In 2014, the World Bank announced that modern water and energy production systems were on a collision course. Part I of our Water+Energy series covered the collision from the water perspective: how water industries such as wastewater treatment or other water utilities frequently inefficiently use energy to power infrastructure and monitoring systems.
Part II will reveal how energy production often wastes hundreds of gallons of water a day through cooling systems, run-off or other byproducts of the energy extraction process.
The Role of Water in Energy Production
Like most industries, energy leans on water to accomplish many of the most critical tasks. World Bank research shows that 15% of water withdrawn from the environment goes exclusively to energy production. Unfortunately, much of the water used in the energy production cycle returns unusable, barely treatable or harmful to the environment when returned. Here are a few ways water gets used in the energy sector:
Thermoelectric Energy and Water
According to a US Geological Survey conducted in 2014, thermoelectric power plants in the United States consume almost 125 thousand gallons of water a day. Thermoelectric power plants include nuclear reactors, hydroelectric dams and plants that burn fossil fuels, such as coal. The water footprint calculator estimates that 41% of total water withdrawals for 2015 could be traced to thermoelectric power withdrawals. These kinds of plants rely on water for two key reasons: cooling and pressure.
Pressure comes from water volume, such as dams, or from heating, for steam-generated action. Steam may be used to turn turbines that generate electricity. Water remains the number one choice of engineers for cooling systems due to its high heat capacity and low risk of issues. Water cools hot systems, such as reactors or storage containers, by being run through or pooled over the heat-rich areas. Consider nuclear plants with the high heat reactors and waste. They require 615 gallons of cooling water a day to power the average home, according to the Scientific American article “Renewable Energy Saves Water and Creates Jobs.”
In these situations, while the water may only absorb heat energy, it can experience elevated temperatures of several degrees. This significant increase affects the ability of the water to return to the ecosystem. Hot water in waterways can lead to changes in algae, mineral absorption and water-dwelling creatures.
Oil, Gas and Water
Oil and gas industries use water for a range of activities, from extraction to refining. According to the Environmental Defense Fund, “some [oil] wells produce up to 10 times more wastewater than oil.” In the United States, that wastewater production equals 900 billion gallons a year, or one-tenth of The Great Salt Lake’s volume. As well, natural gas teams can use several hundreds of thousands of gallons during the cracking of rock deposits required for fracking. The wastewater created by this and other processes is often saltier than ocean water and, especially in oil industries, contains up to 1600 chemicals that require advanced wastewater storage and treatment – if it can be treated at all.
Alternative Energy and Water
Fortunately, water plays the smallest role in alternative energy resources such as wind power, solar energy and geothermal energy.
The Future of Energy and Water
While there seems to be an endless cycle of wasteful use between energy and water industries, it’s not the guaranteed future. Both sectors have seen declines in waste over the past ten years, and new technologies are available to increase that efficiency.