February 24, 2023
MORIOKA ― The Kitakami River Integrated Dam Management Office in Morioka has launched a trial to increase hydroelectric power generation at the Isawa Dam in Oshu, Iwate Prefecture, as part of efforts to decarbonize society.
The trial, which began on Feb. 15, is expected to generate enough electricity to meet the annual power consumption of about 260 households in the Tohoku region.
With a total storage capacity of 143 million cubic meters, the Isawa Dam generates hydroelectric power while maintaining water levels for agriculture and drinking water.
In spring, the amount of water flowing into the dam increases due to melting snow. When the dam’s maximum storage level is exceeded, water overflows and is not used to generate electricity. About 100 million cubic meters of water — enough to fill about 80 Tokyo Domes — is wasted every year, according to estimates.
The local office of the Land, Infrastructure, Transport and Tourism Ministry and Tokyo-based Electric Power Development Co. or J-Power wanted to find a way to utilize the dam’s overflow for power generation.
During the trial period through April 20, the water level will be lowered by 2 meters from the standard level to make space for the upcoming snowmelt. This would make it possible to divert about 6 million cubic meters of water — about 6% of the overflow in an ordinary year — to power generation.
Since last August, attempts have also been made to increase power generation at Morioka’s Shijushida Dam by utilizing water discharged during heavy rainfall.
“We would like to increase renewable energy with the cooperation of water users and contribute to a clean society,” said Masaaki Katano, deputy director of the Kitakami River Integrated Dam Management Office.