an evaluation of the use of hydraulic fracturing flowback water for thermoelectric cooling in...

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An Evaluation of the Use of Hydraulic Fracturing FlowbackWater for Thermoelectric Cooling in Texas

John Maxwell

April 19, 2012

Energy, Technology & Policy

Spring 2012

Word Count: 1495


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Texas has been and will likely continue to be a leader in the development and practice

of the water intensive hydraulic fracturing (fracing) natural gas recovery method (Rahm

(2011) p.2974-2976). The average hydraulic fractured well in Texas requires about 3

million gallons per well (Galusky (2007) p.4). To perform fracing operations, water is

pumped into the initial well along with other materials like sand and chemicals (Rahm

(2011) p.2975). Though fracing is a small percentage of water use statewide, in local

areas the use of groundwater in fracing can decrease water supply. About 10% of the

water will come back up through the well bore (Jenkins (2012) p.14-16). This returned

water is also known as flowback. Currently, about 90% of flowback is used for other

fracing wells. Texas is also a growing state with the population projected to increase

from about 25 million people in 2010 to 46 million people in 2060 (TWDB (2012) p.130).

Texas is water constrained and with growing demands for water the probability is high

for conflict over water. In addition to the municipal demand, thermoelectric power

production requires large amounts of water cooling (Mielke et al (2010) p.29).

Flowback could be one source of cooling water for thermoelectric plants. This paper will

seek to explore which power plants are the best locations for a pilot program to test the

feasibility of flowback water as well as considerations for policy options which could

encourage a more permanent use of flowback in thermoelectric cooling. Though it may

not be a large source of water, directing attention to developing solutions to address the

water quantity problems should be a high priority for policymakers.

Since water produced for use in the oil and gas industry are exempt in Texas from

permits by the Texas Water Code ( 36.117 (b)(2)), there is less of an incentive to

recycle because the drilling company can just pump new groundwater to complete the

well. If not used for other projects, the water is injected into Class II disposal wells

where it is stored to avoid harming the groundwater supply (RRC 2010). The injection of

this water into Class II disposal wells effectively takes this water out of the system

where it could be put to use in a productive use.

The population growth impacts both municipal water demand as well as thermoelectric

water demand. While most of the electrical capacity growth will likely be fulfilled by

natural gas generation, existing coal and nuclear power plants are 8 or the 10 largest

power plants in Texas (by net summer capacity) (EIA 2012). These large plants must

explore additional water sources to ensure that service interruptions due to lack of

cooling water are minimized.

The state of Texas is the owner of surface water and can decide the allocation of water

rights. For groundwater, Groundwater Conservation Districts (GCD) set the pumping

limits in a given area (Texas Water Code Ch. 36). Since GCDs may limit groundwater

and surface water rights may be difficult to obtain, thermoelectric power plants may see

flowback as a component of cooling water (Nicot and Scanlon (2012) p. 3584). In a


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severe drought, thermoelectric generators could be subjected to water source risks if

either surface or groundwater allocation are changed to benefit municipal systems. At

best, flowback water could a valuable input source of water for a few thermoelectric

plants in Texas and at worst, could be a water hedge for these plants.

The 10 largest power plants in Texas provide a data-set to assess the best possibility ofthe use of flowback for cooling water. 8 of these 10 power plants employ coal or

nuclear thermoelectric technology.

Figure 1: Largest Thermoelectric Generation Sources, Texas 2010

Plant1

PrimaryEnergy

Source1

Net SummerCapacity (MW)

1Cooling Type

2

W A Parish Coal 3,664 Both

South Texas Project Nuclear 2,560 Closed-loop

Martin Lake Coal 2,425 Once-through

Comanche Peak Nuclear 2,406 Once-through

Monticello Coal 1,890 Once-through

Limestone Coal 1,689 Closed-loop

Fayette PowerProject Coal 1,641 Once-through

Welsh Coal 1,584 Closed-loop

This figure indicates the largest thermoelectric plants and the fuel source.

The figure also gives the cool ing type for the plant once-through or closed-loop

MW = Megawatt.Source:

1) EIA, State Electricity Profiles, Texas2) 2010 Form EIA-860

These are the two most water intensive thermoelectric generation types (Macknick et al.

(2011) p.14-15). The State should first start with evaluating which plants would be

optimal for a test of flowback and then develop more permanent policies to encourage

the use of flowback. The main factor to evaluate which power plants are the bestcandidate for testing flowback is whether the plant is proximate to a shale gas play.

Transport is likely the highest cost to reuse this flowback in the cooling process followed

by treatment costs. Transportation options for the flowback to the power plant include

through a pipeline or a truck. For the testing project, trucking the water would be

necessary due to lack of infrastructure. Pipeline or fixed rail would be the best if

flowback is used as a steady supply.


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After evaluating the plants by the distance to counties that had shale gas production, 7

of the 8 plants are proximate to one of the three main shale plays in that they are

located within a formation affected county or within 50 miles. This indicates a possibility

for some or all of the selected plants to conduct a flowback feasibility test.

The three sites with the highest potential to test the acceptance of the flowback water

are: Comanche Peak (CP), Martin Lake, and South Texas Project (STP). Both

Comanche Peak and Martin Lake are located within a county which is located within the

Barnett and Haynesville respectively. STP is proximate to an Eagle Ford county. The

only plant that is not in a proximate footprint of any shale play is W A Parish.

In the Barnett Shale, on average there were 4.4 wells drilled daily from 2005-2011. This

amounts to on average ~13.312 million gallons of water used daily with ~1.3 million

gallons of flowback produced daily (RRC 2011) (EIA 2012). As a once-through cooled

plant CP consumes ~15.5 million gallons of water daily (Macknick et al. (2011) p.14-15).

