NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, 

operated by the Alliance for Sustainable Energy, LLC.

NREL/TP-6A20-62566

ANALYSIS INSIGHTS OCTOBER 2014

MAKING 

SUSTAINABLE 

ENERGY 

CHOICES

Insights on the Energy/Water/Land Nexus
2 MAKING SUSTAINABLE ENERGY CHOICES

Energy heats and lights our homes, fuels our vehicles, and powers our businesses 

and factories. Affordable, reliable energy underpins the economy, security, and our 

quality of life. Meanwhile, growing global populations and economic development 

are increasing demand for energy around the world, and climate change is altering 

our way of thinking about energy options. The Department of Energy’s National 

Renewable Energy Laboratory helps policymakers and investors understand 

and evaluate energy choices within this complex web of connections, or nexus, 

between energy, water, and land. Economics, energy markets and policies, system 

performance, environmental regulations, carbon emissions, and social impacts are 

all important components of this nexus. NREL’s analysis, datasets, and advanced 

integrated modeling capabilities help illuminate the connections between energy, 

environment, economy, security, and quality of life.

A key contributor to the global energy dialogue, NREL enables informed decisionmaking at the local, regional, national, and international levels. 

ENERGY CHOICES 

CAN BE FRAMED 

WITHIN A ‘NEXUS’ OF 

ENVIRONMENTAL, 

ECONOMIC, AND 

SECURITY PRIORITIES

ANALYSIS INSIGHTS OCTOBER 2014

Figure 1. Connecting the dots — NREL helps illuminate the web of connections between energy, environment, economy, security, 

and quality of life

DRIVING FACTORS

GROWING PRESSURES

Governance

LAND ENERGY

food/fiber

WATER

Environment T Economy Social Impacts echnology

Biomass, Plant Siting

Greenhouse Gas

Emissions

Greenhouse Gas

Emissions

Irrigation

Fertilizer, Harvesting,

Storing, Processing

Resource Extraction,

Cooling Water, Transport

Pumping, Water Treatment, Water

Distribution,

Desalinization

Growing Population

Increasing Demand for Energy, Clean 

Water, Food

Climate Change

Increasing Temperature, Floods,

Draught Severity, Sea Level Rise, Land Loss
MAKING SUSTAINABLE ENERGY CHOICES 3

Navajo Generating Station: Helping Stakeholders Understand Complex 

Implications of Energy Options

NREL’s analytical support helped the U.S. Environmental 

Protection Agency (EPA) establish a final best available 

retrofit technology (BART) rule for reducing NOx emissions 

from Arizona’s Navajo Generating Station, a 2,250 MW 

coal plant near Page, AZ. The initial effort, which began 

in 2012, focused on objectively assessing a broad range 

of interrelated technical, environmental, and economic 

issues related to potential options for power in the region—

primarily replacing the coal-fired plant versus installing NOx

reduction retrofits. Several factors make this case unusually 

complex. The Navajo Generating Station came into being 

at the initiative of the federal government, which retains 

the largest share of ownership. Low-cost energy from the 

station powers a major water delivery project that helps 

sustain a multistate water agreement. In addition, the plant 

and the coal mine that supplies it are located on tribal 

lands and support tribal jobs and economies. NREL helped 

federal agencies unravel the complex interconnections and 

understand the implications for various courses of action 

in terms of power supply and prices, water supply and 

prices, air quality, and economic impacts. This work helped 

to attract diverse support for EPA’s final rule. A follow-on 

effort, which will examine strategies for transitioning the 

federal government’s share of the station to clean energy 

alternatives, is now underway.

Electric Sector Factors Emissions, Land, Water into Energy Choices

Lowering carbon emissions is one of many drivers for 

deploying renewable energy technologies. However, more 

robust energy decisions also factor in water and land use. 

Life cycle assessment (LCA) provides a well-established and 

comprehensive framework to compare the impacts of energy 

technologies. Using LCA methodologies, including techniques 

the laboratory has developed, analysts can examine emissions, 

water, and land impacts of energy on a “cradle-to-grave” 

basis—from raw material extraction, manufacturing, transport, 

and construction to operation and end-of-life disposal. 

