Tokyo-based Showa Shell Sekiyu subsidiary Solar Frontier – the largest manufacturer of CIS (copper indium selenium) thin-film photovoltaic (PV) solar modules – says that construction has started on a 15MW solar power plant on a 400,000m2 site at a former golf course in Nakagawa, Tochigi Prefecture, Japan owned by developer Takara Leben Co Ltd. Takara Leben already has eight operating solar power plants in Japan with a combined capacity of 10MW, but aims to expand its capacity to 100MW. Hitachi Zosen is providing engineering, procurement & construction (EPC) services for the new project.
Output of the 120,000 x 165W modules amounts to 19.8MW. With power conditioning (750 x 20kW), the capacity is 15MW. The projected annual capacity of the plant is about 21,000,000kWh (equivalent to 3700 homes), reducting annual CO2 emissions by about 11,000 tons. Power generated by the plant will be sold to the grid.
The project is said to mark the first time that small inverters have been used in an extra-high-voltage megasolar plant in Japan. The overall design is expected to reduce the initial investment cost and ongoing operating expenses for the project, as well as spreading the risk of power loss and the need for site work during construction.
Solar Frontier says that its CIS thin-film PV modules have a higher tolerance for partial shading and heat compared with crystalline silicon modules, providing higher energy output as well as enabling the plant to provide more stable output on north-facing slopes.
The use of small inverters is expected to provide lower ongoing operating expenses and risk for the project. Fairways and other areas in golf courses differ in size, requiring a more complex array layout and electrical system design. Central inverters have, until now, limited this design. However, this project takes a different approach by using small 20kW inverters to overcome the configuration issue. The system design also spreads the risk of power loss since equipment can be replaced on the same day.
The plant’s design is reckoned to reduce the burden on the environment by negating the need for site work due to its use of a one-pile foundation structure. This means that not only is the height difference between modules in east-west installed arrays smaller, but the number of pile-drivers used in the installation is less than half that of previous installations, resulting in shorter installation time and a reduction in environmental burden.
