By Debora Rodrigues, Associate Professor of Civil and Environmental Engineering
People often think of scientists as solitary types, working alone in our labs, focused on a narrow topic. But if that was ever true, it’s not now. Scientific discovery and creating new technologies don’t fit in a box.
That’s certainly the case with questions involving water and energy, and the so-called water-energy nexushas gained attention from both the government and from researchers over the past few years.
The two intersect like this: Producing clean water requires energy – to treat the water, to distribute the water and so on – while it takes water to produce energy, from generating electricity to blasting chemicals and sand into shale rock to extract oil and natural gas. Water is a key component of the cooling process in utility plants powered by fossil fuels, and it generates electricity directly in the case of hydroelectricity. Drought can affect power plants by limiting water availability. Similarly, water treatment plants can be shut down when a storm knocks out the power supply.
I experienced the connection in my work, which focuses on bio- and nanotechnologies for water and wastewater treatment. Growing up in Brazil, I saw firsthand that people in rural areas too often were sick or even died because they didn’t have access to clean, safe drinking water. Established techniques such asreverse osmosis – which forces water through a membrane to remove bacteria and other particles – requires huge amounts of energy, driving up the cost. That may not be a concern for richer countries, but in the developing world, clean water solutions need to be simple and inexpensive.
And now we know it’s not just energy and water. More recently, food has been added to the wheel.
The United Nations reports that agriculture accounts for 70 percent of global freshwater use. Food production and transportation consumes about 30 percent of global energy use. As the demand for food increases to meet projected population growth, it will require both more water and more energy.
It doesn’t stop there, however. Runoff from agricultural operations can lead to pollution, requiring the water to be treated. The treatment requires energy. But agriculture doesn’t just consume water and energy – crops and agricultural waste are used to produce biofuels. About 42 percent of Brazil’s gasoline requirements are fulfilled with ethanol made from sugar cane.
There’s no place to get off the wheel. It goes in so many directions, and if we want to manage our resources sustainably, we have to pay attention.
Why do all of these connections matter? Maybe they don’t to the average consumer. At the height of the California drought last year, the news was full of stories about how much of the state’s dwindling water supply went to almonds, walnuts and other nut crops – almonds and walnuts both require about 50 gallons of water per ounce, a figure that rises almost to $100 an ounce when the nuts are measured unshelled, according to the UNESCO U.S. Institute for Water Education. But people didn’t stop eating pistachios.
Researchers are paying attention, however, and that already has changed the way we think about solving problems. My lab is no longer focused just on finding ways to remove microbes and other toxins from water; instead we make sure the coatings, filters and other technologies we develop are reusable and require little if any energy.
Other researchers are working to reduce water requirements for food production, to more efficiently convert agricultural waste to biofuels, and to address other issues along the wheel.
The Food and Agriculture Organization of the United Nations has called for more data and research to help nations around the world navigate the decisions that these interrelationships will require, allowing individual countries to better manage the tradeoffs that will be required.
We have learned that nothing happens in isolation, and we are moving out of our silos.
Debora Rodrigues is an Associate Professor in the Department of Civil and Environmental Engineering at the Cullen College of Engineering at the University of Houston. Her work focuses on developing bio- and nanotechnologies to reduce energy costs in water and wastewater treatment.