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

Office of Energy Efficiency & Renewable Energy, operated by the 

Alliance for Sustainable Energy, LLC.

Contract No. DE-AC36-08GO28308

Feasibility Study of Economics 

and Performance of Solar 

Photovoltaics at the Sky Park 

Landfill Site in Eau Claire, 

Wisconsin

A Study Prepared in Partnership with the 

Environmental Protection Agency for the 

RE-Powering America’s Land Initiative: 

Siting Renewable Energy on Potentially 

Contaminated Land and Mine Sites

Joe Simon and Gail Mosey

Produced under direction of the U.S. Environmental Protection 

Agency (EPA) by the National Renewable Energy Laboratory (NREL) 

under Interagency Agreement IAG-08-0719 and Task No. 

WFD3.1002. 

Work for Others Report

NREL/TP-7A30-56995

January 2013 
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Contract No. DE-AC36-08GO28308

National Renewable Energy Laboratory

15013 Denver West Parkway

Golden, CO 80401

303-275-3000 • www.nrel.gov

Feasibility Study of Economics 

and Performance of Solar 

Photovoltaics at the Sky Park 

Landfill Site in Eau Claire, 

Wisconsin 

A Study Prepared in Partnership with the 

Environmental Protection Agency for the 

RE-Powering America’s Land Initiative: 

Siting Renewable Energy on Potentially 

Contaminated Land and Mine Sites

Joe Simon and Gail Mosey

Prepared under Task No. WFD3.1002 

Work for Others Report

NREL/TP-7A30-56995

January 2013 
NOTICE

This manuscript has been authored by employees of the Alliance for Sustainable Energy, LLC (“Alliance”) under 

Contract No. DE-AC36-08GO28308 with the U.S. Department of Energy (“DOE”).

This report was prepared as an account of work sponsored by an agency of the United States government. 

Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, 

express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of 

any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately 

owned rights. Reference herein to any specific commercial product, process, or service by trade name, 

trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, 

or favoring by the United States government or any agency thereof. The views and opinions of authors expressed 

herein do not necessarily state or reflect those of the United States government or any agency thereof.

Cover Photos: (left to right) PIX 16416, PIX 17423, PIX 16560, PIX 17613, PIX 17436, PIX 17721

Printed on paper containing at least 50% wastepaper, including 10% post consumer waste. 
iii

Acknowledgments

The National Renewable Energy Laboratory (NREL) thanks the U.S. Environmental Protection 

Agency (EPA) for its interest in securing NREL’s technical expertise. In particular, NREL and 

the assessment team for this project are grateful to the Sky Park Landfill site managers, 

engineers, and operators for their generous assistance and cooperation. 

Special thanks goes to Rosita Clark, Shea Jones, Lura Matthews, and Jessica Trice from EPA; 

Katie Brown, AAAS Science & Technology Policy fellow hosted by the EPA; and Brian 

Amundson, Colleen Schian, and Ned Noel from the City of Eau Claire for hosting the site visit. 

In addition, the authors would like to thank Dan Anderson and Phillips Plastics for their interest 

in the study and allowing use of their facilities during the site visit. Finally, the authors would 

like to thank Ned Noel for his continued support throughout the development of this report, 

particularly with regard to providing relevant background information and site-specific 

opportunities for Sky Park Landfill in Eau Claire. 
iv

Executive Summary

The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering 

America’s Land initiative, selected the Sky Park Landfill site in Eau Claire, Wisconsin, for a 

feasibility study of renewable energy production. The National Renewable Energy Laboratory 

(NREL) provided technical assistance for this project. The purpose of this report is to assess the 

site for a possible photovoltaic (PV) system installation and estimate the cost, performance, and 

site impacts of different PV options. In addition, the report recommends financing options that 

could assist in the implementation of a PV system at the site. This study did not assess 

environmental conditions at the site. 

