Land-Use Requirements for Solar Power Plants in the United States

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Contract No. DE-AC36-08GO28308

Land-Use Requirements for

Solar Power Plants in the United

States

Sean Ong, Clinton Campbell, Paul Denholm,

Robert Margolis, and Garvin Heath

Technical Report

NREL/TP-6A20-56290

June 2013

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

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC.

This report is available at no cost from the National Renewable Energy

Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

National Renewable Energy Laboratory

15013 Denver West Parkway

Golden, CO 80401

303-275-3000 • www.nrel.gov

Land-Use Requirements for

Solar Power Plants in the

United States

Sean Ong, Clinton Campbell, Paul Denholm,

Robert Margolis, and Garvin Heath

Prepared under Task Nos. SS12.2230 and SS13.1040

Technical Report

NREL/TP-6A20-56290

June 2013

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Cover Photos: (left to right) photo by Pat Corkery, NREL 16416, photo from SunEdison, NREL 17423, photo by Pat Corkery, NREL

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iii

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Acknowledgments

This work was made possible by the Solar Energy Technologies Program at the U.S. Department

of Energy (DOE). The authors wish to thank Billy Roberts, Jarett Zuboy, Trieu Mai, Nate Blair,

Robin Newmark, Margaret Mann, Craig Turchi, Mark Mehos, and Jim Leyshon of the National

Renewable Energy Laboratory (NREL) for contributing to and reviewing various versions of the

document, as well as Karen Smith, Rob Horner, Corrie Clark of Argonne National Laboratory

for their thoughtful reviews. The authors also thank Mary Lukkonen of NREL’s

Communications Office for a thorough technical edit of the document.

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Executive Summary

By the third quarter of 2012, the United States had deployed more than 2.1 gigawatts (GWac

) of

utility-scale solar generation capacity, with 4.6 GWac under construction as of August 2012

(SEIA 2012). Continued growth is anticipated owing to state renewable portfolio standards and

decreasing system costs (DOE 2012a). One concern regarding large-scale deployment of solar

energy is its potentially significant land use. Efforts have been made to understand solar land use

estimates from the literature (Horner and Clark 2013); however, we were unable to find a

comprehensive evaluation of solar land use requirements from the research literature. This report

provides data and analysis of the land use associated with U.S. utility-scale

ground-mounted

photovoltaic (PV) and concentrating solar power (CSP) facilities.

After discussing solar land-use metrics and our data-collection and analysis methods, we present

total and direct land-use results for various solar technologies and system configurations, on both

a capacity and an electricity-generation basis. The total area corresponds to all land enclosed by

the site boundary. The direct area comprises land directly occupied by solar arrays, access roads,

substations, service buildings, and other infrastructure. We quantify and summarize the area

impacted, recognizing that the quality and duration of the impact must be evaluated on a case-by-

case basis. As of the third quarter of 2012, the solar projects we analyze represent 72% of

installed and under-construction utility-scale PV and CSP capacity in the United States. Table

ES-1 summarizes our land-use results.

All capacity-based land-use intensity figures in this study are expressed in terms of MWac or GWac. This is to

maintain consistency within the paper because CSP power plants are rated in terms of MWac. The conversion factor

between dc-rating and ac-rating is discussed in Section 3.

We define utility-scale as greater than 1 MWdc for PV plants and greater than 1 MWac for CSP plants.

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Table ES-1. Summary of Land-Use Requirements for PV and CSP Projects in the United States

Technology

Direct Area

Total Area

Capacity-

weighted

average land

use

(acres/MWac)

Generation-

weighted average

land use

(acres/GWh/yr)

Capacity-

weighted

average land

use

(acres/MWac)

Generation-

weighted average

land use

(acres/GWh/yr)

Small PV (>1 MW, <20 MW)

5.9 3.1 8.3 4.1

Fixed 5.5 3.2 7.6 4.4

1-axis 6.3 2.9 8.7 3.8

2-axis flat panel 9.4 4.1 13 5.5

2-axis CPV 6.9 2.3 9.1 3.1

Large PV (>20 MW)

7.2

3.1

7.9

3.4

Fixed 5.8 2.8 7.5 3.7

1-axis

9.0

3.5

8.3

3.3

2-axis CPV

6.1

2.0

8.1

2.8

CSP

7.7 2.7 10 3.5

Parabolic trough 6.2 2.5 9.5 3.9

Tower 8.9 2.8 10 3.2

Dish Stirling 2.8 1.5 10 5.3

Linear Fresnel 2.0 1.7 4.7 4.0

We found total land-use requirements for solar power plants to have a wide range across

technologies. Generation-weighted averages for total area requirements range from about

3 acres/GWh/yr for CSP towers and CPV installations to 5.5 acres/GWh/yr for small 2-axis flat

panel PV power plants. Across all solar technologies, the total area generation-weighted average

is 3.5 acres/GWh/yr with 40% of power plants within 3 and 4 acres/GWh/yr. For direct-area

requirements the generation-weighted average is 2.9 acres/GWh/yr, with 49% of power plants

within 2.5 and 3.5 acres/GWh/yr. On a capacity basis, the total-area capacity-weighted average is

8.9 acres/MWac, with 22% of power plants within 8 and 10 acres/MWac. For direct land-use

requirements, the capacity-weighted average is 7.3 acre/MWac, with 40% of power plants within

6 and 8 acres/MWac. Other published estimates of solar direct land use generally fall within

these ranges.

Both capacity- and generation-based solar land-use requirements have wide and often skewed

distributions that are not well captured when reporting average or median values. Some solar

categories have relatively small samples sizes, and the highest-quality data are not available for all

solar projects; both of these factors must be considered when interpreting the robustness of reported

results. Owing to the rapid evolution of solar technologies, as well as land-use practices and

regulations, the results reported here reflect past performance and not necessarily future trends.

Future analyses could include evaluating the quality and duration of solar land-use impacts and

using larger sample sizes and additional data elements to enable a thorough investigation of

additional land-use factors.

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Table of Contents

1 Introduction ........................................................................................................................................... 1

2 Solar Power Plant Land-Use Metrics .................................................................................................. 2

3 Solar Land-Use Data and Methodology ............................................................................................. 4

4 Results ................................................................................................................................................... 6

4.1 Summary Results ........................................................................................................................... 7

4.2 PV Land-Use Results .................................................................................................................... 9

4.2.1 Evaluation of PV Packing Factors ................................................................................. 12

4.2.2 Impact of Location and Tracking Configuration on PV Land Use ................................ 13

4.3 CSP Land-Use Results ................................................................................................................ 15

5 Conclusions ........................................................................................................................................ 17

References ................................................................................................................................................. 20

Appendix A. CSP Solar Multiple Ranges ................................................................................................ 22

Appendix B. PV Projects Evaluated ........................................................................................................ 24

Appendix C. CSP Projects Evaluated ..................................................................................................... 32

Appendix D. Impact of PV System Size and Module Efficiency on Land-Use Requirements ........... 34

Appendix E. Impact of CSP System Size and Storage on Land-Use Requirements .......................... 37

vii

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List of Figures

Figure 1. NREL mesa top PV system—example of direct and total land use .............................................. 3

Figure 2. Map of PV and CSP installations evaluated .................................................................................. 7

Figure 3. Distribution of solar land-use requirements—whiskers indicate maximum and minimum

values, box indicates 75

(top of box) and 25

(bottom of box) percentile estimates ............. 8

Figure 4. Distribution of generation-based solar land-use requirements—whiskers indicate maximum

and minimum values, box indicates 75

(top of box) and 25

(bottom of box) percentile

estimates. Blue dot represents eSolar’s Sierra Sun Tower (10 acres/GWh/yr), separated

for clarity (but not considered an outlier) ................................................................................ 9

Figure 5. Distribution of small PV land-use requirements—whiskers indicate maximum and minimum

values, box indicates 75

(top of box) and 25

(bottom of box) percentile estimates ........... 11

Figure 6. Distribution of large PV land-use requirements—whiskers indicate maximum and minimum

values, box indicates 75

(top of box) and 25

(bottom of box) percentile estimates ........... 12

Figure 7. Capacity-weighted average packing factor for PV projects evaluated—whiskers indicate

maximum and minimum values, box indicates 75

(top of box) and 25

(bottom of box)

percentile estimates ................................................................................................................ 13

Figure 8. Modeled data showing relationship between CSP thermal storage and land-use intensity ......... 16

Figure D-1. Total-area requirements for small PV installations as a function of PV plant size ................. 34

Figure D-2. Total-area requirements for large PV installations as a function of PV plant size .................. 35

Figure D-3. Capacity-based direct-area land-use requirements for all PV systems as a function of

module efficiency ................................................................................................................... 35

