Nouvelles

President Museveni is today expected to officially commission the 183-megawatts Isimba hydro-dam in Kayunga District, some 67 kilometres north-east of Kampala, capping a 47-month frantic construction of the flagship energy infrastructure.

The installed electricity capacity in the country will gross 1,000 megawatts with the launch, a significant feat that the government said could prompt tariff reduction for large-scale consumers supplied from the national grid.

“It (power price reduction) is not immediate for everybody across the board at once,” said Mr Robert Kasande, the Energy ministry permanent secretary.

He said a marked decrease is likely to happen when the ongoing construction of the 600-megawatts Karuma dam is completed and electricity transmission and distribution infrastructure upgraded to improve supply efficiency and quality.

Energy losses, accelerated in part by old infrastructure, is a significant contributor to power tariffs and modernising the transmission and distribution network, PS Kasande said, will help reduce the cost.

The government calculation, according to senior officials, is that targeted incremental tariff relief to industrialists will enable them produce goods efficiently and on the cheap, lowering market prices and stimulating demand to spur economic growth.
Uganda Electricity Generation Company Ltd (UECGL) says it will sell the electricity it generates at Isimba at about $5 cents per unit or 1,000 watts, lower than the $8 cents charged for Bujagali dam power.

The UEGCL spokesman, Mr Simon Kasyate, said: “The construction and completion of Isimba dam gives confidence to investors that Uganda has adequate and reliable electricity [to power any investment].”

Technical staff at Isimba have been running tests of gradual loading of the electricity generated from the dam onto the national grid since last December, when the plant was originally planned to be commissioned.

They, in coordination with other power generators, yesterday afternoon activated all the four turbines to run at full capacity and Isimba dam during the hour-long trial supplied 183.5 megawatts of electricity on the national grid.
Construction of the Shs2 trillion plant has been largely bankrolled by China’s Export-Import (Exim) Bank, with Uganda covering 15 per cent of the project cost.

The government is currently pursuing an ambitious infrastructure development, covering road, rail, oil and energy sectors, after President Museveni in the past slashed 30 per cent off budgets of all ministries to muster required internal resources.

Converting water to electricity.
The potential energy in the water from the reservoir converts to kinetic energy as it plunges, in the case of Isimba dam, 25 metres to spin the turbine blades inside the power house. The rotation of the blades generate mechanical energy that powers on the generators.

Copper wires in the generators cut the magnetic fields, inducing electricity in the copper wires. This electricity is conducted to the transformers (on the back of the power house). The electricity is transmitted to the Switchyard from where it is stepped up, in the case of Isimba Hydro-dam, to 132KV for transmission over 42 kilometres to the Bujagali Hydro-dam Switchyard for onward connection to the national grid.

The power voltage is stepped up to reduce the current and reduce losses in transmission due to resistance over longer distances.
Usually the voltage is lowered at sub-station transformers to increase the current available for distribution to users.