The ruling paves the way for the state power producer Taipower to proceed with the construction of a major storage facility intended to improve grid stability and enhance the flexibility of electricity dispatch.
Taipower plans to use the existing Deji reservoir and Guguan reservoir as the upper and lower basins, to be linked by a 10.7 km-long tunnel, taking advantage of an elevation difference of about 450 m between the two sites to circulate water for electricity generation. The project will comprise four reversible pump-turbine units with a combined installed capacity of 610 MW.
Taipower said the main facilities will be built underground and no new dams will be constructed, minimizing impacts on the Dajia River’s water flow. The Deji Reservoir, in the upper reaches of the Dajia, has an effective storage capacity of about 180 x 106 m3. Located at an altitude of 1400 masl, it is the highest reservoir in the country and the fourth largest in Taiwan. The Guguan Reservoir has a storage capacity of about 5 x 106 m3.
The new project will be Taipower and Taiwan’s third pumped-storage hydropower plant. Taiwan already operates two pumped-storage hydropower plants using the Sun Moon Lake: the 1602 MW (6 x 267 MW) Mingtan and 1000 MW (4 x 250 MW) Daguan II or Minghou plant, which are both located in Nantou County. Mingtan was commissioned in 1993 while Daguan II was commissioned in 1985.
In March of this year, Taipower completed upgrades to the Minghou pumped-storage plant by raising the height of the downstream Minghou Dam. The project, which took two years at a cost of NT$ 240 million raised the height of the dam by 1.9 m, increasing water storage capacity by 1 million tons (2.83 x 106 m3) to 7.9 million tons (22.37 x 106 m3). This will result in additional annual output of 222 GWh.
The Guangming project has faced years of delay because of tunnel construction concerns and disposal of excavated earth and rock. Taipower said it will rely on its experience and follow expert guidance, adding that construction and operations will be carefully monitored. Taipower said a portion of the project is located within Indigenous tribal territories, requiring careful communication with local communities and compliance with the Indigenous Peoples Basic Law. The utility also pledged to adopt environmentally friendly construction practices to protect the surrounding ecology and environment.
With plans to more than double installed renewable capacity by 2035, Taipower has been looking at some of its existing reservoirs such as the Shimen, Feicui and Mudan reservoirs to build additional pumped-storage hydropower storage facilities. A feasibility study has already been completed for a smaller pumped-storage project to be built using the Shimen Reservoir as the upper basin and the Houchi weir as the lower reservoir. This project could be completed before the Guangming project.
