Eskom invests shs.888m to renovate Nalubaale powerhouse staircases

Eskom Uganda on Thursday commissioned the renovated Nalubaale Powerhouse staircases a project that cost shillings 888 million, aimed at restoring the structural integrity of Units 1, 5 and 9 staircases.

The refurbishment of the Units 1,5 and 9 staircases was undertaken by Babcon Ltd, a Ugandan Company to improve their structural integrity and ease accessibility to the lower gallery of the powerplant in order to access the turbines and waterways for maintenance.

The project has cured cracks first identified in 1964 due to Alkaline Silica Reaction (ASR), a ‘concrete cancer” which causes structural movements to civil hydro infrastructure in the presence of water.

Speaking at the commissioning, Ms Thozama Gangi, the  Managing Director, Eskom Uganda said, “This project is of important significance to the lifespan of Nalubaale Power Station, because it is the first of a number of projects that Eskom is currently undertaking to address a historical challenge of the Alkali Silica Reaction (ASR) which has troubled civil hydro infrastructure the world over and Nalubaale in particular.

Thozama added that the project, as well as other ASR related projects currently under execution, will ensure that the structural integrity of the Power Station will be robust for many years to come.

This project is the first of a number of projects that Eskom is currently undertaking to address a historical challenge of the Alkali Silica Reaction (ASR) which has troubled civil hydro infrastructure the world over and Nalubaale in particular.

Nalubaale Powerhouse, constructed in 1954, consists of 3 levels; the machine floor, upper (below the machine floor) and lower galleries (below upper gallery) connected through concrete stairwells.

Deterioration of the powerhouse structure was first noticed in 1964, when hairline cracking in the generator floor started to appear, gradually resulting in degradation of the generator floor, upper gallery, and structure frame of the powerhouse.

In 1990, the cracking was diagnosed as being due to concrete expansion caused by Alkali Silica Reaction (ASR), a chemical reaction which in the presence of water may cause structural movements and detrimental effects of civil hydro infrastructure.

Over the years, the staircases were observed to be moving off the wall and experiencing cracking in various sections which is why Eskom commenced the staircase remediation project.

While handing over the project, Mr Godfrey Zaribwende, the Managing Director, Babcon Uganda Limited described the renovation project  as  a delicate job that required precision in fabrication and installation of equipment as well as identifying and sealing leakages in the concrete.

"We are thankful to Eskom for the opportunity to extend the life span of Nalubaale Hydropower Plant. The exposure acquired from this project will take us miles in the construction industry.” Zaribwende said.

Eskom has year to date invested shillings 147.5 billion (USD 40m) in both Nalubaale and Kiira power stations and plans to invest an additional shillings 88 billion (USD 23.7 million) by March 2023.