Utility-Scale Solar 2012

An Empirical Analysis of Project Cost, Performance, 

and Pricing Trends in the United States

Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory

Authors: Mark Bolinger and Samantha Weaver

Executive Summary ...................................................................................................... i

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

References .................................................................................................................... 30

2. Installed Prices .......................................................................................................... 3

3. Operations and Maintenance Costs ........................................................................... 8

Projected Operating Costs Are Similar for Different PV Configurations, Higher for CSP ................................... 8

Limited Sample of Empirical Operating Costs Seems to Conform to Projections .............................................. 9

4. Capacity Factors ....................................................................................................... 11

5. Power Purchase Agreement (“PPA”) Prices ............................................................. 19

6. Conclusions .............................................................................................................. 28

PV Capacity Factors Vary Considerably by Project, but Time Trend Proves Elusive ......................................... 11

Performance Degradation Not Observable Within Limited Timeframe of PV Project Sample ............................ 13

Oversizing of PV Array Relative to Inverter Capacity Boosts Capacity Factor .................................................... 14

PV Capacity Factors Influenced More by Location and Tracking, Less by Module Type ................................... 15

Parabolic Troughs Have a Long and Reliable Performance Record (Power Towers Less So) ............................ 16

Figure 1. Installed Price of Utility-Scale PV, 2007-2012 .................................................................................... 4

Figure 2. Installed Price of Utility-Scale PV by Configuration, 2007-2012 ......................................................... 5

Figure 3. Installed Price by Configuration and Project Size for 2012 PV Projects .............................................. 6

Figure 4. Capacity-Weighted Average Installed Price for PV by Geographic Region ........................................... 7

Figure 5. Projected O&M and Total Operating Costs for Three Utility-Scale Solar Projects ................................ 9

Figure 6. Empirical O&M Costs by Project Type .............................................................................................. 10

Figure 7. Cumulative Capacity Factor by Commercial Operation Date (PV Only) ............................................. 12

Figure 8. Generation-Weighted Capacity Factor by Project Vintage (West Region) ........................................... 13

Figure 9. Capacity Factor Over Time For Projects With At Least 3 Years of History .......................................... 14

Figure 10. DC/AC Nameplate Ratio vs. Capacity Factor and Commercial Operation Date ................................. 15

Figure 11. Cumulative PV Capacity Factor by Region and Project Configuration ............................................. 16

Figure 12. Capacity Factor of CSP Projects (Solar Portion Only) Over Time .................................................... 17

Figure 13. Levelized PPA Prices by Technology and PPA Execution Date ......................................................... 21

Figure 14. Levelized PPA Prices by Operational Status and PPA Execution Date .............................................. 24

Figure 15. Generation-Weighted Average PPA Prices Over Time by Contract Vintage ...................................... 24

Figure 16. Levelized Generation-Weighted Average PPA Prices by Contract Vintage ....................................... 25

CSP and CPV Installed Prices ............................................................................................................................. 5

Time-of-Delivery Pricing: Delivering Electricity When It Is Most Valuable ....................................................... 20

Macho Springs: Solar Co-Located With—And Competitive With—Wind ....................................................... 23

Copper Mountain Projects Illustrate Strong Time Trend in PPA Prices .............................................................. 26

Price Comparison With Feed-In Tariff (“FIT”) Programs That Support Utility-Scale Projects ............................ 27

Table of Contents

List of Figures

List of Text Boxes

Installed PV Prices Continued to Drop in 2012, but Less Than in Previous Years............................................. 3

Installed PV Prices Vary by Configuration, Project Size, and Region ................................................................ 5

LBNL-6408E
i

Executive Summary

With a critical mass of new large-scale or “utility-scale” solar projects (including PV, CPV, and 

CSP) now online and in some cases having operated for a number of years (generating data in 

addition to electricity), the utility-scale sector of the solar market is ripe for analysis. This 

report, which is envisioned to be the first in an ongoing annual series, meets this need through indepth, data-driven analysis of not just installed project costs or prices – i.e., the traditional realm 

of solar economics analyses – but also operating costs, capacity factors, and power purchase 

agreement (“PPA”) prices from a large sample of utility-scale solar projects in the U.S. (where 

utility-scale is defined as any ground-mounted project larger than 2 MWAC). As such, it provides 

a more-integrated and holistic view of the market than is commonly found.

Given the nascent state of the utility-scale solar market, data availability is still, in places, an 

issue in this inaugural edition. Moreover, given its current dominance in the market, utility-scale 

PV also dominates much of this report, though more balanced coverage is expected in future 

editions, given that a number of large CSP projects are currently under construction. Despite 

these challenges, the report nevertheless paints a coherent picture that will be refined, enriched, 

and solidified over time as more data become available. Until then, some of the more-notable 

findings from this year’s report include the following:

• Installed Prices: Installed PV project prices have fallen by nearly one-third since the 2007-

2009 period, from around $5.6/WAC to $3.9/WAC on average for projects completed in 2012 

(with some projects higher and others lower). Most of the decline has been concentrated 

among projects using c-Si modules, as the gap between c-Si and thin-film steadily eroded 

over this period. In response to falling c-Si module prices, there has been a marked increase 

in the proportion of projects using c-Si (rather than thin-film) modules.

• O&M Costs: Although O&M cost data are extremely limited at present, what little empirical 

data exist suggest that actual costs have largely been in line with pro forma operating cost 

projections gleaned from several bond offering prospectuses. For PV, O&M costs appear to 

be in the neighborhood of $20-$40/kWAC-year, or $10-$20/MWh. CSP O&M costs (for 

parabolic trough) are higher, presumably due to the plumbing and thermal components, and 

come in around $60/kWAC-year.

• Capacity Factors: Like insolation levels, PV capacity factors vary by region. They also 

vary depending on whether a project is installed at a fixed-tilt or uses a tracking device, with 

single-axis trackers able to achieve capacity factors in excess of 30% in some of the better 

locations (thus confirming the industry rule of thumb that single-axis tracking provides a 

20% boost in output). In lieu of trackers, and enabled by the sharp decline in module prices, 

some projects have instead opted to oversize the PV array relative to the capacity rating of 

the inverters as a way to boost capacity factor. On the CSP side of the market, parabolic 

trough systems that have been operating in the U.S. for more than 20 years are still (in 2012) 

achieving capacity factors in excess of 20% (solar portion only, no storage), which is 

comparable to newer trough projects. Meanwhile, a pilot project for power tower technology 

has underperformed relative to expectations, but several much larger power tower projects 

under construction will soon test that technology on a truly commercial scale in the United 

States (several commercial power tower projects have been operating in the Mediterranean 

region for several years).
ii

• PPA Prices: Driven primarily by lower installed PV project prices (which, in turn, have 

been driven primarily by declining module prices), as well as expectations for further cost 

reductions in future years, levelized PPA prices have fallen dramatically over time, by 

$25/MWh per year on average. Some of the most-recent PPAs (for PV projects) in the West 

have levelized PPA prices as low as $50-60/MWh (in 2012 dollars), which, in some cases, is 

competitive with wind power projects in that same region. Solar appears to be particularly 

competitive when considering its time-of-delivery pricing advantage over wind (roughly 

$25/MWh in California at current levels of penetration).
1

1. Introduction

Until the mid-2000s, large-scale solar projects primarily consisted of (and the corresponding 

term “utility-scale solar” most often referred to) concentrating solar power (“CSP”) projects 

using parabolic trough technology to produce steam and generate electricity; a number of such 

projects have been in operation in the United States since the 1980s. More recently, however, 

utility-scale solar increasingly refers to large, centralized photovoltaic (“PV”) projects that sell

wholesale electricity directly to utilities, rather than displacing on-site consumption (as has been 

the more-traditional application for PV). In the United States, utility-scale has been the fastestgrowing sector of the PV market, and now dominates: 2012 marked the first year that it captured 

the largest share of the overall PV market in terms of new MW installed, a distinction that is 

projected to continue through at least 2016 (GTM/SEIA 2013). Moreover, although a number of 

new CSP projects – featuring not just parabolic troughs but also newer technologies including

compact linear Fresnel reflectors and power towers – have been built in recent years or are 

currently under construction, PV has largely surpassed CSP as the preferred utility-scale solar 

technology, with nearly five times as much PV as CSP capacity either currently operating, under 

construction, or under development in utility-scale configurations (SEIA 2013).

This growing utility-scale sector of the solar market is ripe for analysis. Historically, empirical 

analyses of solar economics have focused primarily on up-front installed costs or prices (see, for 

example, Barbose et al. 2013), and principally within the residential and commercial PV sectors. 

But as more utility-scale projects have come online and begun to acquire an operating history, a 

wealth of other empirical data has begun to accumulate as well. Utility-scale solar projects can 

be mined for data on not only installed prices, but also project performance (i.e., capacity factor), 

operations and maintenance (“O&M”) costs, and power purchase agreement (“PPA”) prices 

($/MWh) – all data that tend to be unavailable publicly, and also less meaningful,1 within the 

residential and commercial sectors.

The operating history of utility-scale PV in the U.S. has been brief, however. According to

GTM/SEIA (2013), more than 2.8 GWDC of the 3 GWDC of utility-scale PV online in the U.S. at 

the end of 2012 were built in 2010 (0.27 GWDC), 2011 (0.76 GWDC), and 2012 (1.78 GWDC). 

The back-loaded nature of this progression, along with ongoing strong deployment in 2013 and 

 1 For example, even if performance data for residential systems were readily available, they might be difficult to 

interpret given that residential systems are often partly shaded or otherwise constrained by roof configurations that 

are at sub-optimal tilt or azimuth. Utility-scale projects, in contrast, are presumably less-constrained by existing site 

conditions and better able to optimize these basic parameters, thereby generating performance data that are more 

normalized and easier to interpret. Similarly, even if known, the price at which third-party owners of residential PV 

systems sell electricity to site hosts is difficult to interpret, because residential PPAs are often priced only as low as 

they need to be in order to present an attractive value proposition relative to retail rates (this is known as “valuebased pricing”). In contrast, utility-scale solar projects must often compete (policy incentives notwithstanding) for 

PPAs against other generating technologies within competitive wholesale power markets, and therefore tend to offer 

PPA prices that reflect the minimum amount of revenue needed to recoup the project’s initial cost, cover ongoing 

operating expenses, and provide a normal rate of return (this is known as “cost-plus” pricing). Whereas cost-plus 

pricing data provide useful information about the amount of revenue that solar needs in order to be economically 

viable in the market, value-based PPA price data are less useful, and often reflect the “price to beat” more so than 

the lowest possible price.
2

beyond, suggests that while there are currently useful data to analyze, data availability will grow 

rapidly in the coming years.

As such, this report is the first edition in what is envisioned as an ongoing annual series that will,

each year, compile and analyze the latest empirical data from the growing fleet of utility-scale 

solar projects in the U.S. In this inaugural edition, we define “utility-scale” as any groundmounted project with a nameplate capacity of 2 MWAC or larger. Within this subset of projects, 

the relative emphasis on different solar technologies within the report largely reflects the 

distribution of those technologies in the broader market – i.e., most of the data and analysis 

naturally focuses on PV given its large market share, but concentrating photovoltaic (“CPV”)

and CSP projects are also included where data are available.

The report proceeds to analyze the data in a logical order, starting with up-front installed prices

in Section 2, then moving on to operating costs and performance (i.e., capacity factor) in 

Sections 3 and 4, all of which influence the PPA prices that are reported and analyzed in Section 

5. Data sources are diverse and vary depending on the type of data being presented, but in 

general include the Federal Energy Regulatory Commission (“FERC”), the Energy Information

Administration (“EIA”), state and federal incentive programs, state and federal regulatory

commissions, industry news releases, and trade press articles. Sample size also varies by section, 

and at least in this first edition of the report, relatively few projects have sufficiently complete

data to be included in all four data sets. All data involving currency are reported in constant or 

real U.S. dollars – in this edition, 2012 dollars.2

Finally, we note that this report complements several other related studies and ongoing research 

activities, all funded as part of the DOE’s SunShot Initiative, which aims to reduce the cost of 

PV-generated electricity by about 75% between 2010 and 2020. Most notable is LBNL’s longstanding Tracking the Sun series (e.g., Barbose et al. 2013), which focuses on trends in PV 

installed prices with a primary emphasis on the residential and commercial sectors (but also 

including some of the utility-scale data presented in this report). In addition, LBNL and the 

National Renewable Energy Laboratory (NREL) jointly issue an annual briefing that summarizes

historical, current, and projected PV installed prices, drawing upon data from Tracking the Sun

(and perhaps in the future, this report) along with modeled installed price benchmarks and 

projections of near-term system pricing developed through research efforts underway at NREL 

(Feldman et al. 2013).

 2 Conversions between nominal and real dollars use the implicit GDP deflator. Historical conversions use the actual 

GDP deflator data series from the U.S. Bureau of Economic Analysis, while future conversions (e.g., for PPA 

prices) use the EIA’s projection of the GDP deflator in Annual Energy Outlook 2013.
3

2. Installed Prices

Berkeley Lab has gathered installed price data for 202 utility-scale (i.e., ground-mounted and 

larger than 2 MW) solar projects totaling more than 2,000 MWDC (1,735 MWAC) and installed 

between 2007 and 2012. The sample consists largely of PV projects (194 projects totaling 1,544 

MWAC), but also includes five CSP projects totaling 149 MWAC, two CPV projects totaling 35 

MWAC, and one 7 MWAC project that employs a mix of PV and CPV technology. In general, 

only fully operational projects for which all individual phases were in operation at the end of 

2012 are included in the sample.3 These definitional choices obviously impact the sample 

boundaries, and may lead to differences between the average installed prices presented in this 

section and those reported elsewhere (e.g., GTM/SEIA 2013). Furthermore, by definition, our 

sample is backward-looking, and therefore may not reflect installed price levels in 2013 and 

beyond.

4

This section analyzes installed price trends5 among just the sample of PV projects described 

above (installed prices for the eight CSP, CPV, and mixed-technology projects are discussed 

separately in the text box on page 5). It begins with an overview of installed prices over time, 

and then examines utility-scale system prices by technology, system size, and geographic region. 

Sources of installed price information include the Treasury Department’s Section 1603 Grant 

database, data from applicable state rebate and incentive programs, FERC Form 1 filings, trade

press articles, and data previously gathered by the National Renewable Energy Laboratory 

(NREL). All prices are reported in real 2012 dollars.

Installed PV Prices Continued to Drop in 2012, but Less Than in Previous Years

Figure 1 shows installed price trends for PV projects installed since 2007 in both DC and AC 

terms. Because solar project capacity is commonly reported in DC terms (particularly for PV in 

the residential and commercial sectors), the installed cost or price of solar is most often reported 

in $/WDC terms as well (see, for example, Barbose et al. 2013 and GTM/SEIA 2013). For utilityscale solar applications, however, $/WAC is a more appropriate metric, for two reasons. First, all 

other conventional and renewable utility-scale generation sources to which utility-scale solar is 

compared are described in AC terms – both in terms of their capacity ratings and their per-unit 

costs. Second, as discussed later in Section 4, some utility-scale PV projects intentionally 

oversize the DC PV array relative to the AC capacity of the inverters as a way to maximize 

 3 In contrast, later sections of this report do report data for individual phases of projects that are online, or (in the 

case of Section 5 on PPA prices) even for phases of projects or entire projects that are still in development and not 

yet operating.

4 Anecdotal information suggests that installed prices have continued to move lower in 2013. For example, on July 

1, 2013, the Public Service Company of New Mexico filed for regulatory approval of 23 MWAC of thin-film PV 

projects to be built in 2014 at an installed price of just $2.03/WAC, compared to $2.29/WAC for 20 MWAC of PV 

currently under construction in 2013 and $4.15/WAC for 22.5 MWAC built in 2011 (O’Connell 2013). 5 Installed “price” is reported (as opposed to installed “cost”) because in many cases, the value reported reflects

either the price at which a newly completed project was sold (e.g., through a sale/leaseback financing transaction), 

or alternatively the fair market value of a given project – i.e., the price at which it would be sold through an armslength transaction in a competitive market.
4

average inverter load and efficiency and thereby boost the AC capacity factor. In these cases, the 

difference between a project’s DC and AC capacity ratings will be significantly larger than one 

would expect based on conversion losses alone, and since the project’s output will ultimately be 

constrained by the inverters’ AC rating, $/WAC (where the AC rating equals the aggregate

inverter capacity rating) is the more appropriate cost or price metric to use. Here (in Figure 1)

we show installed prices both ways (in both $/WDC and $/WAC terms) as a way to provide some 

continuity between this report and others (namely Barbose et al. 2013). The remainder of this 

section, however, as well as the rest of this document, report data exclusively in AC terms.

As shown in Figure 1, installed prices among the sample of utility-scale PV projects have 

declined by nearly one-third on average from the 2007-2009 period through 2012, dropping from 

$5.6/WAC to $3.9/WAC over this period. Most of this decline occurred in 2010 and 2011, as 

capacity-weighted average prices fells by only $0.3/WAC from 2011 to 2012.

Figure 1. Installed Price of Utility-Scale PV, 2007-2012

Though capacity-weighted average prices have declined over time, there is nevertheless a 

considerable spread in individual project prices. Among the 113 projects in the sample 

completed in 2012, for example, installed prices range from $2.8/WAC to $8.0/WAC, and

preceding years show similar levels of variability. This price variation can be explained in part 

by differences in system configuration, project size, and geographic region, all of which are 

explored in greater detail below.6

 6 Other factors may also have an influence. For example, some of the higher-priced projects built in 2012 and 

shown in Figure 1 are not only small, but are also interconnected on the customer side of the meter, which presents a 

different value proposition (potentially subject to value-based pricing) than that offered by a truly wholesale project. 

In addition, some of these higher-priced projects are installed on top of capped landfills, which – much like roofmounted projects – requires customized mounting and installation procedures that can drive up installed costs or 

prices.

$0

$1

$2

$3

$4

$5

$6

$7

$8

$9

$10

2007-2009

n=10 (81 MW-AC)

2010

n=17 (196 MW-AC)

2011

n=54 (429 MW-AC)

2012

n=113 (838 MW-AC)

Installed Price (2012 $/W)

Installation Year

 Capacity-Weighted Averages

 Individual Projects - $/W-DC

 Individual Projects - $/W-AC
5

Installed PV Prices Vary by Configuration, Project Size, and Region

The price variation noted in the previous section is partially attributable to project configuration 

– i.e., whether PV projects use crystalline silicon (“c-Si”) or thin-film modules, and whether 

those modules are mounted at a fixed-tilt or on a tracking system. Figure 3 breaks out installed 

prices over time among these project configurations. 

Figure 2. Installed Price of Utility-Scale PV by Configuration, 2007-2012

Note: Capacity-weighted average price not shown for system configurations with fewer than two data points.

CSP and CPV Installed Prices

The installed price sample includes five CSP projects (three parabolic troughs, one compact linear Fresnel reflector, and one 

power tower), two CPV projects, and one project using a mix of CPV and PV. The installed price estimates for these eight

projects are not included in any of the Section 2 figures because two of these projects have high enough installed prices that it 

does not make sense to include them on the same graph with PV projects, yet there are simply too few of these “non-PV” 

projects at present to warrant separate graphs. Instead, the installed prices of these eight projects are discussed separately 

within this text box, and nowhere else in this report (though capacity factor and PPA price data for a subset of these projects 

are presented in Sections 4 and 5, respectively). All prices reported below are in 2012 $/WAC.

Among the CSP systems are a 3.2 MWAC compact linear Fresnel reflector project (Ausra’s Kimberlina project) and a 5 MWAC

power tower project (eSolar’s Sierra SunTower), both online since 2009. Both are considered to be pilot projects, and based on 

Section 1603 grant data, have installed prices of roughly $15.3/WAC and $13.7/WAC, respectively. The remaining three CSP 

projects in the sample all feature parabolic trough technology, and have installed price estimates of $8.4/WAC (a 2 MWAC

Sopogy MicroCSP project in Hawaii, built in 2009), $6.6/WAC (FPL’s 75 MWAC Martin Next Generation Solar Energy Center in 

Florida, built in 2010) and $4.5/WAC (the 64 MWAC Nevada Solar One project, built in 2007).

The two CPV projects are more recent. The 5.04 MWAC Hatch Solar Center in New Mexico was built in 2011 at an installed price

of $4.2/WAC, while the 30.24 MWAC Cogentrix Alamosa project in Colorado was built in 2012 at an installed price of $3.8/WAC. 

Both projects feature Amonix technology and dual-axis tracking. 

Finally, the 6.9 MWAC SunE Alamosa project in Colorado – which features a mix of PV and CPV technology, as well as fixed-tilt, 

single-axis, and double-axis tracking – was built in 2007 with an installed price of $9.4/WAC.

0

1

2

3

4

5

6

7

8

9

10

2007-09 2010 2011 2012 2007-09 2010 2011 2012 2007-09 2010 2011 2012 2007-09 2010 2011 2012

 3 3 27 83 3 7 14 22 4 7 12 7 - - 1 1

 7 20 146 386 39 54 155 241 35 123 108 186 - - 20 25

c-Si, Fixed-Tilt c-Si, Tracking Thin-Film, Fixed-Tilt Thin-Film, Tracking

Installed Price (2012 $/WAC)

 Individual Project

 Capacity-Weighted Average

Year:

Projects:

MW:

c-Si, Fixed-Tilt c-Si, Tracking Thin-Film, Fixed-Tilt Thin-Film, Tracking
6

Trends of particular note include:

• There has been a convergence in the average installed price of c-Si and thin-film projects. 

