solar PV

solar thermal (hot water) collectors at upper left.  remainder of panels are PV (photovoltaic for electricity).

solar thermal (hot water) collectors at upper left. remainder of panels are PV (photovoltaic for electricity).

our solar contractor is Revision Energy. here’s a detailed description (excerpted from Revision’s system design/proposal) of the PV (photovoltaic) system.

Economic & Environmental Return on Investment – This solar energy system uses a clean, renewable ‘fuel’ called sunshine. Because it displaces finite, polluting and increasingly expensive fossil fuel, the solar energy system is guaranteed to pay for itself through avoided costs. After you get all of your initial solar investment back, the system will continue to deliver a valuable household revenue stream for years to come. Every time energy costs go up, your financial return on investment improves proportionally.  Plus, the system will be eliminating thousands of pounds of CO2 emissions each year, delivering a powerful environmental benefit for you, your community and future generations.

PV (photovoltaic) Major System Components  Based on an evaluation of available roofspace, site configuration, and energy demand, ReVision Energy proposes a roof-mounted photovoltaic array of 7.20 kilowatts (nominal).

The system features these major components: (30) 240 watt Monosilicon Canadian Solar photovoltaic panels; CS6P-240M or equivalent ( and (1) SMA Sunny Boy 7000 US grid-tied solar electric inverter (

Whenever sun shines on the solar electric panels, they will generate direct current (DC) electricity. That DC electricity is transmitted to an inverter, which then converts it into AC electricity which can be used in your home. Any electric loads (TV, dryer, electronics, etc.) operating while the sun is shining will use available solar electricity. Any excess will flow out to the grid and you will receive a credit for the production.

Whenever the sun is not out, you will continue to purchase grid electricity as you do now. The local utility company will install record electricity you feed into the grid. If at the end of the month your generation is greater than your consumption, you will earn a credit on your next bill. You can bank your surplus from month to month for up to a year.

System Performance  The proposed 7.20 kilowatt system is expected to generate roughly 8,830 kilowatt hours of clean electricity annually and offset roughly 11,479 lbs. of CO2 emissions annually

These predictions are based on weather data specific to location and adjusted based on conditions at the site. Snow accumulation and shading of the array will effect system production.  Production will vary from year to year. Data estimates based on that of NREL PVWatts:

Incentives  This system qualifies for the following state and federal rebates:

  • The solar system is eligible for a 30% federal tax credit. This credit (not deduction) is subtracted directly from an existing tax liability.
  • This system is eligible for a Solar Electric Program rebate from Efficiency Maine. This rebate offers an incentive of $500 per 1,000 kWh of annual projected production up to a maximum of $2,000 for residential installations.

a post describing the solar thermal (hot water) system will follow in a few days.

c'mon, tell us what you're a thinkin'!