Water Withdrawals in Water Stressed Areas: Impacts of the Steam Electric Effluent
Limitations Guidelines

Patrick Walsh and Matt Massey, OP/NCEE

Introduction

Steam electric power plants use large quantities of water

. Power plants using a thermal cycle employing steam to generate electricity

, which will be regulated in the new effluent limitations and guidelines (ELGs)

, use water in several parts of the thermodynamic process that drives the steam engine. Additionally

, s team electric plants use vast amounts of water for cooling, ash handling

, and the operation of wet flue gas desulfurization ( FGD ) scrubbers

. The United States Geological Survey (USGS) estimated on a national level that 41% of all freshwater withdrawals

in the United States in 2005 were for thermoelectric power operations, primarily for cooling

needs ( USGS, 2009 )

. 1 Given the importance of water to this power sector, it is therefore highly

vulnerable to changes in the availability and condition of water ( USDE 2013 ). Droughts and severe dry conditions can lead to diminished electricity production and water

- related shutdowns, due to shallow or exposed cooling water intake locations and water temperatures too high for proper cooling, among other reasons (NETL, 20 09 ; Eaton, 2012 ). Since current forecasts indicate that climate change will result in more frequent and severe droughts (Feely et al., 2008) , the impacts on the power sector may expand in the future.

A number of steam electric power plants operate in regio ns of the country that experience regular or intermittent drought conditions. Several of the proposed regulatory options have requirements

that would reduce the amount of intake water required at each plant. For example, b y eliminating or reducing water us ed in ash sluicing operations, the proposed ELGs are expected to reduce

water withdrawal from both surface waterbodies and aquifers. T o investigate the impacts of the rule on facilities in water stressed areas, t his section explores the exposure of the reg ulated community to drought

- related conditions and quantifies th e reduced water intake in water

stressed areas.

Background

Due to the dependence of steam electric power plants on intake water, increased water scarcity and temperature can induce a range of negative impacts, including higher electricity prices, shutdowns, diminished production, and higher emissions. 2 Several recent drought

- prone summers have exposed a number of these negative impacts. Summers present a particularly troubling time for this in dustry, as drought conditions worsen and air conditioning usage increases power demand.

1 In 2005, 71% of thermoelectric water withdrawals were from freshwater sources (Kenny et al 2009). Saline withdrawals are primarily concen trated in California, Florida and the coastal northeast, with the rest of the country relying on freshwater.

2 Eyer and Wichma n (2014) explore emissions impacts of droughts on the power sector.For example, the severe drought experienced in Texas in 2011 resulted in low water reservoir levels at a number of Texas power plants. A number of plants were forced t o either reduce their generation or pump in the needed water from distant locations (Scanlon et al. 2013). T he 2007 drought in the southeast forced nuclear and coal

- fired plants within the TVA system to shut down some reactors and curtail operations in oth ers (DOE/NETL 2009). Record heat and drought in 2012 caused shutdowns as far north as Connecticut, when the Long Island Sound reached temperatures too high to be used as cooling water (Eaton, 2012).

Water availability can also have several other indirect effects. McDermott and Nilsen (2014) found that high water temperatures and reduced availability both contribute to higher electricity prices. Eyer and Wichman (2014) examine several implications of w ater supply shocks and find that hydroelectric generation is reduced in favor of coal and natural gas. They also find that pollutant emissions increase as a result of water scarcity. Another important externality of water withdrawals is the impingement and entrainment of aquatic organisms. Al though quantifying the effect is beyond the scope of this analysis, the regulatory options of the present rule that reduce water withdrawals will also likely reduce these impacts to aquatic life (US EPA, 2014).

Analys is

The technology options for fly ash and bottom ash proposed in th e Steam E lectric ELGs will eliminate or reduce water use associated with current wet sluicing operating systems. EPA estimated the reductions in water use by calculating the amount of ash transport water, specifically that amount of water identified as intake process water that will no longer be discharged as part of the proposed rulemaking. In order to calculate this reduction, EPA used data from Part C of the Steam Electric Survey to calc ulate an average percentage of ash transport water identified as intake water. EPA multiplied this percentage by the amount of transport water discharged by each plant to calculate the estimated process water reduction. See the

memorandum entitled “Steam E lectric Effluent Guidelines Non

- Water Quality Impacts” for more information (ERG, 2013)

. To minimize double counting between rules, for all units that are projected to be converting to dry ash handling of fly ash or bottom ash under the CCR Rule, a
0% redu ction was assumed. So if a unit is converting under the CCR Rule, there are no

additional reductions for the Final ELG rule.

