Greenfield Community College is engaged in an on-going effort to reduce our carbon footprint. Look for sites around campus including our solar greenhouse, electric vehicle recharging station, and geothermal wells.
Where is our solar?
Look behind the East Building. These are solar electric or photovoltaic (PV) modules that convert sunlight directly into electricity to provide lighting, power computers and maintain proper ventilation in our buildings. Photovoltaic modules harvest a renewable,inexhaustible and free source of energy: the sun. They do not burn any fossil fuels – coal, oil or natural gas – and do not release any harmful pollutants or greenhouse gasses (such as CO2) into the atmosphere. They provide us with electricity without contributing to climate change.
These 392 ground-mounted modules were installed in 2011 and have a 30-year lifespan. The maximum amount of power they can generate is 79 kilowatts (79,000 watts). To the east of the ground-mounted array is a pole-mounted, 2 kilowatt (2,000 watt) array that tracks the sun from east to west, installed in 2007.
How do photovoltaic modules work?
Photovoltaic modules have no moving parts, require very little maintenance, and last for decades. They act like electron pumps. On one side of the solar cells that make up a module there are atoms that produce a surplus of electrons, and on the other side there are atoms that produce a deficit of electrons. This establishes a voltage difference between the two sides. When the sun is shining, bundles of light energy called photons strike the cell. Electrons get “excited” by the photons and begin to flow down the voltage difference much as water flows down a slope. This flow forms an electric current, producing electricity.
What difference can PV modules make?
Installing photovoltaic modules is one way to decrease our reliance on non-renewable forms of energy. Because they generate electricity when the sun is shining they produce more electricity during the long days of summer than the short days of winter. On average, these 81 kilowatts of photovoltaics produce approximately 79,800 kilowatt- hours (KWh) of electricity per year, saving the college approximately $11,200 per year on electricity (2012 data). This is enough to provide for the electrical needs of eleven average homes. The college, like the rest of Franklin County, still relies on non-renewable sources of energy like nuclear, coal, natural gas and oil for most of our electricity. This is why it is so important to reduce our energy use through efficiency upgrades and conservation practices by faculty, staff and students.
How did these modules get here?
The modules on the ground were installed by Ostrow Electric from Worcester, Massachusetts and paid for by the state with federal funds. The 2 KW pole-mounted modules were purchased from and installed by Pioneer Valley Photovoltaics, a Greenfield-based renewable energy company. Real time and historic power generation data for these panels is available at www.deckmonitoring.com/Greenfield_cc.