The Sky Park Landfill is a 26-acre site located on the southwest side of Eau Claire, Wisconsin, 

near Highway 37 and I-94. The site operated as a municipal waste facility from 1948 until 

closure in 1965. The present site is capped and unused, except for a small area used for excess 

snow and storm damage vegetation storage. A majority of the site has dense vegetation, 

including trees, which would need to be removed should the entire site be developed for a solar 

array. The site is located in an industrial district with adjacent manufacturing, offices, and 

municipal facilities. 

The feasibility of a PV system is highly impacted by the available area for an array, solar 

resource, distance to transmission lines, and distance to major roads. In addition, the operating 

status, ground conditions, and restrictions associated with redevelopment of a closed and capped 

landfill site can impact the feasibility of a PV system. Based on an assessment of these technical 

factors, the Sky Park Landfill is suitable for deployment of a large-scale PV system, should a 

reasonable power purchase agreement (PPA) be secured for the electricity produced. 

There are approximately 3 acres available for installation of a PV system without the removal of 

significant vegetation and with minimal concern regarding ground settlement. The areas laden 

with excess vegetation following city-wide storms is less ideal due to the potential for 

differential settlement. Depending on interest in the system, the City of Eau Claire has indicated 

that it would be possible to remove the existing vegetation and develop the entire site. As this 

cost would be separate from the developer’s necessary work, this preparation cost is not 

considered in this analysis. For the purposes of this report, 23 acres, representing approximately 

92% of the site is considered feasible for development. Calculations for this analysis use the 

entire feasible area. 

The economic feasibility of a potential PV system on the Sky Park Landfill site depends greatly 

on the purchase price of the electricity produced. The economics of the potential system were 

analyzed using the current Xcel Energy policies, net-metering options, the city’s average blended 

commercial electric rate of $0.08/kWh, and incentives available to the site. Current incentives 

considered include the federal tax credit, Xcel Energy standard policies, and the State of 

Wisconsin tax incentives. Table ES-1 summarizes the system performance and economics of a 

potential system that would use the assumed 23-acre feasible area surveyed at the Sky Park 

Landfill site. The table shows the annual energy output from the system along with the number 

of average American households that could be powered through such a system, as well as 

estimated job creation. 
v 

For this analysis, two distinct scenarios were considered, the first using virtual net metering 

(VNM) to offset other city energy use and the second assuming energy produced would be sold 

under a PPA. 

Table ES-1 summarizes the estimated production, feasibility, and payback of potential systems 

installed at the site. This analysis considers the current cost of energy, expected installation cost, 

site solar resource, and existing incentives for the proposed PV system. While the net present 

value for this system is negative, the value to the community associated with meeting its 25% by 

2025 renewable energy generation goal, public perception, and community support for 

renewable energy development may justify the net cost of the system. 

Table ES-1 also indicates the results for potential systems developed under a PPA arrangement 

and assumes that the project would be developed by a third party on land leased from the City of 

Eau Claire and that electricity would be either sold to the utility or to an adjacent energy 

consumer. The analysis calculates the estimated required PPA price to allow for an overall 

project internal rate of return (IRR) of 8%. If a PPA at the rate associated with each type of 

system, approximately $0.10/kWh increasing at 3.5% annually, could be developed, the system 

would be an attractive investment for the city as well as the solar developer.

Table ES-1. Sky Park Landfill PV System Summary

System Type

Financial 

Model PV System Sizea Array Tilt Annual Output

Number of 

Houses 

Poweredb

Construction 

Period Jobsc Jobs Sustainedd

(kW) (deg) (kWh/year)

Crystalline Silicon (Fixed Tilt) VNM 4,007.52 LAT 4,837,763 438.2 n/a n/a

Crystalline Silicon (Single-axis Tracking) VNM 3,506.58 n/a 5,337,797 483.5 130.9 1.4

Crystalline Silicon (Dual-axis Tracking) VNM 3,005.64 n/a 4,572,138 414.1 n/a n/a