Figure D-4. Generation-based direct-area land-use requirements for all PV systems as a function of

module efficiency ................................................................................................................... 36

Figure E-1. Total-area requirements for CSP installations as a function of plant size ............................... 37

Figure E-2. Direct-area requirements for CSP installations as a function of plant size .............................. 38

Figure E-3. Total generation-based area requirements for CSP installations as a function of

storage hours .......................................................................................................................... 38

Figure E-4. Total capacity-based area requirements for CSP installations as a function of storage hours . 39

List of Tables

Table ES-1. Summary of Land-Use Requirements for PV and CSP Projects in the United States .............. v

Table 1. Summary of Data Categories Used for PV and CSP Plants ........................................................... 4

Table 2. Summary of Collected Solar Power Plant Data (as of August 2012) ............................................. 6

Table 3. Total Land-Use Requirements by PV Tracking Type .................................................................. 10

Table 4. Direct Land-Use Requirements by PV Tracking Type ................................................................. 10

Table 5. Impacts of 1-Axis Tracking on Land-Use Intensity Compared With Fixed-Axis Mounting ....... 14

Table 6. Total Land-Use Requirements by CSP Technology ..................................................................... 15

Tab

le 7. Direct Land-Use Requirements by CSP Technology ................................................................... 15

Table 8. Summary of Direct Land-Use Requirements for PV and CSP Projects in the United States ....... 18

Table 9. Summary of Total Land-Use Requirements for PV and CSP Projects in the United States ......... 19

Table A-1. CSP Solar Multiple Ranges and Corresponding Estimated Annual Generation Values .......... 22

Table B-1. PV Land-Use Data .................................................................................................................... 24

Table C-1. Concentrating Solar Power Land-Use Data .............................................................................. 32

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1 Introduction

By the third quarter of 2012, the United States had deployed more than 2.1 gigawatts (GWac

) of

utility-scale solar generation capacity, with 4.6 GWac under construction as of August 2012

(SEIA 2012). Continued growth is anticipated owing to state renewable portfolio standards and

decreasing system costs (DOE 2012a). One concern regarding large-scale deployment of solar

energy is its potentially significant land use. Estimates of land use in the existing literature are

often based on simplified assumptions, including power plant configurations that do not reflect

actual development practices to date. Land-use descriptions for many projects are available from

various permitting agencies and other public sources, but we were unable to locate a single

source that compiles or summarizes these datasets. The existing data and analyses limit the

effective quantification of land-use impacts for existing and future solar energy generation,

particularly compared with other electricity-generation technologies.

This report provides data and analysis of the land use associated with U.S. utility-scale ground-

mounted photovoltaic (PV) and concentrating solar power (CSP) facilities, defined as

installations with capacities greater than 1 MW. The next section (Section 2) discusses standard

land-use metrics and their applicability to solar power plants. We identify two major classes of

solar plant land use—direct impact (disturbed land due to physical infrastructure development)

and total area (all land enclosed by the site boundary)—by which we categorize subsequent

results. Section 3 describes our solar land-use data collection and analysis methods. We derived

datasets from project applications, environmental impact statements, and other sources and used

them to analyze land use based on the capacity and generation of solar plants. Section 4 presents

our results. In addition to summarizing PV and CSP land use, we examine relationships among

land use, plant configuration, location, and technology. Finally, in Section 5, we identify

limitations to the existing solar land-use datasets and suggest additional analyses that could aid in

evaluating land use and impacts associated with the deployment of solar energy. Appendices

include tables of our solar project data as well as more detailed analyses of specific land-use

relationships.

All capacity-based land-use intensity figures in this study are expressed in terms of MWac or GWac. This is to

maintain consistency within the paper because CSP power plants are rated in terms of MWac. The conversion factor

between dc-rating and ac-rating is discussed in Section 3.

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2 Solar Power Plant Land-Use Metrics

There are many existing and proposed metrics for evaluating land-use impacts. Recent methods

for quantifying land use include evaluating the direct and indirect life-cycle use (Fthenakis and

Kim 2009) and assessing temporary and permanent land-area requirements (Denholm et al.

2009). While there is no single, generally accepted methodology (Canals et al. 2007), at least

three general categories are used to evaluate land-use impacts: (1) the area impacted, (2) the

duration of the impact, and (3) the quality of the impact (Koellner and Scholz 2008). The quality

of the impact (also called the “damage function”) evaluates the initial state of the land impacted

and the final state across a variety of factors, including soil quality and overall ecosystem quality

(Koellner and Scholz 2008).

This report closely follows the methodology outlined in a National Renewable Energy

Laboratory (NREL) U.S. wind power land-use study (Denholm et al. 2009). We quantify and

summarize the area impacted, recognizing that the quality and duration of the impact must be

evaluated on a case-by-case basis. We consider two land-use metrics. The first is the total area,

which corresponds to all land enclosed by the site boundary. The perimeter of this area is usually

specified in blueprint drawings and typically fenced or protected. The second metric is the direct-

impact area, which comprises land directly occupied by solar arrays, access roads, substations,

service buildings, and other infrastructure. The direct-impact area is smaller than the total area

and is contained within the total-area boundaries. Figure 1 illustrates the two types of areas, with

the total area shaded yellow and the direct-impact area shaded orange.

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Figure 1. NREL mesa top PV system—example of direct and total land use

Access roads, infrastructure, and other direct impact areas are not shown in Figure 1.

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3 Solar Land-Use Data and Methodology

We collected PV and CSP land-use data from four categories of sources, in the following

prioritized order. First, where available, we collected official project data from federal, state, or

local regulatory agencies, including environmental impact statements, environmental

assessments, and project applications to regulatory bodies. These sources typically contain

detailed project information, but their availability is highly dependent on federal, state, and local

regulations as some states require very detailed environmental assessments, while others require

little land-use analysis. Second, we collected project fact sheets, news releases, and other data

provided by the project owner or developer. Data from these sources were used when additional

information was needed and not found in regulatory documents. When no other source of data

could be located, we used news articles, websites unaffiliated with the developer/owner or

regulatory bodies, and other secondary sources. Finally, when official project drawings were

unavailable or documents did not include information necessary to estimate total and direct land

area, we analyzed satellite images to identify plant configuration, direct land use, and project-

area boundaries. Table 1 shows the proportion of data source categories used for each technology

and also indicates the percentage of sites where satellite imagery was analyzed in addition to the

documents collected.

Table 1. Summary of Data Categories Used for PV and CSP Plants

Technology

Official

Documents

(%)

Developer

Documents

(%)

Third-Party

Sources

(%)

Percent of Projects

That Required

Satellite Imagery

PV 18% 36% 46% 40%

CSP 44% 28% 28% 40%

For PV, we used these datasets to analyze the relationship between land-use intensity (defined as

land use per unit of capacity or generation) and stated PV module efficiency, array configuration,

and tracking type. For CSP, we analyzed the land-use intensity of several different technologies.

For PV and CSP, we limited the analysis to systems larger than 1 MW in capacity. We classified

systems smaller than 20 MW as “small” and those larger than 20 MW as “large.”

We quantified land-use requirements on a capacity (area/MWac) and a generation

(area/GWh/yr

) basis. Capacity-based results are useful for estimating land area and costs for

new projects because power plants are often rated in terms of capacity. The generation basis

provides a more consistent comparison between technologies that differ in capacity factor and

enables evaluation of land-use impacts that vary by solar resource differences, tracking

configurations, and technology and storage options. Most of the data collected for this analysis

included the reported capacity of power plants but not annual generation. Because capacity-

based land-use requirements are based on reported data, the capacity-based results are expected

to have less uncertainty than the generation-based results.

Percentages add up to over 100% because power plants evaluated with satellite imagery also required additional

data sources to determine solar plant characteristics.

Generation results are reported in area/(GWh per year) which we display as area/GWh/yr.

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We simulated PV and CSP electricity generation using the System Advisor Model (SAM;

Gilman and Dobos 2012). When available, we used project-specific inputs, such as location,

array configuration, derate factor, and tracking technology. When project-specific inputs were

unavailable, we used SAM default assumptions (e.g., if the tilt angle for fixed-tilt PV was

unknown, we used SAM’s latitude-tilt default assumption). The PV derate factor

was

determined by dividing the AC reported capacity by the DC reported capacity for each project.

The weighted-average derate factor (0.85) was used for projects that did not report both AC and

DC capacity. All capacity-based land-use intensity figures in this study are expressed in terms of

MWac. For CSP projects, a range of solar multiple

values was used to simulate annual

generation output (see Appendix A for CSP solar multiple assumptions). Hourly solar resource

and weather data for all projects were obtained from the NREL Solar Prospector tool

for each

project’s latitude and longitude. Each power plant was assigned to a cell within the National

Solar Radiation Database (Wilcox 2007) equal in area to 0.1 degrees in latitude and longitude

(approximately equal to a 10 km x 10 km square) (Perez et al. 2002). PV and CSP projects were

simulated with typical direct-radiation-year weather data

(NREL 2012).

