Solar panels arrayed above tunnel

Shirahamacho, in northern Wakayama Prefecture, where forest accounts for about 80% of the entire area, is the transportation and tourist core of the Kii Peninsula, which is blessed with abundant nature and forms part of Yoshino-Kumano National Park and boasts the "Nanki-Shirahama Airport" and "Adventure World," which is popular because of its pandas.

As you drive south on the Minami Shirahama Road and turn inland from the coast through the forest, orderly arrayed solar panels on a steep slope will come into view just before entering a tunnel. The view of the whole slope covered by black solar panels is nothing but overwhelming (Fig. 1).

Fig. 1: "Nanki-Shirahama Solar Way" viewed from Minami Shirahama Road (source: Nikkei BP)

This solar power plant is the "Nanki-Shirahama Solar Way" run by Kokusai Kogyo Co Ltd (Chiyoda-ku, Tokyo) of the Japan Asia Group. The solar panel and grid capacities are 2.5088MW and 1.995MW, respectively, with an annual power generation expected to amount to about 3,231,429kWh, which is equivalent to the consumption of about 729 general households. Its completion ceremony took place Jan 29, 2019.

Constructed on the site of Nanki-Shirahama Airport owned by Wakayama Prefecture, the tunnel, in fact, runs under the airport, and the solar panels can be viewed from around its mouth. Right above the tunnel is the airport runway. The mega-solar plant was built on the southwest side slopes within the airport site (Fig. 2).

Fig. 2: Solar panels set up above tunnel mouth (source: Nikkei BP)

14,300 panels set up parallel to slopes

Kokusai Kogyo was selected in a public offering for "a solar power generation project using prefectural property (unused areas in Nanki-Shirahama Airport)" placed by Wakayama Prefecture and started constructing the plant in April 2018. Effectively using side slopes of about 34,408m2, the company set up roughly 14,300 solar panels in parallel with the 25-degree slopes (Fig. 3 & 4).

Fig. 3: East side of Nanki-Shirahama Solar Way (source: Kokusai Kogyo)

Fig. 4: West side of Nanki-Shirahama Solar Way (source: Kokusai Kogyo)

CIS compound-type solar panels of Solar Frontier KK and two 500kW PV inverters of Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) were adopted. JAG Energy Co Ltd provided engineering, procurement and construction (EPC) services and subsequently operates and maintains the plant after the operation began. All generated power is sold to the Kansai Electric Power Co Inc.

Depending on the direction, the Nanki-Shirahama Solar Way can even be viewed from the windows of flights taking off from and landing in Nanki-Shirahama Airport. The solar panels on the upper side slopes can also be viewed slightly further away from the "Airport Park" on the hill adjacent to the airport (Fig. 5).

Fig. 5: Nanki-Shirahama Solar Way viewed from Airport Park (source: Nikkei BP)