In calculating the impact on intake water, we presen t two estimates for each plant

. The first

estimate (referred to in Tables 2 and 3 as Maximum Recycle)

, assumes units that currently recycle at least a portion of transport water will have a reduction in intake flow that is equal to the discharge flow . That would be accomplished by eliminating the intake water requireme nts using recycled transport water (i.e., 100% of discharge flow is the reduction in intake flow) . The second, referred to as the intake reduction only

, is based on the percentage of the ash transport flow that comes from intake water indicated by the plan t in their survey response and represents

a more conservative estimate. The se two estimates therefore represent a possible range of water

use reductions under the rule.To examine the exposure of regulated steam electric plants to drought, we use drought maps from the US Drought Monitor, which are produced jointly by the National Oceanic and Atmospheric Administration (NOAA), the US Department of Agriculture (USDA), and the National Drought Mitigation Center (NDMC) at the University of Nebraska Lincoln. 3 T he US Drought Monitor releases weekly maps of drought conditions, indicating the spatial extent of

water stressed areas. Figure 1 shows an example of t hese maps, one from the week of May 19 th

, 2009, and the other from the week of July 1st

, 2014

. This analysis uses categories D0

- D4 from drought monitor to classify water

- stressed areas. 4

Figure 1 : Example Drought Maps from US Drought Monitor

Findings

U sing GIS

, plant locations from the Steam Electric survey were overlaid on weekly drought maps for the years 2009 through 2014. To present a broad view of facilities in water

- stressed

areas, Table 1 portrays the distribution of all plants that would be affected by the technology requirements for fly ash and bottom ash under regulatory option D

. Plants are sorted by the number of weeks they were in water stressed c onditions. For example, in 2009, 41 plants had

between 1

- 5 water stressed weeks, while 31 plants experienced 6 to 10 water stressed weeks.

3 The maps are hosted by NDMC at http://droughtmonitor.unl.edu/Home.aspx

4 The lowest of these categories is “abnormally dry,” which usually precedes or follows a drought, and is characterized by damage to crops and water deficits. These water deficits and other associated conditions could impact the operation of steam electric plants. See http://droughtmonitor.unl.edu/AboutUs/ClassificationScheme.aspx for addit ional information.Under the preferred options of the proposed ELGs many of these will experience decreased

water withdrawals.

Table 1

. Number of Steam Electric Power Plants and Weeks (May

- October) in Water
Stressed Conditions

# of Weeks 2009 2010 2011 2012 2013 2014

0 108 60 50 2 68 96

1

- 5 41 42 36 11 42 53

6

- 10 31 49 41 20 26 20

11

- 15 11 34 29 32 30 13

16

- 20 5 17 17 39 13 7

21

- 25 4 2 9 72 29 19

26 8 4 27 32 0 0

Total 208 208 208 208 208 208

At Least One Week 100 148 154 206 146 112

Table 2 narrows the focus to plants that will reduce their water intake under Option D of the

Final Steam Electric ELG ( which would establish requirements that lead to dry handling of fly

ash and dry handling or closed

- loop operation for bottom ash ) that face d at least one week of drought

- like condition s , by year (between May and October) from 2009 to 2014

. The first

column of th e table presents the number of those plants located in one of the water stressed areas contained in the Drought Monitor maps. The table indicates 2012 was a particularly dry year,

with 98 plants operating under at least one week of drought

- related conditions. The later columns

of Table 2 calculate the reductions in water withdrawals in millions of gallons per day ( MGD )

that would have been achieved under regulatory Option D by those plants. 5 Betw een 2009 and

2014 , the average amount of intake water reduced would have been 138

– 146 million gallons per day . This translates to an annual average of 50

- 53 billion gallons of water no longer withdrawn from drought

- prone areas.

Table 2

. Plants that would Reduce Water Intake under Option D with at Least 1 Week of

Water

- Stressed Conditions

Year (May

- Oct.) # of Plants Reduced Water Intake, Intake Reduction Only ( MGD ) Reduced Water Intake, Maximum Recycle Reduction ( MGD )

2009 41 59.8 63.8
2010 63 170.6 178.5

2011 76 172.8 184.8
2012 98 209.5 222.7

5 Note that t he MGD figures should not be added across columns

, because there will be overlap in facilities affected

across years.2013 70 133.8 142.9
2014 47 81.8 85.2 Average MGD

--- 138.1 146.3 Annual Average (Average MGD *365) --- 50,393.1 53,402.2

Finally, examining areas with more chronic drought

- like conditions, Table 3 presents the potential intake water reductions from Option D for plants with at least 5 or 10 weeks of water
stressed conditions

. Across the years 2009

- 2014, the average reductions in water intake for plants under at least 5 weeks of water

- stressed condit ions is projected to be 105

– 112 MGD

. This translates to 38

- 41 billion gallons across an entire year . For facilities under at least 10 weeks of water stressed conditions, the average water reduced is projected to be 75

- 80 MGD

, which corresponds to approximately 27

- 29 billion gallons reduced per year.