The derate factor is used to determine the AC power rating at Standard Test Conditions (STC). The overall DC to

AC derate factor accounts for losses from the DC nameplate power rating. We do not calculate the derate factor

from component losses, but rather estimate the derate factor from the reported AC and DC power rating at each

plant. For a discussion on derate factors, see

http://rredc.nrel.gov/solar/calculators/pvwatts/version1/change.html#derate

(accessed April 2013).

The solar multiple is the CSP field aperture area expressed as a multiple of the aperture area required to operate the

power cycle at its design capacity (NREL 2012).

The Solar Prospector is a mapping and analysis tool designed to provide access to geospatial data relevant to the

solar industry. For more information, visit http://maps.nrel.gov/prospector

(accessed May 2013).

For consistency, PV and CSP data were both simulated using typical direct-radiation-year (TDY) weather data.

Normally, CSP power plants are simulated using TDY data and PV power plants are simulated using typical

meteorological year (TMY) data.

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4 Results

We obtained land-use data for 166 projects completed or under construction (as of August 2012),

representing 4.8 GWac of capacity, and 51 proposed projects, representing approximately

8 GWac of capacity (Table 2).

Table 2. Summary of Collected Solar Power Plant Data (as of August 2012)

Small PV (<20 MW) Large PV (>20 MW) CSP

Projects

Capacity

(MWac)

Projects

Capacity

(MWac)

Projects

Capacity

(MWac)

Completed 103 413 10 256 9 508

Under construction 17 165 20 1,846 7 1,610

Proposed 6 70 36 6,376 9 1,570

Total

126

762

9,961

3,688

We collected data on 4.8 GWac (72%) of the 6.7 GWac of completed or under-construction U.S.

utility-scale solar capacity reported by SEIA (SEIA 2012). Figure 2 maps the solar projects

evaluated. Appendix B and Appendix C detail all the projects and data sources. There are over

24 GWac of PV and CSP proposed (under development but not under construction) as of August

2012

(SEIA 2012), and the results reported in this study must be taken in light of a rapidly

growing installed base. The results reported in this study reflect past performance and not

necessarily future trends. For example, many of the largest PV systems currently proposed

consist primarily of thin-film technology on fixed-tilt arrays, which may have different land use

requirements than the results presented in this study.

As of February 2013, there are 26 GWac of PV and CSP proposed (SEIA 2013).

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Figure 2. Map of PV and CSP installations evaluated

4.1 Summary Results

Figure 3 summarizes capacity-based total and direct land-use results for small and large utility-

scale PV and CSP projects. Direct land-use requirements for small and large PV installations

range from 2.2 to 12.2 acres/MWac, with a capacity-weighted average of 6.9 acres/MWac.

Direct land-use intensity for CSP installations ranges from 2.0 to 13.9 acres/MWac, with a

capacity-weighted average of 7.7 acres/MWac. Figure 4 shows generation-based total and direct

land-use results. Direct land-use requirements for PV installations range from 1.6 to

5.8 acres/GWh/yr, with a generation-weighted average of 3.1 acres/GWh/yr. Direct land-use

intensity for CSP installations ranges from 1.5 to 5.3 acres/GWh/yr, with a generation-weighted

average of 2.7 acres/GWh/yr.

Solar direct land-use estimates in the literature generally fall within these ranges but are often

smaller than the PV capacity-weighted averages we report and on par or larger for CSP capacity-

weighted averages we report. Hand et al. (2012) estimate 4.9 acres/MWac for PV and

8.0 acres/MWac for CSP. Denholm and Margolis (2008) estimate 3.8 acres/MWac for fixed-tilt

PV systems and 5.1 acres/MWac for 1-axis tracking PV systems. Our results indicate

5.5 acres/MWac for fixed-tilt PV and 6.3 acres/MWac for 1-axis tracking PV (capacity-weighted

average direct land-use requirements for systems under 20 MW; see Table 4 in Section 4.2).

Horner and Clark (2013) report 3.8 acres/GWh/yr for PV and 2.5 acres/GWh/yr for CSP.

Fthenakis and Kim (2009) estimate 4.1 acres/GWh/yr for CSP troughs and 2.7 acres/GWh/yr for

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CSP towers. Our results indicate 2.3 acres/GWh/yr for CSP troughs and 2.8 acres/GWh/yr for

CSP towers (see Table 7 in Section 4.3).

Figure 3. Distribution of solar land-use requirements—whiskers indicate maximum and minimum

values, box indicates 75

(top of box) and 25

(bottom of box) percentile estimates

Comparisons of generation-based land use results should be taken in light of the fact that annual generation

(GWh) varies with solar resource (location). For example, generation-based results determined from solar power

plants in a specific location may differ from results presented in this study, which includes solar plants from a

variety of locations throughout the United States.

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Figure 4. Distribution of generation-based solar land-use requirements—whiskers indicate

maximum and minimum values, box indicates 75

(top of box) and 25

(bottom of box) percentile

estimates. Blue dot represents eSolar’s Sierra Sun Tower (10 acres/GWh/yr), separated for clarity

(but not considered an outlier)

4.2 PV Land-Use Results

Table 3 and Table 4 summarize PV land requirements by tracking type for total and direct area,

respectively. Total-area data were available for all systems evaluated; however, direct-area data

were only available for a subset of these systems. Fixed-tilt and 1-axis PV systems account for a

majority (96%) of projects evaluated.

On average, fixed-tilt systems use 13% less land than 1-axis tracking on a capacity basis but use

15% more land on a generation basis. This difference is due to increased generation resulting

from tracking technologies. One-axis tracking systems can increase PV generation 12%–25%

relative to fixed-tilt systems, and 2-axis tracking systems can increase PV generation by

30%–45% (Drury et al. 2012). We evaluated ten 2-axis PV plants: four flat panel (non-

concentrating) projects and six concentrating PV (CPV) projects. Two-axis, flat panel systems

appear to use more land than fixed and 1-axis plants on a capacity and generation basis, but

general conclusions should not be drawn until the sample size is increased.

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Table 3. Total Land-Use Requirements by PV Tracking Type

Tracking Type

Total Area

Projects

Capacity

(MWac)

Capacity-weighted

average area

requirements

(acres/MWac)

Generation-

weighted average

area requirements

(acres/GWh/yr)

Small PV (less than 20 MW)

Fixed

52 231 7.6 4.4

1-axis 55 306 8.7 3.8

2-axis flat panel

4 5 13 5.5

2-axis CPV

4 7 9.1 3.1

Large PV (greater than 20 MW)

Fixed

14 1,756 7.5 3.7

1-axis 16 1,637 8.3 3.3

2-axis CPV

2 158 8.1 2.8

Table 4. Direct Land-Use Requirements by PV Tracking Type

Tracking Type

Direct Area

Projects

Capacity

(MWac)

Capacity-weighted

average area

requirements

(acres/MWac)

Generation-

weighted average

area requirements

(acres/GWh/yr)

Small PV (less than 20 MW)

Fixed 43 194 5.5 3.2

1-axis

41 168 6.3 2.9

2-axis flat panel

4 5 9.4 4.1

2-axis CPV 4 7 6.9 2.3

Large PV (greater than 20 MW)

Fixed

7 744 5.8 2.8

1-axis 7 630 9.0 3.5

2-axis CPV

1 31 6.1 2.0

Figure 5 shows the capacity-based total and direct land-use requirement distributions for PV

plants smaller than 20 MW. Direct land-use requirements for fixed-tilt PV installations range

from 2.2 to 8.0 acres/MWac, with a capacity-weighted average of 5.5 acres/MWac. Direct land-

use requirements for 1-axis tracking PV installations range from 4.2 to 10.6 acres/MWac, with a

capacity-weighted average of 6.3 acres/MWac. Figure 6 shows the capacity-based total and

Forty-two proposed projects representing 5,842 MWac could not be categorized by tracking type owing to

insufficient information. These projects are not represented in this table.

Forty-two proposed projects representing 5,842 MWac could not be categorized by tracking type due to

insufficient information. These projects are not represented in this table.

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direct land-use requirement distributions for PV plants larger than 20 MW. Relatively large

deviations between the median and weighted average values are due to a few very large PV

installations (over 100 MW) contributing heavily to weighted average results. We found that PV

system size appears to have no significant impact on land-use requirements per unit of capacity

(see Appendix D).

