Koskienergia oy has applied to Lupa- ja valvontavirasto (LVV) for a permit to build a pumped-storage plant at its Parantalankoski hydropower plant in Äänekoski, Yle reported. The plan came as a surprise to villagers in Parantala.
The company would build a pumping station next to the existing plant, pumping water from Kiimasjärvi below the plant back into Pyhäjärvi above it. Parantalankoski has had a power plant since the 1960s. Pyhäjärvi has clear water and excellent ecological status, while Kiimasjärvi's ecological status is satisfactory.
A few hundred summer cottages and some permanent residents line Pyhäjärvi's shore.
Saara Pakkala, who lives with her family near the plant, said she is upset by the plans. "We have clean, clear water here and I swim with my spouse all year round, so it really upsets me," she said. Hannu Ruotsalainen, Koskienergia's CEO, said the pumped-storage plant is needed as balancing power for wind and solar electricity.
"When it is calm or cloudy, weather-dependent production is not available. We need balancing power to replace it," he said. Water would be pumped into storage when electricity is cheap and used to generate power when it is expensive.
The plant would not increase the amount of electricity produced by the Parantala plant, but electricity could be generated when little is available.
Ruotsalainen said he has received several contacts from villagers and is aware of their concerns. "With the permit application we are specifically examining whether licensing a pumped-storage plant is possible and under what conditions, so that water quality in Pyhäjärvi does not deteriorate," he said. He said company modeling shows water pumped into Pyhäjärvi would be the same water released below it, directed into the surface layer so it would not affect bottom sediment.
"The possible impact [on sediment] would be very local. It would only be visible in the bay above the power plant," he said. Koskienergia also seeks permission from LVV to remove the Pyhäkoski regulation dam at Pyhäjärvi's north end, replacing it with a natural bottom sill that would allow later restoration of Pyhäkoski for migratory fish.
Ruotsalainen did not detail the cost but called the investment. Construction could start in about two years if permits are granted.