On a life cycle basis, renewable technologies, nuclear 

generators, and coal generators with clean coal 

technologies produce fewer carbon emissions than 

traditional fossil fuel combustion technologies. However, 

water used in power plant operations varies widely based 

on the electricity generation technology and cooling 

system. Life cycle comparison of water consumption 

illustrates the potential for renewable electricity generation 

technologies to reduce the water intensity of the U.S. 

energy sector (Figure 2). Solar photovoltaic and wind 

technologies have the lowest total life cycle water use. But 

as can be seen, the technologies with the lowest carbon 

emissions don’t always have the lowest water consumption.

Calculating land use impacts is more challenging, and results 

vary widely—particularly for wind and geothermal systems—

depending on assumptions used. NREL’s preliminary work 

in this area indicates that land use for renewables makes up 

a small fraction of total U.S. land area. In addition, recent 

studies have identified workable strategies for minimizing 

land use for large-scale renewable deployment, including 

co-location of PV and wind on farms and ranches, and 

deployment on underutilized or degraded land sites (such 

as highway medians or landfills).
4 MAKING SUSTAINABLE ENERGY CHOICES

ANALYSIS INSIGHTS OCTOBER 2014

Future Impacts of Today’s Energy Choices in a Changing Climate

Water Use in Low-Carbon Futures

NREL has completed a series of studies to better understand 

the impact of different low-carbon electricity generation 

pathways on future power sector water use. Figure 3 

compares the water consumption impacts of a “businessas-usual” baseline scenario to three alternative scenarios 

based on use of different generating technologies to comply 

with assumed carbon constraints. The different scenarios 

lead to significantly different water profiles due to the wide 

variation in water use between thermochemical power plants 

and low- or no-water technologies such as wind and energy 

efficiency measures. 

Overall, investing in renewable energy and energy efficiency 

to meet carbon emission reduction targets is projected to 

result in significant water savings, lower energy costs, and 

net savings to consumers. Investing in new nuclear and 

coal with CCS facilities is projected to result in the highest 

long-term water consumption and highest electricity costs. 

Shifting from once-through cooled thermal generation to 

recirculating cooling technologies by 2050 reduces water 

withdrawals in all scenarios considered.

Figure 2. Life cycle emissions, water use, and land use comparisons for electricity generation technologies.1 The low and high 

estimates reflect a range in published analyses.

1. Lifecycle GHG emissions: IPCC Special Report on Renewables (and NREL website) http://srren.ipcc-wg3.de/report/IPCC_SRREN_Ch09.pdf

Lifecycle Water: http://iopscience.iop.org/1748-9326/8/1/015031/pdf/1748-9326_8_1_015031.pdf

Lifecycle Land: http://www.iea.org/publications/freepublications/publication/Renew_Policies.pdf

PV

CSP

Geothermal

Wind

Nuclear

Natural Gas

Coal

GHG Emissions

(million gCO2e/GWh)

Water Consumption

(thousand gal/GWh)

Land Use

(M2/GWh)

0 200 400 600 800 1,000 1,200 0 200 400 600 800 1,000 1,200 0 500 1,000 1,500 2,000 2,500 3,000

Upstream Upstream-High Operations Operations-High Downstream Total (no data by LC stage available)
MAKING SUSTAINABLE ENERGY CHOICES 5

Will Climate Change Alter the Water Supply 

Available for Electricity Generation? It Depends

on Where You Live.

Electricity generation can be water intensive, and climate 

change could lead to changes in precipitation or increases 

in surface water temperatures that limit the amount of 

water that is available and suitable for electricity generation. 

To support long-term, “what if” decision-making, NREL 

developed and demonstrated an integrated modeling 

approach to investigate the trade-offs among climate, water, 

and electricity systems [see text box]. Analysts found that, 

at both national and regional levels, average climate 

change projections have little impact on capacity growth 

and water withdrawal and consumption in 2050. In general, 

abundant unappropriated surface water rights overshadow 

the comparably small changes in surface water resources. 

Potential climate impacts were notable only for select 

southwestern states (Arizona, California, Nevada, New 

Mexico, and Texas), which tend to be more arid and where 

water supplies tend to be more strictly allocated. NREL can 

use the methodology developed for this study to investigate 

more extreme climate scenarios and a more rigorous 

representation of legal and physical water availability.

Figure 3. Future electricity choices can place different demands on regional water supplies (forecast for 2050). In general, 

relying primarily on nuclear and coal with CCS to meet assumed carbon constraints increases water consumption and 

withdrawals. Carbon constraints alone and carbon constraints with high renewable and energy efficiency show more consistent 

reductions in water use.

