Consumptive water-use estimates for thermoelectric power plants in the Apalachicola-Chattahoochee-Flint basin

Transcription

1 Consumptive water-use estimates for thermoelectric power plants in the Apalachicola-Chattahoochee-Flint basin Jenny Murphy and Tim Diehl, USGS Tennessee Water Science Center, Nashville

2 Thermoelectric water use Withdrawal vs. Consumption (Evaporation) Once-through cooling Three Mile Island Nuclear Plant Cooling Towers Thermal plume Brunner Island Coal Plant

3 Consumption Coefficients 1 Once-through cooling at coal plants 3.1 Gallons per kwh Literature References See last slide for citation

4 Basis of model Heat-budget model Thermodynamics of evaporation (Diehl, poster: Abstract 6e) Synthesized published methods: Leung and Moore 1970 Ward 1980 Harbeck 1964 FUEL HEAT RIVER RIVER Once-through cooling

5 Basis of model Heat-budget model Thermodynamics of evaporation (Diehl, poster: Abstract 6e) Synthesized published methods: Leung and Moore 1970 Ward 1980 Harbeck 1964 FUEL HEAT Tower cooling

6 Structure of model Cooling Tower model Percent evaporation OR Consumption model: amount of evaporation Once-Through cooling model Percent evaporation (Diehl, poster: Abstract 6b)

7 Structure of model: input data Environmental variables Monthly average 1) Dry bulb temperature 2) Wet bulb temperature 3) Wind speed 4) Water temperature

8 Structure of model: input data Environmental variables Power plant variables & characteristics 1) Cooling system type 2) Boiler efficiency 3) Monthly net generation 4) Monthly fuel heat

9 Consumption Coefficients, revisited 1 Once-through cooling at coal plants 3.1 Gallons per kwh Literature References See last slide for citation

10 Consumption Coefficients, revisited Gallons per kwh Once-through cooling at coal plants Literature References See last slide for citation Unrealistic Realistic Unrealistic

11 Consumption Coefficients, revisited Gallons per kwh Once-through cooling at coal plants Literature References See last slide for citation Unrealistic Realistic for individual plants Unrealistic

12 Jack McDonough Case Study: ACF Plants ranked by size 1) Wansley 2) Joseph M Farley 3) Yates 4) Jack McDonough 5) Wansley Unit 9 6) Wansley Combined Cycle 7) Chattahoochee Energy Facility 8) Mitchell 9) Scholz 10) Crisp Plant

13 Consumption Scenarios Environmental conditions Generation Average (20-30yr avg) 2007 (Drought) Average ( ) Maximum monthly consumption in cfs

14 Consumption Scenarios Environmental conditions Generation Average (20-30yr avg) 2007 (Drought) Average ( ) Maximum monthly consumption in cfs 2007 August streamflow in ACF = 6,209 cfs

15 Consumption Scenarios Environmental conditions Generation Average (20-30yr avg) 2007 (Drought) C Average ( ) Maximum monthly consumption in cfs 2007 August streamflow in ACF = 6,209 cfs

16 Sensitivity analysis: Once-through cooling High sensitivity Wind speed Water temperature Low sensitivity Dry bulb temperature Wet bulb temperature Example: Mitchell power plant Flint River, Georgia (Harbeck 1964)

17 Sensitivity analysis: Cooling Tower High sensitivity Wet bulb temperature Dry bulb temperature Insensitive Water temperature

18 Jack McDonough

19 Tower versus Once-Through: Seasonal Jack McDonough Consumption in cfs Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

20 Conclusions Published estimates of water consumption vary widely and most fall outside range of plausible thermodynamic limits Thermoelectric water consumption in ACF was **~5%** of 2007 summer low flow Towers consume more water but reduce thermal load on the stream

21 Conclusions Published estimates of water consumption vary widely and most fall outside range of plausible thermodynamic limits Thermoelectric water consumption in ACF was 2% of 2007 August streamflow Towers consume more water but reduce thermal load on the stream

22 Conclusions Published estimates of water consumption vary widely and most fall outside range of plausible thermodynamic limits Thermoelectric water consumption in ACF was 2% of 2007 August streamflow Cooling towers consume more water but reduce thermal load on the stream

23 Acknowledgments Melissa Harris, Susan Hutson, Kim Shaffer, David Stannard Questions?

24 Citations Leung and Moore, Water consumption determination for steam power plant cooling towers: A heat-and-mass balance method. Combustion 42: Ward, Accuracy of Harbeck diagram for forced evaporation. Journal of the energy division ASCE 106: Harbeck, Estimating forced evaporation from cooling ponds. Journal of the Power Division ASCE 90: 1-9. Once-through consumption coefficient references: (1) & (2) Stiegel, et al, prepared for NETL, Estimating freshwater needs to meet future thermoelectric generation requirements. DOE/NETL-2006/1235 (3) (table ES-1) & (9) (table ES-1) Dziegelewski et al., Water use benchmarks for thermoelectric power generation, Project Completion Report. Research report from the Dept of Geography and Environmental Resources: Carbondale, IL 203 pg. (4) Sledge et al, prepared for the Texas water development board, Power generation water use in Texas for the years 2000 through Final report pg 141. (5) (table S-1) Water & Sustainability (Volume 3): U.S. Water Consumption for Power Production- The Next Half Century, EPRI, Palo Alto, CA: (6) Gleick, Chapter 6: Water and energy, Essays on fresh water issues pg (7) (table 1.5) King, Duncan & Webber, Prepared for Texas Water Development Board, Water demand projections for power generation in Texas. Contract No , 268 pg. (8) Young and Thompson, Forecasting water use for electric power generation. Water Resources Research 9: