The water-energy nexus - the fundamental connection between water and energy - may not seem an overly complex concept to initially grasp - and yet its implications are not fully understood in our industrial, resource-strained, climate-changed world.
The fact is, climate is the third component of the water-energy nexus. No discussion on managing the energy-water nexus for a sustainable future is complete with considering the impacts and consequences of climate change.
Climate change, energy and the hydrological cycle
As climate change disrupts the global hydrological cycle, water-stressed regions, particularly in the developing world, face even greater impacts in the coming decades. Recent studies indicate climate models underestimate the rate of change in the global water cycle by as much as half. Adaptation to climate change is now a reality and the degree to which there is effective mitigation depends on how well - and how quickly - we manage a transition to a new, carbon-free energy economy. But to look only at the energy sector as a path to sustainability in a changing climate isn't enough. Power plants dependent on water for cooling are already forced to scale back production as water levels in reservoirs and rivers fall due to heat waves and drought.
How do we respond in a world already experiencing rapid climate change and growing demand for power? Transitioning to non-carbon sources of energy is essential, but water implications are almost never a part of the policy and scaling considerations of these energy sources. Solar thermal and especially biofuel production can be more water intensive than the systems they may replace. Adapting to low-carbon energy systems must take into account complete life-cycle water impacts.
Getting the water where it is needed: energy and infrastructure
In a predominantly urbanized world 27 percent of people living in cities lack water pipes in their homes. Where there is infrastructure, it is often woefully outdated. In the United States there are 850 water main breaks every day, costing $52 billion annually and wasting enough water to supply the state of California for one year.
As global freshwater supplies become more strained, the trend is toward more energy-intensive water such as desalination, deep aquifer production, long distance pipelines and inter-basin transfer. As with the energy sector, analysis of water policy most often neglect implications of energy requirements.
"Energy constraints become water constraints. Water constraints become energy constraints," says University of Texas associate professor Dr. Michael Webber.
Policy fragmentation: putting the pieces together
Despite the inexorable link between water and energy, the policy governing the two is often hopelessly fragmented. At the national and international level, this lack of policy integration is a core challenge for effectively addressing the water-energy nexus in a sustainable society. Only in the past several years has there been serious discussion on the water-energy nexus, let alone designing and implementing effective policy.
The challenge for policymakers is integrating the water-energy nexus in their decision and analytical process at a regional, national and global scale. There is no "one size fits all" solution. A study in Ecology and Society suggests the "first four steps" for assessing regional water security and energy sustainability - in summary:
- Is the region currently water and energy secure?
- What is the future outlook? Are future energy-water issues identified?
- What current policies weaken energy and/or water security?
- What policies can be implemented to strengthen energy/water security in the face of resource constraints and climate change?
Conservation and efficiency: buying time
Energy conservation and water conservation are essentially synonymous. "Conservation buys us time," says Webber. "It might not be an ultimate answer for everything, but it sure does buy us a lot of time so we can find some good solutions."
Tackling the water-energy nexus
There is little doubt that addressing the water-energy nexus in a climate changed world is the ultimate challenge of our time. It lay at the heart of all human issues of social justice and sustainability. And there are no easy answers. We must begin by integrating policy with a holistic understanding of the tight interrelationships between energy and water. We must conserve and manage our fundamental resources if we hope to survive and thrive.
Image credit: Argonne National Laboratory, courtesy flickr