We also evaluated the impacts of efficiency on land-use intensity. We would expect land-use

intensity to decrease with increasing module efficiencies, but we observed no significant trends

between land-use intensity and module efficiency for small and large PV systems (see

Appendix D). Variations in land-use intensity that remain after isolating for module efficiency

and tracking type are not clearly understood. One source of variability could be the large range

of packing factors described in the next section.

Figure 5. Distribution of small PV land-use requirements—whiskers indicate maximum and

minimum values, box indicates 75

(top of box) and 25

(bottom of box) percentile estimates

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Figure 6. Distribution of large PV land-use requirements—whiskers indicate maximum and

minimum values, box indicates 75

(top of box) and 25

(bottom of box) percentile estimates

4.2.1 Evaluation of PV Packing Factors

We evaluated array spacing for various PV tracking technologies. The area between arrays is

quantified using the packing factor metric, which is the ratio of array area to actual land area for

a system

(DOE 2012b). Figure 7 shows the average packing factor for each tracking

technology evaluated. An evaluation of system packing factors shows that there is large

variability in array spacing. Packing factors range from 13% (Prescott Airport CPV, Arizona) to

92% (Canton Landfill Solar Project, Massachusetts). Fixed-tilt systems have a capacity-weighted

average packing factor of 47%, followed by 1-axis systems with 34% and 2-axis systems with

25%. Packing factor estimates from the research literature range from 20% to 67% (Horner and

Clark 2013). The large variability in packing factor may contribute to the variability in land-use

intensity observed, given an expectation that packing factor directly impacts land-use intensity.

We did not attempt to isolate the impacts of packing factor, efficiency, capacity, and other

factors on land-use intensity due to limited data availability. The availability of more data

elements and larger sample sizes will enable a robust evaluation of these factors on

land-use intensity.

We display the packing factor ratio as a percentage. A 100% packing factor would represent complete coverage of

solar panels with no spacing between arrays.

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Figure 7. Capacity-weighted average packing factor for PV projects evaluated—whiskers indicate

maximum and minimum values, box indicates 75

(top of box) and 25

(bottom of box)

percentile estimates

4.2.2 Impact of Location and Tracking Configuration on PV Land Use

Given the relatively small amount of data, it is difficult to isolate the impact of any single factor

on land-use requirements. This section isolates the theoretical impact of tracking arrays by

simulating the performance of PV in multiple locations holding all other factors constant.

Table 5 summarizes the relative impacts of tracking on land-use intensity, simulated for a variety

of locations throughout the United States. Although tracking systems generate more energy than

fixed-tilt systems, they also require more land per unit of capacity, as shown in Section 4.2. We

assume the capacity-weighted average land-use requirements (as reported in Table 4) for PV

systems smaller than 20 MW when evaluating the impact of tracking arrays: 5.5 acres/MWac for

fixed-tilt systems, 6.3 acres/MWac for 1-axis tracking systems, and 9.4 acres/MWac for 2-axis

tracking systems. These results indicate that the expected increase in energy yield from 1-axis

tracking systems (12%–22%) is partially countered by increases in land-use requirements per

unit of capacity. While the land use per unit of generation generally decreases for 1-axis tracking

systems compared with fixed-tilt systems, this metric generally increases for 2-axis tracking

systems compared with fixed-tilt systems. This is because the spacing required for 2-axis

tracking increases more than the relative increase in energy yield. The land-use advantage of

1-axis tracking is more pronounced in regions with higher direct normal irradiation (DNI) levels.

Similarly, the negative land-use impacts of 2-axis tracking are less pronounced in regions with

higher DNI levels. Denholm and Margolis (2008) estimated that land use per unit of generation

would increase moving from fixed systems to 1-axis tracking systems and moving from fixed

systems to 2-axis tracking systems.

47%

34%

36%

51%

22%

25%

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Table 5. Impacts of 1-Axis Tracking on Land-Use Intensity Compared With Fixed-Axis Mounting

Region

Direct

normal

radiation

(kWh/m2/yr)

Estimated energy

production (kWh/kW)

1-axis

tracking

increase in

energy

yield

relative to

Fixed

2-axis

tracking

increase in

energy

yield

relative to

Fixed

Land-use intensity

(acres/GWh/yr)

1-axis

tracking

change in

land-use

intensity

relative to

fixed

2-axis

tracking

change in

land-use

intensity

relative to

fixed

Fixed

axis

2-axis Fixed

axis

2-axis

San Francisco,

1,883 1,551 1,828 1,951 17.9% 25.8% 4.94 4.72 5.44 -4.40% 9.30%

San Diego, CA

1,965

1,607

1,864

1,974

16.0%

22.8%

4.77

4.65

5.39

-2.70%

11.40%

Alamosa, CO

2,530

1,813

2,200

2,606

21.3%

43.7%

4.23

3.93

4.08

-7.50%

-3.60%

Phoenix, AZ

2,519

1,733

2,113

2,419

21.9%

39.6%

4.42

4.1

4.4

-8.00%

-0.60%

Jacksonville, FL

1,507

1,380

1,634

1,504

18.4%

9.0%

5.56

5.29

7.07

-4.90%

21.40%

Newark, NJ

1,263

1,268

1,422

1,321

12.1%

4.2%

6.03

6.08

8.06

0.70%

24.90%

Seattle, WA

1,112

1,100

1,249

1,136

13.5%

3.3%

6.97

6.92

9.37

-0.60%

25.50%

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4.3 CSP Land-Use Results

Table 6 and Table 7 summarize total and direct land-use requirements by CSP technology,

respectively. Note there are significantly fewer CSP projects in the United States than PV

projects, and due to reliance on solar DNI resource, most CSP projects are in the Southwest

(Figure 2). We collected data for 25 CSP projects, with only one linear Fresnel project and one

dish Stirling project. It is more important to evaluate CSP in terms of land use per unit of

generation because of the effect of storage and solar multiple, which can increase the amount of

energy produced per unit of capacity (Turchi et al. 2010). Direct land-use requirements for CSP

trough technology range from 2.0 to 4.5 acres/GWh/yr, with a generation-weighted average of

2.5 acres/GWh/yr. Direct land-use requirements for CSP tower technology range from 2.1 to

5.3 acres/GWh/yr, with a generation-weighted average of 2.8 acres/GWh/yr. We found that

system size appears to have little impact on generation-based CSP land-use requirements (see

Appendix E).

Table 6. Total Land-Use Requirements by CSP Technology

Technology

Total Area

Projects

Capacity

(MWac)

Capacity-weighted average

area requirements

(acres/MWac)

Generation-weighted average

area requirements

(acres/GWh/yr)

All 25 3,747 10 3.5

Trough

8 1,380 9.5 3.9

Tower

14 2,358 10 3.2

Dish Stirling 1 2 10 5.3

Linear Fresnel

4.7

4.0

Table 7. D

irect Land-Use Requirements by CSP Technology

Technology

Direct Area

Projects

Capacity

(MWac)

Capacity-weighted average

area requirements

(acres/MWac)

Generation-weighted average

area requirements

(acres/GWh/yr)

All

18 2,218 7.7 2.7

Trough

7 851 6.2 2.5

Tower 9 1,358 8.9 2.8

Dish Stirling 1 2 2.8 1.5

Linear Fresnel

2.0

1.7

Data for CSP with multi-hour energy storage were also collected. Eight facilities included

thermal storage technology, ranging from 3 to 15 hours of storage. One of the eight CSP

facilities with storage is a parabolic trough system, while the remaining seven are tower systems.

Little correlation is observed between storage and land-use intensity, both on a capacity and

generation basis (see Appendix E). We would expect to see a trend of decreasing generation-

based land use with increasing storage and increasing capacity-based land use with increasing

storage based on modeled results as shown in Figure 8 (Turchi et al. 2010). Given the relatively

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small amount of data, it is difficult to isolate the impact of any single factor on land-use

requirements. Higher sample sizes and additional data elements will enable a more robust

evaluation of CSP land use.

Figure 8. Modeled data showing relationship between CSP thermal storage and land-use intensity

Source: Turchi et al. 2010

0 5 10 15

Estimated Direct Land Use

(acre/GWh-yr or acre/MW-yr)

Thermal Storage (hours)

Area per Capacity (acre/MW/yr)

Area per Gen. (acre/GWh/yr)

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5 Conclusions

Table 8 and Table 9 summarize the U.S. utility-scale PV and CSP land-use requirements

evaluated in this report. Average total land-use requirements are 3.6 acres/GWh/yr for PV and

3.5 acres/GWh/yr for CSP. Average direct-area requirements are 3.1 acres/GWh/yr for PV and

2.7 acres/GWh/yr for CSP. On a capacity basis, the total-area capacity-weighted average for all

solar power plants is 8.9 acres/MWac, with 22% of plants within 8 and 10 acres/MWac. For

direct land-use requirements, the capacity-weighted average is 7.3 acre/MWac, with 40% of

power plants within 6 and 8 acres/MWac. Solar land-use estimates from the literature generally

fall within these ranges. Within the broad technology categories of PV and CSP, land-use metrics

are also impacted by specific technology choices, such as cell efficiency, tracking method, and

inclusion of thermal energy storage, and are a function of the solar resource available at

each site.

