Case Study of an Actual Avery and Sun Installation

May 26, 2008

Six-Month PV Case Study

System Capacity: 13 panels, each 200 watts = 2600 watts (2.6 kw)

Maximum Actual Power Recorded: 2.872 watts, 12:30 pm Dec 14, 2007

Maximum Actual Full-Day Energy Output: 16.10 kw hours, March 21, 2008

Total Solar Energy Produced, Six Months: 1251.3 kw hours

Total Household Energy Consumed, Six Months: 1218 kw hours (201.5/month)

Electric Meter Reading at Installation, March 23, 2007 3243 kw hours

Electric Meter Reading after Six Months, May 23, 2008 3209 kw hours

Percentage of Household Energy Supplied by PV System: 102.6%

This installation is of average size and cost. Roof is easily accessible and orientation is due south. There is a small amount of late afternoon tree shading but the site is otherwise unobstructed.

Its successful performance is due as much to the energy consciousness of the household as to its size and professional installation. The household cooks with electricity, uses power tools, televisions, computers, and other electronic appliances, and even heats a greenhouse electrically on the coldest nights, but does not have air conditioning, a hot tub, electric cloths drier or other high-energy consuming appliances. 200 kw hours per month is a very conservative use of electricity and this family was away for part of the case study time period. They use all fluorescent lighting and have a solar water heater with electric backup. Since the PV system has been installed household members have become much more energy conscious, have been watching their meter, and made an effort to avoid the use of coal-generated power. The fact that they have succeeded illustrates the point that the PV system is only half of the equation; the other half is how you live.

This is a model household. They have made a large initial investment, but if they continue living as they are now they will have bought a lifetime of carbon-free electricity. They have invested in the new age.