On the 20th (local time), we visited Solomon Islands, a South Pacific island nation of 820,000 people. It is more than 8,000 km away from Korea by air and has had little diplomatic or economic connection. About 20 km southeast of the capital, Honiara, lies the Tina River.
Here, there is a construction site with heavy equipment bearing the "HYUNDAI" logo moving around. Korea Water Resources Corporation (K-water) and Hyundai Engineering are building Solomon Islands' first hydroelectric dam. A hydroelectric dam is a generating facility that produces electricity by turning turbines with the force created when water stored upstream of a river is dropped.
Solomon Islands depended on fossil fuels for 97% of its national electricity and sent an SOS to Korea in 2015. When the dam is completed in 2028, Honiara's total power capacity is expected to increase from 27 megawatts (MW) to 42 MW. That means the share of the capital's 90,000 residents who can use electricity will rise from the current 50% to 70%.
For K-water and Hyundai Engineering, the project will also become a new source of revenue. K-water and Hyundai Engineering will shoulder 5% of the total project cost of $272 million (about 400 billion won). The rest will be raised by Solomon Islands through grants and loans from the World Bank and others. After the dam is completed, K-water and Hyundai Engineering will operate the dam, generate electricity, and sell it to the Solomon Islands Electricity Authority to earn revenue.
◇ Tina Dam to generate power with the force of 7 million tons of river water
At the Tina River on the 20th, work was in full swing on an upstream cofferdam to prevent flooding ahead of the main dam construction. A 10-ton (t) vibratory roller compacted concrete with its massive drum, and 20 to 30 workers in safety vests moved back and forth on both sides to check whether the concrete had been properly compacted.
About 20 meters from the cofferdam site, an excavator was digging deep into the riverbed. The main dam, about 71 meters high and 232 meters wide, will be built here. Cho Han-yong, Director General of the Solomon SPC at the Global Business Division of Korea Water Resources Corporation (K-water), said, "Once the dam is completed, about 7 million tons of water will fill this valley."
About 20 km away, work was also in full swing on the outlet of a straight waterway tunnel that will connect to the main dam. The blasted, concave mountainside created with dynamite had already reached a depth of 33 meters. A TBM (Tunnel Boring Machine), a cylindrical tunnel excavator, will be deployed here to slowly bore a 3.8-meter-diameter passage. On the slope, the site for the penstock where the turbines will be installed was also being compacted.
◇ Korea's technology to lower Solomon Islands' electricity rates by 30% to 40%
When the Tina Dam is completed, increased power capacity is expected to lower Solomon Islands' electricity unit cost by about 30% to 40% from current levels. Household electricity rates in Solomon Islands now average $0.81 per kilowatt-hour (kwh, the amount of energy used for one hour at 1 kilowatt of power). That is higher than Korea ($0.10) and the Pacific region average of $0.4. McKinnie Dentana, vice finance minister of Solomon Islands, said, "Our goal is to supply 100% of Honiara's 20 MW power demand with renewable energy by 2030, with most of it to be covered by the Tina hydropower project."