Crystalline Silicon (Fixed Tilt) PPA 4,007.52 LAT 4,837,763 438.2 130.9 1.4

Crystalline Silicon (Single-axis Tracking) PPA 3,506.58 n/a 5,337,797 483.5 n/a n/a

Crystalline Silicon (Dual-axis Tracking) PPA 3,005.64 n/a 4,572,138 414.1 n/a n/a

System Type

Financial 

Model Annual Output

Cost of 

Electricty/PPA Pricee System Cost

Total System 

Cost

1ST Year 

Savings/Revenue After-tax NPV

(kWh/year) (¢/kWh) ($/watt) ($/year)

Crystalline Silicon (Fixed Tilt) VNM 4,837,763 8 $ 2.79 $ 11,179,632 $ 387,021 $ (1,007,989.90)

Crystalline Silicon (Single-axis Tracking) VNM 5,337,797 8 $ 3.35 $ 11,688,105 $ 427,024 $ (807,095.57)

Crystalline Silicon (Dual-axis Tracking) VNM 4,839,482 8 $ 3.68 $ 10,979,756 $ 387,159 $ (900,799.34)

Crystalline Silicon (Fixed Tilt) PPA 4,837,763 10.61 $ 2.79 $ 11,179,632 $ 513,066 $ 96,991.21

Crystalline Silicon (Single-axis Tracking) PPA 5,337,797 9.94 $ 3.35 $ 11,688,106 $ 530,635 $ 101,219.94

Crystalline Silicon (Dual-axis Tracking) PPA 4,839,482 10.35 $ 3.68 $ 10,979,756 $ 500,767 $ 95,158.14

a Data assume a maximum usable area of 23 acres was used for all arrays. Array size determined by energy density indicated in Table 1. 

b Number of average American households that could hypothetically be powered by the PV system assuming 11,040 kWh/year/household.

c Job-years created as a result of project capital investment including direct, indirect, and induced jobs.

d Jobs (direct, indirect, and induced) sustained as a result of operations and maintenance (O&M) of the system.

e Assumes a utility rate that increases at 2% per annum and a PPA that increases at 3.5% per annum. Inflation assumed to be 1.5%/year.

U.S. Energy Information Administration. http://www.eia.doe.gov/ask/electricity_faqs.asp#electricity_use_home. Accessed November 2, 2010.
vi 

Table of Contents

1 Study and Site Background................................................................................................................. 1

2 Development of a PV System on Landfill........................................................................................... 3

3 PV Systems ........................................................................................................................................... 5

3.1 PV Overview.................................................................................................................................... 5

3.2 Major System Components.............................................................................................................. 6

3.2.1 PV Module.......................................................................................................................... 6

3.2.2 Inverter................................................................................................................................ 8

3.2.3 Balance-of-System Components......................................................................................... 9

3.2.4 Operation and Maintenance .............................................................................................. 11

3.3 Siting Considerations..................................................................................................................... 11

4 Proposed Installation Location Information.................................................................................... 13

4.1 Sky Park Landfill Site PV System................................................................................................. 13

4.2 Utility-Resource Considerations.................................................................................................... 15

4.3 Useable Acreage for PV System Installation................................................................................. 16

4.4 PV Site Solar Resource.................................................................................................................. 16

4.5 Sky Park Landfill Energy Usage.................................................................................................... 18

4.5.1 Current Energy Use .......................................................................................................... 19

4.5.2 Net Metering..................................................................................................................... 19

4.5.3 Virtual Net Metering......................................................................................................... 20

4.5.4 Community Solar.............................................................................................................. 20

5 Economics and Performance............................................................................................................ 22

5.1 Assumptions and Input Data for Analysis ..................................................................................... 22

5.2 SAM Forecasted Economic Performance ...................................................................................... 25

5.3 Job Analysis and Impact ................................................................................................................ 26

5.4 Financing Opportunities................................................................................................................. 27

5.4.1 Owner and Operator Financing......................................................................................... 27

5.4.2 Third-Party Developers with Power Purchase Agreements.............................................. 28

5.4.3 Third-Party “Flip” Agreements......................................................................................... 28