Though projects using c-Si modules have historically been significantly more expensive 

than projects using thin-film modules, the price gap has eroded considerably over time. 

This convergence has been driven primarily by the price of c-Si modules falling more 

quickly than the price of thin-film modules, attributable to both a decline in the price of 

silicon as well as a global excess of c-Si module manufacturing capacity.

• Tracking systems remain only slightly more expensive than fixed-tilt systems within the 

sample – a difference of less than $0.2/WAC in 2011 and 2012 among c-Si projects. The 

small size of this gap may be due in part to the previously mentioned higher DC/AC 

capacity ratio among fixed-tilt projects in general (this trend is explored further in 

Section 4), which boosts their installed prices in AC terms.

• As the price of c-Si projects has converged with thin-film, the number of c-Si projects in 

the sample (particularly fixed-tilt projects) has grown almost exponentially. Figure 2 

shows that in 2011 and 2012 – coinciding with the timing of the convergence – c-Si 

projects overwhelmingly surpassed thin-film as the most frequently installed project type 

in the sample. This trend is mirrored in the broader market as well.

Project size may also explain some of the variation in installed prices, as PV projects in the 

sample range from 2 MWAC to nearly 100 MWAC. Figure 3 investigates whether scale 

economies potentially allow the larger projects in the sample to achieve lower costs, by focusing 

on just those PV projects in the sample that were installed in 2012 (recall from Figure 2 that 

average installed prices did not vary widely across system configurations in 2012, thereby 

making it a convenient year for this purpose). As might be expected, utility-scale PV projects do 

exhibit economies of scale, though the impact is most pronounced at the very low end of the size 

range. Out beyond 5-10 MW, scale economies appear to diminish considerably.

Figure 3. Installed Price by Configuration and Project Size for 2012 PV Projects

$0

$1

$2

$3

$4

$5

$6

$7

$8

$9

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Installed Price (2012$/WAC)

System Size (MWAC)

 c-Si, Fixed-Tilt

 c-Si, Tracking

 Thin-Film, Fixed-Tilt

 Thin-Film, Tracking

 Trendline (All Systems)

Figure only includes PV projects installed in 2012
7

Finally, installed prices might also vary between geographic regions, due to variations in 

prevailing project sizes, land costs, labor costs, regulatory environments, landscape type, 

environmental conditions, number of active developers, and presence of industry infrastructure, 

among other factors. Figure 4 shows that solar projects in the West region (defined here to 

include Arizona, California, Colorado, Nevada, New Mexico, Oregon, and Texas) have 

historically had lower prices than projects elsewhere, but that this gap has narrowed over time as 

prices in other regions have fallen more significantly. The West’s historical price advantage can 

perhaps be attributed to at least two factors: (1) larger projects have typically been built in 

western states due to relatively easy acquisition of land, potentially offering cost savings due to 

economies of scale, and (2) the region has more experience with utility-scale solar installations

(with a number of projects in operation since 2007 or earlier), and thus likely more mature 

infrastructure and more competition within the solar market.

Figure 4. Capacity-Weighted Average Installed Price for PV by Geographic Region

Note: Capacity-weighted average prices not shown for years in which fewer than two installed price data points are available.

As other areas of the country have gained installation experience with utility-scale PV, their 

prices have converged with those in the West. In 2012, for example, the capacity-weighted 

average price in the West was $3.7/WAC, compared to $3.9/WAC in the Southeast (defined here to 

include Florida, Kentucky, North Carolina, and Tennessee) and $4.4/WAC in the Northeast 

(defined here to include Delaware, Illinois, Massachusetts, Maryland, New Jersey, Ohio, 

Pennsylvania, and Vermont). This $0.7/WAC range from lowest to highest compares favorably 

with the more-than-$2.0/WAC range experienced as recently as 2010.

0

1

2

3

4

5

6

7

West Southeast Northeast

 2007-2009

 2010

 2011

 2012

Capacity-Weighted Average Installed Price (2012 $/WAC)

n=7, MW=51

n=9, MW=132 

n=25, MW=307

n=24, MW=450

n=4, MW=40

n=6, MW =17

n=57, MW=229

n=2, MW=5

n=4, MW=25

n=23, MW=105

n=32, MW=159
8

3. Operations and Maintenance Costs

In addition to up-front installed project costs or prices, utility-scale solar projects also incur 

ongoing operations and maintenance (“O&M”) costs. This section reviews and analyzes the 

limited data on O&M costs that are in the public domain. It starts with a review of projected

O&M costs from three large projects that have financed a portion of their capital costs through

public bond offerings, thereby necessitating the disclosure of detailed project information. Then 

it turns to empirical historical data from a very limited sample of projects that are owned by 

investor-owned utilities and, as such, are required to report operating expenses for those projects 

each year on FERC Form 1.

Projected Operating Costs Are Similar for Different PV Configurations, Higher for CSP

In the past two years, there have been at least three utility-scale solar projects in the U.S. that 

have issued bonds to finance a portion of their construction. The 550 MW Topaz project is a 

fixed-tilt, thin-film PV system; the 579 MW Solar Star projects (formerly known as the Antelope 

Valley Solar Projects) are two adjacent PV projects that will utilize c-Si with single-axis 

tracking; and the 250 MW Genesis project is a parabolic trough CSP project without storage. 

None of these three projects – all of which are in California – was fully online at the time of 

writing, though all were under construction and Topaz had begun to deliver some energy from 

early phases of the project.

Though not empirical data, projected operating expenses for these three projects are nevertheless 

instructive, not only because the projects are all very large (i.e., truly utility-scale), but also 

because they represent a diversity of technologies that happens to be highly representative of the 

majority of utility-scale solar installations in the U.S. today, ranging from fixed-tilt-thin-film PV 

to tracking c-Si PV to parabolic trough CSP without storage. That said, it is important to keep in 

mind that these three projects may not be entirely representative of their respective technology 

configurations. For example, given that these projected operating expenses are obtained from

documentation intended to support a credit rating, they may be conservatively high in order to 

provide comfort to potential bond buyers. In fact, in its published research on each project, the 

credit rating agency Fitch noted the robust nature of operating cost projections, referring in 

particular to long-term, fixed-price O&M contracts with experienced operators covering both 

routine maintenance and major repair and replacement costs, as well as the allocation of 

additional funds for any O&M contingencies that might arise (FitchRatings 2013, 2012, 2011). 

For this reason, actual operating expenses (among these projects, as well as others that fall into 

these three technology categories) might tend to be lower than shown in the figures below. On 

the other hand, these are all large projects, and smaller projects might experience higher per-unit 

O&M costs.

Figure 5 shows projected operating expenses for all three projects over time, expressed both in 

$/kWAC-year (on the left) and $/MWh (on the right). Since the vast majority of O&M expenses 

for solar projects are fixed (i.e., incurred regardless of how much electricity the system 
9

generates),7 $/kWAC-year is seemingly a more appropriate metric than $/MWh, but the latter is 

included for ease of comparison to PPA prices (presented later in Section 5). For each project, 

Figure 5 shows not only total operating expenses (“OpEx” – shown by the solid lines), but also 

just those expenses allocated to actual O&M (the dashed lines, which make up 70%-80% of total 

OpEx).

8

Source: FitchRatings 2013, 2012, 2011

Figure 5. Projected O&M and Total Operating Costs for Three Utility-Scale Solar Projects

Although one might expect tracking systems to have higher O&M costs than fixed-tilt systems 

on a $/kW-year basis, the two PV projects have very similar O&M and total operating cost 

projections, with O&M costs in the $20 to $30/kWAC-year range. Given Solar Star’s expected 

capacity factor advantage from tracking, however, its projected O&M costs are lower than 

Topaz’s on a $/MWh basis – increasing from $8-$13/MWh over time, compared to $16-

$21/MWh for Topaz. Perhaps not surprisingly (given not only the solar tracking components, 

but also the rest of the infrastructure needed for a CSP project – e.g., plumbing for the heattransfer fluid, heat exchangers, condensers, steam turbines, etc.), O&M and operating expenses 

for the Genesis project are projected to be considerably higher than for either of the PV projects, 

and with a recurring spike every seven years related to scheduled maintenance and/or overhaul of 

the steam turbines (full inspection, tune-up, re-blading as necessary).

Limited Sample of Empirical Operating Costs Seems to Conform to Projections

Empirical data on the operating costs of utility-scale solar projects are hard to come by. Not only 

have relatively few utility-scale solar projects been operating for more than a year, but even 

fewer of those projects are owned by investor-owned utilities, which are required by FERC to 

report on Form 1 the O&M costs of the power plants that they own.9

 And even fewer of those 

 7 Of the three projects in question, only Genesis – the parabolic trough CSP project, which includes a gas turbine 

component – broke out O&M expenses into fixed and variable costs, with fixed costs accounting for 96%-98% of 

total O&M costs each year. PV projects presumably have even fewer variable O&M costs.

8 In addition to O&M costs, total operating expenses also include property taxes, insurance, land royalties, 

performance bonds, various administrative and other fees, and overhead (FitchRatings 2013, 2011). 9 FERC Form 1 uses the “Uniform System of Accounts” to define what should be reported under “operating 

expenses” – namely, those operational costs associated with supervision and engineering, maintenance, rents, and 

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201620172018201920202021202220232024202520262027202820292030203120322033203420352036203720382039

Operating Costs (2012 $/kWAC-yr)

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Solar Star Topaz

Total

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10

investor-owned utilities that do own utility-scale solar projects actually report operating cost data 

in FERC Form 1 in a manner that is useful.10 Nevertheless, Figure 6 shows historical O&M 

costs for a very small sample of utility-scale solar projects – a total of nine projects totaling 137

MW – in both $/kW-year and $/MWh terms.11 Only three of these projects (denoted by the three

lines to represent project continuity over multiple years) have historical data for more than a 

single year; the other six only have data for 2012. Despite the extremely limited sample, 

reported costs are seemingly in line with the projected O&M costs in the early years of Figure 5

above – i.e., in the neighborhood of $20-$40/kWAC-year or $10-$20/MWh for PV, and around 

$60/kWAC-year for the lone CSP parabolic trough project.

Figure 6. Empirical O&M Costs by Project Type

As utility ownership of operating solar projects increases in the years ahead, the sample of 

projects reporting O&M costs will grow, potentially allowing for more interesting analyses in 

future editions of this report.

 

training. As such, the FERC Form 1 data are more closely aligned with, and therefore more comparable to, the 

projected O&M costs (rather than the total operating expenses) reported in Figure 5. 10 For example, a number of investor-owned utilities in California and the Southwest that own large solar projects 

either do not report operating costs for their solar projects on Form 1 at all, or else report them in an aggregated 

manner that does not readily lend itself to analysis.

