The Water-Energy Nexus: From Crisis to Opportunity

David EJ GarmanDean School of Freshwater Sciences

Overview

Brief overview of water and water quality issues from existing generation systems in USA look at alternative and emerging technologies in terms of water implicationsAn assessment of whether there is hope or not!

ENERGY AND WATER RELATIONSHIPSWATER FOR ENERGY

ENERGY FOR WATER

Hydropower

Thermo electric Cooling

Fuel Production (Ethanol, hydrogen)

Extraction & Refining

Extraction and Transmission

Drinking Water Treatment

Waste Water Treatment

Energy Associated with Uses of Water

USES OF WATER

WITHDRAWALS OF WATER

UNICEF Urban WASH workshop, October, 2009 Vörösmarty et al. 2000

• 80% of future stress from population & development, not climate change!

•Correct Priorities? (E.g. 85% US global change research funding to climate and carbon)

Water Stress Changes to 2025

UNH

WATER CONSUMPTION & ENERGY

US Power Water Use 2003

• Thermal water cooled - 87%• Evaporation 2.5% or 3310 million gals/day• 0.47 gal/kWh of power(1.8L/kWh)

• Hydroelectricity - 9%• Evaporation – not given

• Renewables – 4% • Water consumption - low

Source: Torcellini et al. 2003 NREL/TP-550-33905

Sources of power in USA 2006

Projected Water Use for PowerAssumptions• US population grows by 70 from 2006 to 2031

(25 years)• Electricity demand grows by 50%• Other

laws/regs/policies/technology/consumer preferences - business as usual

• Most growth in SE, SW and far WestMost of the growth occurs in areas of limited water availability Source EIA

Evaporation & Generation

Evaporative Cooling Consumption• 89% US electricity is produced with thermally driven

water-cooled energy conversion cycles. • Evaporative or consumptive use is ~ 2.5% or 3,310

MGD (12,530 ML/d). • Hydroelectric plants produce ~ 9% electricity.• In thermoelectric plants, 0.47 gal (1.8 L)/kWhr • Hydroelectric plants 18 gal (68 L)/kWhr • Weighted average TE & HE water use is 2.0 gal

(7.6 L) per kWh

ENERGY AND INTERACTIONS & ALTERNATIVE FUELS

Are we making the right decisions now in terms of water?

ENERGY AND WATER RELATIONSHIPSWATER FOR ENERGY

ENERGY FOR WATER

Hydropower

Thermo electric Cooling

Fuel Production (Ethanol, hydrogenmethane)

Extraction & Refining(Oil, sands, biofuels)

Extraction and Transmission

Drinking Water Treatment

Waste Water Treatment

Energy Associated with Uses of Water

Distribution and Collection

Source Virginia Water Resources Research Center 2006/2011

Alternative fuels

Fuel ethanol – 32 to 376 L /kWh depending on source

Fuel from water rich areas transferred to water poor areas provides a transfer of

virtual water

Water Related Electricity Use in California - 2001

Including Agriculture Without AgricultureGWh % GWh % KWh/pp

Water Supply and TreatmentUrban 7,554 16% 7,554 20% 218 Agricultural 3,188 7% 0%

End UsesAgricultural 7,372 15% 0%Residential 13,526 28% 13,526 36% 391 Commercial 8,341 17% 8,341 22% 241 Industrial 6,017 13% 6,017 16% 174

Wastewater Treatment 2,012 4% 2,012 5% 58

Total Water Related Energy Use 48,010 100% 37,450 100% 1,082

Total California Electricity Use 250,494 250,494 7,240

Water Related as % of Total 19% 15%

Population (Millions) 34.600

MULTIPLE (AND COMPLENTARY) APPROACHES TO EFFICIENCY GAINS IN WATER SYSTEMS

User Side - Optimization • Utility interventions at the end-use

levels• Appliance standards• Building standards • Quasi-market mechanisms

Both Sides – System and Building Rethink at the City Level

• Densification• Water-energy integration• Water plants as energy and water

factories • Closing the loop -- water sensitive

design

Production – Extraction & Transmission,DW Treatment and WW Treatment • Efficient pumps • More efficient processes• Energy recovery from wastewater treatment

OTHER WATER IMPACTSMore than just the volume measure the quality

Issues of Power Production

• Loss of habitat• Loss of fish, fish eggs and larvae• Thermal impact of discharges – good and bad

• Cold water from hydro systems• Sediment discharges• Decommissioning of dams• Warm water from cooling

• Changes in water quality from use

Fuels as a source of pollution• Coal – typically sulphur, particulates, mercury

and trace metals, dioxins and ash leachates• Modern plants remove these at source after combustion• Coal gasification is an option• Pulverized coal injection is a major improvement for coal

quality and combustion efficiency • Clean coal - equivalent to natural gas is still not an option

• Most water quality issues other than thermal and CO2 are now historical, albeit persistent in some areas

UNICEF Urban WASH workshop, October, 2009

Water Quality Challenges Add to the Complexity

Traditional pollutants, micropollutants, and nutrients associated with urban, agricultural, and industrial use are also a key part of the challenge we face.Global warming exacerbates this challengeTraditional energy generation – coal fired has left a legacy of issues

The projected change is compared to the present day with a ~1% increase per year in equivalent CO2Source: The Met Office. Hadley

Center for Climate Prediction and Research

Projected Changes in Annual Temperatures for the 2050s

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Related Water & Energy Impacts• Water Shortages - exacerbated• Flooding – changes to frequency and

intensity • Water Quality impacts from acidification

and trace contaminants • Sea levels rise and lake levels fall • Increased competition

Water Re-use Queensland

Due to water shortage $6.4 b was spent on a recycle system in Queensland including a a desalination plant.

A major commitment was to supply water to power stations

NEW TECHNOLOGIESHow quickly can these become large scale generation capacity

HIGH INTENSITY SOLAR SYSTEMS

Linkage to heat recovery systems and special use energy generation systems

Small scale generation at present.

New technologies• Tri stage gas and geothermal (gas)• Photovoltaic • Heat recovery systems (household & commercial) • Fuel cells – hydrogen based• New battery systems linked to solar• High intensity solar• Microbial fuel cells• Carbon sequestration

Restructuring the InputsOptions• Integrated large, medium & small generation

systems• Multiple source generation Outcomes• Reduced water use• Increased flexibility

CONCLUSIONS

Conclusions

• It is likely that water availability will be a driver to change generation location and technology and improve water use efficiency

• Improvements to water use reduction include overall reductions in energy consumption

• New technologies can offset water quantity and quality losses but a re-think is required to enable rapid uptake

Acknowledgements

• Paul Reiter & IWA staff• Many colleagues members that contributed

slides

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