Bonnie Johnson and Paul Torrence represent ideal candidates for a residential grid-tied system. The retired couple has a goal of achieving net zero energy use and prior to the PV installation had invested in energy-efficient household appliances. The installed 6.58 kW array is sized to generate approximately 75% of their annual electricity. When a planned domestic solar water heating system is installed, their overall energy use will be close to net zero.
A DPW Solar Multi-Pole Mount system was specified to provide adequate ground clearance and to minimize the number of ground penetrations required, reducing installation time and cost compared to other ground-mount options that were considered. DPW Solar provided engineering assistance for the footing specifications and asso- ciated racking components. Dirt work was subbed out to a local skid steer operator with a 24-inch auger.
DPW Solar’s redesigned Multi- Pole Mounts, released in 2010, have improved setscrews in the rail-to-pipe brackets that strengthen the mounting system. The installed Sharp NU-235F3 modules feature two cross rails that add to the array’s overall rigidity and resis- tance to wind loading.
Wildfires are a real concern in this part of the country. To protect against this threat, the ground underneath the array was surfaced with weed barrier and crushed rock extending 4 feet beyond the southern edge.
“I’ve seen what a hot, fast- burning grass fire can do to ground-mounted PV arrays that are installed without adequate ground clearance or surface preparation—it melts aluminum racking and modules whole- sale. In our location, it’s worth it to take every reasonable precaution to minimize the risk of potential array damage due to wildfire.” —Eric Hansen, True South Solar