"Tracking is only helpful in sunny areas, certainly not in a cloudy place like Seattle."
This is not strictly correct, tracking does help as the numbers from the DOE calculator show. However, the cost of purchasing, installing, and maintaining a tracking system will cancel out some, or possibly all of the gain. How much so is not clear.
In this case, a 4500Wp fixed angle installation, which appears to be available for around $12,000 not including installation or installation brackets generates 4364kWh per year in Seattle, saving the homeowner $279.30 in annual electric costs given the alleged 6.4ยข/kwH rate in Seattle (which seems very low to me). This is equivalent to a 2.3% return on the investment, with, unlike in savings, the principal is non-recoverable and expires after 25 years as the panels reach their end of life.
The numbers are better for other cities true. The DOE calculator gives 5491 kWh/yr for a 4500Wp fixed angle installation in Hawaii, with 18.1 cent electricity. Over a year, the electricity value is $993.87, an 8.2% annual return, but again, with the principle not returned and the investment expiring after 25 years.
This is not strictly correct, tracking does help as the numbers from the DOE calculator show. However, the cost of purchasing, installing, and maintaining a tracking system will cancel out some, or possibly all of the gain. How much so is not clear.
In this case, a 4500Wp fixed angle installation, which appears to be available for around $12,000 not including installation or installation brackets generates 4364kWh per year in Seattle, saving the homeowner $279.30 in annual electric costs given the alleged 6.4ยข/kwH rate in Seattle (which seems very low to me). This is equivalent to a 2.3% return on the investment, with, unlike in savings, the principal is non-recoverable and expires after 25 years as the panels reach their end of life.
The numbers are better for other cities true. The DOE calculator gives 5491 kWh/yr for a 4500Wp fixed angle installation in Hawaii, with 18.1 cent electricity. Over a year, the electricity value is $993.87, an 8.2% annual return, but again, with the principle not returned and the investment expiring after 25 years.