Executive Summary
As we confront the challenges posed by climate change, decisions on supplying energy and water to the world’s growing population should no longer be made in isolation. The challenges facing Texas and the rest of the globe require that we recognize the deep inter‐connections and trade offs involved in deciding how to meet power and water needs in an increasingly resource‐constrained world.
This report is the first in a series designed to explore aspects of the energy‐water nexus in Texas. It examines the water requirements for various types of electricity generating facilities, both for typical systems nationwide and here in Texas. It also addresses the use of energy by water supply and wastewater treatment systems, comparing national averages with Texas- specific values.
Future installments in this report series will include case studies of the implications for energy of future water supply strategies for Texas and more place‐specific water supply implications of the future fuel mix for electricity production. There are several other aspects of the energy‐water nexus that are being investigated by several other entities but are not contemplated in this series, including hydroelectric power generation, unconventional fossil fuel production, and the development of biofuels such as ethanol.
Analysis of available data for Texas reveals that approximately 157,000 million gallons (482,100 acre‐feet) of water annually – enough water for over 3 million people for a year, each using 140 gallons per person per day – are consumed for cooling the state’s thermoelectric power plants while generating approximately 400 terawatt‐hours (TWh) of electricity. At the same time, each year Texas uses an estimated 2.1 to 2.7 TWh of electricity for water systems and 1.1 to 2.2 TWh for wastewater systems each year – enough electricity for about 100,000 people for a year. These estimates for water and wastewater combined represent approximately 0.8 to 1.3% of total Texas electricity and 2.2 to 3.4% of industrial electricity use annually. The report presents a geographic distribution of the current water use for electricity generation and electricity use for water supply and wastewater treatment, which may be useful as policymakers begin to examine these aspects of the energy‐water nexus.
In preparing the report, however, it became clear that substantially more site‐specific data are necessary for a full understanding of the nature of the energy‐water nexus in Texas. Thus, we recommend that the state increase efforts to collect accurate data on the withdrawal and consumption of cooling and process water at power plants, as well as data on electricity consumption for public water supply and wastewater treatment plants and distribution systems. These data will also be useful in planning for the future.
In the future, water use for electricity generation will depend on several factors, including the fuel mix for new generating capacity, the type of power plant and the type of power plant cooling systems that are deployed. Likewise, the amount of electricity used to pump, treat and deliver public water supply and to treat wastewater will depend on choices about water source and treatment technology. These trends, and tradeoffs still need to be better understood, but it is undeniable that there will be important implications for water and energy policy at the state and local level. Some steps can be taken now to build the basics of a framework for more integrated energy and water planning, including:
- Amend state law to require that applications for new power plants include an analysis of the water and efficiency implications of various types of cooling options applicable to the proposed plant. The analysis should include factors relating to local climate and air quality, regional air quality, water availability, including instream flow requirements, fuel type and plant efficiency.
- Require a clear demonstration of water availability in the siting of new fossilfueled power plants or concentrated solar (this analysis should consider average rainfall years as well as availability during extreme drought events).
- Provide state statutory and regulatory incentives for implementation of power plant cooling technologies that are less water‐intensive than traditional systems, such as air‐cooling or hybrid wet‐dry cooling.
- Provide state‐approved guidance (from the Texas Water Development Board and or the State Energy Conservation Office) to water suppliers and wastewater treatment providers to help quantify energy use and cost savings associated with water conservation.
The overarching message is that implementing advanced efficiency is the key to the sustainable use of both energy and water. Improving water efficiency will reduce power demand and improving energy efficiency will reduce water demand. Greater efficiency in usage of either energy or water will help to stretch our finite supplies of both, as well as reduce costs to water and power consumers. The state and local governments should continue, and wherever possible, increase funding and technical support for water and energy conservation and efficiency programs.
