Swiss hydropower dam. The Swiss Federal Office of Energy is part of the IEA Hydro Executive Committee.

The International Energy Agency’s (IEA) Hydropower Technology Collaboration Programme was started in 1995. It is a working group of IEA member countries and other non-members who have a common interest in advancing sustainable hydropower worldwide. 

“It was recognised that hydropower was by far the largest provider of renewable electricity,” says programme secretary Niels Nielsen, “but there are many strategic issues to be addressed to fully value and maximise its potential.”

IEA is the energy arm of the Organisation for Economic Co-operation and Development (OECD), and its mandate is focused on the "3Es" of effectual energy policy: 

  • Energy security.
  • Economic development.
  • Environmental protection – focused on mitigating climate change.

Many OECD electricity markets are in transition and IEA’s Hydropower Technology Collaboration Programme (TCP) addresses key issues related to hydropower. Through awareness, knowledge and support, it encourages countries to cooperate in innovative research and the sustainable use of water resources for the development and management of hydropower. Such international cooperation is important as it is not only cost-effective but facilitates learning from other countries’ experiences.

Membership of the IEA Hydro Executive Committee includes:

  • Australia – Hydro Tasmania.
  • Brazil – Ministry of Mines and Energy, CEPEL.
  • China – China Yangtze Power Co/International Centre for Small Hydropower.
  • European Union – European Commission.
  • Finland – Finnish Funding Agency for Technology & Innovation/Kemijoki Oy.
  • Japan – New Energy Foundation, Agency for Natural Resources & Energy.
  • Norway – Norwegian Water Resources & Energy Directorate.
  • Switzerland – Swiss Federal Office of Energy.
  • USA – US Department of Energy.

As a fundamental activity within the Hydropower TCP, member countries have collaborated to add value, importance and relevance to hydropower. This has been achieved through R&D programmes that address important challenges and opportunities by providing a cost-effective means to leverage available research funds through international effort. The research portfolio was defined by the countries participating in the Executive Committee, based on enabling knowledge transfer and effective collaborative research. 

This innovative research is divided into different subgroups known as Annexes. The following are currently in progress:

Annex XVI – Hidden Hydropower Opportunities 

In many countries and jurisdictions, a significant number of the most economic and technically simple hydropower projects have been developed, and hydropower is considered a mature technology with little room for growth. However, there are still ‘hidden’ opportunities to add or increase hydropower generation at new and existing project sites that are often overlooked by planners, governments, and developers.  In this context, hidden hydro can be identified as:

  • Updating and refining existing hydropower resource inventories to seek additional sustainable hydropower potential
  • Improving the performance of existing hydropower facilities 
  • Adding power to non-powered dams and distribution infrastructure such as irrigation schemes and water supply facilities. 
  • Developing and utilising novel or improved hydroelectric machinery to harvest unused hydropower potential (e.g. low-head applications)

The IEA Hydropower Technology Cooperation Programme’s Hidden Hydro Opportunities initiative has set an overall objective to “provide a framework to enable and support increased development of hidden hydro opportunities globally”. Participants are collaborating in an international knowledge gathering and research programme.

The initiative recognises that there are a number of challenges for developers to overcome. These have been bundled as Enablers, Barriers, Benefits and Misunderstandings and are the focus of this paper. Identifying barriers and the means to overcome them is a prime deliverable from the IEA Hydro’s work program.

Annex IX – Valuing Hydropower and Energy Water Services  

Stage 1 investigated the value provided by storage hydro projects through the establishment of the economic values of energy management, water management and other socio-economic services. 

Stage 2 will help develop an understanding of two key strategic themes: how hydropower will be valued in future electricity market scenarios, and how hydropower will be valued under alternate climate change scenarios

As the need for flexible and balancing capacity increase, there are fewer or no competitors to hydropower that can deliver emission-free solutions – particularly over long durations. Investigating the value of flexibility to the power system and the users of electricity is the subject of this phase of research. Initial findings have been published in a White Paper posted on the IEA Hydro website

The research on valuing hydropower’s role in adaptation and mitigation climate change themes will be defined at a workshop taking place in December. 

Annex XII – GHG Emissions from Freshwater Reservoirs

This has increased knowledge on processes connected to reservoir GHG emissions, established best practice guidelines for planning studies on the carbon balance in reservoirs, and standardised GHG flux evaluation methods. The Annex initially overlapped with the GHG assessment protocol development undertaken by a cooperative effort of UNESCO and the International Hydropower Association (IHA).  While the two initiatives proceeded in parallel, a cooperative MoU was signed. The IHA has developed a screening tool for initial reservoir GHG assessment, with the Annex covering complementary and more in-depth approaches to best practice modelling and complex assessment.   

Annex XIII – Hydropower and Fish

A roadmap/guideline for sustainable fish populations and management of rivers with hydropower production will be developed. The work programme undertakes collaborative research to better understand the challenges for sustainable fish populations in rivers with hydropower production. A recent initiative was the 1st International Symposium on Hydropower and Fish Management with a focus on global issues related to hydropower development and the impacts on fish biology and ecology.

Annex XIV – Management Models for Hydropower Cascade Reservoirs

Challenges can be compounded in cascade systems having different owners, stakeholders and operating requirements. Research is examining key issues and developing best practice in the design of new hydropower cascade reservoir schemes and the operation and management of existing plants 

Annex XV – Maintenance Works and Decision-Making for Hydro Plant Renewal

As hydro plants age, requirements for renewals and opportunity for upgrades are based on risk reviews and asset assessments. A key component of the process is decision-making relating to scope, timing and duration. A new research programme will cover best practices in optimal decision-making, which will complement the recently completed study (Annex XI) on technical aspects. 


During the Phase 5 term of the IEA Hydropower TCP (2015-2020), significant global trends emerged which will be important for Phase 6. These are in part a result of some countries reduced dependence on fleets of thermal and nuclear power stations. However, the significant deployment of variable renewable sources of energy (VRE), primarily in the form of wind energy and solar power, is demanding new and different roles for hydropower as a major provider of low cost sustainable dispatchable energy, storage and system security services. This has created renewed interest in developing new storage schemes and modernising existing fleets to provide such services.  The work of the IEA Hydropower TCP in these areas is a critical contribution to the value, importance and relevance of the IEA’s mission. IEA Hydro, in collaboration with the RE Integration Unit of IEA in Paris is investigating the technical and economic aspects of hydropower’s role integrating significant penetration levels of VREs 

In summary, IEA TCP will continue to address emerging issues in the future:

  • The transformation of energy markets that include hydropower, covering changing demand patterns.
  • Two Climate Change interrelated themes
  • Impacts and risks from weather (extreme events), operations and inflow prediction
  • Impacts on water quality and sedimentation.
  • VRE integration and the role of hydropower to balance power systems and provide storage. 
  • Approaches for economic decision-making for ageing hydro plants.
  • Policy and regulatory frameworks to remove barriers and provide incentives for development in Hidden Hydro.

The IEA welcomes participation from government agencies, utilities and research organisations with an interest in collaborative research on hydropower topics to support the sustainable use of water resources.