Although our results stem from an empirically based effort to estimate solar land use, several

caveats are warranted. Some solar-technology categories have relatively small samples sizes,

which must be considered when interpreting the robustness of reported results. Over 26 GWac of

PV and CSP are under development as of February 2013 (SEIA 2013), and the results reported in

this study must be understood in light of a rapidly growing installed base. Additionally, various

data sources were used when gathering information about solar projects. Although we tried to

obtain the highest-quality sources (project applications and regulatory documents, referred to as

“official documents” in this report), we collected official documents for only 20% of all projects

evaluated. Other data sources are expected to have higher levels of uncertainty (although how

much higher is unclear), which could contribute to the observed variability in results. With the

exception of a few CSP projects, we collected reported capacity of power plants but not annual

generation. The generation-based land-use results are expected to have higher levels of

uncertainty because annual generation is simulated. Although generation-based results provide a

more consistent approach when comparing land-use requirements across technologies, capacity-

based results are useful for estimating land area and costs for new projects because power plants

are often rated in terms of capacity. Finally, owing to the rapid evolution of solar technologies as

well as land-use practices and regulations, the results reported here reflect past performance and

not necessarily future trends.

We analyze elements that affect the area of solar impact, but we recognize that the duration of

use and impact on land quality are also important when considering land use impacts. Future

analyses could include evaluating the quality of land impacts, assessing both the initial state of

the land impacted and the final states across a variety of factors, including soil quality and

overall ecosystem quality. Finally, larger sample sizes and additional data elements would

improve the robustness of the conclusions and enable a more thorough investigation of the

impacts of additional factors, such as tilt angle, azimuth, PV module technology, CSP solar

multiple, and storage technologies.

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Table 8. Summary of Direct Land-Use Requirements for PV and CSP Projects in the United States

Technology

Direct Area

Number of

projects

analyzed

Capacity for

analyzed

projects

(MWac)

Capacity-weighted

average land use

(acres/MWac)

Capacity-weighted

average land use

(MWac/km

)

Generation-

weighted average

land use

(acres/GWh/yr)

Generation-

weighted average

land use

(GWh/yr/km

)

Small PV

92 374 5.9 42 3.1 81

(>1 MW, <20

MW)

Fixed 43 194 5.5 45 3.2 76

1-axis 41 168 6.3 39 2.9 86

2-axis flat panel 4 5 9.4 26 4.1 60

2-axis CPV 4 7 6.9 36 2.3 105

Large PV

15 1,405 7.2 34 3.1 80

(>20 MW)

Fixed 7 744 5.8 43 2.8 88

1-axis 7 630 9.0 28 3.5 71

2-axis CPV 1 31 6.1 41 2.0 126

CSP

18 2,218 7.7 32 2.7 92

Parabolic trough 7 851 6.2 40 2.5 97

Tower 9 1,358 8.9 28 2.8 87

Dish Stirling 1 2 2.8 88 1.5 164

Linear Fresnel 1 8 2.0 124 1.7 145

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Table 9. Summary of Total Land-Use Requirements for PV and CSP Projects in the United States

Technology

Total Area

Number of

projects

analyzed

Capacity for

analyzed

projects

(MWac)

Capacity-weighted

average land use

(acres/MWac)

Capacity-weighted

average land use

(MWac/km

)

Generation-

weighted average

land use

(acres/GWh/yr)

Generation-

weighted average

land use

(GWh/yr/km

)

Small PV

115 550 8.3 30 4.1 61

(>1 MW, <20

MW)

Fixed 52 231 7.6 32 4.4 56

1-axis 55 306 8.7 29 3.8 66

2-axis flat panel 4 5 13 19 5.5 45

2-axis CPV 4 7 9.1 27 3.1 80

Large PV

32 3,551 7.9 31 3.4 72

(>20 MW)

Fixed 14 1,756 7.5 33 3.7 67

1-axis 16 1,637 8.3 30 3.3 76

2-axis CPV 2 158 8.1 31 2.8 89

CSP

25 3,747 10 25 3.5 71

Parabolic trough 8 1,380 9.5 26 3.9 63

Tower 14 2,358 10 24 3.2 77

Dish Stirling 1 2 10 25 5.3 46

Linear Fresnel 1 8 4.7 53 4.0 62

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References

Canals, L.M.; Bauer, C.; Depestele, J.; Dubreuil, A.; Freiermuth Knuchel, R.; Gaillard, G.;

Michelsen, O.; Müller-Wenk. R.; Rydgren, B. (2007). “Key Elements in a Framework for Land

Use Impact Assessment in LCA.” The International Journal of Life Cycle Assessment (12:1); pp.

5–15.

Denholm, P.; Hand, M.; Jackson, M.; Ong, S. (2009). “Land-Use Requirements of Modern Wind

Power Plants in the United States.” NREL/TP-6A2-45834. Golden, CO: National Renewable

Energy Laboratory.

Denholm, P.; Margolis, R. (2008). “Land-Use Requirements and the Per-Capita Solar Footprint

for Photovoltaic Generation in the United States.” Energy Policy (36:9); pp. 3531–3543.

DOE (U.S. Department of Energy). (2012a). SunShot Vision Study. DOE/GO-102012-3037.

Accessed July 2012: http://www1.eere.energy.gov/solar/pdfs/47927.pdf.

DOE. (2012b). Solar Energy Glossary. Accessed August 2012:

http://www1.eere.energy.gov/solar/sunshot/glossary.html.

Drury, E.; Lopez, A.; Denholm, P.; Margolis, R. (2012). “Relative Performance of Tracking

versus Fixed Tilt Photovoltaic Systems in the United States.” Golden, CO: National Renewable

Energy Laboratory.

Fthenakis, V.; Kim, H.C. (2009). “Land Use and Electricity Generation: A Life-Cycle Analysis.”

Renewable and Sustainable Energy Reviews (13); pp. 1465–1474.

Gilman, P.; Dobos, A. (2012). System Advisor Model, SAM 2011.12.2: General Description.

NREL/TP-6A20-53437. Golden, CO: National Renewable Energy Laboratory.

Hand, M.M.; Baldwin, S.; DeMeo, E.; Reilly, J.M.; Mai, T.; Arent, D.; Porro, G.; Meshek, M.;

Sandor, D. (2012). Renewable Electricity Futures Study. eds. 4 vols. NREL/TP-6A20-52409.

Golden, CO: National Renewable Energy Laboratory.

Horner, R.; Clark, C. (2013). “Characterizing variability and reducing uncertainty in estimates of

solar land use energy intensity.” Renewable and Sustainable Energy Reviews (23); pp. 129–137.

Koellner, T.; Scholz, R. (2008). “Assessment of Land Use Impacts on the Natural Environment.”

The International Journal of Life Cycle Assessment (13:1); pp. 32–48.

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Documentation. https://www.nrel.gov/analysis/sam/help/html-php/.

Perez, R.; Ineichen, P.; Moore, K.; Kmiecikm, M.; Chain, C.; George, R.; Vignola, F. (2002). “A

New Operational Satellite-to-Irradiance Model.” Solar Energy (73:5); pp. 307–317.

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

SEIA (Solar Energy Industries Association). (2012). Utility-Scale Solar Projects in the United

States: Operating, Under Construction, or Under Development (Updated August 15, 2012).

Washington, DC: SEIA.

SEIA. (2013). Utility-Scale Solar Projects in the United States: Operating, Under Construction,

or Under Development (Updated February 11, 2013). Washington, DC: SEIA.

Turchi, C.; Mehos, M.; Ho, C.; Kolb, G. (2010). “Current and Future Costs for Parabolic Trough

and Power Tower Systems in the US Market.” NREL/CP-5500-49303. Golden, CO: National

Renewable Energy Laboratory.

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This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Appendix A. CSP Solar Multiple Ranges

For CSP projects, a range of solar multiple values were used to simulate annual generation output. Assumptions for CSP solar multiple

ranges are shown in Table A-1.