5.4.4 Hybrid Financial Structures.............................................................................................. 29

5.4.5 Solar Services Agreement and Operating Lease............................................................... 29

5.4.6 Sale/Leaseback.................................................................................................................. 30

6 Conclusions and Recommendations ............................................................................................... 31

Appendix A. Provided Sky Park Landfill Site Information.................................................................... 33

Appendix B. Assessment and Calculations Assumptions................................................................... 34

Appendix C. Solar Access Measurements ............................................................................................. 35

Appendix D. Results of the JEDI Model.................................................................................................. 36

Appendix E. Results of the Solar Advisor Model................................................................................... 39
vii 

List of Figures

Figure 1. Generation of electricity from a PV cell ...........................................................................5

Figure 2. Ground-mounted array diagram .......................................................................................6

Figure 3. Mono- and multi-crystalline solar panels .........................................................................7

Figure 4. Thin-film solar panels installed on (left) solar energy cover and (middle and right) 

fixed-tilt mounting system .........................................................................................................7

Figure 5. String inverter ...................................................................................................................9

Figure 6. 2-MWp PV system with fixed tilt on former landfill in Fort Carson, Colorado ............10

Figure 7. Aerial view of the feasible area (green) for PV at the Sky Park Landfill site ................14

Figure 8. Views of the feasible area for PV at the Sky Park Landfill ............................................15

Figure 9. Solar market insight 2011 year-end summary of PV costs ............................................23

Figure A-1. High resolution plan, available from City of Eau Claire, Wisconsin .........................33

Figure C-1. Solar access measurements for Sky Park Landfill PV site .........................................35

List of Tables

Table ES-1. Sky Park Landfill PV System Summary ......................................................................v

Table 1. Energy Density by Panel and System ..............................................................................10

Table 2. Site Identification Information and Specifications ..........................................................17

Table 3. Performance Results for 45-Degree Fixed-Tilt PV .........................................................17

Table 4. Performance Results for Zero-Degree Single-Axis PV ...................................................18

Table 5. Performance Results for Two-Axis PV ...........................................................................18

Table 6. Installed System Cost Assumptions .................................................................................23

Table 7. PV System Summary .......................................................................................................26

Table 8. JEDI Analysis Assumptions ............................................................................................27

Table B-1. Cost, System, and Other Assessment Assumptions .....................................................34

Table D-1. Summary Results of the NREL JEDI Model ...............................................................36

Table E-1. Summary Inputs and Results for the SAM Model .......................................................39
1 

1 Study and Site Background

The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering 

America’s Land initiative, selected the Sky Park Landfill site in Eau Claire, Wisconsin, 

for a feasibility study of renewable energy production. The National Renewable Energy 

Laboratory (NREL) provided technical assistance for this project. The purpose of this 

report is to assess the site for a possible photovoltaic (PV) system installation and 

estimate the cost, performance, and site impacts of different PV options. In addition, the 

report recommends financing options that could assist in the implementation of a PV 

system at the site. This study did not assess environmental conditions at the site. 

The Sky Park Landfill is a 26-acre site located on the southwest side of Eau Claire, 

Wisconsin, near Highway 37 and I-94. The site operated as a municipal waste facility 

until closure. The present site is capped and unused, except for a small area currently 

being used for excess snow and storm damage vegetation storage. A majority of the site 

has dense vegetation, including trees, which would need to be removed should the entire 

site be developed for a solar array. The City of Eau Claire, Wisconsin, currently owns 

and maintains the site. Located in western Wisconsin, approximately 90 miles from 

Minneapolis, Minnesota, the site experiences an average annual solar resource of 

4.49 kWh/m2

/day. 

Under the RE-Powering America’s Land initiative, EPA Region 5 provided funding to 

NREL to support a feasibility study of solar renewable energy generation at the Sky Park 

Landfill site in Eau Claire, Wisconsin. The site is surrounded by a light industrial park 

zoned for industrial and office uses. Adjacent functions include offices, manufacturers, 

municipal facilities, and a local operations and call center for the utility, Xcel Energy. 

