Reducing the cost and impact of civil works

Why is this gap important?

The cost of civil works associated with new hydropower project construction can be up to 70% of total project costs, and their social and environmental impacts can be considerable, so improved methods, technologies and materials for planning, design and construction have considerable potential.

Technology solutions

A roller-compacted concrete (RCC) dam is built using much drier concrete than traditional concrete gravity dams, allowing speedier and lower-cost construction. Trapezoidal cemented sand and gravel (CSG) dams (e.g. in Japan) use more local materials, reducing costs and environmental impact. Recent improvements in tunnelling technology have also reduced costs, particularly for small projects.

Some improvements in turbine technology aim directly at reducing the environmental impacts of hydropower, such as fish-friendly turbines. Aerating turbines use the low pressures created by flows through the turbines to induce additional air flow. This increases the proportion of dissolved oxygen, protecting aquatic habitats in waters below dams. Oil-free turbines use oil-free hubs and water-lubricated bearings to eliminate the possibility of oil leakage into the river. Other benefits include easy maintenance and lower friction than with the oil-filled hubs.

Extensive research to reduce mortality as fish pass downstream through the hydraulic turbines has significantly improved turbine design. In recent years, minimum gap runner (MGR) technology has achieved fish survival rates in excess of 95% for large axial flow units in the field. New designs, such as the Alden turbine, expand the range of fish-friendly units to smaller turbine applications but have not yet been widely applied.

Continuous improvements in material properties have been driven by requirements to: improve resistance to cavitation, corrosion and abrasion to extend component life and reduce outages; reduce runner weight and improve efficiency through increased strength of materials; and improve machinability to increase power output as more complex shapes can be manufactured. This has led to increased use of proven and new materials such as stainless steel and corrosion- or abrasion-resistant coatings in turbines, and lower-cost and higher-performance fiberglass and plastic materials in construction.

Colored bars represent the Technology Readiness Level (TRL) of each technology. Learn more about TRLs

Recommended actions

Environment and energy/resource ministries

Next 5 years:

  • Promote policy frameworks that cover the development of sustainable and appropriate hydropower projects that avoid, minimise, mitigate or compensate any legitimate and important environmental and social concerns.

Industry

Next 5 years:

  • Consider sustainability issues in the co-ordinated operation of hydropower plants.

Intergovernmental organisations and multi-lateral development agencies

Next 5 years:

  • Provide capacity building for regulatory frameworks and business models to help developing countries implement sustainable hydropower development.