Not Just Hydropower: Energy Needs Water And Water Needs Energy, Report Finds

Posted on

"Not Just Hydropower: Energy Needs Water And Water Needs Energy, Report Finds"

resized-lightbulbEverybody knows that water and electricity don’t mix in the bathtub. But it turns out that in most other realms of modern life — driving, watching television, preparing dinner — they are inextricably linked. It takes water to generate energy, and energy to move water.

The extent of this relationship, and the scale of it, literally pumping water over mountains in some cases, is rarely seriously considered outside of the wonky water-energy nexus circle. But with the demand for both growing while supplies shrink or rise in cost, a reckoning with these two trends is as foreseeable as the reckoning of climate change. In fact, it is exacerbated by climate change, which leads to reduced precipitation and hotter temperatures in many places, elevating demands for water and energy.

A new study by Water in the West, a research center at Stanford University, lays this all out in a report called, “Water and Energy Nexus: A Literature Review.” The report finds robust opportunities for reductions in greenhouse gas emissions, as well as for the conservation of scarce water resources. A comprehensive survey of publications by academic, government and nonprofit sectors over the last 23 years, it also identifies substantial money- and energy-savings opportunities for water and wastewater managers.

The report itself is laden with down-and-dirty details, but certain facts stand out in understanding the extent of the issue. For example, the energy required for groundwater extraction is estimated to be roughly one to two percent of total U.S. electricity production. That’s a lot of electricity.

Or, more illustratively,

“For much of history, both people’s use of water and the location of their communities have been limited by their proximity to clean, abundant supplies of water. Thus, people have had to rely upon human power, animal power or gravity to convey water from its source to where it is used. Romans, Mayans and other organized civilizations developed intricate systems of water conveyance, including reservoirs, canals, pipes and aqueducts, and leveraged gravity to move the water from source to end use. In contrast, modern societies have the ability to harness large amounts of cheap energy to move water long distances.”

Current demographic trends in which populations continue to grow and sprawl, especially across the arid Southwestern U.S,. will exacerbate the problem. Already, to meet Southern California’s demand, water is pumped through 4,800 kilometers of pipelines, tunnels and canals, including a 3,000 foot climb over the Tehachapi mountain range. The California State Water Project alone is the largest single user of energy in California.

Approximately 46.4 quads of 2010 US annual energy consumption was used for water-related purposes. The majority of this energy (33.1 quads) was used to make steam for electricity, space heating and industrial process use. Only 12.3 quads of energy was used for direct water services (i.e. 8.2 quads for heating, chilling, treating, pressurizing and pumping water) and direct steam use.

Approximately 46.4 quads of 2010 US annual energy consumption was used for water-related purposes. The majority of this energy (33.1 quads) was used to make steam for electricity, space heating and industrial process use. Only 12.3 quads of energy was used for direct water services (i.e. 8.2 quads for heating, chilling, treating, pressurizing and pumping water) and direct steam use.

CREDIT: Kelly T Sanders and Michael E Webber

Recycled water could provide some of the required new sources of water across the water-stressed Southwest. According the report, wastewater treatment plants discharge about 32 billion gallons per day of effluent in the U.S., most of which is returned to streams, rivers or lakes. However, about 38 percent is discharged to an ocean or estuary. Reusing this water, especially the coastal discharges, could increase available water resources in the U.S. by up to six percent.

Substantial amounts of water are also used to extract resources such as natural gas, oil, uranium and coal, and to generate electricity and transportation biofuels. Every step of that cycle involves water inputs. One especially salient example is the amount of water used in the process of hydraulic fracturing. Many farmers and ranchers living near these oil and gas wells have seen their water tables drop precipitously.

This diagram summarizes the water-related energy flows in the United States included in the direct water services and direct steam use categories. Primary fuels (on the left) are used directly and indirectly via electricity generation for different purposes (on the right). The thickness of the flows is proportional to the amount of energy consumed. About 58% of the total energy consumption is lost as waste heat

This diagram summarizes the water-related energy flows in the United States included in the direct water services and direct steam use categories. Primary fuels (on the left) are used directly and indirectly via electricity generation for different purposes (on the right). The thickness of the flows is proportional to the amount of energy consumed. About 58% of the total energy consumption is lost as waste heat.

CREDIT: Kelly T Sanders and Michael E Webber

« »

By clicking and submitting a comment I acknowledge the ThinkProgress Privacy Policy and agree to the ThinkProgress Terms of Use. I understand that my comments are also being governed by Facebook, Yahoo, AOL, or Hotmail’s Terms of Use and Privacy Policies as applicable, which can be found here.