The development and proximity of the Barnett Shale to CP could produce ~9% of the

daily water needs of CP.


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For a closed-loop system like STP (which on average consumes nearly three times as

much water as a closed-loop system) the flowback produced would need to be much

higher to satisfy the demands for the plant (Macknick et al. (2011) p.14-15). The Eagle

Ford shale is projected to have the greatest growth of water production, nearly 500

billion gallons of water used between 2010 and 2060 and the daily flowback would be

~2.7 million gallons which is 6% of the water needed by STP (Nicot and Scanlon (2012)

p.3582). In water constrained future, this could be a small but significant source of

cooling water.

Scaling and corrosion could affect the operational integrity of the heat exchangers and

other sensitive parts of the power plant system (NETL (2009) p.14). For use of flowback

in nuclear plants, the scaling and mineral standards are likely to be higher than for coal

plants due public concern over nuclear plant integrity. The small-scale testing of

flowback will allow the advantages and disadvantages to be made known.

Developing policy mechanism to make flowback a more permanently available sourceto thermoelectric plants could be one way to help Texas address freshwater concerns.

Using a template of incentives from Gillette and Veil 2004, there are numerous policy

levers the state could use to entice the shale gas producers and power plant operators

to work together to use flowback. The types of incentives are discussed in order of the

level government burden (lowest to highest):

Reduced water costs to user

o Adjust the costs for surface water use which the plants currently pay to

make flowback water relatively more cost-effective.

Direct grantso Provide grants to both power plant operators and shale gas producers to

buy and sell the water. This may lead to behavior change and enhance

power plant industrys public image in the face of freshwater constraints.

Assured market

o By guaranteeing a market exists, the transportation infrastructure may be

built and shale gas producers may be more prudent with their produced

water knowing there will be a market for it.

Regulatory enforcements

o Take away exempt status of the wells used in oil gas production unless

the water is used in a secondary process for thermoelectric power

generation.

At the federal level, 316(b) of the Clean Water Act requires cooling water intake

structures reflect the best technology available for minimizing adverse environmental

impact. (EPA 2012). Depending on the interpretation of the law, the employment of


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flowback water could be seen as a best technology and is addressing environmental

impacts of reduced water quantity.

Total projected water use in the three shale plays from 2010-2060 totals around 910

billion gallons (Nicot and Scanlon (2012) p.3582). If 10% of the water is returned to the

surface, 9.1 billion gallons could be available to be used by the electric power industry.Though on a per year basis, flowback available for thermoelectric cooling may be small,

more water may flow back than anticipated (Jenkins (2011) p.14-15). Due to its

proximate location to the well-developed Barnett Shale leading to lower transportation

costs, the best location for a flowback test at the current time is Comanche Peak.

Though flowback is not a very large source of water, this water was going to be injected

into the ground and put out of productive use. Texas faces dire water shortages in the

future and many solutions will need to be developed. The use of flowback in power plant

cooling is a small, but serious attempt to address these concerns. With the correct state

incentive policies, flowback water could provide at least a water hedge to thermoelectric

plants. No proposed engineering solution should be turned away by policymakers as

technology could help alleviate the very serious water quantity concerns.


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Works Cited:

EPA (2012). Cooling Water Intake StructuresCWA 316(b). United StatesEnvironmental Protection Agency.

Galusky L.P., J. (2007). "Fort Worth Basin/Barnett Shale Natural Gas Play: AnAssessment of Present and Projected Fresh Water Use."

Gillette J. L. and Veil J. A. (2004). Identification of Incentive Options to Encourage theUse of Produced Water, Coal Bed Methane Water and Mine Pool Water. Office of FossilEnergy - National Energy Technology Laboratory Dept. of Energy. Argonne NationalLaboratory.

Jenkins, S. (2012). "Frac Water Reuse." Chemical Engineering 119(2): 14-16.

Macknick J., N. R., Heath G., and Hallett K. (2011). A Review of Operational Water

Consumption and Withdrawal Factors for Electricity Generating Technologies. NationalRenewable Energy Laboratory-Dept. of Energy.

Mielke E., Anadon L.D., and Narayanamurti V. (2010). Water Consumption of EnergyResource Extraction, Processing, and Conversion, Energy Technology InnovationPolicy Research Group - Belfer Center - Kennedy School - Harvard University.

National Energy Technology Laboratory (NETL) (2009). Use of Non-Traditional Waterfor Power Plant Applications: An Overview of DOE/NETL R&D Efforts. Dept. of Energy.

Nicot, J.-P. and B. R. Scanlon (2012). "Water Use for Shale-Gas Production in Texas,U.S." Environmental Science & Technology 46(6): 3580-3586.

Office of the Governor - Rick Perry (2006). Texas County Map. TexasCounties.jpg.

Rahm, D. (2011). "Regulating hydraulic fracturing in shale gas plays: The case ofTexas." Energy Policy 39(5): 2974-2981.

Railroad Commission of Texas (RRC) (2010). Saltwater Disposal Wells - FAQs.

Railroad Commission of Texas (RRC) (2011). Barnett Shale Well Count 1993-2011.barnettshalewellcount1993-2011.

Railroad Commission of Texas (RRC) (2012). Well Distribution by County - Well CountsFebruary 2012.

Texas Water Code (2005). 36.117. EXEMPTIONS; EXCEPTION; LIMITATIONS.(b)(2). State of Texas.


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Texas Water Development Board (TWDB) (2012). Water For Texas - 2012 State WaterPlan.

U.S. Energy Information Administration (EIA) (2010). Form EIA-860 Annual ElectricGenerator Report. Dept. of Energy.

U.S. Energy Information Administration (EIA) (2012). State Electricity Profiles - 2010Texas. Dept. of Energy.

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