As previously indicated, the site operated as a municipal waste facility from 1948 and 

was ultimately closed in 1965. The site was capped and since that time, significant 

vegetation has grown throughout a majority of the site. Due to the time elapsed, all 

differential settlement of the landfill is assumed to be complete. A small, approximately

half-acre portion of the site, however, has been used for removal and storage of stormdamaged vegetation from throughout the city after a 1980 significant storm event. This 

area still experiences significant differential settlement and is not being considered 

feasible for a solar installation. 

Approximately 3 acres of the site is clear of vegetation and reasonably flat, such that it 

could be developed with minimal site preparation work. The remainder of the site would 

require removal of vegetation and basic grading, which would be undertaken by the site 

owner, the City of Eau Claire. As such, approximately 92%, or 23 acres, of the site is 

considered feasible for a solar installation. As the site owner would be responsible for the 

removal of vegetation and initial grading of the site, the cost of this initial site preparation 

work is not considered in this analysis for the virtual net metering (VNM) scenerio. 

As this site is a historical landfill, all its site contaminants are not known. However, the 

site is considered contained and successfully capped. Long-term ground monitoring is in 

place throughout the perimeter of the site and has not indicated any areas of concern. The 
2 

depth and construction of the landfill cap is mainly 12–18 inches of granular soils, so a 

ballasted system is recommended for this feasibility study, but upon further evaluation of 

this site, it may be possible to develop alternate mounting solutions and the estimated 

installed cost can be reduced accordingly. 

Alternative solutions could include a shallow spread footing foundation or, after 

investigation is completed as to the exact location of the system and ground conditions, a 

more traditional foundation system could be used. All information relating to the history 

of the site and contaminants was provided to the authors and is not independently 

verified. The purpose of this report is not to analyze the contaminants or history but to 

analyze the potential for a solar development. 

The site is not directly served by any utility infrastructure, but it is located in a developed 

industrial park within the City of Eau Claire. The adjacent site occupants are significant 

energy users and the available utility services, including transmission lines, are assumed 

to be capable of supporting up to a 4-MW solar installation, depending on system type. 

Zoning restrictions for the site are minimal and should not affect the implementation of a 

successful solar development. Site access is sufficient, with an existing gravel access road 

that begins at the adjacent public street and ends at the center of the site. The site is 

surrounded to the south and east by industrial properties and is bounded to the north and 

west by Hamilton Avenue. 

Feasibility assessment team members from NREL, the City of Eau Claire, the State of 

Wisconsin, and EPA Region 5 conducted a site visit on May 30, 2012, to gather 

information integral to this feasibility study. The team considered information including 

solar resource, transmission availability, community acceptance, and ground conditions. 
3 

2 Development of a PV System on Landfill

Through the RE-Powering America’s Land initiative, the EPA has identified several 

benefits for siting PV facilities on closed municipal waste landfills, noting that they:

• Can be developed in place of limited greenfields, preserving the land carbon sink 

• May have environmental conditions that are not well-suited for commercial or 

residential redevelopment and may be adequately zoned for renewable energy 

• Generally are located near existing roads and energy transmission or distribution 

infrastructure 

• May provide an economically viable reuse for sites that may have significant 

cleanup costs or low real estate development demand 

• Can provide job opportunities in urban and rural communities 

• Can advance cleaner and more cost-effective energy technologies and reduce the 

environmental impacts of energy systems (e.g., reduce greenhouse gas emissions).

By taking advantage of these potential benefits, PV can provide a viable, beneficial reuse, 

in many cases, generating significant revenue on a site that would otherwise go unused. 

The Sky Park Landfill site is owned by the City of Eau Claire, which is interested in 

potential revenue flows on the site. The city is also interested in opportunities for public 

outreach and demonstration associated with the installation of renewable energy on the 

Sky Park site. For many closed landfill sites, the local community has a significant 

interest in seeing such land be brought into some form of productivity. Thus, community 

engagement is critical to match future reuse options to the city’s vision for the site. 