11 O&M costs for the single CSP project (a 75 MW parabolic trough project) are only shown in $/kW-year terms 

because this project provides steam to a co-located combined cycle gas plant (i.e., the solar plant acts as a natural 

gas fuel saver). The amount of generation attributed to the solar plant is not tracked separately (or at least not 

reliably); instead, the solar plant serves to reduce the heat rate of the combined cycle gas plant.

0

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2010 2011 2012

O&M Costs (2012 $/kWAC-year)

 Generation-Weighted Average (PV only)

 Tracking c-Si (1 project, 25 MW)

 Fixed-Tilt c-Si (2 projects, 15 MW)

 Fixed-Tilt Thin-Film (5 projects, 22 MW)

 CSP (1 project, 75 MW)

5 projects 

overlap

(A)

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 Tracking c-Si (1 project, 25 MW)

 Fixed-Tilt c-Si (2 projects, 15 MW)

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(B)
11

4. Capacity Factors

At the close of 2012, a number of utility-scale solar projects had been operating for at least one 

full year (and in some cases for several or even many years), thereby enabling the calculation of 

capacity factors.12 Sourcing net generation data from FERC Electronic Quarterly Reports, FERC 

Form 1, EIA Form 923, and state regulatory filings, this section presents net capacity factor data 

for 73 PV projects totaling 743 MWAC (including one 5 MWAC dedicated CPV project and one 7 

MWAC project that uses both PV and CPV technology) and eleven CSP projects (ten parabolic 

trough and one power tower, none with storage) totaling 423 MWAC (and for which only the 

solar generation is reported here – no gas or oil augmentation is included). This sample size will 

increase significantly in next year’s edition, as the large amount of new utility-scale solar 

capacity that came online in 2012 will have its first full operating year in 2013. As sample size 

increases, so too will the information content of this section in future editions of this report.

Unless otherwise noted, the capacity factors presented here represent cumulative capacity factors 

– i.e., calculated over as many years of data as are available for each individual project (going 

back to 2007), rather than for just a single year. In all cases, capacity factors are calculated in 

AC terms (i.e., using the MWAC rather than MWDC nameplate rating),13 which results in higher 

capacity factors than if reported in DC terms, but allows for direct comparison with the capacity 

factors of other generation sources (e.g., wind energy or conventional energy), which are also 

calculated in AC terms. All capacity factors reported herein are also expressed in net, rather than 

gross, terms – i.e., they represent the output of the project net of its own use.

PV Capacity Factors Vary Considerably by Project, but Time Trend Proves Elusive

Figure 7 presents the cumulative capacity factors for all 73 PV projects, broken out by 

commercial operation date. As many as five years of net generation data go into the cumulative 

capacity factor calculations for the three projects that achieved commercial operations in late 

2007, while the 45 projects in the sample that came online in 2011 have just a single year (2012) 

impacting their capacity factors.

As shown, there is a wide spread of capacity factors across the entire period. For example, 

projects built in 2010 feature capacity factors ranging from 13.8% up to 30.2%, and other years 

have spreads that are almost as wide. A number of factors could be responsible for this wide 

range, including: whether the project is mounted at a fixed-tilt or uses tracking technology (this 

distinction is already noted in Figure 7, where projects with trackers generally, though not 

always, yield a higher capacity factor);14 in what part of the country the project is located (as 

 12 Because solar generation is seasonal (generating more in the summer and less in the winter), capacity factor 

calculations should only be performed in full-year increments. 13 The formula is: Net Generation (MWhAC) over Single- or Multi-Year Period / [Project Capacity (MWAC) * 

Number of Hours in that Same Single- or Multi-Year Period] 14 The overwhelming majority of PV projects in the sample that use tracking systems use single-axis trackers. Dualaxis trackers are limited to just one PV project in the sample, plus the two projects that use CPV technology (either 

exclusively or in combination with PV). For PV, where direct focus is not as important as it is for CPV or CSP, 
12

average insolation levels vary across the U.S.); what type of solar technology is used (e.g., c-Si 

versus thin-film versus CPV); the size of the PV array relative to the inverter capacity; inter-year 

resource variability; and finally, when the project was built.15

Figure 7. Cumulative Capacity Factor by Commercial Operation Date (PV Only)

Regarding the last variable, there does not seem to be much of a time trend evident in Figure 7: 

the best-fit line for fixed-tilt systems does slope slightly upward over time, but with a very low 

R2, while the best-fit line for tracking systems slopes slightly downward (and with an even lower 

R2). Any time trend could be obscured by other influences, however – for example, regional 

differences in the solar resource or use of different technology. Figure 8 attempts to control for 

these influences by focusing only on those projects located in the West region (defined rather 

liberally here to include Colorado, Texas, New Mexico, Arizona, Nevada, and California, and 

where 69% of the capacity in the sample resides), and breaking them out by both technology 

type (c-Si vs. thin-film) and whether or not tracking is used. The capacity factors shown in each 

year represent the generation-weighted average of the cumulative capacity factor from all 

projects that achieved commercial operations in that particular year. 

 dual-axis tracking is a harder sell than single-axis tracking, as the roughly 10% boost in generation (compared to 

single-axis) often does not outweigh the incremental costs, depending on the PPA price. 15 Other factors such as tilt and azimuth will also play a role, though since we are focusing only on ground-mounted 

utility-scale projects, our operating assumption is that these fundamental parameters will be optimized to maximize 

energy production.

R2 = 0.0313

R2 = 0.0193

0%

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35%

Jan-07 Jan-08 Jan-09 Jan-10 Jan-11

Net Capacity Factor

Commercial Operation Date

 Fixed-Tilt

 Tracking
13

Figure 8. Generation-Weighted Capacity Factor by Project Vintage (West Region)

Even after controlling for these other influences, Figure 8 does not suggest much of a time trend 

– i.e., with the possible exception of fixed-tilt thin-film systems (though that trend is skewed by a 

single 2007 project), there is no indication that projects built more recently have higher capacity 

factors. This lack of a time trend is somewhat notable given that: (A) PV project performance 

degrades slightly over time, which – all else equal – would lead one to expect that older projects 

would have slightly lower cumulative capacity factors than newer projects, and (B) falling 

module prices have led some projects to oversize the DC solar array relative to the AC inverter 

capacity rating as a way to boost capacity factor.16 We explore each of these variables below.

Performance Degradation Not Observable Within Limited Timeframe of PV Project Sample

Although performance degradation is commonly accounted for in power purchase agreements,17

it does not appear to be a strong influence in the sub-sample of eleven projects (totaling 96 

MWAC) for which three or more years of data are available (each of these eleven projects is 

shown as an individual line in Figure 9).18 To be fair, the impact of degradation would be 

 16 One might also expect that newer projects would have higher capacity factors because the efficiency of PV 

modules (both c-Si and thin-film) has increased over time. As module efficiency increases, however, developers 

simply either use fewer of them to reach a fixed amount of capacity (thereby saving on balance-of-system and land 

costs as well) or, alternatively, use the same number of them to boost the amount of capacity installed on a fixed 

amount of land (which directly reduces at least $/WDC costs, if not also $/WAC costs). In other words, for PV more 

so than for other technologies like wind power, efficiency improvements over time show up more as cost savings 

rather than as higher capacity factors.

17 For example, among a sample of power purchase agreements for fifteen projects (not all of which are yet online) 

totaling 2,138 MWAC, the projected decline in contracted generation ranges from 0.5%/year to 0.9%/year, with a 

capacity-weighted average of 0.65%/year (the mean and median are also 0.65%/year). These contractual 

degradation rates are likely somewhat conservative or over-stated, since they are typically tied to performance 

thresholds (which the developer presumably does not want to breach) within the PPA.

18 Figure 9 is not on a cumulative basis. Instead, it shows individual project capacity factors in each individual 

calendar year, as a means of checking for signs of performance degradation.

0%

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2007 2008 2009 2010 2011

Net Capacity Factor (Gen-Wgtd Avg) 

Project Vintage (Commercial Operation Date)

 Fixed-Tilt c-Si

 Fixed-Tilt Thin-Film

 Tracking c-Si
14

difficult to perceive after just three to five years – e.g., all else equal, a degradation rate of 

0.65%/year would reduce a 30% capacity factor in year one to 29.6% in year three and 29.2% in 

year five, leaving the cumulative three-year capacity factor at 29.8% (or 29.6% over five years). 

In other words, over this short time frame, degradation of capacity factors would be barely 

perceptible, particularly with other variables (e.g., inter-year variability in the solar resource) 

influencing the trend as well.

Figure 9. Capacity Factor Over Time For Projects With At Least 3 Years of History

Oversizing of PV Array Relative to Inverter Capacity Boosts Capacity Factor

One design element that varies considerably among utility-scale PV projects is the ratio of the 

project’s DC capacity rating – determined by the size of PV array – to the aggregate AC capacity 

of the inverters. Adding module capacity beyond what is considered optimal (in terms of 

maximizing solar generation) given the inverters’ capacity rating will increase the amount of DC 

power flowing to the inverters at any given time (except during peak production times, when the 

inverters will be maxed out and excess power will be spilled), thereby boosting the average 

inverter load and efficiency and leading to a higher capacity factor.19 With the cost of modules 

having dropped precipitously in recent years, this strategy is now more cost-effective than it once 

was, and can be a viable alternative to a tracking system as a means of maximizing production 

during on-peak periods and boosting capacity factor. This strategy may also contribute to the 

small difference in installed prices between fixed-tilt and tracking systems detected earlier in 

Figure 2.

Figure 10(A) plots the DC/AC nameplate capacity ratio against cumulative net capacity factor 

for the 73 PV projects in the sample. The relationship appears to be fairly strong for fixed-tilt 

systems (high R2 best-fit line) – the higher the DC/AC ratio, the higher the capacity factor – but 

 19 This is analogous to the boost in capacity factor achieved by a wind turbine when the size of the rotor increases 

relative to the turbine’s nameplate capacity rating. This decline in “specific power” (W/m2 of rotor swept area) 

causes the generator to operate closer to (or at) its peak rating more often, thereby increasing capacity factor.

0%

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35%

2008 2009 2010 2011 2012

Net Capacity Factor

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15

not for tracking systems (much flatter best-fit line with low R2

),

20 which have not pushed the 

DC/AC envelope in the way that fixed-tilt systems have. This is not surprising: tracking 

systems are already operating at or near peak capacity for a significant proportion of each day 

(by virtue of the fact that they follow the sun), and therefore have less to gain from oversizing –

particularly given the incremental expense of oversizing the tracking system itself (not just the 

modules).