Jordan Macknick, Sandra Sattler, Kristen Averyt, Steve Clemmer, John Rogers. (2012). “The water implications of generating electricity: water use 

across the United States based on different electricity pathways through 2050.” Environmental Research Letters (7:4). NREL/ JA-6A20-56211. 

Business-as-usual Water Consumption for Electricity Producers (billions of gallons)

Scenarios - Change from Business-as-usual in Consumption (%)

0-39 40-79 80-119 120-159 160-199 200-239 240-279 280-319 320-359 360-400

-100 to -81 -80 to -61 -60 to -41 -40 to -21 -20-0 0-75 76-150 151-225 226-300 301-400

CARBON CONSTRAINTS ONLY CARBON CONSTRAINTS +

NUCLEAR AND COAL WITH CCS

CARBON CONSTRAINTS +

HIGH RENEWABLES AND EFFICIENCY
6 MAKING SUSTAINABLE ENERGY CHOICES

ANALYSIS INSIGHTS OCTOBER 2014

BioSpatial H2O Model Quantifies 

Bioenergy Water Requirements

Bioenergy adds more dimensions to analysis of the energy/

water/land nexus. In addition to the water used to produce 

biofuels or generate biopower (for example in fermentation, 

distillation, and cooling processes), bioenergy requires 

water—both from irrigation and rainfall—to grow the biomass 

feedstock. This generally competes with water used for 

irrigation of food, feed, and fiber crops. Consequently, 

expanding biomass feedstock production has important 

implications with regards to managing water resources. 

To estimate crop water requirements in future scenarios, 

NREL developed a unique model, BioSpatial H2O, based on 

a database of detailed climate, soil, and plant physiological 

data in a system dynamic modeling framework. The model 

improves water consumption analyses by providing results at 

several geographic levels, disaggregated over multiple water 

sources, and over time. BioSpatial H2O facilitates estimates 

of annual crop requirements for water, and helps quantify 

how much of that water is suitable for other human needs, 

such as cooling power plants. Ultimately, this powerful model 

enables a more robust understanding of bioenergy water 

consumption and will help decision-makers evaluate tradeoffs 

between bioenergy systems, other sources of energy, and 

other agricultural commodities.

I N T E G R AT I N G WAT E R R E Q U I R E M E N T S A N D 

CONSTRAINTS INTO THE REEDS MODEL

NREL analysts and partners developed a platform for 

assessing power plant cooling water withdrawals and 

consumption under different electricity pathways 

at geographic and time scales appropriate for both 

electricity and hydrology/water management. 

This platform uses estimates of regional electricity 

generation by the Regional Energy Deployment 

System (ReEDS) as input to a hydrologic and water 

management model—the Water Evaluation and 

Planning (WEAP) system. In WEAP, this electricity 

use represents thermoelectric cooling water 

withdrawals and consumption within the broader, 

regional water resource context. Linking the 

electricity and water models—including translating 

electricity generation results from ReEDS-relevant 

geographies to the water-relevant geographies of 

WEAP—allows analysis of water use by the electric 

sector at the regional watershed level, which can be 

used to examine the water resource implications of 

future electricity pathways.

Energy and Water

Thermal power plant cooling accounts for 41% of total 

U.S. water withdrawals. Withdrawal is the amount of 

water removed from sources like aquifers and lakes for 

use, but then returned to the source. 

Water and Land

Irrigation accounts for 81% of U.S. water consumption. 

Consumption is the amount of water removed from the 

source—for example, through evaporation or incorporation 

into products—such that it is not available for reuse at the 

same location or downstream.
MAKING SUSTAINABLE ENERGY CHOICES 7

Systems Approaches to Making Energy Decisions in Broader Contexts

Mathematical models like ReEDS and BioSpatial H2O enable 

analyses of a variety of energy futures. NREL is also engaged 

around the world using less data- and resource-intensive 

tools and approaches to enable energy decisions within 

broader contexts. Low emission development strategies 

(LEDS) lay out pathways for countries to achieve longterm national development goals, while also minimizing 

greenhouse gas (GHG) emissions historically associated 

with economic growth. LEDS are typically economy-wide 

approaches, encompassing all economic sectors, aligned 

with a country’s development priorities such as poverty 

alleviation, job creation, and energy security. 

