Many of our corporate clients often ask whether or not their commercial rooftops are good physical candidates for solar photovoltaic projects. And while every situation is unique, there are several critical factors that should always be taken into consideration when assessing the feasibility of a rooftop solar project for a commercial facility.
Firstly, the structural integrity of the building itself and the reserve capacity of the roof must be adequate to handle the incremental loading associated with a solar photovoltaic project. Fortunately, today’s commercial solar systems are efficiently designed and typically add only ~3-5 pounds per square foot on a distributed load basis. Although most of our client’s buildings are readily able to safely install a rooftop solar system, it is absolutely imperative that a licensed structural PE perform all of the required analyses to ensure that this is the case prior to installation.
Another key consideration is the condition of the roof surface itself. One of the best attributes of solar systems is the long asset life (well in excess of 20 years) and the basic nature of the technology (entirely passive/solid state usually with no moving parts). As a consequence, you do not want to install solar on a roof that is in imminent need of replacement, and ideally, solar can be installed on new or almost new roof with significant remaining useful life. It is important to know the type of roof on your building (membrane, built-up, metal seam, etc.) as well as the age and pertinent warranty information.
Other rooftop solar considerations include shading issues (i.e. are there existing or planned structures that could cause portions of your roof to be shaded at certain times of the day), potential changes to rooftop unit configurations (i.e. are you adding or removing HVAC units), and special considerations depending on your facility’s locations (snow removal protocols or high-wind requirements are specific examples).
Overall, there are a number of key factors to consider when evaluating a rooftop solar system, and for businesses looking seriously at solar for their facilities, we recommend partnering with an experienced solar development firm early in the exploratory process.