Inaction at the federal level
In 2005, Congress mandated a federal water and energy roadmap. The Department of Energy partially responded to the call in December 2006 with a report on the interdependency of energy and water called “Energy Demands on Water Resources.” Yet, to date, there is still no national research program directly aimed at understanding the intimate and complex relationship between water and energy in a comprehensive way.
Growing energy demands in the arid U.S. West
There is growing concern whether an appropriately-routed and affordable supply of water will exist to support the U.S.’s growing electricity demands, in particular around matching geographical water availability to energy need. For example, in the 1990’s, the largest regional population growth of 25% occurred west of the Rocky Mountains, one of the most water deficient regions in the U.S. Water consumption in the western U.S. is much higher than other regions because of farming demands. It is estimated that over one million gallons of water is needed each year to irrigate one acre of farmland in arid conditions. This means that in 2000, the majority of freshwater withdrawals (86 percent) and irrigated acres (75 percent) were in the western states.
Managing water and energy together at the state level
State lawmakers and natural resource managers have traditionally addressed water and energy as two separate issues. However, water and energy are deeply connected, so the sustainability of one requires consideration of the other. Thus, resource managers and lawmakers in many places are beginning to take a more holistic approach to the management of water and energy.
At least nine states (Arizona, California, Colorado, Connecticut, Nevada, South Dakota, Washington, West Virgina, and Wisconsin) have statutes that recognize the nexus between water and energy. A statute is legislative law. Three states in the more arid West (Arizona, California, and Nevada) have statutes that specifically refer to the use of water for electricity power generation.
In Arizona, Statute § 45-156 requires electricity facilities to request legislative authorization in order to divert water to generate over 25,000 horsepower (18,642 Megawatt-hour) of electric energy. Statute § 45-166 says that an electricity generating plant (most of which are coal-operated) can use up 34,100 acre-feet of water each year, including water used for mining, coal transportation, and ash disposal.
In California, Code § 5001 exempts individuals who extract groundwater or surface water for generating electricity from submitting a “Notice of Extraction and Diversion of Water”. In Nevada, Statute § 533.372 says the State Engineer can approve or disapprove any application of water from beneficial use to a use that generates energy that will be exported out of Nevada.
What does this mean?
In California, generating electricity is one of the few reasons that exempts individuals from notifying the state that they are diverting water and how much they’re diverting. In contrast, in Arizona and Nevada, legislation is trying to apply some limits to the amount of water that can be used for electricity generation, or at least toward electricity that leaves the state.
I suspect one of the main reasons for the contrast is resource priorities. Arizona and Nevada are two of the most arid states in the U.S.: Nevada ranks number one and Arizona fourth for the least amount of annual precipitation. Nevada’s Division of Water Resources says its mission is “to conserve, protect, manage, and enhance the state’s water resources … through the appropriation and allocation of the public waters.” Arizona’s Department of Water Resources is stronger with their intention and directly say that the state places a high priority on managing its limited water.
California, in contrast, does not even make the top 10 most arid states based on annual precipitation. With the California electricity crisis of 2000 and 2001 and the one more recently in 2011 fresh in memory, California officials are much more worried about managing electricity demands and do whatever is necessary to avoid perennial summer blackouts. Understandably so — the early 2000’s electricity crisis costed the state $40 to $45 billion.
Taking a much harder look
Though they exhibit a step in addressing water and energy issues together, these state-level legislation have weak influence on the impacts that conventional electricity generation has on water supply and quality. “US policy makers continue to overlook the implications of increasing water scarcity when they evaluate the use of coal and nuclear power,” says a report, “The Hidden Costs of Electricity: Comparing the Hidden Costs of Power Generation Fuels,” released in September by the Civil Society Institute.
When it comes to water impacts, the report finds that renewable energy sources have the least water impact. However, coal, nuclear, and natural gas resources have the highest hidden costs. This is worrisome since these are also the three most dominant means of producing electricity in the U.S. today.
Coal and nuclear plants use (and lose) 300-1,000 gallons of water per Megawatt-hour (MWh). However, these plants withdraw a lot more water than that for its steam heating and cooling process — anywhere from 500 to 60,000 gallons per MWh depending on the cooling system. The water that is returned to the environment is wastewater which degrades river water quality. Furthermore, the mining processes for the energy resources in these plants (coal and uranium) contaminate groundwater. For natural gas, the major water costs come from extraction processes, such as fracking and coalbed methane recovery, which require large volumes of water and contaminate ground and surface water.
Arizona is beginning to regulate how much water can be used for electricity generation. But, the water-energy nexus issue is far more complex:
- How can we ensure the quality of water that returns to the environment after it’s used by power plants?
- How can power plants be more water efficient so there aren’t such vast differences in the amount of water required for cooling?
- How much water should be used for extraction and mining?
- How can these processes be better regulated to minimize contamination effects?
- How do we include water impacts to strengthen transitions to renewable energy sources?
All these are questions that have yet to be addressed by legislation and government management in an integrated way both at the state and national levels.