SYMPOSIUM ON THE 1,500MW TUNNEL ENERGY SCHEME AT BUTIABA

On 28th May 2019, all roads led to boardroom no 118 at the Ministry of Energy and Minerals in Kampala. The Minister of State for Energy and Minerals, Hon Eng Simon D’Ujanga, on behalf of the Minister of Energy, Hon Eng Irene Muloni, chaired a meeting between the key ministry staff, those working with relevant departments under the ministry  and 8M Construction Digest (8M CD). In attendance were staff from the Electricity Regulatory Authority (ERA), Uganda Electricity Generation Company Limited (UEGCL), Uganda Electricity Transmission Company Limited (UETCL) and UMEME. Also in attendance were the following: Eng Elias A Mugisha,  the private secretary to His Excellency the President on Infrastructure and Public Works; Eng Livingstone Kangere, a past Secretary to the Uganda Institution of Professional Engineers (UIPE), a past member of the Engineers’ Registration Board (ERB) and a member of the 8M Information Forum; and Eng Hans JWB Mwesigwa on behalf of the author, Hon Eng Hilary Onek, who had presented the article at the Fifth 8M Symposium at Naguru, Kampala, on 21st December 2018.

About 8M Construction Digest/8M Information Forum:

As a way of supporting industrialization, construction and engineering-related activities, 8M Construction Digest created the 8M Information Forum (WhatsApp active) where members share engineering and construction-related views for social, economic and technological development. Members comprise engineers, heads of manufacturing and production entities, surveyors, architects, planners, contractors, heads of engineering and professional bodies and others of public and business repute like engineering students in various institutions. These members yearn for information and business connections as ardent stakeholders and readers of 8M Construction Digest.  Some of them, at the echelon of engineering management in Uganda through ERB have the law’s mandate to monitor the practice of engineering in Uganda.

Summary of the 1,500MW project as an innovative renewable source of energy

The presentation is about “Exploitation of lake levels for hydropower in Uganda.” The presentation bears in mind energy-scheme developments along the Nile to date.

It is feasible and viable to construct a hydropower scheme that can yield between 1,100MW and 1,500MW of energy at less the cost and time than what was spent on the four power dams of Kiira180MW, Bujagali 250MW, Isimba 180MW, Karuma 600MW.  Masindi Port and Butiaba on Lake Albert via a westward tunnel are about 79.5km apart. At Butiaba, there is a water head of about 400m between the two places. Producing a gigantic amount of electricity needs a volume of water falling down onto turbines through a mighty height.  This water head is not comparable with those at the different waterfalls of the four dams of Kiira, Bujagali, Isimba and Karuma, which are each about 20 metres!

Some important technical issues that are highlighted:

Hydrological studies of Lake Kyoga, Lake Albert and River Nile;

The feasibility of River Nile diversion into tunnels to Lake Albert;

Schematic delivery of high pressure water to Pelton-wheel turbines;

Cross-sections of the tunnels – Lake Kyoga to Lake Albert (Masindi Port to Butiaba);

Hydraulic design of the tunnels, complete with engineering calculations;

The intake at Masindi Port area;

Approximate comparative analysis of the tunnel diversion system (volume of work) and technology of the tunnel construction.

Summary of observations bearing the current status of dam’s development around the area:

If implemented, the design would generate 1,100 MW of energy out of the 300m3/s diversion of the Nile at Masindi Port to Butiaba. If 400m3/sec of the Nile water is diverted to the tunnel, 1,500MW of power would be generated. This is environmentally possible as the Nile needs only 281m3/s to maintain its ecology, based on the 1923 flow level;

Removing 300m3/s from the Nile at Masindi Port, letting 412m3 flow to the Nile would reduce 190MW from Karuma hydropower dam and about the same amount from the projected Ayago hydropower scheme. A total of about 380MW would be lost from the two power facilities downstream;

Removing and diverting to the tunnel 400m3/sec from the flow, the Nile would reduce 250MW from Karuma and about the same amount from Ayago when constructed, but gaining 1,000MW (1500 – 500);

However, 380MW loss at the expense of adding 1,100 MW would provide additional power of 730MW to the system in the country. Or 500MW loss at the expense of adding 1,500MW would provide a net gain of 1,000MW;

The cost of constructing the tunnels and the underground powerhouse will have to be evaluated against the gains of 730MW or 1,000MW. At its conception in 1981, the project would have cost about US$200m. If the current costs are about $2m per megawatt – the internationally considered normal rate for hydropower construction or at US$2.5m compared to the current Ugandan rates of over US$3m per megawatt, then it would be cheaper than Bujagali and Karuma hydropower plants rated at much higher costs, but with generation capacity of 850MW (Bujagali at 250MW and Karuma at 600MW put together), which capacity is under-utilized due to error in hydrological evaluation. This proposal is based on over 100 years’ observation of the Nile, and therefore will have minimal deviation from the natural hydrology of the Nile.

Eventually, a detailed evaluation and cost-benefits analysis would be required to decide whether to build more dams in series for hydropower on the Nile or take this option. We could comfortably divert 400m3/sec of water to generate 1,500MW of power, losing a total of about 500MW from Karuma and Ayago and the country gains 1,000MW;

The proposal is environmentally feasible with minimum impact arising out of the diversion. As stated earlier, during 1923, the Nile’s lowest discharge was recorded at 281m3/sec and there was no reported significant environmental impact reported;

It is a more energy-efficient and effective proposal compared to the proposed costly in-series multiple dams;

It is economically more beneficial to the country with least interference to the existing activities and the National Parks;

It is more professionally exciting and can trigger more scientific research in hydrology and the geo-sciences.

On behalf of 8M Information Forum, Eng Hans Mwesigwa requested the Ministry of Energy to arrange a symposium, as recommended by the Office of the Prime Minister, which symposium would discuss the proposed scheme in detail with a view to carrying out a feasibility study.

At the end of the presentation and a fruitful discussion, the following, among others, were noted:

The proposed scheme presented both positive and controversial aspects which needed technical internalization before the next step could be taken. In this regard, the Minister established a committee, to be headed by Eng Emmanuel S Nsubuga, the Senior Energy Officer in the ministry, to be assisted by selected staff from ERA and UEGCL. The committee was given two months within which to peruse the presentation and forward their findings. The Minister also promised to liaise with Hon Hilary Onek.

The ministry will continue to strengthen a forum to discuss and  exchange vital information on value engineering at the inception stage with key relevant Ugandan professionals, which information may be vital for the design and implementation of strategic projects with better assurance of value for money.