Reconsidering Solar PV for my house.

As solar PV systems become more common, the prices are falling.
Incentives are policy based, and have limited availability at this time. With the installation of a "smart meter" we expect rates to jump up. Marin has the local sustainable power agency, with net metering available. This is a good option worth considering.

Recently, I calculated that the payback for a small residential system is about 7 years. There are also favorable effects on after-tax income. Unfortunately, my home has shade much of the time from our canopy of trees and bamboos.

During the summer, The green canopy makes a huge difference in the temprature of the house, saving us from air conditioning load. So we have a green roof, for real.

I'm planning to record the actual solar isolation where we currently have our solar thermal panels. This data may indicate that we could add four or five Solar PV panels, I'll have to compare a simulation of the value once I have the base data.

I also want to circulate water through the solar panels, and record data on a typical sunny day, so that I can figure the thermal performance before spending much money to recommission the system. Now that we can easily incorporate some data about weather, solar isolation, and have a model of system performance, we can only run the system when the gain will be worth it. The initial expense is zero for panels and mounting, it's just a question if the pumps, etc. are working.