NREL’s Development Impacts Assessment tool provides 

a user-friendly approach to visualizing and comparing 

carbon mitigation strategies according to a customizable 

set of client priorities, such as development priorities or 

ease of implementation. The tool does this using simple 

graphics to indicate a positive, neutral, or negative impact 

of each mitigation option on the competing client priorities. 

Originally designed to leverage existing optimization 

tools that focus primarily on cost and carbon mitigation 

(e.g., marginal abatement cost curves and technical needs 

assessments), practical application in the field has shown 

that these detailed data are not a prerequisite to populating 

the tool. In fact, a particular value of the tool is its ability to 

leverage qualitative impact assessments and data.

Figure 4. NREL’s Development Impacts Assessment tool makes it easy to assess carbon mitigation strategies according to a 

customizable set of additional priorities.

-$50 $0 $50 $100

500

High Positive

Positive

Neutral

Negative

1,000

1,500

2,000

Annual Abatement

Potential (MtCO2e)

Cost

39

38

37 36

35

33

32

31

30

29 28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12 11 10 

9

8

7 6 5 4

3

2

1

34

MARGINAL ABATEMENT COST CURVE TECHNOLOGIES

1. Lighting

2. Smart Grid – Automated Residential Systems

3. Smart Grid - AMI with Visual Display

4. Building Management Systems

5. Hybrid Vehicles

6. Geothermal

7. Landfill Gas Power Generation

8. Wind (low-cost)

9. Industrial Improvements (retrofits, new builds)

10. Soil Sequestration (mid-cost)

11. Soil Sequestration (high-cost)

12. Crop Rotations

13. Afforestation (low-cost)

14. Forest Management (mid-cost)

15. Efficiency-Commercial Retrofits

16. Efficiency-Residential Retrofits

17. Wind (high-cost)

18. Afforestation (mid-cost)

19. Forest Management (high-cost)

20. Plug-in Vehicles

21. Ethanol-fueled Vehicles

22. Solar PV (utility scale)

23. Nuclear

24. CCS (new build, post-combustion coal)

25. Efficiency-Residential New Builds

26. Landfill Projects (high-cost)

27. Biomass

28. Gas Industry Projects

29. Electric Vehicles

30. CCS (retrofit, post-combustion coal)

31. Afforestation (high-cost)

32. Solar PV (residential)

33. CCS (new build, oxyfuel, coal)

34. Coal Mine, Oil Industry, High GWP, Wastewater Projects

35. Coal-gas Fuel Switch for Installed Fleet

36. CCS (new build, pre-combustion IGCC)

37. CCS (retrofit, oxyfuel, coal)($107)

38. Solar Thermal ($140)

39. Gas Industry Project (high-cost)(>$1,000)

 

The randomized data inserted in this table is for purposes of demonstration only and does not represent actual research.

SOCIAL IMPACTS ECONOMIC IMPACTS ENVIRONMENTAL

IMPACTS

EASE OF IMPLEMENTATION

HealthAlignment with 

 Political Priorities

EducationGDPWaterVariety and Number of 

 Stakeholders Involved

GenderEmploymentBiodiversityProximity to Current 

 Regulation

Rural DevelopmentLocal IndustryAwareness and 

 Acceptance

Energy AccessTrade
ANALYSIS INSIGHTS 2014 FIRST QUARTER OCTOBER 2014

National Renewable Energy Laboratory

15013 Denver West Parkway, Golden, CO 80401

303-275-3000 • www.nrel.gov

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency 

and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC

Front page photo by iStock_000006927873 • NREL/TP-6A20-62566 • October 2014

NREL prints on paper that contains recycled content.

Helping Policymakers and Investors Evaluate Energy Choices in 

Framework of Sustainability

Renewable energy technologies have the potential to reduce the environmental impacts of the energy sector. NREL is 

engaging stakeholders, developing tools, and conducting robust analysis to help today’s energy leaders understand the tradeoffs of energy choices in the context of broader social, economic and environmental priorities and increasing pressures of a 

changing climate.

Learn More about the Energy/Water/Land Nexus

Doug Arent, Jacquelyn Pless, Trieu Mai, Ryan Wiser, Maureen Hand, 

Sam Baldwin, Garvin Heath, Jordan Macknick, Morgan Bazilian, Adam 

Schlosser, Paul Denholm. (2014) “Implications of high renewable 

electricity penetration in the U.S. for water use, greenhouse gas 

emissions, land-use, and materials supply.” Applied Energy (123). 

