts Boston and Island Alliance, May 2005) [PDF]

The islands in Boston harbor are especially well suited for harvesting renewable energy because they have wide open landscapes for excellent solar exposure, constant high quality wind for turning turbines, and good wave and tidal cycles to capture water power.

More . . . about Renewable Energy: What? Why?