Switching to green energy with a solar photovoltaic (PV) system is a smart move for homeowners. Besides lowering your energy bills and contributing to cleaner air, a PV system is one of only a few types of home improvement projects which ultimately pay for themselves. You’re even smarter, however, when you take steps from the start to ensure that you are getting the maximum performance from your solar PV system.
The Right Angle and Tilt
A major factor which affects the performance of a solar array is the position at which it is installed. It’s recommended that you get the assistance of an experienced professional to ensure that the panels on your roof or property have a 9 am to 3 pm solar window that is free of obstructions.
The tilt and azimuth (the compass bearing) of your solar array greatly affects production. Fixed arrays are oriented to face true south, which is different from magnetic south; ideally fixed solar arrays should face within 20 degrees of true south for optimum production and should be set at a tilt that approximates your latitude. Seasonal adjustment or the array’s tilt can enhance performance as well.
Solar PV panels have a drop in efficiency when the temperature rises. For this basic reason, it’s important to allow for a sufficient amount of airflow around the mounted PV panels. Typically, allowing an unrestricted air gap of 3 to 5 inches between your roof and flat-mounted solar modules will be sufficient. But if aesthetics aren’t an issue, panels which are tilted upward from the plane of the roof will stay even cooler and perform better in hot climates.
Any amount of shade on your solar array lowers its performance. In fact, shade is the top system performance problem. To maximize efficiency, take every angle into consideration when installing panels; and avoid positioning which is shaded by trees, exhaust vents, overhangs, chimneys, and multiple levels. Even partial shading results in a significant decrease in performance and ultimately lost revenue. Particularly if you take advantage of performance-based incentives, you don’t want to make the mistake of installing PV panels which are shaded.
The help of professionals is also essential when it comes to the issue of shading because the rows of panels can shade one another if improperly installed. It takes a fair amount of knowledge and experience get this right. For example, closer spacing is sometimes possible in the southern states; but wider spacing of the panels can help pull more energy from the sun in the early morning and late afternoon.
Solar panels usually carry a 20-year warranty, which ensures that your investment truly will pay for itself over time. But PV modules gradually become somewhat less efficient over their realistic life expectancy which is thirty to fifty years. Panels can often produce 80% or more of their rated efficiency well beyond their 20 year guarantee. PV panels with tight tolerance ratings make a better choice up front.
Inverters are components which convert the energy generated by the sun from DC into AC, suitable for household use. Inverters need to installed away from any direct sunlight, protected from the weather, and kept as cool as possible, for maximum efficiency. It all begins, however, with choosing the best inverter with “weighted efficiency.” This term has to do with the fact that the amount of available sunlight fluctuates constantly as do array operating conditions. Weighted efficiency can better predict system performance.
Flat-mounted arrays are more susceptible than others, but soiling can contribute to an efficiency loss of up to 25%. Bird excrement, dust, and snow should all be cleared away; otherwise, they can filter out some of the sunlight which produces clean energy. Keeping your solar modules clean usually requires nothing more than water and a squeegee.
Your PV system should be periodically inspected to ensure that everything is functioning properly. Look for any shading problems, such as trees which may have grown. Look for broken modules. Check the amount of power being produced; grid-connected inverters usually have a meter which displays this information.
Obviously, most of the steps you can take to maximize the efficiency of your solar PV array are up front, during installation. But regular monitoring for the lifetime of the system is also important and can ensure that you are getting the most from your system.