Water levels at the 2,075-MW Cahora Bassa hydroelectric project in Tete province, Mozambique, are dangerously low, according to the facility’s operator, Hidroelectrica de Cahora Bassa (HCB). As a result, HCB has cut electricity supplies to South Africa’s power utility Eskom by 13%.
This information is in sharp contrast to that released in January by Mozambique’s National Water Board (DNA), which said, “the Cahora Bassa reservoir is 61% full, and the dam is discharging water at the rate of 1,900 cubic meters per second. For the foreseeable future there is no danger that Cahora Bassa will be obliged to reduce its generation of electricity.”
Cahora Bassa Dam impounds the Zambezi River creating Cahora Bassa Lake, which has a capacity of about 55.8 km3. According to HCB, as of the end of November the reservoir was only 34% full, which is 8.8 m (29 ft) lower than in January.
Information from HCB indicates the facility’s water level is only 17 m (55 ft) above the minimum operating level.
HCB is a member of the Southern African Power Pool, currently 16 companies in a common electricity market for 12 countries, of which hydropower accounts for 21% of generated electricity.
Zambia, which depends almost entirely on hydroelectric power from the Zambezi River, has suffered power shortages since last year. Published information indicates the 1,830-MW Kariba hydroelectric facility, upstream from Cahora Bassa that supplies almost all of the electricity in Zambia and Zimbabwe, fell to 12% capacity in summer 2016.