The Impact of Emissions Mitigation on Water Demand for Electricity Generation

Transcription

1 The Impact of Emissions Mitigation on Water Demand for Electricity Generation PAGE KYLE, EVAN DAVIES, JAMES DOOLEY, STEVE SMITH, MOHAMAD HEJAZI, JAE EDMONDS, AND LEON CLARKE Joint GCAM Community Modeling Meeting and GTSP Technical Workshop Joint Global Change Research Institute College Park, Maryland, USA September 2, 212

2 Motivation! The electric sector accounts for about 4% of present-day water withdrawals in the US, and is projected to grow substantially in all regions over the next century! Could be important for resolving basin-level water supplies and demands! The water demands are dependent on the generation technology! Contributes to uncertainty in the magnitude of the future water draw from this sector! Creates a natural link with the electricity system in GCAM Total Industrial Withdrawals (km 3 /yr) Electric Sector Withdrawals (km 3 /yr) Region USA Canada Western Europe Japan 16 5 Australia_NZ 3 6 Former Soviet Union China Middle East 5 3 Africa 11 8 LaIn America 32 1 Southeast Asia 46 1 Eastern Europe 3 23 Korea 3 2 India Global total

3 A Brief Review of Cooling System Types! Water is required at power plants for! Re-condensing steam from the boiler! Boiler feed water make-up! Flue gas de-sulfurization! Other uses! Three basic methods of re-condensing steam, which differ in the primary mechanism of heat displacement System type Once- through flow EvaporaIve (recirculaing) Mechanism of Heat Displacement Increase in water temperature EvaporaIon of water Cost ($/ kw) Withdrawal Intensity (m 3 /MWh) ConsumpKon Intensity (m 3 / MWh) Dry cooling Dissipated to air

4 Specific Coefficients Used Technology Cooling system Water Withdrawals Water ConsumpKon 1- thru Evp Coal Pond thru w/ccs Evp w/ CCS thru Oil / Natural gas Evp Pond thru Other Steam Evp Pond thru Nuclear Evp Pond thru Evp Natural gas combined Pond cycle 1- thru w/ccs Evp w/ CCS thru IGCC Evp thru w/ccs Evp w/ CCS Geothermal Evp (convenkonal) Hybrid/Dry EGS Evp Hybrid/Dry CSP Evp Hybrid/Dry.3.3 PV n/a.2.2 Wind n/a Hydro n/a 17! Cooling ponds function in similar fashion to oncethrough flow OR evaporative cooling (depends on the specific plant configuration)! Hybrids generally function as dry cooling but use some evaporative cooling (e.g. during times with high temperature)

5 Modeling the Electric Sector s Water Demands in GCAM! The current version of GCAM does not have water markets, so there is no technology competition between the different cooling system types! For this reason, we assume the different shares of cooling systems that will be deployed for each power plant type and each region in future periods Cooling system type Once- Through * Of which EvaporaKve Region Power Plant Type Time period Flow Saline Cooling Cooling Pond Dry USA Coal Base year 39% 3% 48% 13% % USA Fossil, non- coal Base year 59% 3% 24% 17% % USA Combined cycle Base year 12% 3% 77% 2% 1% USA Nuclear Base year 38% 3% 44% 18% % USA Geothermal Base year % % 6% % 4% USA IGCC/CCS Base year n/a n/a n/a n/a n/a USA CSP Base year n/a n/a n/a n/a n/a USA Coal Future periods 5% 5% 8% 1% 5% USA Fossil, non- coal Future periods 5% 5% 8% 1% 5% USA Combined cycle Future periods 5% 5% 33% 2% 6% USA Nuclear Future periods 5% 5% 85% 1% % USA Geothermal Future periods % % 6% % 4% USA IGCC/CCS Future periods 5% 5% 9% % 5%

6 Scenarios in this Analysis Scenario Technology Strategy Climate Policy NucCCS Nuclear and CCS None RE Renewables None NucCCS_4.5 Nuclear and CCS 4.5 W/m2 RE_4.5 Renewables 4.5 W/m2 NucCCS_3.7 Nuclear and CCS 3.7 W/m2 RE_3.7 Renewables 3.7 W/m2 8 7 W/m NucCCS RE NucCCS_4.5 RE_4.5 NucCCS_3.7 RE_3.7

7 Global Electricity Generation by Scenario EJ/yr NucCCS NucCCS_4.5 NucCCS_3.7 RE RE_4.5 RE_3.7 1% 9% 8% 7% 6% 5% 4% 3% 2% 1% % Developed Reforming Developing! Five- to seven-fold expansion in all scenarios! Developing economies account for greater than 7% of electricity by the end of the century! By 25, 85% of electricity is produced at facilities that did not exist in 25! Climate mitigation policy leads the electricity sector to expand by up to 25%

