Energy costs are a major component in any housing environment, and one of the main areas where boards and managers look at to optimize efficiency and save money. One already popular — and growing — alternative to fossil fuels is solar energy. But how much solar can conceivably be produced in an urban environment, and how much will it really save?
Those of us unfamiliar with the technology of solar energy might think that it’s a warm weather, ‘sunny days only’ source of energy. But in fact, “cold doesn’t hurt the efficiency of solar energy,” says Brian Haug, a solar energy specialist with Continental Electrical Construction Company, which has offices in Illinois. “As a matter of fact, solar works better when it’s cooler.” (More on that later!) The efficiency of solar is more dependent on the angle of the solar panels than how hot or cold the environment is.
Alan Burchell, Founder and Principal of Urbanstrong, an alternative energy firm in Brooklyn, New York, expounds on that idea: “The way to determine solar power generation efficiency is through a test called a solar shade analysis. This test measures these factors on an annual basis, providing the best positioning for the array. The test will also determine whether a solar array is feasible for a particular roof,” to begin with.
So clearly, solar is not as simple as it looks. “If a co-op or condo wants solar on their building in an urban setting,” says Haug, “there are a few challenges. One is that rooftops are typically small, though a flat roof does not make a difference in efficiency. A smaller rooftop will limit the size of the solar array you can put there.” He adds that “with fewer sunny days, you may rely on other technologies too.” Solar will not meet 100 percent of your building’s energy needs. The question is, how much of your needs can be met by solar? The generally held consensus among solar professionals we spoke with is that solar can supply between 10 and 15 percent of a multifamily building’s energy needs.
How Does Your Solar Array Work?
When anyone—an individual owner or the co-op or condo—uses electricity, the usage is typically recorded on a meter. Individual metering is the standard method by which electrical companies account for what you use. Solar energy generation works in a kind of backwards way. “The power generated by the solar array back feeds into your panel,” says Haug. “When you generate more than you are using, the meter direction will reverse,” indicating a positive outflow, reducing your consumption from the municipal energy provider. “Generally, this energy production is funneled to the meter for the common areas in an apartment building that runs house loads like elevators, laundry room, hallway lights, etc. It can benefit the common usage, but won’t supply individual apartment needs.”