Table A-1. CSP Solar Multiple Ranges and Corresponding Estimated Annual Generation Values

Name State

Storage

(hours)

Solar

multiple low

Solar multiple

high

Estimated

generation low

(GWh/yr)

Estimated generation

high (GWh/yr)

Crossroad Solar AZ 10 2.2 2.8 683 822

Quartzsite AZ 10 2.2 2.8 489 578

Saguaro Power Plant AZ 0 1.1 1.4 2 2

Solana AZ 6 1.9 2.4 992 1,155

Abengoa Mojave CA 0 1.1 1.4 520 645

Coalinga CA 0 1.1 1.4 9 28

Ford Dry Lake (Genesis) CA 0 1.1 1.4 480 617

Hidden Hills 1 CA 0 1.1 1.4 545 655

Hidden Hills 2 CA 0 1.1 1.4 545 655

Ivanpah (all) CA 0 1.1 1.4 869 1,024

Kimberlina CA 0 1.1 1.4 9 11

Palmdale Hybrid Plant CA 0 1.1 1.4 107 138

Rice Solar CA 7 1.8 2.2 541 692

Rio Mesa 1 CA 0 1.1 1.4 529 659

Rio Mesa 2 CA 0 1.1 1.4 529 659

Rio Mesa 3 CA 0 1.1 1.4 529 659

SEGS (all) CA 0 1.1 1.4 725 888

Solar Two CA 3 1.3 1.7 20 30

Victorville 2 hybrid CA 0 1.1 1.4 101 125

Saguache Solar CO 15 2.6 3.2 1,073 1,216

Martin Next Generation FL 0 1.1 1.4 71 105

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Name State

Storage

(hours)

Solar

multiple low

Solar multiple

high

Estimated

generation low

(GWh/yr)

Estimated generation

high (GWh/yr)

Nevada Solar One NV 0.5 1.2 1.5 114 144

Tonopah (Crescent Dunes) NV 10 2.2 2.8 525 590

Crossroad Solar AZ 10 2.2 2.8 683 822

Quartzsite AZ 10 2.2 2.8 489 578

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Appendix B. PV Projects Evaluated

Table B-1. PV Land-Use Data

Asterisks represent data calculated from power plants that reported only AC capacity, as described in Section 3.

Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Prescott Airport (CPV) AZ 0.2 1.9 1.0

2 axis

CPV

29% Complete Third party

Pima County Wastewater AZ 1.1 8.4 6.4 1 axis 14% Complete Developer

Johnson Utilities AZ 1.1 10.6 7.5 1 axis

Complete Third party

Prescott Airport (1-Axis Phase 1) AZ 2.8 22.6 22.3 1 axis

Complete Third party

Springerville AZ 6.5 85.2 45.3 fixed 11% Complete Developer

Kingman Plant AZ 10.0 70.5

1 axis 14% Construction Third party

Prescott Airport (1-Axis Phase 2) AZ 11.8 94.0

1 axis

Construction Third party

Luke Air Force Base AZ 15.0 107.1

1 axis 19% Complete Third party

Hyder Plant AZ 17.0 152.7

1 axis 14% Construction Third party

Paloma Plant AZ 20.3* 234.9

fixed 11% Complete Third party

Cotton Center Plant AZ 21.0 169.2

1 axis

Complete Third party

Copper Crossing Solar Ranch AZ 23.5* 169.1 139.1 1 axis 19% Complete Developer

Chino Plant AZ 23.5* 187.9 164.4 1 axis 14% Construction Official documents

Tucson Solar AZ 25.0 233.7

1 axis

Construction Developer

Avra Valley AZ 30.5* 352.4

1 axis 11% Construction Developer

Mesquite Solar 1 AZ 170.0 1,020.0

Unknown 15% Construction Official documents

Agua Caliente AZ 340.6* 2,818.9

fixed 11% Construction Developer

Sonoran Solar Energy Project AZ 352.4* 2,364.3

1 axis

Proposed Official documents

Mesquite Solar Total AZ 700.0 4,698.1

Unknown

Proposed Third party

Western Riverside County Regional

Wastewater Authority

CA 1.0 11.2 10.6 1 axis 20% Complete Developer

The North Face PV Plant CA 1.0 5.9 5.9 1 axis

Complete Third party

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Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Inlands Empire Utility Solar Farm CA 1.0 12.6 8.9 1 axis 20% Complete Developer

West County Waste Water PV Plant CA 1.0 11.7 6.9

2 axis

flat

14% Complete Developer

Nichols Farms PV Plant CA 1.0 8.0 8.0

2 axis

CPV

25% Complete Third party

Budweiser PV Plant CA 1.1 9.4 7.2 1 axis 15% Complete Official documents

Wal-Mart Apple Valley PV Plant CA 1.1 10.7 7.8 1 axis 15% Complete Official documents

Rancho California PV Plant CA 1.1 13.6 8.9 1 axis 19% Complete Developer

Hayward Wastewater PV Plant CA 1.2 13.2 8.6 1 axis 14% Complete Third party

Chuckawalla State Prison PV Plant CA 1.2 8.4 4.8 fixed 14% Complete Official documents

Ironwood State Prison PV Plant CA 1.2 14.4 9.0 1 axis 13% Complete Official documents

Sacramento Soleil CA 1.3 10.0 8.1 fixed 11% Complete Developer

USMC 29 Palms CA 1.3 10.6 7.0 fixed

Complete Developer

Box Canyon Camp Pendleton CA 1.4 9.6 5.6 fixed 14% Complete Third party

Vaca-Dixon Solar Station CA 2.6 17.8 11.5 fixed 14% Complete Developer

Newberry Springs PV Plant CA 3.0 25.8

1 axis

Proposed Third party

Sunset Reservoir CA 5.0 15.3 15.3 fixed

Complete Third party

Aero Jet Solar Project CA 6.0 47.0 32.3 1 axis

Complete Developer

CALRENEW-1 CA 6.2 60.4 46.5 fixed 9% Complete Third party

Porterville Solar Plant CA 6.8 37.6 31.4 fixed 14% Complete Third party

Palm Springs project 1 CA 8.0 42.9

1 axis 14% Construction Third party

Dillard Solar Farm CA 12.0 94.3 70.4 1 axis 15% Complete Developer

China Lake PV Plant CA 13.8 138.6

1 axis 20% Construction Third party

Bruceville Solar Farm CA 16.4 131.1 92.9 1 axis 15% Complete Official documents

Kammerer Solar Farm CA 16.6 129.1 111.1 1 axis 15% Complete Official documents

Antelope Solar Farm CA 20.0 234.9

Unknown

Proposed Developer

Mojave Solar CA 20.0 204.4

Unknown

Proposed Developer

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Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Tuusso Energy Antelope Plant CA 20.0 211.4

Unknown

Proposed Third party

Grundman/Wilkinson Solar Farm CA 21.1* 163.5 117.5 Fixed 11% Complete Official documents

Adobe Solar CA 23.5* 187.9

Unknown

Proposed Developer

Orion Solar CA 23.5* 311.2

Unknown

Proposed Developer

Atwell Island Solar Project CA 23.5 188.0

Unknown

Construction Third party

FSE Blythe CA 25.2 223.2 161.3 Fixed 10% Complete Developer

Imperial Valley Solar Company CA 28.7 153.5

Unknown 15% Proposed Third party

McHenry Solar Farm CA 29.4* 180.9

1 axis 19% Construction Developer

Del Sur Solar Project CA 38.0 219.6

Unknown

Construction Third party

Lucerne Valley Solar CA 40.5 495.6 495.6 Fixed 10% Construction Official documents

Chocolate Mountains PV Plant CA 49.9 375.8

Unknown

Construction Developer

Calipatria Solar Farm 2 CA 50.0 352.4

Unknown

Proposed Third party

Salton Sea 1 CA 50.0 375.8

Unknown

Proposed Developer

Avenal SunCity SandDrag Avenal

Park

CA 57.7 641.3 442.5 Fixed 9% Complete Developer

Copper Mountain PV Plant CA 58.0 459.2 393.9 Fixed 10% Proposed Third party

Midway Solar Farm 1 CA 58.7* 352.4 325.3 Unknown

Proposed Developer

Regulus Solar CA 75.0 872.7

Unknown

Proposed Developer

Calipatria Solar Farm 1 CA 82.2* 352.4 288.9 Unknown

Proposed Developer

Salton Sea 2 CA 100.0 730.6

Unknown

Proposed Third party

Quinto Plant CA 110.0 1,191.0

1 axis 20% Proposed Official documents

Imperial Solar Energy Center South CA 130.0 1,111.1

1 axis 11% Proposed Developer

Imperial Solar Energy Center West CA 150.0 1,241.5

2 axis

CPV

25% Proposed Developer

Midway Solar Farm 2 CA 182.1* 1,097.5

Unknown

Proposed Third party

Calexico Solar Farm 1 CA 234.9* 1,468.2

Unknown

Proposed Developer

Calexico Solar Farm 2 CA 234.9* 1,468.2

Unknown

Proposed Developer

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Mount Signal PV Plant CA 234.9* 1,644.3