Figure 10. DC/AC Nameplate Ratio vs. Capacity Factor and Commercial Operation Date

If the oversizing of fixed-tilt systems has been a recent development (e.g., as module costs have 

decreased), then this might be another reason to expect a time trend in capacity factor. Figure 

10(B) suggests that there is, in fact, a positive relationship between commercial operation date 

and the DC/AC ratio among fixed-tilt (but not tracking) systems, but it is very weak (i.e., low 

R2

). Hence, based on Figures 7-10, we conclude that while there may be a bit of a positive time 

trend influencing the capacity factors of fixed-tilt (but not tracking) systems, that relationship is 

weak. To the extent that it does exist, it is likely driven by a general increase in the DC/AC ratio 

among newer projects.

PV Capacity Factors Influenced More by Location and Tracking, Less by Module Type

Without a strong time trend to complicate the analysis, we can analyze the remaining influences 

on capacity factor with just a single graph. Figure 11 parses the sample (excluding the one CPV 

and one mixed-technology project, neither of which fits neatly into any of these buckets21) in 

three different ways: by region, by fixed-tilt versus tracking, and by c-Si versus thin-film.

 20 Most of the tracking projects with capacity factors around 20% or less are in northern climates – Vermont, 

Illinois, Delaware, New Jersey, and Ohio – which presumably explains their lower capacity factors relative to other 

tracking systems in the sample.

21 The 5.04 MWAC Hatch CPV project in New Mexico had a 20.9% capacity factor in 2012, while the mixedtechnology 7 MWAC SunE Alamosa project in Colorado has had a 29.1% cumulative capacity factor (with very little 

annual variation) over the 5-year period from 2008-2012. Finally, though technically not included in this year’s 

capacity factor sample because it came online in early 2012, the 30.24 MWAC Cogentrix Alamosa CPV project in 

Colorado had a 24.8% capacity factor in the twelve-month period from July 2012 through June 2013.

R2 = 0.6036 R2 = 0.0044

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 Fixed-Tilt

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(A)

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(B)
16

Figure 11. Cumulative PV Capacity Factor by Region and Project Configuration

Although sample size can become an issue when sub-dividing the sample this narrowly, the 

results are nevertheless largely as expected. Projects located in the Northeast region (broadly 

defined here to include Delaware, Illinois, Ohio, Pennsylvania, New Jersey, New York, 

Massachusetts, and Vermont) feature the lowest capacity factors, followed by the Southeast 

(which includes just Florida and North Carolina at this time), while the West (Texas, Colorado, 

Arizona, New Mexico, Nevada, and California) features the highest capacity factors. Within 

each region, projects using trackers (overwhelmingly single-axis) feature higher capacity factors 

than fixed-tilt systems.22 And finally, thin film technology appears to have a slight edge over cSi in the West region, where ambient temperatures are highest, while c-Si wins out in the other 

two regions.23

Parabolic Troughs Have a Long and Reliable Performance Record (Power Towers Less So)

There are thirteen CSP projects in the U.S. that are larger than 2 MW and that have been 

operating for one or more years. Two of these projects, however, do not have reliable net 

 22 A rule of thumb in the industry is that single-axis trackers will boost energy yield (i.e., capacity factor) by 20%, 

and this is roughly borne out by the sample of projects in the West. The c-Si trackers in the West sample have a 

19% higher generation-weighted average capacity factor than the fixed-tilt c-Si systems, while the lone thin-film 

tracker in the sample has a 22% higher capacity factor than the fixed-tilt thin-film systems. The use of trackers is 

not as common among thin-film systems because the lower efficiency of thin-film relative to c-Si requires more land 

area per nameplate MW – an expense that is exacerbated by the use of trackers, which require even more land area 

to avoid shading as the modules move throughout the day. In addition, thin-film modules have historically been 

cheaper than c-Si modules, perhaps making array over-sizing a more-viable alternative to tracking as a means to 

boost capacity factor.

23 The vast majority of thin film systems in the sample (82% of all thin-film capacity in the sample) use CdTe panels 

from First Solar. On its web site (http://www.firstsolar.com/en/Innovation/Advanced-Thin-Film-Modules), First 

Solar claims that its CdTe technology provides greater energy yield (per nameplate W) than c-Si at module 

temperatures above 25° C (77° F) – i.e., conditions routinely encountered by PV systems located in the Southwest 

region.

0%

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c-Si Film c-Si Film c-Si Film c-Si Film c-Si Film c-Si Film

Fixed-Tilt Tracking Fixed-Tilt Tracking Fixed-Tilt Tracking

Northeast Southeast West

Net Capacity Factor

 Generation-Weighted Average

 Individual Project

15 projects115 MW

3 projects15 MW

7 projects40 MW

1 project10 MW

1 project13 MW

3 projects36 MW

5 projects57 MW

19 projects238 MW

16 projects187 MW1 project20 MW
17

generation data, because one of them (the Kimberlina compact linear Fresnel lens project in 

California) primarily produces steam for industrial uses, while the other (the Martin parabolic 

trough project in Florida) feeds steam to a co-located combined cycle gas plant, with the 

resulting generation attributed to the gas plant. That leaves eleven CSP plants in the sample: the 

nine parabolic trough SEGS plants (totaling 354 MW) that have been operating in California for 

more than twenty years, the 64 MW Nevada Solar One parabolic trough project that has been 

operating in Nevada since mid-2007, and the 5 MW Sierra SunTower project that has been 

online in California since mid-2009.

Figure 12 shows the net annual capacity factors from just the solar portion of these projects (i.e. 

no augmentation with natural gas or fuel oil is included in Figure 12), going back to 2001. The 

eleven projects fall roughly into three groupings: SEGS III-IX, along with Nevada Solar One

(represented by the dashed black line), have the highest capacity factors; SEGS I and II are 

grouped in the middle; and the Sierra SunTower has by far the lowest capacity factor.

Figure 12. Capacity Factor of CSP Projects (Solar Portion Only) Over Time

Figure 12 provides several insights:

• Capacity factors among the uppermost grouping, which includes SEGS III-IX and 

Nevada Solar One, have converged in the past three years, in part as a result of 

refurbishments and upgrades. For example, SEGS VIII and IX, which prior to 2010 

regularly had the lowest capacity factors within this grouping, upgraded (with the help of 

the Section 1603 grant program) their heat collection elements in early-2010 to make the 

projects more efficient. The resulting improvement in their capacity factors is evident. 

Nevada Solar One also took advantage of the Section 1603 grant program in late-2009 to 

expand the size of its solar field by 5%; the resulting step-up in capacity factor from 

2010-2012 (relative to 2008-2009) is also evident in Figure 12.

• One likely reason for the consistently lower capacity factors of the SEGS I and II projects 

is that they feature smaller solar fields (relative to nameplate capacity) than the other 

seven SEGS projects. Just as oversizing a PV array relative to inverter capacity can boost 

0%

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15%

20%

25%

30%

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Net Capacity Factor (solar portion only)

SEGS III-IX and Nevada Solar One (dashed)

SEGS I & II

Sierra SunTower
18

capacity factor, so too can increasing the number of parabolic trough collectors relative to 

the nameplate rating of the steam turbine. Another potential factor is that SEGS I and II 

are owned and operated separately from SEGS III-IX, and have reportedly been used as 

somewhat of a test-bed for new collector technologies in recent years.

• Though considered a pilot project, the Sierra SunTower has, nevertheless, not lived up to 

performance expectations, and appears to be operating only a portion of the time 

(Gunther 2013).

24

• Finally, Figure 12 reflects only the net capacity factor attributable to the sun. Most of 

these projects also use gas-fired turbines to supplement their output (e.g., during shoulder 

months, into the evening, or during cloudy weather). In the case of Nevada Solar One, 

for example, gas-fired generation has boosted historical capacity factors by twenty to 

forty basis points depending on the year (e.g., from 22.9% solar-only to 23.2% gasincluded in 2012), with gas usage most often peaking in the spring and fall (shoulder 

months).

With a handful of major CSP projects – including two large power tower facilities (Ivanpah and 

Crescent Dunes) and three large parabolic trough projects (Genesis, Mojave, Solana) – currently 

under construction in the U.S., the availability of CSP performance data will improve in future

years.

 24 In response to a query regarding this project’s low capacity factor, eSolar (the project sponsor) described this 

project as a “multipurpose facility” that “operates and produces power on a part time basis” and is “also used for 

product development, research, and technology demonstration,” and later clarified that “Sierra SunTower is an 

operating full-scale facility where power generation is blended with product development on heliostats, control 

software and O&M areas” (Huibregtse, 2013). More recently, Greentech Media (Wesoff 2013) reported that 

“eSolar is now pursuing enhanced oil recovery applications, rather than power generation in the U.S.”
19

5. Power Purchase Agreement (“PPA”) Prices

The cost of installing, operating, and maintaining a utility-scale solar project, along with its 

capacity factor – i.e., all of the factors that have been explored so far in this report – are key 

determinants of the price at which solar power can be profitably sold through a long-term power 

purchase agreement (“PPA”). Relying on data compiled from FERC Electronic Quarterly 

Reports, FERC Form 1, EIA Form 923, and a variety of regulatory filings, this section presents 

trends in PPA prices among a sample of utility-scale solar projects in the U.S. The sample 

includes a total of 57 contracts totaling 4,289 MWAC and broken out as follows: 51 PV PPAs

totaling 3,822 MWAC, two CPV PPAs totaling 35 MWAC, one 7 MWAC PPA that is a mix of PV 

and CPV, and 3 CSP PPAs (two parabolic trough, one power tower) totaling 424 MWAC. 

The universe from which this sample is drawn includes only those utility-scale projects that sell 

electricity (as well as the associated capacity and renewable energy credits or “RECs”) in the 

wholesale power market through a long-term, bundled PPA. Utility-owned projects, as well as 

projects that sell electricity directly to end-users (i.e., on a retail basis, and often in conjunction 

with net metering), are therefore not included in the sample. We also exclude those projects that 

unbundle and sell RECs separately from the underlying electricity, because in those instances the 

PPA price alone is not indicative of the project’s total revenue requirements (at least on a postincentive basis). PPAs resulting from feed-in tariff (“FIT”) programs are excluded for similar 

reasons – i.e., the information content of the pre-established FIT price is low – although the 

prices paid by FIT programs are discussed in a text box on page 27. In short, the goal of this 

section is to learn how much post-incentive revenue a utility-scale solar project requires to be 

viable, and as such, the PPA sample comes entirely from utility-scale projects that sell bundled 

energy, capacity, and RECs to utilities (both investor-owned and publicly-owned utilities) 

through long-term PPAs resulting from competitive solicitations or bilateral negotiations.25

 25 Because all of the PPAs in the sample include RECs (i.e., transfer them to the power purchaser), we need not 

worry too much about REC price trends in the unbundled REC market. It is, however, worth noting that some states 

(e.g., Colorado) have implemented REC “multipliers” for solar projects (whereby each solar REC is counted as 

more than one REC for RPS compliance purposes), while others have implemented solar “set-asides” or “carveouts” (requiring a specific portion of the RPS to be met by solar) as a way to specifically encourage solar power 

development. In these instances, it is possible that utilities might be willing to pay a bit more for solar through a 

bundled PPA than they otherwise would be, either because they need to in order to comply with a solar set-aside, or 

because they know that each bundled solar REC has added value (in the case of a multiplier). So even though REC 

prices do not directly impact the analysis in this report, policy mechanisms tied to RECs might still influence 

bundled PPA prices in some cases – presumably to the upside.
20

For each of the contracts in the sample,26 we have collected the contractually locked-in PPA 

price data over the full term of the PPA,27 and have accounted for any escalation rates and/or 

time-of-delivery (“TOD”) pricing factors employed (see the text box on this page).28 The PPA 

prices presented in this section, therefore, reflect the full revenue available to (and presumably in 

many cases, the minimum amount of revenue required by29) these projects over the life of the 

contract – at least on a post-incentive basis. In other words, these PPA prices do reflect the 

 26 In general, each PPA corresponds to a different project, though in some cases a single project sells power to more 

than one utility under separate PPAs, in which case there may be two or more PPAs tied to a single project.

