Texas Energy-Water Nexus

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The energy-water nexus is the interconnected relationship between our most coveted natural resource (water) and the driving force behind modern global culture (energy). Across the world, water resources are used to irrigate crops and raise livestock, supply water, develop technologies, convey our wastes and byproducts, and to fulfill biological and geologic processes. Energy, on the other hand, is required to fuel the irrigation of crops, raise and distribute livestock to market, purify and deliver drinking water to our hospitals, schools, homes, businesses, and industries, and to process our waste products.

The energy-water nexus represents the point where two essential ingredients - energy and water - overlap. By running a tap or turning on the lights, you participate in the energy-water nexus - a relationship between the water needed to produce and consume energy and the energy required to produce and transport water supplies or treat and convey waste water. In the United States 19 gallons of water (about half of a bathtub) is used to produce 1 kilowatt-hour (equivalent to powering a 100-watt light bulb for ten hours) on average (2010).

Energy + Water = Nexus - a relationship between the water needed to produce and consume energy and the energy required to transport and treat waste or drinking water.

In fact, 90% of electricity produced in the United States is dependent on water and the thermoelectric process, where an energy source heats up readily-available water, creating steam to turn electricity-generating turbines. The need for water is a common theme shared among coal, natural gas, hydropower, and nuclear electrical power supplies. Despite the diversity of the power supply sector, water is required for production... and lots of it. 

Select map points and features to explore surface water (streams, rivers, creeks, bayous, lakes, and reservoirs), power plant characteristics, and water usage.

To meet Texas’ 2006 electricity consumption, thermoelectric power plants (which includes fossil fuel and/or generated nuclear) consumed more water than the volume of Lake Conroe. Once used, the steam must be condensed so it can be reused in the thermoelectric process - water withdrawals from reservoirs or groundwater supplies are needed to cool the steam. 

Due to this high degree of connectivity and dependence electric power supplies can be at risk during periods of drought. The degree to which Texas' energy infrastructure is able to withstand and bounce back from disturbances such as drought is known as resilience. The future resilience of Texas' power grid should be considered as changing climatic conditions could bring additional stresses placing pressure on Texas' energy and water supplies. Energy systems must be designed and constructed to withstand a multitude of extreme weather events while considering current and future impacts on the electric power system. In recent years, Texas has experienced extreme weather patterns resulting in significant power outages and disruption to communities.

Texas leads the nation in wind-power generation with more than 18,500 megawatts of capacity. In 2014 and 2015, Texas wind turbines produced more electricity than the state's two nuclear plants. Solar and wind energy production provide benefits in relation to water and resilience to drought because they require little to no water inputs for electricity production. 

However, as of 2015 natural gas is the primary energy source in Texas. Despite leading the United States in total net electricity generation, Texas is ranked sixth in total energy consumed per capita. Half of the electricity produced in Texas is used by the industrial sector while transportation requires 24%, followed by residential (13%) and commercial (12%) users. 

The Electric Reliability Council of Texas (ERCOT) oversees the majority of Texas' energy production, transport, and consumption.

Surface water resources (streams, rivers, creeks, bayous, lakes, and reservoirs) and groundwater aquifers are the two predominate sources of water in Texas. 2015, the most recent year available for annual statewide water use, saw a reduction of total estimated water use. This is likely due to ample spring rains which broke precipitation records across the state resulting in a reduction of water use for irrigation. Despite the power industries' relatively low consumptive water use compared to irrigation, industry withdraws water at a much higher rate. The total water withdraw (withdraw means that some of the water is returned to the system) for thermoelectric production in Texas (2010) was estimated to be 66% while the industry accounted for 4.2% of total water consumption (single-use). 

2010-2014 was the second-longest and worst drought period in Texas after the record setting drought of 1950 to 1957. 2011 is the single driest year on record for the State of Texas since 1895. Up to 100 days of 100 degree or higher heat broke records for electricity demand as consumers cranked the AC. Meanwhile, further exacerbating this difficult situation, an increase of irrigation for agriculture, landscapes, and sod yards and increased evaporation drained surface water reservoirs to their lowest levels since 1967. This multi-year drought placed considerable pressure on power generation because of the dependency on water for thermoelectric cooling. During the drought, there was either not enough water to cool plants or available water was too warm for cooling.

A drought of the magnitude reached in 2011 stems from an aligning of climate phenomena. Specifically, the La Nina phase of the El Nino Southern Oscillation drove the associated dry weather and lack of rainfall across the state. These effects were further amplified by the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation which flipped from fueling extensive rainfall to supporting widespread dry conditions. Warmer than average air temperatures further dried conditions and lowered drought resilience thresholds across the State.

Dry conditions brought on by the shift in climatic conditions sparked wildfires across the State endangering lives, property, water, and power supplies. The Bastrop County Complex fire damaged 1,691 homes and resulted in $325 million in losses.

Although the State was already suffering from a record dry year, Texans consumed about 4 million acre-feet more water in 2011 compared to 2010. The 2011 water use was the highest estimated water used in the historical record since 2006. However, not all water losses were a direct result of water consumption. One study estimated the amount of water lost for a portion of 2011 from soil evaporation, groundwater, and surface water reservoirs was enough to fill the nations largest reservoir, Lake Mead, twice. To help put this in perspective, imagine enough water to cover the State of Texas in 3.5 inches of water.

Electricity demands and production increased by 6% from 2010 to 2011 which increased water needs for electricity production by 9%. Power plants switched to water saving technologies. During 2011, ERCOT, the organization that manages the Texas grid, was concerned about losing “potentially several thousand megawatts” if the drought did not end. The peak electricity demand reached in 2011 was 4% higher than the previous record. Rolling blackouts were avoided because ERCOT released excess electricity that was generated to meet the peak load. There were also power plants during this time curtailing operations at night so they would have plenty of water to provide power during the day, as well as plants that were piping water from other sources to ensure they could operate.

Due to increased consumption and compounding pressures caused by drought conditions water and energy - two resources ingrained in our daily lives - were in short supply. The largest estimated water use categories in 2011 were irrigation and municipal. Over 1,000 water utilities established water supply restrictions and several Texas towns ran low or even out of water. The supply shortage created resource conflicts between uses such as municipal and agriculture as well as upstream and downstream water users, particularly straining downstream water supply in the Colorado and Brazos river basins. As a result agricultural losses totaled $7.6 billion in 2011 alone. Some water bodies dried up completely while manufacturing and power industries were also deeply impacted.

A recent paper by Argonne National Lab titled  "Impact of Future Climate Variability on ERCOT Thermoelectric Power Generation”  considered the drought implications for the ERCOT grid. The findings indicate that out to 2030, unless we become less dependent on water, the Texas grid could face severe stress due to lack of water availability both in drought and non-drought scenarios, as well as derating of thermoelectric plants due to high water temperatures. This stress on the power system due to water supply is not limited to Texas. It is a nationwide issue, particularly across the western United States.

Check back for more on Emerging Conflicts, A Changing Climate, and A Resilient Future.

This Story Map is part of the HARC GIS Applications collection.