Unknown

Proposed Developer

AV Solar Ranch One CA 284.0 2,593.0 2,414.0 1 axis 11% Proposed Developer

California Valley Solar Ranch CA 293.6* 2,037.8

1 axis

Construction Developer

Centinela Solar CA 323.0* 2,427.7

Unknown

Proposed Developer

Superstition Solar 1 CA 500.0 6,562.1

Unknown

Proposed Official documents

Edwards Air Force Base CA 500.0 3,736.4

Unknown

Proposed Developer

Desert Sunlight CA 646.0* 4,985.9 3,529.4 Fixed 10% Proposed Official documents

Topaz Solar Farm CA 646.0* 4,110.8

Fixed 11% Construction Developer

Alamosa Water Treatment Facility

PV Plant

CO 0.6 6.5 5.6 1 axis 16% Complete Official documents

Rifle Pump Station CO 0.6 5.3 4.3 1 axis 13% Complete Official documents

SunEdison Alamosa PV Plant (Fixed-

Tilt)

CO 0.6 7.0 3.6 Fixed 14% Complete Official documents

Arvada Ralston Water Treatment

Plant

CO 0.6 7.1 4.5 1 axis 16% Complete Official documents

NREL Mesa Top PV Project CO 0.7 5.9 3.3 1 axis 16% Complete Official documents

SunEdison Alamosa PV Plant (2

Axis)

CO 1.0 14.0 7.3

2 axis

flat

14% Complete Official documents

NREL National Wind Technology

Center

CO 1.1 11.5 7.1 1 axis 13% Complete Official documents

Buckley Air Force Base CO 1.1 4.5 3.8 Fixed 14% Complete Official documents

Denver Federal Center Solar Park

Phase 1

CO 1.2 7.6 6.0 Fixed 13% Complete Official documents

Colorado State University Pueblo

Plant

CO 1.2 5.1 4.1 Fixed

Complete Third party

Denver International Airport Phase 2

(Fuel Farm)

CO 1.6 10.6 8.3 Fixed

Complete Developer

Rifle Waste Water Reclamation

Facility

CO 1.7 14.0 9.9 1 axis 14% Complete Official documents

Colorado State University Ft. Collins

Phase 1

CO 2.0 17.6 15.0 1 axis

Complete Third party

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Denver International Airport 1 Pena

Blvd

CO 2.0 11.7 11.7 1 axis

Complete Developer

Ft. Carson PV Plant CO 2.0 14.7 12.6 Fixed 11% Complete Developer

Colorado State University Ft. Collins

Phase 2

CO 3.3 15.4 14.0 Fixed

Complete Third party

Denver International Airport Phase 3 CO 4.4 35.2 26.9 Fixed

Complete Developer

Air Force Academy CO Springs CO 6.0 50.5 31.4 1 axis

Complete Third party

SunEdison Alamosa PV Plant (1

Axis)

CO 6.6 74.1 38.5 1 axis 14% Complete Official documents

Greater Sand Hill Solar Plant CO 20.0 206.6 132.6 1 axis 20% Complete Third party

San Luis Valley Solar Ranch CO 35.2 258.1

1 axis 20% Complete Developer

Cogentrix Alamosa Solar Generating

Project

CO 37.0 271.0 224.0

2 axis

CPV

31% Construction Developer

Kent County Waste Water DE 1.2 7.0 6.6 Fixed

Construction Third party

Dover Sun Park DE 11.7* 121.0 59.1 1 axis 20% Complete Third party

NASA PV FL 1.0 6.1 2.8 Fixed

Complete Developer

Stanton Energy Center FL 5.9 41.1 29.1 1 axis

Complete Developer

Rinehart Solar Farm FL 8.0 28.2

Unknown 16% Construction Third party

Space Coast FL 11.7* 52.9 35.2 Fixed

Complete Developer

Jacksonville Solar FL 15.0 114.4 83.9 Fixed 11% Construction Third party

DeSoto Plant FL 28.0 263.2 201.6 1 axis 19% Complete Developer

Sorrento Eagle Dunes phase 1 FL 40.0 164.4

Fixed 14% Construction Developer

Sorrento Eagle Dunes phase 2 FL 60.0 422.8

Fixed 16% Proposed Third party

Babcock Ranch Solar FL 75.0 469.8

Unknown

Proposed Developer

Liberty County Solar Farm FL 100.0 1174.5

Unknown

Proposed Third party

Hardee County Solar Farm FL 200.0 2,349.1

Unknown

Proposed Third party

Gadsden Solar Farm FL 400.0 4,698.1

Unknown

Proposed Third party

Blairsville Plant GA 1.0 5.7

Fixed

Complete Third party

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Kopolei Sustainable Energy Park HI 1.2 4.7 3.2 Fixed 14% Complete Third party

Kalaeloa Oahu HI 5.0 47.0

1 axis 19% Construction Official documents

Exelon City Solar IL 10.0 48.2 37.6 1 axis

Complete Developer

Grand Ridge Solar Plant IL 23.0 187.9

Unknown 12% Construction Third party

Indianapolis Airport Solar Farm IN 10.0 70.5

Fixed

Construction Third party

Bowling Greens Solar Farm KY 2.0 15.3 10.6 1 axis

Complete Third party

William Stanley Business Park MA 1.9 10.9 7.3 Fixed 14% Complete Official documents

Berkshire School MA 2.0 10.8 9.4 Fixed 15% Complete Third party

Northfield Mountain MA 2.0 12.9 9.3 Fixed

Complete Third party

Indian Orchard Solar MA 2.3 14.1

Unknown

Complete Third party

Springfield Plant MA 4.2 72.8 47.0 Unknown

Complete Third party

Mueller Road Holyoke Plant MA 4.5 22.3

Fixed 15% Complete Third party

Canton Landfill MA 5.7 17.2 12.8 Fixed 15% Complete Official documents

Mount St. Mary's University MD 17.4 158.6 105.7 Fixed 11% Construction Third party

Progress Energy NC 1.2 11.3 9.1 1 axis 14% Complete Official documents

Mayberry/Mt. Airy Solar Farm NC 1.2 7.0

Fixed 14% Complete Third party

Neuse River Waste Water NC 1.3 11.7

Fixed 14% Complete Third party

SAS Solar Farm 1 and 2 NC 2.2 20.0 14.1 1 axis 15% Complete Developer

Kings Mountain Solar Farm NC 5.0 32.9

Unknown

Complete Third party

Murfreesboro NC 6.4 36.7 30.6 1 axis 19% Complete Developer

Davidson County Solar NC 17.2 221.9 129.3 1 axis

Complete Developer

Trenton Solar Farm NJ 1.3 6.5 5.3 Fixed

Complete Third party

Silver Lake Solar Farm NJ 2.1 9.4 6.7 Fixed 14% Complete Third party

Mars Solar Garden NJ 2.2 14.4 11.9 Fixed 10% Complete Developer

NJMC landfill NJ 3.0 15.3

Fixed

Complete Third party

Linden Solar Farm NJ 3.2 11.7

Unknown

Complete Third party

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

Janssen Pharmaceutical NJ 4.1 29.4 21.9 1 axis

Complete Third party

Vineland NJ 4.1 32.9 17.6 Fixed

Complete Developer

Yardville Solar Farm NJ 4.4 18.4 16.6 Fixed 14% Complete Third party

Homdel Solar Farm NJ 4.8 39.9 18.8 1 axis

Proposed Third party

Princeton University NJ 5.3 31.7

1 axis 19% Complete Third party

Lawrenceville School NJ 6.1 35.2

1 axis 15% Complete Third party

NJ Oak Solar Farm NJ 12.5 122.5 97.5 Fixed 14% Complete Third party

Upper Pittsgrove NJ 14.4 105.7

1 axis

Proposed Third party

Tinton Falls NJ 19.9 111.6

Unknown

Construction Third party

Pilesgrove Project NJ 20.0 148.9 85.3 Fixed 14% Complete Third party

Santa Fe Waste Water Plant NM 1.1 10.4 7.9 1 axis 14% Complete Developer

City of Madera Waste Water NM 1.2 11.2 10.6

2 axis

flat

14% Complete Third party

Questa NM 1.2* 20.0 12.6

2 axis

CPV

25% Complete Third party

Albuquerque Solar Center NM 2.0 21.7 12.8 Fixed 11% Complete Third party

Deming Solar Energy Center NM 5.0 58.7 40.0 Fixed 11% Complete Third party

Alamogordo Solar Center NM 5.0 58.7

Fixed 11% Complete Third party

Hatch Solar Center NM 6.5 50.1 38.9

2 axis

CPV

29% Complete Developer

SunEdison Jal NM 10.7 117.5 86.4 1 axis

Complete Third party

SunEdison Carlsbad NM 10.8 100.7 90.3 1 axis

Complete Third party

Elephant Butte NM 22.0 187.9

Fixed

Construction Third party

Roadrunner Solar Facility NM 23.5* 246.7 198.8 1 axis 11% Complete Developer

Cimarron NM 35.2* 293.6 260.7 Fixed 10% Complete Developer

Estancia Solar Farm NM 50.0 187.9

Unknown

Proposed Third party

Guadalupe Solar NM 300.0 2,936.3

Unknown

Proposed Third party

Las Vegas Solar Center NV 5.0 58.7

Unknown 11% Complete Third party

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Name State MW - DC

Total area

(acres)