8 Electricity Generation by Technology 1% NucCCS 1% RE 9% 9% 8% 8% 7% 7% 6% 5% 4% 3% 2% 1% % 1% 9% 8% 7% 6% 5% 4% 3% 2% 1% % NucCCS_ % 5% 4% 3% 2% 1% % 1% 9% 8% 7% 6% 5% 4% 3% 2% 1% % RE_ Hydro Wind PV CSP Geothermal Nuclear Biomass CCS Biomass Oil CCS Oil Gas CCS Gas Coal IGCC CCS Coal IGCC Coal

9 Water Withdrawals by Scenario km 3 /yr 8 Withdrawals m 3 /MWh 35 Withdrawal Intensity NucCCS NucCCS_4.5 NucCCS_3.7 RE RE_4.5 RE_3.7 Hydro (all)! Dramatic decline in withdrawal intensity in all scenarios as older power plants are retired! This change is consistent with the trends of the last two decades based on the available evidence! RE scenarios generally have lower water withdrawal intensity

10 Water Consumption by Scenario km 3 /yr 3 ConsumpKon m 3 /MWh 1.8 ConsumpKon Intensity NucCCS NucCCS_4.5 NucCCS_3.7 RE RE_4.5 RE_3.7 Hydro (all)! Switch from once-through flow to evaporative cooling amounts to a shift from water withdrawals to water consumption! The consumption:withdrawal ratio is.5 in the base year! In the NucCCS scenarios, it increases to.2! In the RE scenario, it increases to ~.3! In the RE_policy scenarios, it increases to ~.6

11 Water Withdrawals by Technology 8 7 NucCCS 8 7 NucCCS_ km^3/yr km^3/yr RE RE_3.7 Hydro Wind PV CSP Geothermal Nuclear Biomass CCS Biomass Oil CCS Oil Gas CCS Gas Coal IGCC CCS Coal IGCC Coal 1 1

12 Water Consumption by Technology 35 3 NucCCS 35 3 NucCCS_ km^3/yr km^3/yr RE RE_3.7 Hydro Wind PV CSP Geothermal Nuclear Biomass CCS Biomass Oil CCS Oil Gas CCS Gas Coal IGCC CCS Coal IGCC Coal 5 5

13 Sensitivity Analysis - CCS Water Demands! The potential range of CCS water demands is large. Switching from a pulverized coal power plant without CCS to! PC with post-combustion capture doubles the water demands! IGCC or oxy-fuel with CCS increases the water demands marginally! IGCC or oxy-fuel with CCS and using either dry cooling or seawater-based cooling reduces the water demands by 8%! Switching from evaporative cooling to dry cooling also increases costs and decreases thermal efficiency EJ/yr Electricity GeneraKon NucCCS NucCCS_3.7_hi km 3 /yr 1 9 Water ConsumpKon NucCCS_3.7 NucCCS_3.7_lo

14 Sensitivity Analysis CSP Water Demands! CSP with thermal storage is very large in scenarios with limited other options for producing baseload electricity! The range in the water demand intensities depends on cooling systems. Compared to the baseline scenarios here! Using only evaporative cooling towers doubles the water demands! Using only dry/hybrid cooling systems reduces electricity generation by 3% (due to higher costs), and water demands by 85% 25 CSP Electricity 25 CSP Water ConsumpKon 2 2 EJ/yr 15 1 km 3 /yr RE RE_3.7 RE_3.7_hi RE_3.7_lo

15 Conclusions! Water withdrawals in all scenarios investigated here remain relatively flat for the next few decades! Retirement of old power plants with once-through flow systems! New builds use mostly evaporative cooling systems! By 25, 85% of the stock did not exist in the model base year, so there is a high degree of capital turnover! Water consumption increases in all scenarios! Where the present-day electric sector only consumes (evaporates) 5% of its water withdrawal, these scenarios describe systems where this ratio is between 2% (NucCCS technology) and 6% (RE technology with mitigation policy)! Water should not be seen as an obstacle to CCS in the long term! For post-combustion capture (whether retrofits or new builds), the water demand increases from CCS are substantial! However, in the long run with known or expected carbon prices, the IGCC and/or oxy-fuel plants would be the more relevant choices to analyze! Finally, the additional costs of dry cooling do not increase the costs prohibitively; this technology set remains valuable in mitigation

16 Extra Slide: Characteristics of Technology Strategies Technology strategy Technology area NucCCS RE Nuclear Power Carbon Capture & Storage (CCS) Solar Wind Geothermal Capital and O&M costs decline at.1% per year CCS not limited by availability of CO 2 storage reservoirs Costs decline by 1%- 2% per year, Costs decline by.25% per year, EGS not available Very high capital costs ($1, / kw) Small storage capaciies for geologic CO 2 storage Costs decline by 2%- 3% per year, Costs decline by.5% per year, EGS available and cost- effecive