According to the Energy Information Administration , the U.S. will add 21.5 gigawatts of solar power in 2022, representing 46% of anticipated new capacity. Solar energy is now the fastest growing source of electricity in the country, and the modular design of photovoltaic panels makes them viable at all project scales.
Commercial buildings with large roofs can take advantage of their space by installing solar panels to reduce energy bills and emissions. These solar installations also benefit from economies of scale: according to data collected by the Solar Energy Industries Association, a home solar system has an average price of $3.06/watt in the US, but that drops to $1.45/watt. watt in commercial systems.
Get a professional electrical design for your commercial solar photovoltaic system.
The first step before installing a commercial solar panel is to ensure you have a suitable roof. In the case of new commercial buildings, owners have the advantage of being able to design a solar-ready roof from the beginning. Here are five recommendations for optimizing your commercial roof design for solar panels.
1) Flat commercial roofs are ideal for solar energy
A flat roof simplifies installing solar panels on a new commercial building. Since solar installers will not work on inclined surfaces, the process becomes safer and easier. You can also use a ballast mounting system, which holds the solar panels in place with concrete pads. In other words, you won't be drilling holes in your new roof, which is necessary when solar panels are installed on sloped surfaces. Once your commercial solar array is in operation, a flat roof also simplifies maintenance.
2) The structural design of the roof must consider the photovoltaic solar panel
A 72-cell commercial solar panel can weigh more than 60 pounds, and large commercial arrays can have hundreds of them. According to the National Renewable Energy Laboratory (NREL), a photovoltaic system increases the load on a roof by up to 6 pounds per square foot when you consider racking systems and other components.
To design the roof correctly, the structural engineer responsible for your project must know the load distribution of your solar panel. Keep in mind that ballast-mounted systems are heavier, as they use concrete weights to hold the solar panels in place.
3) Optimize the orientation of solar panels and avoid shading
Because the sun's position in the sky is always changing, the angle from which solar panels receive sunlight also varies. Ideally, solar panels should have an orientation and tilt angle that maximizes the amount of sunlight received throughout the year. On a flat commercial roof, this can be easily accomplished with a ballast system with an ideal pitch angle. There are also tracking systems that keep solar panels pointed toward the sun, but these are better suited for terrestrial installations.
Solar panels become more productive when they have ideal placement, but only if the area is not covered by shadows. Compared to houses, commercial buildings are less likely to be shaded by trees or other buildings. However, keep in mind that shadows move throughout the day, and an area of the roof that is bright in the morning may be completely shadowed in the afternoon. Solar designers use special software that simulates the sun's movement throughout the year to determine the ideal layout for a photovoltaic system.
4) Make sure your commercial PV system is sized appropriately
Your roof design can be optimized if the size and layout of your solar panel are known in advance. However, an undersized system will provide minimal savings on energy bills, while an oversized system incurs unnecessary costs. To find the ideal size of a commercial solar panel there are two important factors to consider:
- Your building's energy consumption profile.
- Local net metering regulations: How do you get paid for excess energy?
Solar panels reach their peak productivity around noon, and a large array will likely exceed the building's consumption at that time. Excess production is not a problem if your electricity supplier offers net metering, but keep in mind that this benefit is not available in some locations.
If net metering is not available, your solar panel must be sized according to your consumption, avoiding excess production as much as possible. With net metering you can use a larger matrix, since the production surplus is also subtracted from your consumption.
Keep in mind that net metering conditions vary depending on your electricity supplier and there is typically a maximum credit you can get. There are cases where you can reduce your energy bill to zero with net metering, and the unused credit usually rolls over to the following month. However, net metering programs that pay credits in cash are extremely rare. This means you cannot indefinitely increase the size of a commercial solar panel with the intention of billing your power company.
5) Consider zoning regulations, building codes and local laws
Last but not least, you should consider all local requirements for commercial solar before starting your project. For example, your city may have historic neighborhoods where solar panels are not allowed. The opposite can also happen: in New York City, Local Laws 92 and 94 of 2019 require sustainable roofing systems in new construction, renovations and roof replacements. You can meet this law with solar panels or green roofs, but the ROI offered by solar energy is better.