27 The minimum PPA term in the sample is 15 years, the maximum is 30 years, the average (both simple and 

capacity-weighted) is 23.4 years, and the median is 25 years. 28 In cases where PPA price escalation rates are tied to inflation, the EIA’s projection of the U.S. GDP deflator from 

Annual Energy Outlook 2013 is used to determine expected escalation rates. For contracts that use time-of-delivery 

pricing and have at least one year of operating history, each project’s average historical generation profile is 

assumed to be replicated into the future. For those projects with less than a full year of operating history, the 

generation profiles of similar (and ideally nearby) projects are used as a proxy until sufficient operating experience 

is available.

29 In a competitive “cost-plus” pricing environment – where the PPA price is just sufficient to recoup initial capital

costs, cover ongoing operating costs, and provide a normal rate of return – PPA prices will represent the minimum 

amount of revenue required by a project. In contrast, “value-based” pricing occurs when the project developer or 

owner is able to negotiate a higher-than-necessary PPA price that nevertheless still provides value to the buyer.

Time-of-Delivery Pricing: Delivering Electricity When It Is Most Valuable

55% of the nearly 4,300 MW in the solar PPA price sample feature prices that vary by time of delivery (both diurnally and 

seasonally – there are no solar PPAs in the sample that vary prices diurnally but not seasonally or vice versa). This stands in 

stark contrast to Berkeley Lab’s much larger sample of wind project PPAs (>25 GW), where only 15% (of MW) vary prices 

diurnally, only 10% vary prices seasonally, and only 8% vary prices both diurnally and seasonally. This disparity is partly 

attributable to geography – a large number of solar projects in the sample are located in the West and sell power within or into 

California, where time-of-delivery (“TOD”) pricing is relatively common, while the wind PPA sample is more-evenly distributed 

throughout the country. It also potentially reflects, however, the fact that solar tends to benefit from TOD pricing, while wind 

is often indifferent to or even hurt by it.

For example, based on actual diurnal and seasonal production profiles of both a PV and a wind project that have PPAs with 

PG&E, TOD pricing (using PG&E’s 2011 TOD factors) benefits PV over wind by $23/MWh on a levelized basis (in real 2012 

dollars). Similarly, for a different pair of projects that have PPAs with Southern California Edison (which uses its own TOD 

factors, different from PG&E’s), PV has a $26/MWh TOD advantage over wind. In other words, if these PV and wind PPAs all 

had the same “base price” (i.e., pre-TOD adjustment), the PV projects would earn $23-$26/MWh more revenue than the wind 

projects over the full terms of the contracts once the TOD factors had been applied to that base price. Or, stated another way, 

the PV projects could offer a base price that is at least $20/MWh lower than the wind projects’ base price and still earn roughly 

the same amount of post-TOD revenue (levelized $/MWh) as those wind projects over the full contract terms.

Not surprisingly, most (>90%) of the relative benefit comes from diurnal variation in the TOD factors. PV generates the bulk of 

its daily output mid-day when prices are highest, and does not produce at night, thereby avoiding the lowest-priced period of 

each day. Wind production profiles vary from site to site and by region, but tend to be more evenly distributed throughout the 

day – i.e., not as concentrated as PV in the high-priced on-peak periods, and instead generating some portion of daily output 

during the low-priced off-peak periods. Seasonal differences in production between wind and PV tend not to be as large as the 

diurnal difference; nor are the seasonal TOD adjustments as stark as the diurnal.

Of course, PV’s TOD advantage over wind is heavily dependent on the TOD factors currently in use, and so should not be 

considered generalizable or static. For example, Mills and Wiser (2012) use a capacity expansion model to demonstrate that at 

progressively higher solar penetrations in California, solar’s TOD advantage will decrease as the net peak load (i.e., peak load 

net of solar generation) shifts progressively later into the afternoon and eventually evening, when solar production starts to 

fade (absent storage). Presumably in such a potential future scenario, TOD factors would no longer favor mid-day generation 

as much as they currently do, which would, in turn, likely erode solar’s TOD advantage over wind.
21

receipt of federal (e.g., the 30% ITC or cash grant, accelerated tax depreciation) 30 and state 

incentives (e.g., grants, production incentives, various tax credits), and would be higher if not for 

these incentives.31 As such, the levelized PPA prices presented in this section should not be 

equated with a project’s levelized cost of energy (“LCOE”).

Figure 13 shows trends in the levelized PPA prices from the entire sample (not all of which is yet 

operational) over time. Each bubble in Figure 13 represents a single PPA, with the area of the 

bubble corresponding to the size of the contract in MW and the placement of the bubble 

reflecting both the levelized PPA price (along the vertical y-axis) and the date on the which the 

PPA was executed (along the horizontal x-axis).32 Different solar technologies (e.g., PV versus 

CPV versus CSP) are denoted by different colors and patterns.

Figure 13. Levelized PPA Prices by Technology and PPA Execution Date

 30 In addition to the other federal incentives listed, seven projects within the sample also received DOE loan 

guarantees through the Section 1705 program. In all seven cases, however, the projects had already executed PPAs 

by the date on which the loan guarantee was awarded, suggesting that the guarantee had no impact on the PPA price.

31 For example, taking a simplistic view (i.e., not considering financing effects), the average PPA price could be as 

much as 50% higher if there were no federal ITC (i.e., 30%/(1-federal tax rate)). Though there is too much variety 

in state-level incentives to try and systematically quantify their impact here, one example is New Mexico’s 

refundable Production Tax Credit, which pays varying amounts per MWh (averaging $27/MWh) of solar electricity 

produced over a project’s first ten years. One PPA for a utility-scale PV project in New Mexico allows for two 

different PPA prices – one that is $43.50/MWh higher than the other, and that goes into effect only if the project 

does not qualify for the New Mexico PTC. Based on New Mexico’s top corporate tax rate of 7.6%, a $43.50/MWh 

price increase due to loss of New Mexico’s PTC seems excessive (a more appropriate 20-year adjustment would 

seemingly have been roughly half that amount), but nevertheless, this is one tangible example of how state (and 

federal) incentives can reduce PPA prices. 32 Because PPA prices reflect market conditions at the time a PPA is executed – which could be a year or more in 

advance of when the project achieves commercial operations – the PPA execution date is more relevant than the 

commercial operation date when analyzing PPA prices. In contrast, installed prices (and, to a lesser extent, capacity 

factors) are more closely tied to when a project achieves commercial operations; hence, commercial operation date 

is used in earlier sections.

$0

$50

$100

$150

$200

$250

$300

Sep-02Sep-03Sep-04Sep-05Sep-06Sep-07Sep-08Sep-09Sep-10Sep-11Sep-12Sep-13

PPA Execution Date

 PV (3,822 MW, 51 contracts)

 CPV (35 MW, 2 contracts)

 Mix (7 MW, 1 contract)

 CSP (424 MW, 3 contracts)

Levelized PPA Price (2012 $/MWh)

550 MW

210

MW

32 MW (New York)
22

Figure 13 provides a number of insights:

• The utility-scale solar market is relatively young, particularly for PV. Utility-scale CSP 

projects have been around since the 1980’s, and one PPA in the sample for a new CSP 

project was executed back in late 2002, but with a few limited exceptions (e.g., the 

PVUSA facility in California from the 1980s), utility-scale PV has only been a reality in 

the U.S. since 2006/2007.

• Not surprisingly, the highest-priced contract in the sample comes from the Northeast 

(Long Island), which does not enjoy the abundant sunshine of the West (where 96% of 

the PPAs in the sample, and 99% of the capacity represented by those PPAs, are located).

• PPA pricing has, in general, declined over time, to the point where recent PPAs have 

been priced as aggressively as $50-$60/MWh levelized (in 2012 dollars). In the 

West/Southwest (where these low-priced projects are located), pricing this low is, in 

some cases, competitive with wind power (Wiser and Bolinger 2013), as illustrated in the 

Macho Springs text box on the next page. This is particularly the case when considering 

solar’s on-peak generation profile, which – as discussed in the time-of-delivery text box

on page 20 – can give solar a TOD pricing advantage relative to wind.33

• Although at first glance there does not seem to be a significant difference in the PPA 

prices required by different solar technologies, it is notable that virtually all of the recent 

PPAs in the sample employ PV technology. Back in 2002 when the Nevada Solar One 

CSP PPA was executed, PV was too expensive to compete at the wholesale level, but by 

2009 when the other two CSP PPAs in the sample were executed, PV had caught up in 

terms of pricing. Since then, virtually all new contracts have employed PV technology, 

while a number of previously-executed CSP contracts have either been canceled or 

converted to PV technology. CPV was seemingly competitive back in 2010 when the 

two contracts in the sample were executed, but lack of any new contracts since then (at 

least within the sample) prevents a more-recent comparison – and is perhaps telling in its 

own right.

• Smaller projects (e.g., in the 20-50 MW range) feature PPA prices that are just as 

competitive as larger projects (>200 MW). Though scale economies are present in PV 

projects (at least at the low end of the size range, per Figure 3 earlier), very large projects 

often face greater development challenges than smaller projects, including greater 

environmental sensitivities and more-stringent permitting requirements, as well as more 

interconnection and transmission hurdles. Once a project grows beyond a certain size, 

the costs of overcoming these incremental challenges may outweigh any benefits from 

scale economies in terms of the impact on the PPA price.

