Water is energy is water
The cover story of Scientific American’s special issue, “Earth 3.0,” sheds some light on the debate that will define our efforts to become independent of foreign oil.
In “Catch-22: Water vs. Energy,” Michael E. Webber spells out the dilemma: Water is needed to generate energy and energy is needed to deliver water. Webber knows from whence he speaks, as associate director of the Center for International Energy and Environmental Policy at the University of Texas at Austin where he teaches mechanical engineering.
His point: Any switch from gasoline to electric vehicles or biofuels, the two most popular choices to solve transportation usage, is a strategic decision to switch our dependence from foreign oil to domestic water. So far, we’re not hearing much about that from our leaders.
To understand the link and the dire consequences of poor planning we need to compare some numbers. Stay with me here. Alternative vehicles use less gas but to do so, use way more water. An ordinary gasoline automobile might use anywhere from 7 to 14 gallons of depleted water to travel 100 miles; a plug-in hybrid would use 24 gallons; a hydrogen fuel-cell vehicle, 24 gallons. By contrast, the same size vehicle using corn-based ethanol could displace up to 6,200 gallons if one factors in the water used to irrigate the corn. Ethanol made from cellulose (think switch grass) presumably requires no irrigation (or fertilizer) but the technology isn’t quite there yet. Nor, it seems, are corn farmers willing to give up their subsidies just yet.
In the same way, various methods of generating power require varying amounts of water to produce one megawatt-hour of electricity. Gas/steam combined takes the least from 7,400 to 20,000 gallons; coal and oil use from 21,000 to 50,000 (while emitting copious quantities of carbon dioxide). Nuclear is cleaner but uses even more water for cooling at 25,000 to 60,000 for those plants that draw and dump water; cooling towers use less. Solar and wind power, virtually nada.
Consider that coal-fired and nuclear plants withdraw large amounts of water primarily from lakes and rivers, the same sources of fresh water needed for households and farming.
The energy required to deliver water to users also varies by source. One million gallons of clean water from a lake or river uses 1,400 kilowatt-hours of electricity; from ground water (underground aquifers) a bit more; treated wastewater can take from 2,350 to 3,300 kwh. Desalinization plants use about four times as much energy.
“Water and energy are the two most fundamental ingredients of modern civilization,” Webber writes. “Without water, people die. Without energy, we cannot grow food, run computers, or power homes, schools or offices.”
Parts of this country already experience drought on a regular basis. More than the result of climate change, in many metropolitan areas, water scarcity is the result of poor planning, rampant overpopulation and development.
Restricted water flows threaten fish populations, farmers’ crops, and, you guessed it, the amount of electricity produced by hydroelectric dams. Throughout the past year, Georgia, Alabama and Florida have battled over water flowing from reservoirs in Georgia into the Apalachicola River. The U.S. Army Corps of Engineers, tasked by Congress to manage the country’s water resources, has been caught in the middle.
The Colorado River, which supplies water to California, Nevada and five other states, has been fought over for years. Development in Las Vegas has been drawing down groundwater traditionally used by farms to the north, while water levels in Lake Mead drop, threatening electricity produced by Hoover Dam.
Scientists at Scripps Institution of Oceanography in La Jolla warn that Lake Mead could dry up by 2021 if the climate continues to change and future water use is not curtailed, Webber states.
The California Aqueduct is the biggest consumer of electricity in the state, transporting water from wetter, more sparsely populated areas in the north to metropolitan Los Angeles and beyond. First envisioned by then Gov. Pat Brown, it seemed like a good idea at the time. Power was cheap and development was fueling the state’s economy. And all those single-family ranch houses had to have pools and great lawns. How times change.
During many years of drought, cities and counties passed moratoriums on drilling wells and building houses. Established homeowners were restricted to sprinkling their gardens every other day. Some water companies added surcharges based on usage that exceeded amounts used in past years. In some areas, fines were assessed if irrigation water ran into the gutters. We learned to save water the hard way.
Meanwhile, farmers had generous water allotments at cheap rates that encouraged wasteful practices. Run-off not only wastes water but also pollutes streams and lakes with fertilizer and pesticides.
To solve the current dilemma, Webber suggests we need to put a realistic price on water, to move away from our long-standing expectation that water should be free or at least cheap. Once true pricing is established, perhaps consumers and regulators will understand how much the price of water raises the price of energy and vice versa. “The two metrics will bring us face to face with the dilemma of conserving both resources, prompting effective solutions,” Webber writes.
We may even have to abandon our current love affair with corn ethanol.