Outdoor parking lot rooftops are drawing attention as the remaining frontier of solar power plant usage. Outdoor parking lots are located on flat and sunny sites and are normally adjacent to facilities such as buildings that consume power, which means easy grid connection and allows selection of self-consumption models in the future.
The "solar carport," which uses solar panels as parking lot roofing materials, is environmentally conscious because of its function to reduce CO2 emissions and improve the comfort of parking lot users, protecting them from the sunlight and rain. In addition, its function as a disaster management base has recently begun to be evaluated.
First mega solar facility at Michi-no-Eki (roadside station) in Japan
The Tanuma District in Sano City, Tochigi Prefecture, is at the center of the Japanese archipelago. When lines are drawn connecting the standard points at the four ends of the Japanese archipelago, the lines cross on the Tanuma District (formerly Tanuma Town). The roadside station in the district was named "Domannaka (dead center) Tanuma" because of the location.
The "ceremony to commemorate completion of the local disaster management base" was held Aug 29, 2016. The "local disaster management base" that was completed is a carport-type mega (large-scale) solar power plant installed on the outdoor parking lot to the north of the roadside station (Fig. 1).
The plant was constructed by Domannaka Tanuma based in Sano City, Tochigi Prefecture, which is financed by Sano City, JA Sano, the Sano Aso Chamber of Commerce and Industry, Mikamo Forest Owners' Cooperative and others. The plant is normally operated to sell solar power and is used as a disaster management base during disasters. It is the first large-scale carport-type solar power facility installed at a roadside station in Japan, according to Domannaka Tanuma.
The approximately 5,000m2 outdoor parking lot, which is to the north of the roadside station, was turned into a roofed parking lot, and solar panels were installed on the rooftop. The parking lot has space for 350 vehicles, and the output is approximately 1.1MW. Solar panels were fixed on folded-plate roofing materials attached to steel columns.
The foundations were fixed to reinforced concrete installed at a depth of 1m below the ground surface. Four vehicles, two each in longitudinal and latitudinal directions, can be parked in a space surrounded by four columns.