REPUBLIKA.CO.ID, SITANDIANG -- Batang Toru hydropower plant claimed the construction of the project will not cause flooding or droughts in surrounding areas as many parties concerned.
PT North Sumatra Hydro Energy (NSHE) as the builder of Batang Tour hydropower plant project said the hydropower plant was designed to serve peak loads with a capacity of 510 Megawatts (MW) produced from 4 turbines driven from hydropower from a daily pool of 90 hectares. It would produce 2,124 GWh / year of electricity.
According to NSHE Senior Adviser on Environment and Sustainability Agus Djoko Ismanto, Batang Toru hydropower plant has its function to serve electricity peak load from 18.00 to 24.00 WIB (Indonesia West Standard Time). There was a perception that hydropower only operated six hours and would be closed for 18 hours, so it was considered to cause flooding.
“So there is perception dry at day and flooding at night. However, Batang Toru hydropower plant operates 24 hours,” said Agus in a journalist trip on Thursday (May 2).
Batang Toru hydropower plant has no reservoir, so it does not store water. The total water which will be stored when it first operates is 15 million cubic meters at dam, which will be built on a narrow slope leading to the downstream of the river. A total of 15 million square meters is needed to raise the altitude, so that the outflow meets the turbine operations.
"The first filling is not done by closing the total. It can be very small. The principle of filling the first one will not cause drought below it," Agus explained.
Furthermore, for the availability of water at dam, river water will be stored once or twice a month, depend on the available water debit. After operating, at peak load, the total water needed for 6 hours is 3.4 million cubic meters. However, because water also flows, there is a reduction of half that of around two million cubic meters which will be filled for 18 hours.
Agus explained the water storage at dam would not cause the river to dry out. Batang Toru hydropower plant has a discharge limit of 45 cubic meters per second.
If it enters dry days or below 45 cubic meters of discharge, then all water will flow. In addition, the affected river, the Batangtoru River, will get a flow of water from the DAM plus the tributaries.
"So it won't dry out. Hydropower plant uses only running water," Agus said.
Batang Toru hydropower plant ensured dam operation will not cause flooding. At the downstream, there were our villages which often experience flooding up to four times a year, namely Taman Sari Village, Pulo Lobang, Benteng, and Banjarmasin.
Before Batang Toru hydropower plant built, flood occurred when the water debit was 325 cubic meters per second. Meanwhile in maximum operation, the hydropower plant has a capacity of 200 cubic meters per second.
"So even if there is a flood, it’s not because of the hydropower plant. Even though the discharge here is small, it can be flooded below because of the tributaries, one of those is Parsarirang river," Agus said.
Batang Toru hydropower plant is expected to operate in 2022. The hydropower plant will supply energy of 2.124 GWh per year, which contributes to 15 percent of the peak load requirement of North Sumatra at that time.