Table 3

. Water Intake Reductions under Option D for Plants under Water Stressed
Conditions for at least 5 or 10 Weeks

.

At Least 5

Weeks At Least 5
Weeks At Least 10
Weeks At Lea st 10
Weeks

Intake Only
Reduction

( MGD ) Maximum Recycle
Reduction

( MGD ) Intake Only
Reduction

( MGD ) Maximum Recycle
Reduction

( MGD )

2009 38.0 40.1 15.8 17.4

2010 90.3 96.3 72.8 78.4

2011 155.1 166.4 77.1 79.8

2012 195.7 208.9 192.8 205.5

2013 111.7 119.9 74.3 82.2

2014 38.0 40.5 14.1 14.7
Average 2009

- 2014 104.8 112.0 74.5 79.7

Annual Gallons (Average 2009

- 2014 MGD *365) 38,256.5 40,887.8 27,189.4 29,078.9

References

DOE/NETL. 2009. Impact of Drought on US Steam Electric Power Plant Cooling Water Intakes and Relater Water Resource Management Issues. http://www.circleofblue.org/waternews/wp

- content/uploads/2010/08/Impact

- of

- Drought

on

- Steam

- Electric

- Power

- Plant

- Cooling

- Water

- Intakes.pdf Eaton, J. “ Record Heat, Drought Pose Problems for U.S. Electric Power. ”National Geographic Ne ws , 17 August 2012. Available: http://news.nationalgeographic.com/news/energy/2012/08/120817

- record

- heat

- drought

pose

- pro blems

- for

- electric

- power

- grid/ (Accessed April 2015). Eyer, J. and Wichman, C.J. (2014) “The Effect of Water Supply Shocks on the Electricity Generation Mix: Implications for Climate Change.” Working paper, University of Maryland, Department of Agricultural and Resource Economics. Available at: http://caseyjwichman.com/wp

- content/uploads/2014/07/waterenergy_oct2014.pdf

. Feeley

, T. J

. III, T

. J

. Skone, G. J

. Stiegel Jr, A. McNemar, M

. Nemeth, B

. Schimmoller, J

. T

. Murphy, and L

. Manfredo. “ Water: A critical resource in the thermoelectric power industry. ” Energy , 33(1):1{11, 2008. Kenny, J.F., Barber, N.L., Hutson, S.S., Linsey, K.S., Lovelace, J.K., and Maupin, M.A., 2009,
Es timated use of water in the United States in 2005: U.S. Geological Survey Circular 1344, 52 p.
Macknick , J. , R Newmark, G Heath and K C Hallett (2012) Operational water consumption and withdrawal factors for electricity generating technologies: a review of existing literature

. Environ. Res. Lett. 7 1

- 10

. McDermott , G.R. and Nilsen , O.A

. (2014) “ Electricity prices, river temperatures, and cooling

water scar city.” Land Economics , 90(1):131

- 148

. National Energy Te chnology Laboratory (NETL) 2009 “ Impact of Drought on US Steam Electric Power Plant Cooling Water Intakes and Related Water Resource Management
Issues .” (Pittsburgh, PA: National Energy Technology Laboratory)

. Scanlon, B.R., Duncan, I. and Reedy, R. C. ( 2013 )

. “ Drought and the water

- energy nexus in
Texas. ” Environmental Research Letters

, 8 (4): 1

- 14.
US EPA. 2014. Technical Development Document for the Final Section 316(b) Existing
Facilities Rule. http://water.epa.gov/lawsregs/lawsguidance/cwa/316b/upload/Cooling

Water_Phase

- 4_TDD_2014.pdf
USDE. 2013. US Energy Sector Vulnerabilities to Climate Change and Extreme Weather. http://energy.gov/sites/prod/files/2013/07/f2/20130716

- Energy %20Sector%20Vulnerabilities%20Report.pdf
USGS. 2009. Estimated Use of Water in the United States in 2005: U.S. Geological Survey
Circular 1344 . Reston, VA: United States Geological Survey. http://pubs.usgs.gov/circ/1344/pdf/c1344.pdf

.