Commercial rooftops offer a ton of potential job opportunities for solar installers and developers going forward. Analysts at the Energy Department’s National Renewable Energy Laboratory (NREL) estimate a technical potential of 1,118 GW of capacity and 1,432 TWh of annual energy generation, equivalent to 39 percent of the nation’s electricity sales.

This current estimate is significantly greater than that of a previous NREL analysis, which estimated 664 GW of installed capacity and 800 TWh of annual energy generation. Analysts attribute the new findings to increases in module power density, improved estimation of building suitability, higher estimates of the total number of buildings and improvements in PV performance simulation tools.

To calculate these estimates, NREL analysts used LiDAR data, Geographic Information System methods and PV-generation modeling to calculate the suitability of rooftops for hosting PV in 128 cities nationwide-representing approximately 23 percent of U.S. buildings-and provide PV-generation results for 47 of the cities. The analysts then extrapolated these findings to the entire continental United States. The result is more accurate estimates of technical potential at the national, state and ZIP code level.

Within the 128 cities studied, the researchers found that 83 percent of small buildings have a suitable location for PV installation, but only 26 percent of those buildings’ total rooftop area is suitable for development. Because of the sheer number of this class of building across the country, however, small buildings actually provide the greatest combined technical potential. Altogether, small building rooftops could accommodate up to 731 GW of PV capacity and generate 926 TWh per year of PV energy — approximately 65 percent of the country’s total rooftop technical potential. Medium and large buildings have a total installed capacity potential of 386 GW and energy generation potential of 506 TWh per year, approximately 35 percent of the total technical potential of rooftop PV.

Key in this segment is the selection of the right mounting and racking system that makes your life easier, won’t damage the roof and is overall safe from wind and weather peril. Here’s a rundown of a few such systems and how they might save you time and cost.