Wall-Mounted Solar: A Rising Trend or Barely Hanging On?

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By Canute Haroldson, account manager and Paul Grana, co-founder, Folsom Labs

Installing solar on the side of a building is rarely the first choice for solar developers, but sometimes the customer prefers a wall-mounted array. In one instance that caught our eyes, New York installer Quixotic Systems built a 37-kW array on the side of Urban Health Plan’s Simpson Pavilion. The hospital’s limited roof space made a traditional rooftop array impractical, but at four stories high, there was ample room on the south side of the building. This unique array made us wonder when vertical installations can make sense.

High-quality roofs for installation are becoming difficult to come by. A wall-mounted array may not be the first choice, but when a roof is almost completely obstructed, it may be a decent option. So Folsom Labs decided to run a few tests to see how walls compare to roofs for solar panel installation.

The first comparison we wanted to make was the output of the wall-mounted array vs. the output of a fixed-tilt array on this specific roof. The complexity of the rooftop provides very little space to fit modules. Taking the space that was available, there was only enough room for an 11.8-kWdc installation, with significant shading losses. Even given the orientation of a wall-mounted array, this rooftop would only make around 12.1 MWh per year, vs. an estimated 33.9 MWh for the wall-mounted array. It was quickly apparent that the wall installation was the correct choice for reducing the hospital’s energy needs….

This article can be read in its entirety at Solar Power World.