A building with solar panels on the roof

Solar power is a sustainable energy source that harnesses energy from the sun and converts it to usable electrical power. This is done through the use of solar panels that are made of semiconductor materials that collect photons of sunlight as direct current electricity. This direct current must be converted into an alternating current in order to be used to power homes and offices, which is done by an electronic inverter. If there is an excess supply of power it can be stored in batteries for later use or if the system is connected to a utility company’s grid, it will be sent into the utility lines. Your account would be credited for the amount of power supplied to the grid. Solar panels can be placed on rooftops, in open fields, on poles, or any location that is exposed to sunlight.

Additional Uses

Solar energy can also be used to provide hot water and/or supplemental heat. To provide solar hot water for buildings, the system must have two parts: a solar collector and a storage tank. The solar collector is usually referred to as a flat-plate collector, which is typically mounted on a roof although vacuum tube designs are gaining popularity. The water that is to be heated is carried through tubes that pass through the solar collector. The heat that is collected in the black solar panel or vacuum tube element passes to the water in the pipes which is then carried to the storage tank. A modified water heater can be used for this, but typically the storage tank will be larger and better insulated. The water can be moved through the tubes actively by use of a pump or passively using gravity and the natural motion of water when it is heated.

Reducing Energy Usage

Solar energy can be harnessed to provide supplemental heat and hot water to residential and commercial building and to reduce the large amount of energy needed to heat the air used in ventilation systems. Preheating air can be accomplished through a thin, black metal panel called a transpired collector placed on the south wall of a building allowing the most exposure to the sun. This panel contains many tiny holes in which air can pass through. In a space behind the panel, the air that has passed through can mix together and become heated from the sun’s absorbed energy. This heated air is sucked out of the space behind the panel and into the ventilation system of the building.

Manufacturing Information*

  • Assured Solar Energy
    Northern Comfort Solar Systems
    460 Mountfort Road
    North Yarmouth, ME 04097
    Phone: 207-221-2916
  • MaineStream Energy Alternatives, Inc.
    dba/Saco Solar Store
    Route 1, 743 Portland Road
    Saco, ME 04072
    Phone: 207-283-1413
    Fax: 207-283-1414
    Cell: 207-229-1411
  • Revision Energy website
  • Solar Water Heating Diagram Courtesy of Solar Options
    Solar Water Heating Diagram Courtesy of Solar Options
    Conservational Systems Inc.-Solar Wall
    4242 Ridge Lea Road Suite 28
    Buffalo, NY 14226
    Phone: 716-835-4903

* City of Biddeford does not endorse any specific manufacturer.

Solar Panel Diagram


  • Solar Technologies: Clean Energy Solutions for Northern California. 2007. How Does Solar Power Work. Accessed July 2008.
  • U.S DOE Energy Efficiency and Renewable Energy. 2006 August 9. Solar Heating. Accessed August 2008.