Understanding studies performed at similar sites demonstrates the potential for PV 

system development. Municipal solid waste landfills such as the Sky Park site in Eau 

Claire are particularly well-suited for solar development because they are often located 

near critical infrastructure, adjacent to a significant population base, are constructed with 

large areas of minimal grade, and have a lower land cost due to limitations on alternative 

uses. Large-scale solar developments have been successfully completed on closed 

landfills in the past, using PV integrated into a geomembrane and ballasted system. As a 

landfill constructed before the 1960s prior to legislation requiring particular construction 

methods, the engineering design, siting criteria, lining, and implementation is relatively 

unknown. As the Sky Park Landfill is already closed, and considering its construction, 

using a ballasted system to minimize impact of the system is expected. 

The subject site may have potential to be used for other functions beyond the solar PV 

systems proposed in this report. Any potential use should align with the community 

vision for the site and should work to enhance the overall utility of the property. A solar 

facility on the site represents a significant opportunity for development. 

Beyond the financial benefits of installing a solar facility and selling the electricity 

produced, there are additional non-financial benefits to consider. There are many 
4 

compelling reasons to consider moving toward renewable energy sources for power 

generation instead of fossil fuels, including: 

• Renewable energy sources offer a sustainable energy option in the broader energy 

portfolio. 

• Renewable energy can have a net positive effect on human health and the 

environment. 

• Deployment of renewable energy bolsters national energy independence and 

increases domestic energy security. 

• Fluctuating electric costs can be mitigated by locking in electricity rates through 

long-term power purchase agreements (PPAs) linked to renewable energy 

systems. 

• Generating energy without harmful emissions or waste products can be 

accomplished through renewable energy sources. 
5 

3 PV Systems

3.1 PV Overview

Solar PV technology converts energy from solar radiation directly into electricity. Solar 

PV cells are the electricity-generating component of a solar energy system. When 

sunlight (photons) strikes a PV cell, an electric current is produced by stimulated

electrons (negative charges) in a cell layer designed to give up electrons easily. The 

existing electric field in the solar cell pulls these electrons to another layer. By 

connecting the cell to an external load, this current (movement of charges) can then be 

used to power the load (e.g., light bulb). 

Figure 1. Generation of electricity from a PV cell

Source: EPA

PV cells are assembled into a PV panel or module. PV modules are then connected to 

create an array. The modules are connected in series and then in parallel, as needed, to 

reach the specific voltage and current requirements for the array. The direct current (DC) 

electricity generated by the array is then converted by an inverter to useable alternating 

current (AC) that can be consumed by adjoining buildings and facilities or exported to the 

electricity grid. PV system size varies from small residential (2–10 kW), to commercial 

(100–500 kW), to large utility scale (10+ MW). Central distribution plants are also 

currently being built in the 100+ MW scale. Electricity from utility-scale systems is 

commonly sold back to the electricity grid. 

(-)

(+)

-

- -

-

Electron

Current flow

-

Solar cell

- - -

Load
6 

3.2 Major System Components

Figure 2. Ground-mounted array diagram

Source: NREL 

A typical PV system is made up of several key components, including: 

• PV modules

• Inverter 

• Balance-of-system components. 

These, along with other PV system components, are discussed in turn below. 

3.2.1 PV Module

Module technologies are differentiated by the type of PV material used, resulting in a 

range of conversion efficiencies from light energy to electrical energy. The module 

efficiency is a measure of the percentage of solar energy converted into electricity. 

Two common PV technologies that have been widely used for commercial- and utilityscale projects are crystalline silicon and thin film. 

3.2.1.1 Crystalline Silicon

Traditional solar cells are made from silicon. Silicon is quite abundant and nontoxic. It 

builds on a strong industry on both supply (silicon industry) and product side. This 

technology has demonstrated consistent and high efficiency for over 30 years in the field. 

