China's Sino Hydro won the tender for the US$355mn project, the bulk of which will be funded by the Export Import Bank of China, under a deal signed with the Zimbabwe government in 2013.
ZESA spokesperson Fullard Gwasira said, "Shovels should start hitting ground in January.
According to Zimbabwe-based news agency The Source, the government secured funding for the project after signing a US$319mn deal with the China Export and Import Bank.
Zimbabwe is expected to contribute 10 per cent of the total cost of the expansion exercise, it added.
At present, ZESA is generating between 1,300 and 1,400MW against a daily national demand of 2,200MW, industry sources said.