This was a project to install a solar based electrical-power generation system on the roof of our house, under the Ontario Government's MicroFIT program. The power generated is fed back into the grid through a separate outbound line. In this model, we continue to consume power from grid, as we have in the past, however, each period we receive a cheque from Hydro for the power we supplied.
The diagram below shows the major components that comprise the system. The flow of electricity goes from right to left, exiting through a meter, to the grid. The major functional components are described in the Technical Section.
The major design decision was the choice of string vs. micro-inverters. In the former design, a single inverter receives power inputs from all panels and converts it to AC. In the latter design, there is a micro-inverter for each panel. The major benefit with the micro-inverter design is more effective power generation in situations were there may be partial shade at times during the day. However, in our case, our south-facing roof has full sun all day so the benefit would be marginal if at all. Thus the added system complexity, cost and potential for failure were not worth it.
A second decision was to use squirrel guard. As the solar panel are raised some 10-15 cms above the roof, this gap can become the home for squirrels. Squirrel guard is basically a wire mesh that is placed around the perimeter of the panels preventing anything from getting underneath. As we live next door to a park, and have had problems with squirrels in the past, we decided that this was a prudent choice; a form of insurance. Confirmation that this was the right choice was got the day we were to connect to the grid. The work needed to include people from Hydro so they could cut power at the local transformer. They were late arriving, due to squirrels.
The project started with vendor selection on July 24th 2015, and completed with the final payment on November 20th. There was no activity in October as I was away that month. The major events:
Monthly power generation is estimated using the PV Watts Calculator, summarized below. These figures were used to develop the business case for the project.
Please see here
These real time reports show electrical generation of the solar panel system.