Hydropower has triggered intense discussion and conflict for decades. While debates over individual dams carry great weight for local rivers and communities, they are also the most visible flash points of an even larger underlying global challenge: how can the world provide sufficient electricity to support stable, prosperous societies – including delivering electricity to the one billion people who currently lack access – and do so through energy systems that neither push the climate past safe boundaries nor degrade the natural values of the planet whose climate we seek to maintain?
In short, the world needs to more than double electricity supply by 2050, generated by low-carbon energy systems that do not degrade land and river ecosystems and the values they provide. This is no small task.
Many countries will look to hydropower. While it is true that some hydropower reservoirs have high emissions of greenhouse gases (particularly shallow reservoirs in the tropics), globally, hydropower is by far the largest source of low-carbon electricity. Even with the anticipated – and urgently needed – massive increases in solar and wind generation, most global projections include a major role for hydropower within the future renewable energy mix. But without careful planning and implementation, the expansion of hydropower poses serious risks to people and nature.
By inundating valleys, blocking rivers and changing flows, hydropower can displace communities and damage river ecosystems that provide food and livelihoods to hundreds of millions of people. These impacts tend to fall disproportionately on low-income, rural communities and indigenous groups. A dramatic expansion of hydropower risks helping to solve the climate crisis at the cost of many of the world’s rivers and what makes them unique and so culturally, socially and economically valuable to so many people.
To successfully navigate through the dilemmas of the energy-climate-nature challenge will require new approaches to hydropower – and energy more broadly. In a report launched this week at the World Hydropower Congress – The Power of Rivers: a business case – I and colleagues at The Nature Conservancy and several partners argue that shifting hydropower planning and management to the system scale must be the foundation of any new approach.
Energy development and generation will always have some negative impacts. Tradeoffs are unavoidable. However, in The Power of Rivers, we demonstrate that many impacts can be avoided or reduced and that tradeoffs can be eased. Importantly, the report also shows that this direction makes economic sense for countries and provides financial value to dam developers.
These better outcomes arise by shifting the scale of hydropower planning and management – decisions about which projects get built and how they are operated – away from single dams and towards the system scale, such as river basins, grids, countries or regions – an approach called Hydropower by Design (HbD).
In an earlier report, we showed that global application of HbD could result in 100,000km more free-flowing rivers for the level of development projected for 2050, but only if there is broad uptake within the hydropower sector. Catalyzing widespread adoption will require that diverse decision makers see value beyond just environmental gains. And this is what The Power of Rivers is designed to do – drawing on a series of quantitative case studies to demonstrate to governments, developers and funders that HbD can provide value to them.
For governments and development organizations, the report demonstrates that HbD can deliver a “better deal” for development in the form of improved economic performance across a range of sectors and resources. In river basins across the world, hydropower development and management will interact with water management services – including water supply, flood-risk management and irrigation storage – that have an aggregate estimated value of up to nearly US$800 billion per year. Hydropower that is planned and operated as part of a larger system has the potential to increase the benefits from these services. The report shows that implementation of HbD within river basins could result in improved performance in these other important economic values – ranging from 5 per cent to 50 per cent for the same or even greater electricity generation, relative to status quo development and operation.
These gains could often be achieved alongside large improvements in environmental performance, such as dramatic increases in the length of rivers accessible to migratory fish, ranging from hundreds to tens of thousands of kilometers – critical since hydropower development will be concentrated in river basins that support the highest levels of riverine fish harvest and the highest diversity of freshwater fish species.
As promising as these results are, sustainable plans are unlikely to be implemented if they are composed of financially non-viable projects that can’t attract investment. But as a case study on the Magdalena River basin in Colombia demonstrates, through HbD, a strategic and sustainable system could be composed of individual projects with improved financial performance compared to current approaches based on two significant sources of value – system-scale engineering efficiencies and improved risk management.
Undoubtedly, system-scale approaches can move hydropower development and management toward more sustainable outcomes with broader benefits. Ultimately, however, the most comprehensive and balanced solutions for the climate, energy and nature may emerge from strategic planning across multiple energy sources at the scale of a grid – comparing how different mixes of renewables perform in term of both energy systems and ecosystems.
Indeed, a final case study on Malaysian Borneo shows how decentralized renewable sources, added to existing hydropower dams, could meet future electricity demand at a lower investment cost than additional hydropower dams, with far lower impacts on forests, rivers and indigenous people. This type of integrated planning illustrates how and where hydropower can best contribute to low-carbon and sustainable energy systems, helping to meet that challenge of achieving a world with a stable climate, prosperous societies and healthy rivers.
Now, we just have to convince governments, funders and developers to make the shift – for their own and everyone else’s benefit.