PrintThe Energy-Water Nexus
This nexus is rather straightforward, and we see this has two components- it takes energy to manage water, and it takes water to generate energy. Because with water, we have the same attributes to contend with- water accessibility, reliability, security, and sustainability. The difference is that for the most part, any lapses in these attributes, especially the first three, can mean life or death. One of the biggest reasons for deaths in developing countries is poor quality drinking water and access to sanitation.
Energy for water- We also need to recognize that when we talk about energy and water, we mean the energy needed to transport, collect, treat, and distribute water; as well as the energy needed to collect, treat, and discharge water. When there is a power outage, it is more than the lights going out. It means water supply and treatment plants cannot operate unless they have emergency power sources. To them, energy reliability is paramount.
Water for energy- From the other perspective, we know it takes much water to generate energy. Whether it is cooling water for power plants and solar farms, flowing water for hydropower, or water in the manufacturing process of renewable energy equipment, water is an integral part of power generation and energy supply. Interestingly, in terms of water use for power generation, a great amount of water is used, but very little is actually consumed. In other words, at a power plant, water is used to cool, but then is returned to the same local watershed. As we will see below in the food discussion, in agriculture much water is consumed- meaning it becomes part of the product and leaves the watershed.
A relatively new and contentious issue in the water-energy nexus is the concept of hydraulic fracturing for gas production. This is the practice of injecting water into a subsurface formation to force open fractures, or cracks, to allow the trapped natural gas to flow to the wellhead more freely. Ironically, this is not new technology and use of water for secondary fossil fuel recovery has been around for decades. But with the expansive growth of fracking, and the growing awareness of the sensitivity of water supplies, it is much more in the public eye than ever before.
Required Reading
Read the following pages in the Department of Energy’s report “The Water Energy Nexus- Challenges and Opportunities”
Read pages 1, and 3 to 7. Pay special attention to figure 6. This is a complex, but important-to-understand figure because it gives a sense of proportionality- how energy, water, and food (represented by the agriculture sector) interact. The easiest way to follow this figure is to follow individual color paths from left to right.
Questions to guide your reading:
- In terms of freshwater use, proportionally how much goes to energy production and agriculture?
- How would the recommended integrated approach to water, energy, and food management help?
- Fracking uses water in the process, but also generates more water than it uses because of recovered formation water, how do you think these factors balance out?