 33 The levelized PPA prices shown in Figure 13 (and throughout this section) already incorporate all applicable TOD 

factors. Not all PPAs, however, use explicit TOD factors, though in those instances where they are not used, solar’s 

on-peak generation profile still presumably provides higher implicit value (compared to wind) to the utility 

purchaser.
23

Not all of the projects behind the contracts shown in Figure 13 are fully (or even partially) 

operational, though all of them are still in play (i.e., the sample does not include PPAs that have 

been terminated). Figure 14 shows the same data as Figure 13, but broken out according to 

whether or not a project has begun to deliver power.34 Understandably, most of the morerecently signed PPAs in the sample pertain to projects that are still in development or under 

construction, and have not yet begun to deliver electricity under the terms of the PPA. Given 

that many of these same PPAs are also the lowest-priced contracts in the sample, it remains to be 

seen whether some of these projects can be profitably built and operated under the aggressive 

PPA price terms shown here.35

 34 If a project had begun to deliver power as of June 2013– even if not yet fully operational or built out to its 

contractual size – it is characterized as “operating” in Figure 14. Only those projects that were still in development 

or were under construction but not yet delivering power are characterized as “planned.”

35 There is a history of solar project and PPA cancellations in California, though in many cases these have involved 

projects using less-mature technologies (e.g., stirling dish engines, compact linear Fresnel reflectors, and power 

towers). For PV projects, price revisions are perhaps a more likely risk; for example, one of the lowest-priced PPAs 

in the sample would have had an even lower price (by $5/MWh) if not for an upward price revision stemming from

import duties placed on Chinese-made modules (Palo Alto 2012).

Macho Springs: Solar Co-Located With – And Competitive With – Wind

In November 2012, El Paso Electric filed for approval of 20-year PPA with the 50 MWAC Macho Springs PV project, developed by 

Element Power (and later sold to First Solar). This project has at least two notable features: (1) it is co-located with the 

existing 50.4 MW Macho Springs wind project (also developed by Element Power and selling electricity to El Paso Electric), 

which began commercial operations in late 2011, and (2) it has the lowest PPA price of any solar project in the sample, at 

roughly $50/MWh levelized (real 2012 dollars). In fact, the solar project is priced lower than the co-located wind project

(though the wind PPA was signed more than two years earlier, in 2010), which sells electricity at a levelized price of just below 

$80/MWh (real 2012 dollars). 

The solar project benefits from some of the infrastructure that had already been built for the wind project, such as the 

substation, which no doubt helps to support its lower price. Another factor is New Mexico’s 10-year refundable Production Tax 

Credit, which provides an average of $27/MWh to solar (though actual amounts vary by year over the 10-year period), 

compared to just $10/MWh (flat) for wind. Otherwise, the two projects are essentially the same size, were developed by the 

same developer, have the same PPA term (20 years) and off-taker, and receive essentially the same federal benefits 

(accelerated depreciation and either the 30% ITC or the 30% Section 1603 cash grant – the wind project chose the grant).

To date, the wind project has generated a 29% net capacity factor, while the solar project expects to reach almost 26%. But 

these annual averages mask likely seasonal synergies: so far, the wind project’s lowest monthly output has been in July, 

August, and September – three summer months in which the solar project will presumably generate its highest output. This 

natural complementarity allows the two projects to more fully utilize their interconnection agreement and transmission rights.

Macho Springs is the latest in a growing number of solar projects that are co-located with either wind (Catalina, Grand Ridge, 

Wild Horse, Kingman, Atlantic County Utilities Authority) or geothermal (Stillwater) projects – though so far none of these 

hybrid projects have been truly envisioned or developed as integrated projects (rather, solar has been added later in each case, 

and is sold under a separate PPA). As such, there are presumably still as-yet-untapped synergies to be realized in the future for 

hybrid projects that are envisioned, planned and developed as such right from the start.
24

Figure 14. Levelized PPA Prices by Operational Status and PPA Execution Date

Roughly 60% of the contracts in the sample feature pricing that does not escalate (in nominal 

dollars) over the life of the contract – which means that pricing actually declines over time in 

real dollar terms. Figure 15 illustrates this decline by plotting over time, in real 2012 dollars, the 

generation-weighted average price among all PPAs executed within a given year (i.e., including 

both escalating and non-escalating contracts). In addition to the declining real prices over time 

within each PPA vintage, the steady march downward across vintages is also evident, 

demonstrating substantial reductions in pricing by PPA execution date. All technology types –

PV, CPV, and CSP – are included in Figure 15.

Figure 15. Generation-Weighted Average PPA Prices Over Time by Contract Vintage

$0

$50

$100

$150

$200

$250

$300

Sep-02

Sep-03Sep-04Sep-05Sep-06Sep-07Sep-08Sep-09Sep-10

Sep-11

Sep-12Sep-13

PPA Execution Date

 Operating (2,605 MW, 42 contracts)

 Planned (1,684 MW, 15 contracts)

Levelized PPA Price (2012 $/MWh)

32 MW (New York)

210

MW

550 MW

$0

$50

$100

$150

$200

$250

20062008201020122014201620182020202220242026202820302032203420362038204020422044204620482050

Gen-Weighted Average PPA Price (2012 $/MWh)

2006 (7 MW, 1 contract)

2009 (1,066 MW, 14 contracts) 2008 (770 MW, 3 contracts)

2010 (1,193 MW, 21 contracts)

2011 (463 MW, 7 contracts)

2012 (590 MW, 5 contracts)

2013 (135 MW, 5 contracts)
25

To provide a clearer look at the time trend, Figure 16 simply levelizes the price streams shown in 

Figure 15. Based on this sample, levelized PPA prices for utility-scale solar projects have fallen 

by roughly $25/MWh per year on average over this period.36

Figure 16. Levelized Generation-Weighted Average PPA Prices by Contract Vintage

This strong time trend, along with small sample size in the most-recent years, complicates morerefined analysis of other variables examined in earlier sections, such as regional differences

(though again, nearly the entire sample is in the West), tracking versus fixed-tilt, and c-Si versus 

thin-film. To try and control for the influence of time, one could potentially analyze these 

differences within a single year (e.g., 2009 or 2010, years in which the sample is largest), but 

doing so would divide the sample to the point where sample size is too small to reliably discern 

any differences (and any discernible differences would, by now, be three to four years old, 

calling into question their current relevance). 

Furthermore, it is not clear that some of these variables should even have much of an impact on 

PPA prices. For example, several of the most-recent PV contracts in the sample note uncertainty 

over whether or not tracking systems will be used, or even whether c-Si or thin-film modules 

will be deployed. Yet the executed PPA price is the same regardless of the ultimate project 

configuration, suggesting that the choice of tracking versus fixed-tilt or c-Si versus thin-film is 

 36 In Figures 15 and 16, the small sample size in 2011, 2012, and 2013 relative to the much larger sample of 

contracts signed in either 2009 or 2010 might lead some to conclude that the utility-scale solar market is cooling 

down. Although there has been some chatter in the trade press to this effect (Caley 2013), Figures 15 and 16 should 

not necessarily be used to support that argument. Rather, the declining sample size in Figures 15 and 16 is likely 

more the result of two factors: (1) 2013 represents just a partial year, and (2) FERC Electronic Quarterly Reports, 

which are the principal data source for PPA price data, are only filed once projects are operational and delivering 

power. As a result, the 2011, 2012, and 2013 sample will likely grow in future years with the build-out of projects 

that signed PPAs in those earlier years.

$0

$50

$100

$150

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$250

2006

1

7

2007

0

0

2008

3

770

2009

14

1,066

2010

21

1,193

2011

7

463

2012

5

590

2013

5

135

PPA Year:

Contracts:

MW:

Levelized Gen-Weighted Average PPA Price (2012 $/MWh)
26

(at least in these cases) not a critical determinant of PPA pricing.37 Instead, the time trend – in 

large part reflecting falling module costs, as well as expectations for even further declines in 

module and projects costs in the future38 – has likely been the dominant influence on PPA prices 

in recent years, as illustrated by the somewhat-controlled case study presented in the Copper 

Mountain text box below.

 37 This could be because tracking systems add up-front costs to the system (see Figure 2 in Section 2) that are 

recouped over time through greater energy yield (see Figure 11 in Section 4), thereby leaving the net impact on PPA 

prices largely a wash. In support of this theory, the Public Service Company of New Mexico recently estimated 

(based on a review of 216 solar responses to its 2012 Renewable RFP) that the average PPA price benefit of singleaxis tracking is just $3/MWh, or less than 4% of a levelized PPA price in the mid-$70/MWh range (O’Connell 

2013). 38 The steady decline in levelized PPA prices in recent years is not fully consistent with the moderating decline in 

installed project prices shown earlier in Section 2. A primary reason is that PPA prices are often negotiated on a 

forward-looking basis – i.e., based on what developers think that modules and projects will cost a year or two in the 

future when the project is actually built (recall from Figure 14 that nearly 40% of the PPA price sample in capacity 

terms comes from projects not yet built). The declining cost environment of recent years has, no doubt, influenced 

expectations for future project costs and, in turn, achievable PPA prices. A second potential explanation is that the 

installed project prices presented in Section 2 may be conservative in the sense that they are backward-looking, 

focusing on projects installed through 2012 only.

Copper Mountain Projects Illustrate Strong Time Trend in PPA Prices

Boulder City, Nevada is home to a variety of utility-scale solar projects, including the 64 MWAC Nevada Solar One CSP project as well 

as four phases (each successively larger than the previous) of the Copper Mountain PV projects, which, when fully operational, will 

total 458 MWAC. The four Copper Mountain projects provide a somewhat-controlled example of the strong trend of falling PPA prices 

over time, in the sense that they are all located in the same contiguous area, are all owned and operated by the same independent 

power producer (Sempra Generation U.S. Gas & Power), and the first three phases all use First Solar’s CdTe thin-film modules in a 

fixed-tilt configuration (and therefore have similar actual or expected capacity factors in the mid-20% range) and have long-term 

PPAs with the same counterparty (PG&E). Notably, in a high-profile nod to the increasing cost-competitiveness of c-Si technology 

relative to thin film, Sempra announced in August 2013 that the fourth phase (which has a 20-year PPA with the Southern California 

Public Power Authority) would use c-Si modules made by Trina Solar.