NREL/ JA-6A20-59175. 

Kristen Averyt, Jordan Macknick, John Rogers, Nadia Madden, Jeremy 

Fisher, James Meldrum, Robin Newmark. (2013). “Water Use for 

Electricity in the United States: An Analysis of Reported and Calculated 

Water Use Information for 2008.” Environmental Research Letters (8:1). 

NREL/JA-6A20-56405. 

Stuart Cohen, Jordan Macknick, Kristen Averyt, James Meldrum. (2014). 

Modeling Climate-Water Impacts on Electricity Sector Capacity Expansion: 

Preprint. NREL/CP-6A20-61435 

Shannon Cowlin, Jaquelin Cochran, Sadie Cox, and Carolyn Davidson, 

Wytze van der Gaast . (2012). Broadening the Appeal of Marginal 

Abatement Cost Curves: Capturing Both Carbon Mitigation and 

Development Benefits of Clean Energy Technologies. NREL/CP-6A20-

54487. 

David J. Hurlbut, Scott Haase, Gregory Brinkman, Kip Funk, Rachel 

Gelman, Eric Lantz, Christina Larney, David Peterson, Christopher Worley, 

Ed Liebsch. (2012). Navajo Generating Station and Air Visibility Regulations: 

Alternatives and Impacts. NREL/TP-6A20-53024. 

Jordan Macknick, Courtney Lee, Gail Mosey, Jenny Melius. (2013). 

Solar Development on Contaminated and Disturbed Lands. NREL/

TP-6A20-58485. 

Jordan Macknick, Brenda Beatty, Graham Hill. (2013). Overview of 

Opportunities for Co-Location of Solar Energy Technologies and 

Vegetation. NREL/TP-6A20-60240. 

Anelia Milbrandt, Donna Heimiller, Andrew Perry, Christopher Field. 

(2014). “Renewable energy potential on marginal lands in the United 

States.” Renewable and Sustainable Energy Reviews (29:1). 

Sean Ong, Clinton Campbell, Paul Denholm, Robert Margolis, Garvin 

Heath. (2013). Land-Use Requirements for Solar Power Plants in the 

United States. NREL/TP-6A20-56290. 

John Rogers, Kristen Averyt, Steve Clemmer, Michelle Davis, Francisco 

Flores-Lopez, Doug Kenney, Jordan Macknick, Nadia Madden, James 

Meldrum, Sandra Sattler, Erika Spanger-Siegfried, David Yates. (2013). 

Water-Smart Power: Strengthening the U.S. Electricity System in a 

Warming World. Cambridge, MA: Union of Concerned Scientists. 

Accessed September 2014: http://www.ucsusa.org/clean_energy/ourenergy-choices/energy-and-water-use/water-smart-power.html. 

Mark Ruth, Trieu Mai, Emily Newes, Andy Aden, Ethan Warner, 

Caroline Uriarte, Daniel Inman, Travis Simpkins, Andrew Argo. (2013). 

Transportation Energy Futures Series: Projected Biomass Utilization 

for Fuels and Power in a Mature Market. NREL/TP-6A20-53336; DOE/

GO-102013-3707. 

Sandra Sattler, Jordan Macknick, David Yates, Francisco FloresLopez, Anthony Lopez, John Rogers. (2012). “Linking electricity and 

water models to assess electricity choices at water-relevant scales.” 

Environmental Research Letters (7:4). NREL/JA-6A20-56242. 

U.S. Energy Sector Vulnerabilities to Climate Change and Extreme 

Weather. (2013). DOE/PI-0013. Washington, D.C.: U.S. Department 

of Energy. Accessed September 2014: http://energy.gov/downloads/

us-energy-sector-vulnerabilities-climate-change-and-extreme-weather 

Ethan Warner, Yimin Zhang, Daniel Inman, Garvin Heath. (2014). 

“Challenges in the Estimation of Greenhouse Gas Emissions from 

Biofuel-Induced Global Land-Use Change.” Biofuels, Bioproducts and 

Biorefining (8:1). NREL/JA-5100-61691. 

LEGEND:

 Energy Water Climate Land Social