Monday, May 24, 2010

Solar PV arrives at the Virginia zero energy home!

Every zero energy home needs a renewable power source and ours consists of 20 Schuco SPV 210 panels supplied by Dereck McAvoy of Midsouth Building Supply. These monocrystalline panels are some of the more efficient ones available, rated at PTC/STC 91.5%, indicating that they in effect, under real world conditions, produce very close to their advertised power rating. They are warrantied to produce at least 80% of their initial output for 25 years. They are on the List of Eligible SB1 Guidelines CompliantPhotovoltaic Modules for the Go Solar California program, one of the longest established and most respected state solar programs. They were installed on the back face of the south facing garage by SunFlower Solar and connected to a SMA Inverter SB 5000us attached to the inside wall of the garage, that wirelessly sends production data to my laptop. The inverter, warrantied for 10 years, converts the DC output to AC and feeds it to the house with the excess going back into the Virginia Power grid with the help of a grid-tie connection to their net metering program. This program allows two way metering, so that excess power can flow into the grid, and needed power (ie. at night) can be drawn out. The arithmetic sum is carried over a 12 month period. If you produce excess power it can be carried forward; if you fall short, it can be subtracted from that sum (or you pay a bill). Any excess that is not used in a 12 month period is donated to the grid, and you get warm fuzzy feelings for your kindness to humanity. All of this now sounds very simple, and the panels look neat and clean. Let me tell you, pulling this together was not simple, neat or clean. It took many hours of active research, several false starts, a motivated, thoughtful builder, and several solar resource experts to make this happen. More on this later.