Hydro for More
Water distribution on Earth shows that freshwater comprises only 2.5% of the world’s water, out of which only 0.3% exists as wetlands, lakes, and rivers. This entails that the freshwater species are confined to 0.01% of the world’s available water. The diversity is high with 40% of all known fish species occurring in the freshwater ecosystems. Freshwater ecosystem plays a fundamental role in human lives as a source of economic activities, providing provisional services and a wide range of regulating and cultural services. However, this valuable resource is under rising threat as there is a competing interest for freshwater resources in the light of economic development. For instance, more than 60% of the largest river systems having a mean discharge of more than 350 m3s-1 have been fragmented by either dams or other kinds of infrastructural development. Rivers are now being expansively fragmented and transformed to meet water and energy demands as well as support social and economic development resulting in significant impacts on livelihoods and the environment. Water and energy are inseparably associated. According to Hydropower Status Report, 2018, Worldwide hydropower installed capacity rose to 1,267 GW in 2017, including 153 GW of pumped storage. Hydropower is often valued as a clean & renewable source of energy with lower greenhouse gas (GHG) emission. For many developing countries with huge hydropower potential, it is a strategic national resource and the main driver of economic growth. According to the World Commission on Dams (WCD), construction of dams directly impacted the economic progress in most parts of the world from the 1930s to the 1970s. Hydropower currently provides about 19% of the world’s total electricity supply and is used in over 150 countries. Approximately, 33% of the countries in the world currently rely on hydropower for more than half of their electricity needs.
The Trade-off
Although hydropower is regarded as a clean source of energy, it comes with specific environmental issues such as changes in land use and river flow patterns along with social impacts of displacement. As the main contributor of renewable energy in the face of climate change, hydropower often comes at significant environmental costs particularly to freshwater ecosystems, if not conducted in a sustainable manner. Freshwater ecosystems are amongst one of the most threatened ecosystems in the world today and hydropower development worsens the situation by fundamentally modifies the freshwater ecosystem. Currently, the total annual freshwater withdrawn is estimated at 3,800 km3, which is twice as much as it was just 50 years ago. Freshwater is experiencing a serious decline in biodiversity. Freshwater biodiversity was listed as the over-riding conservation priority during the International ‘Water for Life’ Decade of Action – 2005 to 2015 and beyond.
Global freshwater biodiversity has been facing five distinct threat categories, viz., overexploitation, water pollution, flow modification, destruction or degradation of habitat and invasion by exotic species. Almost all of these threats are direct consequences of hydropower development that lead to an unhealthy riverine ecosystem.
Construction of large dams causes site-specific change in river flow, blockage of migration route, sedimentation, wide habitat fragmentation that lead to irreversible loss of species and the ecosystem. The negative impacts occur both during the construction and operation of the dam and reservoir. Other substantial negative environmental impacts result from ancillary works associated with hydropower development, i.e., access to roads, power transmission lines, residential houses, solid waste disposal pits and so on.
On top of that, major rivers worldwide comprise of multiple dams. The higher the number of dams, the greater the cumulative impacts associated with it. This means greater alteration and fragmentation of riverine ecosystem. Most countries still lack proper R&D on the nature of the cumulative impacts of hydropower development, which is a grave concern.
To a great extent, policy instruments determine decision-making about water resources management and consequently their outcomes. In the current working scenario, hydropower developers contemplate environmental safeguards as a barrier that is unnecessarily integrated into governmental decision-making. The conventional due process ‘environmental assessments’ are frequently seen as an impediment. Environmental assessments are usually carried out as a mere legal prerequisite for any hydropower project. This has led to few environmental assessments being watered-down favoring the hydropower development. Lack of knowledge, insufficient assessments, and vested interests have caused major environmental impacts in the past. However, increasing scientific basis and rigor is improving the understanding of the water-energy nexus.
The global community adopted two important agendas in 2015, viz., sustainable development goals and agreement on climate change to reduce anthropogenic greenhouse gas emissions in order to limit global warming to ‘well below 2°C’. This means increased focus on clean, and cost-effective renewable energy that involves monumental investment towards a low-carbon, resilient and sustainable future. Many countries are encouraged to develop policies pertaining to renewable sources of energy in the name of climate change. Hydropower seems destined to be the most ideal renewable energy option right now. With increased global green demand, the role of hydropower in supporting renewable energy towards a more sustainable future will continue to grow stronger each year. However, with great hydropower future, irrevocable environmental damages will ensue simultaneously.
The Key Issues
Hydropower development projects are inherently challenging. Environmental impacts are one of the main challenges to hydropower-based energy security, which raises a key question of whether sustainable development is feasible when development need for energy and water are crucial for the global common good. Some issues include:
- Given the diverse footprint of hydropower development, is it still the best option to keep up the renewable energy demand?
- Will hydropower developments close the global energy gap?
- Is damming of all rivers for water and energy development an ideal choice?
- Should the ecologists curse dams and developers praise it?
- Is hydropower a setback or a blessing?
- How to balance energy gain and environmental loss from hydropower development?
- What does it take hydropower development to be compatible with conservation?
- Should we accept the potential harm on freshwater biodiversity for the potential climate benefits of hydropower?
Poet and novelist Rainer Maria Rilke once said of art, ‘In this there is no measuring with time, a year doesn’t matter, and ten years are nothing.’ It needs to be assessed as to how true the statement is with regards to the narratives on the nexus between sustainability, economic development and environmental protection; energy & water, and hydropower & freshwater.
