If a system on our roof produced a total annual output of, say, 50% of an unshaded array in the same position, is that enough to justify going ahead? Every kWh produced by rooftop solar displaces one kWh of predominantly coal-fired energy from our grid, assuming it’s self-consumed or exported to the grid.
We are primarily interested in how much total energy (measured in kilowatt hours, kWh) a system would produce each year. Economics are secondary, although still interesting of course. Our household’s main motivation is environmental. But how do I know if it’s worthwhile? Environmental motivation So I started thinking: maybe we can get solar. This tree had caused some shading during summer. We’d also had a tree removed from the southern end of the house. This timing also coincides with peak electricity tariffs for those on a time-of-use tariff. There was also discussion about the advantages of west-facing arrays (which would suit our roof), as their generation may be skewed to the late afternoon, useful on those scorching summer days when everyone gets home from school or work and cranks up the air conditioner. Tech options for shaded roofsįast forward to 2016 and I started hearing about microinverters and DC optimisers, and how they can help when there’s shading on your solar panels. So I walked out disappointed, but resigned to the fact that we couldn’t get solar. When someone who makes their living selling solar refuses to sell you solar because of shading, you tend to listen. Using this tool he looked at images of my roof from different times of the year. The guy behind the counter entered my address into Nearmap, an online service that provides high-quality, recent satellite imagery to paid subscribers such as solar installers. Solar installer says noĪbout eight years ago I walked into the office of a local solar company and made a casual enquiry. In the middle of winter, the roof is almost fully in shade from a row of trees to the north (plus trees to the east and south), but for six months around summer it is almost fully in sun. Our house is aligned roughly north–south, with the large roof areas facing east and west. We love the trees but their shading of the roof posed a question about the feasibility of installing solar. Like many living in the Sutherland Shire, I’m lucky to live in a home surrounded by large gum trees. It also describes the results, one year down the track. This article explains how, given advances in solar equipment, I analysed the impact of shading and was able to justify going ahead with solar. Some years ago I was told that our roof was too shaded to get solar. But with the help of the latest technology, he’s been able to become a net energy exporter. For years, Jay Banyer thought his home’s roof was too shaded for solar.