The PPA for the initial 10 MW phase (called El Dorado, though often considered part of Copper Mountain 1) was executed in 

December 2008 at a levelized price of roughly $150/MWh (in real 2012 dollars). Six months later (June 2009), an additional 48 MW 

PPA (Copper Mountain 1) was executed at the same price as El Dorado (both of these were 20-year PPAs). Roughly two years later 

(July 2011), a 25-year PPA for another 150 MW (Copper Mountain 2) was executed at a levelized price of about $103/MWh (real 2012 

dollars). And finally, in August 2012 (a full year before Trina Solar was selected as the module supplier), a 20-year PPA for another 

250 MW (Copper Mountain 3) was executed at a levelized price of roughly $82/MWh (real 2012 dollars).

Given the underlying similarities among these four projects, the ~$70/MWh decrease in levelized PPA prices over this roughly 3-year 

period (the magnitude of which is consistent with the decline seen across the full sample in Figure 16) can presumably be attributed 

primarily to the declining cost of solar modules (and, to a lesser extent, other balance-of-system costs) over this period. Other 

possible contributors include the realization of greater scale economies with each successively larger phase (though Figure 3 suggests 

that scale economies may diminish beyond 5-10 MW), as well as improvements in operating costs as Sempra gains greater 

experience with these projects. Whatever the true combination of drivers, the controlled nature of this case study supports the 

notion that an analysis of the other variables not examined in this section – tracking vs. fixed-tilt, thin-film vs. c-Si – is not strictly 

necessary in order to explain the strong time trend shown in Figure 16.
27

Price Comparison With Feed-In Tariff (“FIT”) Programs That Support Utility-Scale Projects

At least three feed-in tariff (“FIT”) programs in the U.S. support projects that fall under the definition of utility-scale used in this 

report (i.e., ground-mounted projects larger than 2 MW). The Sacramento Municipal Utility District (“SMUD”) allows projects up to 5 

MW to participate (though larger projects have been subdivided into 5 MW parcels in order to qualify), Vermont’s Sustainably Priced 

Energy Enterprise Development (“VT SPEED”) program allows projects up to 2.2 MW, and the Los Angeles Department of Water and 

Power (“LADWP”) allows projects up to 3 MW. Although projects participating in these three programs are NOT included in the PPA 

price sample analyzed in this report, it is, nevertheless, interesting to review the prices paid by these FIT programs and compare them 

to the prevailing PPA prices in the sample.

SMUD’s FIT prices are split into nine different time-of-delivery periods, and are fixed for the 20-year duration of the contract. Based 

on a typical PV production profile in SMUD’s service territory, SMUD estimates the PV-production-weighted average annual nominal 

dollar price to be around $148/MWh (which equates to a levelized 20-year price of roughly $130/MWh in real 2012 dollars) for 

projects commencing commercial operations in 2012 (i.e., when most of the participating projects came online). SMUD’s program 

was fully subscribed within a week, suggesting that developers considered the pricing to be attractive. Based on where utility-scale 

solar PPA prices in the West were in early 2010 when the program was launched (see Figure 13), however, SMUD’s price does not 

seem to be too out of line with the market.

The VT SPEED program originally offered a price of $300/MWh flat for 25 years (around $260/MWh levelized in real 2012 dollars), 

and was quickly over-subscribed. The price was subsequently reduced to $240/MWh ($210/MWh levelized in real 2012 dollars), and 

in early 2013, the program switched to a competitive reverse-auction format, whereby developers compete for contracts by offering 

the lowest price (below a pre-established price cap of $257/MWh) at which they are willing to sign a contract. The two winning bids 

under that Spring 2013 auction came in at $134-$144/MWh flat for 25 years ($114-$122/MWh levelized in 2012 dollars) –

substantially lower than what earlier participants are being paid (and comparable to what SMUD is paying in the sunny Central Valley 

of California). Until these projects are built and operating, however, it remains to be seen whether $134/MWh is sufficient to 

support solar in sun-challenged New England.

LADWP’s program is divided into five 20 MW blocks, with the base price (to be adjusted by TOD factors) starting at $170/MWh in the 

first block and declining by $10/MWh in each subsequent block (i.e., to $130/MWh for the last 20 MW block). The first 20 MW block 

was offered (and oversubscribed) in early 2013, and allocation of the second block was underway in July 2013. Although the local 

ratepayer advocate has criticized this program as paying too much for solar based on the low market prices available elsewhere (and 

evident in Figure 13), LADWP counters that it can cost up to $30/MWh to wheel that cheap desert solar power into Los Angeles – a 

cost it can avoid by developing smaller projects closer to home. In addition to this 100 MW fixed-price program, LADWP plans to 

launch a related program in the near future that – like Vermont – will use competitive bidding to allocate an additional 50 MW.
28

6. Conclusions

Though parabolic trough CSP projects have been operating in the U.S. since the late 1980s, there 

were virtually no commercial utility-scale PV projects in operation prior to 2007. By 2012 – just 

five years later – utility-scale had become the largest sector of the overall PV market in the U.S. 

Over this same five-year period, CSP also experienced a bit of a renaissance, with new parabolic 

trough systems operating and under construction, and several large power tower projects also 

nearing completion in the United States.

With a critical mass of new projects now online and in some cases having operated for several 

years (generating data in addition to electricity), the utility-scale sector is ripe for analysis. This 

report, which is envisioned to be the first in an ongoing annual series, meets this need through indepth, data-driven analysis of not just installed project costs or prices – i.e., the traditional realm 

of solar economics analyses – but also operating costs, capacity factors, and PPA prices. As 

such, it provides a more-integrated and holistic view of the market than is commonly found.

Given the nascent state of the market, data availability is still, in places, an issue in this inaugural

edition. The report nevertheless paints a coherent picture that will be refined, enriched, and 

solidified over time as more data become available. Until then, some of the more-notable 

findings from this year’s report include the following:

• Installed Prices: Installed project prices have fallen by nearly one-third since the 2007-

2009 period, from around $5.6/WAC to $3.9/WAC on average for projects completed in 

2012 (with some projects higher and others lower). Most of the decline has been 

concentrated among projects using c-Si modules, as the gap between c-Si and thin-film 

steadily eroded over this period. In response to falling c-Si module prices, there has been 

a marked increase in the proportion of projects using c-Si (rather than thin-film) modules.

• O&M Costs: Although O&M cost data are extremely limited at present, what little 

empirical data exist suggest that actual costs have largely been in line with pro forma 

operating cost projections gleaned from several bond offering prospectuses. For PV, 

O&M costs appear to be in the neighborhood of $20-$40/kWAC-year, or $10-$20/MWh. 

CSP O&M costs are higher, presumably due to the plumbing and thermal components, 

and come in around $60/kWAC-year.

• Capacity Factors: Like insolation levels, PV capacity factors vary by region. They also 

vary depending on whether a project is installed at a fixed-tilt or uses a tracking device, 

with single-axis trackers able to achieve capacity factors in excess of 30% in some of the 

better locations (thus confirming the industry rule of thumb that single-axis tracking 

provides a 20% boost in output). In lieu of trackers, and enabled by the sharp decline in 

module prices, some projects have instead opted to oversize the PV array relative to the 

capacity rating of the inverters as a way to boost capacity factor. On the CSP side of the 

market, parabolic trough systems that have been operating in the U.S. for more than 20

years are still (in 2012) achieving capacity factors in excess of 20% (solar portion only, 

no storage), which is comparable to newer trough projects. Meanwhile, a pilot project for 

power tower technology has underperformed relative to expectations, but several much 
29

larger power tower projects under construction will soon test that technology on a truly 

commercial scale in the United States (several commercial power tower projects have 

been operating in the Mediterranean region for several years).

• PPA Prices: Driven primarily by lower installed project prices (which, in turn, have 

been driven primarily by declining module prices), levelized PPA prices have fallen 

dramatically over time, by $25/MWh per year on average. Some of the most-recent 

PPAs in the West have levelized PPA prices as low as $50-60/MWh (in 2012 dollars), 

which, in some cases, is competitive with wind power projects in that same region. Solar 

appears to be particularly competitive when considering its time-of-delivery pricing 

advantage over wind (roughly $25/MWh in California at current levels of penetration).

Utility-scale project developers (as well as utilities) can use these findings and data to refine their 

views of the market and/or to inform the various tradeoffs that they must regularly make, for 

example regarding choice of technology. Policymakers and the general public will presumably 

come away from this report with a newfound understanding of just how competitive utility-scale 

solar has become in a very short time-period. Consultants, modelers, and financiers, meanwhile,

can use these empirical data from actual operating experience to either validate or improve their 

modeling assumptions, thereby leading to better representation of this sector in future studies.

Although the insights in this first edition are compelling, they are nevertheless still constrained 

by limited data availability. As the market itself continues to grow in future years, so too will the 

sample of data available for analysis, highlighting the importance of maintaining and updating 

these fledgling data sets in the coming years so that future editions of this report can continue to 

track this rapidly growing market.
30

A note on the sources of data used in this report:

Much of the analysis in this report is based on primary data, the sources of which are listed 

below (along with some general secondary sources), broken out by data set:

• Nameplate Capacity: Form EIA-860, FERC Form 556, state regulatory filings, trade 

press articles

• Installed Prices (Section 2): Section 1603 grant data from the U.S. Treasury, FERC Form 

1, data from applicable state rebate and incentive programs, state regulatory filings, 

company financial filings, trade press articles, and data previously gathered by the 

National Renewable Energy Laboratory (NREL)

• O&M Costs (Section 3): FitchRatings (projections only) and FERC Form 1 

(actual/empirical data)

• Capacity Factors (Section 4): FERC Electronic Quarterly Reports, FERC Form 1, Form 

EIA-923, state regulatory filings

• PPA Prices (Section 5): FERC Electronic Quarterly Reports, FERC Form 1, Form EIA923, state regulatory filings, company financial filings, trade press articles

In addition, the individual reference documents listed below provided additional data and/or 

helped to inform the analysis.

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Key Report Contacts Acknowledgments

The authors thank Minh Le, Elaine Ulrich, Kelly Knutsen, 

Christina Nichols, and Ammar Qusaibaty of the U.S. 

Department of Energy's Solar Energy Technologies Office 

for their support of this work. The authors would also 

like to thank Justin Baca and Will Lent of the Solar Energy 

Industries Association (“SEIA”) for maintaining and 

sharing SEIA’s list of major solar projects in the U.S. 

Thanks also to the following individuals for reviewing 

earlier drafts of this report: Galen Barbose and 

Ryan Wiser (LBNL); Kelly Knutsen (U.S. DOE); 

Josh Lutton (Woodlawn Associates); Michael Rogol 

(PHOTON Consulting); David Feldman, Ran Fu, and 

Michael Woodhouse (NREL); Mike Taylor (Solar Electric 

Power Association); Will Lent (SEIA); Jim Baak 

(The Vote Solar Initiative); Gwendolyn Bredehoeft 

(Energy Information Administration); and Paul Mayo 

and Tom Anderson (PE/Q Energy, Inc). Of course, any 

remaining errors or omissions are the sole responsibility 

of the authors.

Cover photos courtesy of Sempra U.S. Gas & Power, 

NREL, and BrightSource Limitless.

The work described in this report was funded by the U.S. 

Department of Energy’s Solar Energy Technologies Office, 

within the Office of Energy Efficiency and Renewable 

Energy, under Contract No. DE-AC02-05CH11231.

Lawrence Berkeley National Laboratory:

Mark Bolinger

603-795-4937; MABolinger@lbl.gov

Samantha Weaver

510-486-6375; SLWeaver@lbl.gov

Download the Report

http://emp.lbl.gov/reports/re

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LBNL-6408E/September 2013