Direct

area

(acres)

Tracking

Module

efficiency

Status as of

August 2012

Data source

El Dorado Solar NV 12.0 96.0 84.0 Fixed 11% Complete Developer

Nellis Air Force Base NV 18.0 186.7 148.0 1 axis

Complete Official documents

Searchlight Solar Project NV 20.0 242.3

1 axis

Complete Third party

Fish Springs NV 20.6 211.4

Fixed 10% Construction Official documents

Apex NV 24.9 187.1

Unknown

Proposed Third party

Silver State Solar North NV 65.1 775.0

Fixed 10% Construction Official documents

Boulder City NV 176.2* 1,303.7

1 axis 10% Construction Developer

Silver State Solar South NV 350.0 3,406.1 3484.8 1 axis 10% Proposed Official documents

Mojave Green Center NV 720.0 6,384.7

Unknown

Proposed Third party

Brookhaven Lab NY 37.0 231.3 225.5 Fixed 13% Construction Developer

Washington Township Solar Array OH 1.1 11.5 8.4 Fixed 9% Complete Developer

BNB Napoleon Solar LLC OH 9.8 70.5

1 axis 19% Construction Third party

Wyandot Solar OH 12.6 97.0 78.0 Fixed 11% Complete Developer

Turning Point Solar OH 58.6* 496.4

Unknown

Proposed Official document

Yamhill Solar OR 1.2 11.0

Fixed 10% Complete Developer

Bellevue Solar OR 1.7 14.0

Fixed 10% Complete Developer

Pocono Raceway PA 3.0 27.2 17.9 Fixed

Construction Third party

Exelon Conergy PA 3.0 19.4 12.9 Fixed

Complete Developer

Claysville Solar Project PA 20.0 117.5 99.5 Fixed

Proposed Developer

Shelby Solar Project SC 1.0 10.6 6.5 1 axis 19% Complete Third party

West Tennessee Solar Farm TN 5.0 29.4 26.9 Fixed

Construction Developer

Blue Wing Solar TX 16.1 124.2 95.7 Fixed

Construction Developer

Austin Energy Webberville TX 34.3 434.3

Unknown 15% Complete Third party

Pflugerville Solar TX 60.0 704.7

Unknown

Construction Third party

South Burlington Solar Farm VT 2.2 31.7 25.8

2 axis

flat

Complete Third party

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Appendix C. CSP Projects Evaluated

Table C-1. Concentrating Solar Power Land-Use Data

Note: Additional CSP plant information, such as storage and annual generation, can be found in Appendix A.

Name State MW - AC

Total area

(acres)

Direct

area

(acres)

Technology

Status as of

August 2012

Data source

Maricopa Solar Project AZ 1.5 15 4 Stirling Engine Complete Third party

Quartzsite

100

1,675

Tower

Proposed

Developer

Crossroad Solar AZ 150 2,560

Tower Proposed Developer

Solana

280

1,920

Parabolic trough

Construction

Third party

Sierra SunTower CA 5 50 22 Tower Complete Developer

Kimberlina

7.5

Linear Fresnel

Complete

Developer

Solar Two CA 10 132 110 Tower Decommissioned Third party

Coalinga

Tower

Proposed

Developer

Victorville 2 hybrid CA 50 265 230 Parabolic trough Proposed Official document

Palmdale Hybrid Gas/solar

Plant

CA 57 377 250 Parabolic trough Proposed Official document

Rice Solar CA 150 2,560 1,410 Tower Construction Official document

Abengoa Mojave

250

1,765

Parabolic trough

Construction

Third party

Ford Dry Lake (Genesis) CA 250 4,640 1,800 Parabolic trough Construction Official document

Hidden Hills 1

250

1,640

1,560

Tower

Proposed

Official document

Hidden Hills 2 CA 250 1,640 1,560 Tower Proposed Official document

Rio Mesa 1

250

1,917

Tower

Proposed

Official document

Rio Mesa 2 CA 250 1,917

Tower Proposed Official document

Rio Mesa 3

250

1,917

Tower

Proposed

Official document

SEGS (all) CA 354 2,057 2,057 Parabolic trough Complete Third party

Ivanpah All

370

3,515

3,236

Tower

Construction

Official document

Saguache Solar CO 200 3,000 2,669 Tower Construction Official document

Martin Next Generation

500

400

Parabolic trough

Complete

Developer

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Name State MW - AC

Total area

(acres)

Direct

area

(acres)

Technology

Status as of

August 2012

Data source

Nevada Solar One NV 64 400 290 Parabolic trough Complete Third party

Tonopah (Crescent Dunes)

110

1,600

1,527

Tower

Construction

Developer

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Appendix D. Impact of PV System Size and Module

Efficiency on Land-Use Requirements

System size appears to have little impact on capacity-based land-use requirements. Figure D-1

and Figure D-2 show the total-area requirements for small and large PV systems, with respect to

project capacity. No significant trends are observed for land use and system size for small or

large PV systems.

Land use was also evaluated with respect to module efficiency. Figure D-3 shows capacity-based

direct land-use requirements for all PV systems with respect to module efficiency, and Figure D-

4 shows the generation-based direct land-use requirements. We expect that land use will decrease

with increasing module efficiencies, but no significant trends are observed for land use and

module efficiency for small or large PV systems. A linear regression analysis yields a poor

correlation coefficient for both the capacity-based area data (0.04) and the generation-based data

(0.08). Isolating for fixed-tilt systems reveals that projects with higher efficiency use less land on

a capacity basis (with a correlation coefficient of 0.50). No trends are observed within the pool of

1-axis tracking systems. Variations in land use that remain after isolating for module efficiency

and tracking type are not clearly understood.

Figure D-1. Total-area requirements for small PV installations as a function of PV plant size

0 2 4 6 8 10 12 14 16 18 20 22 24

Total Land Use (Acres/MW)

Capacity (MW-DC)

Small PV

Fixed

1 Axis

2 Axis

CPV

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Figure D-2. Total-area requirements for large PV installations as a function of PV plant size

Figure D-3. Capacity-based direct-area land-use requirements for all PV systems as a function of

module efficiency

0 50 100 150 200 250 300 350 400

Total Land Use (Acres/MW)

Capacity (MW-DC)

Large PV

Fixed

1 Axis

CPV

8% 13% 18% 23% 28%

Direct Land Use (Acres/MW)

Module Efficiency

Fixed

1 Axis

2 Axis

CPV

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Figure D-4. Generation-based direct-area land-use requirements for all PV systems as a function

of module efficiency

8% 13% 18% 23% 28%

Direct Land Use (Acres/GWh/yr)

Module Efficiency

Fixed

1 Axis

2 Axis

CPV

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Appendix E. Impact of CSP System Size and Storage

on Land-Use Requirements

We evaluated the impact of project capacity on land-use requirements and found that system size

appears to have little impact on generation-based CSP land-use requirements. Figure E-1 and

Figure E-2 show the total-area and direct-area requirements for all CSP systems evaluated, with

respect to system size. No significant trends are observed for land-use and capacity for

CSP systems.

Figure E-1. Total-area requirements for CSP installations as a function of plant size

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Figure E-2. Direct-area requirements for CSP installations as a function of plant size

We evaluate the impact of multi-hour energy storage on CSP land-use requirements. Eight

facilities included thermal storage technology, ranging from 3 to 15 hours of storage. One of the

eight CSP facilities with storage is a parabolic trough system, while the remaining seven are

tower systems. Figure E-3 shows the generation-based total-area requirements for all storage-

equipped CSP systems evaluated, with respect to storage capacity in hours. Figure E-4 shows the

capacity-based total-area requirements.

Figure E-3. Total generation-based area requirements for CSP installations as a function of

storage hours

This report is available at no cost from the

National Renewable Energy Laboratory (NREL)

at www.nrel.gov/publications

Figure E-4. Total capacity-based area requirements for CSP installations as a function of

storage hours