| Refurbishment
Key points Key take aways from the Africa study are that: Hydropower modernisation will be critical both globally and in Africa. Modernising hydropower plants goes beyond standard refurbishments. Initial mapping shows Africa has an ageing fleet and good examples of projects that are suitable for modernisation. New technology concepts have a key role to play in hydropower modernisation. Access to financing is essential to move modernisation projects forward. Other matters discussed during the webinar included financing models, cascade hydro, staff training, climate resilience, and different hydropower hybrids such as green hydrogen.
Climate resilience and environmental and social impacts. Increasing electricity demand. While the major barriers to such modernisation hydropower plants are stated as being: Financing.
Low electricity price and demand. Regulations. Commercials contract and permitting. Lacking awareness of existing hydro.
The report found that out of the 87 hydropower stations screened, 21 plants totalling 4621MW – approximately 20% of screened capacity and representing 12% of the total African fleet – were assessed with high modernisation needs; 36 plants equivalent to 10,089MW (about 40% capacity screened) in medium need; and 30 plants totalling 9529MW were categorised as low need. East and Southern Africa had the highest number of plants with high needs, whereas West and Central Africa had the most significant amount in high demand for installed capacity. Most stations that were categorised as high need
exhibited a range of recurrent problems which can result in derating the plant’s design capacity. These issues included high shaft vibration when operating at rated power; high temperature in a turbine thrust bearing; cooling systems malfunctioning; lack of spare parts; and in some cases sedimentation was a major driver for modernisation.
Investment The report also gives an estimate of the
total investment required to carry out such modernisation. Twelve percent of the overall African hydropower fleet is in high need and will require an estimated investment of US$2.1 billion to give a capacity upgrade of about 0.23-0.53GW. While 26% of the overall fleet is of medium need requiring US$4.7 billion of investment to give 0.51-1.17GW of capacity upgrades. The results from this level of investment could help the economic and social development of the continent and secure over 14.7 GW of reliable electricity generation, increase plant flexibility, improve the existing fleet’s health and safety operations and
boost actual generation. In addition the replacement of outdated, deteriorated, or damaged electromechanical components could increase the installed capacity of the fleet between 740MW and 1700MW, thanks to the improved efficiency and increased power capability of modernised systems. As the report acknowledges, decisions about upgrading hydropower stations will be influenced s by project economics that are primarily driven by modernisation costs, electricity prices and market design. While on a national level there is the risk that decommissioning old hydropower stations is viewed as an alternative to such investment, potentially losing reliable, renewable generation capacity. With this in mind governments are encouraged to develop enabling policies to attract re-investment as this will be fundamental to securing these plants’ future ongoing productivity which should be seen as “an immediate priority”.
Solar opportunity Such modernisation projects to increase efficiencies,
replace equipment, and rectify ageing infrastructure issues shouldn’t have any adverse and there is often a great opportunity to implement measures that can even improve the project’s environmental and social footprint. These measures include: The introduction of fish ladders. The adoption of improved turbine seals which eliminate lubricant leakage. Improvements in the health and safety for personnel working at the plant.
An additional benefit that hydropower plants could provide within the development of the African power system is the opportunity to deploy floating solar panels onto exiting projects. Twenty six of the 87 projects in the study were selected for assessment and 11 of these were found to be potential candidates for further development. The characteristics that were used to select these sites were as follows: Solar irradiance was generally higher than the 2000kWh/m2
most candidate sites. Reservoir surface area was more significant than 1 km2
in all cases.
www.waterpowermagazine.com | September 2023 | 31
Above: Aerial view of Merowe Dam in northern Sudan
Below: The Bin El Ouidane dam in Morocco is 70 years old
/yr average for the African continent for
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