The Cahora Bassa South Bank Hydropower Project in Mozambique, one of Africa’s largest hydropower projects, has achieved Silver certification under the Hydropower Sustainability Standard (HSS), following nearly a decade of engagement with international hydropower sustainability practices and continuous improvement.
The 2,075 MW project, owned and operated by Hidroeléctrica de Cahora Bassa (HCB), is located on the Zambezi River in Tete Province. Construction began in 1969, more than half a century ago, with the project entering commercial operation in 1977. Today the project generates an average of more than 15,000 GWh of electricity per year.
Cahora Bassa becomes the second hydropower project in Africa to achieve certification under the HSS, following Ngonye Falls in Zambia in 2024, with several more projects across the continent now progressing towards certification.
A commitment to continuous improvement
Cahora Bassa has been engaging with international hydropower sustainability tools for nearly a decade. The project was first assessed in 2018 under the Hydropower Sustainability Assessment Protocol (HSAP), a predecessor to the HSS, which established a baseline and identified opportunities to strengthen its sustainability performance.
HCB has since implemented a range of measures in response to the first assessment findings. These include a climate resilience assessment and climate risk management plan, a new reservoir management inflow forecasting system, an assessment of greenhouse gas emissions using the G-res Tool and a new biodiversity management plan and formalised support to the neighbouring Mágoè National Park.
A new assessment under the HSS in 2025 found that the project has significantly improved its sustainability performance, going beyond minimum certification requirements to achieve Silver. It shows strong performance in areas including worker health and safety, water quality monitoring, hydrological management, climate change and stakeholder engagement.
The assessment report also identifies areas for continued improvement, including further integration of environmental and social management systems, biodiversity monitoring and emergency preparedness, which HCB is continuing to address through sustainability action plans.
Overall, the biggest change has been the transition from managing sustainability as a set of individual actions to a more structured and integrated approach, supported by stronger systems, clearer priorities and continuous improvement.
Nico Savaio, ESG and Integrated Management System Coordinator at HCB
Raising the bar for legacy hydropower projects
Cahora Bassa was developed decades before modern ESG frameworks and sustainability standards existed. Its certification shows how existing hydropower assets can strengthen their management systems and evolve in line with changing international expectations.
“Achieving certification was a significant milestone for the entire HCB team because it recognised years of dedication, collaboration and continuous improvement,” said Savaio. “Perhaps most importantly, the certification is not seen as the end of the journey, but as a milestone that motivates us to continue improving.”
Cahora Bassa sends an important message to the hydropower sector. A project built more than half a century ago can continue to evolve and meet the sustainability expectations we set today. HCB has shown the value of engaging openly with independent assessment, acting on the findings and making continuous improvement part of how a project is managed. We hope this achievement will inspire other operators across Africa and beyond to follow the same path.
João Costa, Executive Director of the Hydropower Sustainability Alliance
Cahora Bassa’s certification comes as momentum behind the HSS continues to grow across Africa, with several more projects currently progressing through assessment and certification.