Songloulou hydroelectric power plant still very performant - ENEO officials.

The information was disclosed during a one-day press visit to the plant on Thursday May 8, 2025.

ENEO's Director of Operations, Ahmadou Bivoung, and the Director of the Production Unit at Songloulou, Maxime Kath, led journalists through theoretical and technical presentations of the plant.

They provided details of the plant’s operation from the time of creation, it's generation capacity, challenges faced with maintenance, the role it plays in the national distribution package, amongst other aspects.

The facility, it was disclosed, comprises concrete spillway dam 200m long and 8m high, a rockfill dam with earth core, 300m long and 27m high, a spillway 135m long and 20m high. Officials said it is equipped with seven segmental flap gates, an intake dam with buttresses 225m long and 35m high and a plant located at the foot of the intake dam. 

Contextually, the officials said the press visit was necessary for journalists to understand the efforts of various stakeholders in the national electricity system and the input of the Songloulou power plant.

They noted that improving the electricity supply in Cameroon is a major challenge facing the various stakeholders in the national electricity system under the supervision of the Ministry of Water Resources and Energy. 

In order to meet growing demand and the major challenge of ensuring the sector's financial stability, the stakeholders are currently implementing the recovery plan for the sector, with a focus on the transmission and distribution segments, where the current investments are intended to provide a rapid boost. 

Each stakeholder, it was said, is working within its own constraints, with a view to making a major contribution to improving the electricity supply. 

This, officials added, takes into account the fact that the generation segment has reached a certain maturity, driven by the construction of major facilities in recent years and increased maintenance of existing generation facilities. 

They said in this context, safeguarding the historic dams, diversifying sources, with renewable solar energy in particular and the ongoing construction of new dams are the pillars that will enable generation to keep pace with demand growth of around 7%.

However, it is well established that in the Southern Interconnected Grid, SIG, the Songloulou hydroelectric dam is a major infrastructure due to its vital contribution to the national networks. 

Electricity generation and distribution trends in SIG

Explaining the situation, the Director of the Production Unit, Maxime Kath, said Cameroon's Southern Interconnected Grid, SIG, depends mainly on three major hydroelectric power plants:  Songloulou, Edea and Nachtigal. 

Data from 2015 to 2025, he said, has shown a significant evolution. The installed capacity of the Songloulou plant stood at 384 MW, all working machines have a generation capacity of 384 MW with eight units of 48 MW each. Songloulou can therefore inject up to 384 MW into the system, depending on consumer demand via the distribution and transmission networks. 

"It should be noted that the maximum peak of the Songloulou power plant has always been above its installed capacity of 384 MW, with the plant sometimes managing to generate 400 MW. In other words, Songloulou sometimes produces more than 384 MW. The utilisation rate of Songloulou's machines, which is one of the highest in the world, is around 90%," Kath said.

In 2024, Songloulou came first in capacity, with 38% of the total SIG generation, 384 MW of installed capacity, while Edea came second with 25% or 276 MW and Memve'Ele with 12%. 

From the month January to April 2025, Songloulou maintained leadership with 35%, but Nachtigal, with 420 MW capacity, rose to 31%, becoming a key player. Edea, remains at 21%. 

Despite suffering a temporary fall of 3% in March 2025, due to a decline in its capacity, Kath disclosed that Songloulou being a historical pillar in the grid, still provides a stable base, but Nachtigal is reshaping the energy map, reducing the company's historical dependence on Songloulou. 

"Songloulou is stable and reliable. Songloulou's current level of performance is due to the regular investments made in this facility and the implementation of a rigorous maintenance plan year after year. The most high-profile investment programme in recent years has focused on a series of actions designed to secure the foundations of the dam, install cutting-edge monitoring technology and rehabilitate and/or renew a number of modulation facilities, such as the spillways. This is the so-called rehabilitation programme, also known as Dam Safety," Kath explained.  

How the dam safety works

The dam safety programme in question, it was revealed, made it possible to respond to the spread of a defect detected as early as the 1980s called Alkali-Granulate Reaction, AGR. Technical explanations revealed that AGR manifests in racks, swelling of concretes, and reduction in equipment clearances.

Rehabilitation works, through the Dam Safety programme, is said to have cost 11 billion FCFA already assigned for phase one. For phase two, an investment of more than 60 billion FCFA is expected. 

Songloulou in Cameroon is not the only dam to experience AGR. Ahmadou Bivoung, being an Operations Director since the days of SONEL, said Dams like the Chambon dam in France, experienced swellings of one to five mm/year, requiring reinforcement in 1992 and 2012. Another example of AGR experience was seen in Centre Hill dam in United States, cutting of blocks in 2007 and 2013 to limit damage. 

He said AGR is a globally recognised risk for old dams. The measures taken at Songloulou followed Hydro-Québec studies. Sawing of blocks, waterproofing are part of a long-term safety approach, but will require continuous investment, it was stated. 

Hydrological context and flow regulation

The SIG is said to be heavily dependent on the Sanaga basin, which is regulated by several reservoirs: Lom Pangar, 6.2 billion m³, six days to reach Songloulou. Bamendji, 1.8 billion m³, Mape, 3.3 billion m³ and Mbakaou, 2.6 billion m³ with 5.5 to 7.5 days transit. 

To generate power in the plants located on the Sanaga River, the plants must receive water released from these upstream dams, combined with the residual water contained in the river. 

These two volumes of water make up the flow required to turn the turbines. To ensure generation, one of the challenges is therefore to fill the dams by the end of November of each year. The other challenge is to have sufficient residual water in the Sanaga, and the last challenge is to have the machines or units up and running. 

"In 2025, we started the year with a shortfall of around 2 billion m3 in the filling of the dams, and the low-water level on the Sanaga was severe. These two factors led to generation that was often lower than possible at the three major power stations. These reservoirs stabilise flows, enabling Songloulou and Edea to operate at full capacity even during the dry season," Bivoung added, noting that Songloulou remains the oldest and still maintains flow its capacity.

Future prospects and challenges

It was also revealed that Nachtigal dam, with 420 MW capacity, commissioned in 2025, will rebalance the energy mix, but raises the issue of optimal interconnection with Songloulou and Edea. 

The Dam Safety and refurbishment programmes (2008-2025) aims at extending the life of the historic power plants. However, prolonged drought, it was disclosed, could affect reservoirs, highlighting the need to diversify sources to solar and wind. 

On this, Bivoung said if rain must fall to maintain water levels, it has to fall in the right area where the dams are located, if not so, the availability of rain falls in different areas may not necessarily help the situation with power supply.

This article was first published in The Guardian Post Edition No:3448 of Wednesday May 14, 2025