The performance degradation (reduction in power generation due to long-term exposure) 

is under 1% per year. Silicon modules have a lifespan of 25–30 years but can keep 

producing energy beyond this range. 
7 

Typical overall efficiency of silicon solar panels is between 12% and 18%. However, 

some manufacturers of mono-crystalline panels claim an overall efficiency nearing 20%. 

This range of efficiencies represents significant variation among the crystalline silicon 

technologies available. The technology is generally divided into mono- and multicrystalline technologies, which indicates the presence of grain-boundaries (i.e., multiple 

crystals) in the cell materials and is controlled by raw material selection and 

manufacturing technique. Crystalline silicon panels are widely used based on 

deployments worldwide. 

Figure 3 shows two examples of crystalline solar panels: mono- and multi-silicon 

installed on tracking mounting systems. 

 Source: SunPower, NREL PIX-23816 Source: NREL PIX-13823 

Figure 3. Mono- and multi-crystalline solar panels

3.2.1.2 Thin Film

Thin-film PV cells are made from amorphous silicon (a-Si) or non-silicon materials such 

as cadmium telluride (CdTe). Thin-film cells use layers of semiconductor materials only 

a few micrometers thick. Due to the unique nature of thin films, some thin-film cells are 

constructed into flexible modules, enabling applications like solar energy covers for 

landfills, such as a geomembrane system. Other thin-film modules are assembled into 

rigid constructions that can be used in fixed-tilt or, in some cases, tracking system 

configurations. 

The efficiency of thin-film solar cells is generally lower than crystalline cells. Current 

overall efficiency of a thin-film panel is between 6% and 8% for a-Si and 11% and 12% 

for CdTe. Figure 4 shows thin-film solar panels.

 Source: NREL PIX-18068 Source: NREL PIX 14726 Source: NREL PIX 17395

Figure 4. Thin-film solar panels installed on (left) solar energy cover and (middle and right) 

fixed-tilt mounting system
8 

Industry standard warranties of both crystalline and thin-film PV panels typically 

guarantee system performance of 80% of the rated power output for 25 years. After 25 

years, they will continue producing electricity at a lower performance level.

3.2.2 Inverter

Inverters convert DC electricity from the PV array into AC and can connect seamlessly to 

the electricity grid. Inverter efficiencies can be as high as 98.5%. 

Inverters also sense the utility power frequency and synchronize the PV-produced power 

to that frequency. When utility power is not present, the inverter will stop producing AC 

power to prevent “islanding” or putting power into the grid while utility workers are 

trying to fix what they assume is a de-energized distribution system. This safety feature is 

built into all grid-connected inverters in the market. Electricity produced from the system 

may be fed to a step-up transformer to increase the voltage to match the grid.

There are two primary types of inverters for grid-connected systems: string and microinverters. Each type has strengths and weaknesses and may be recommended for different 

types of installations. 

String inverters are most common and typically range in size from 1.5 kW to 1,000 kW. 

These inverters tend to be cheaper on a capacity basis, as well as have high efficiency and 

lower operations and maintenance (O&M) costs. String inverters offer various sizes and 

capacities to handle a large range of voltage output. For larger systems, string inverters 

are combined in parallel to produce a single point of interconnection with the grid. 

Warranties typically run 10 years, which is currently the industry standard. On larger 

units, extended warranties up to 20 years are possible. Given that the expected life of the 

PV panels is 25–30 years, an operator can expect to replace a string inverter at least one 

time during the life of the PV system. 

Micro-inverters are dedicated to the conversion of a single PV module’s power output. 

The AC output from each module is connected in parallel to create the array. This 

technology is relatively new to the market and is in limited use in larger systems because 

of the potential increase in O&M associated with significantly increasing the number of 

inverters in a given array. Current micro-inverters range in size between 175 W and 

380 W. These inverters are typically a more expensive option per watt of capacity than 

string inverters. Warranties range from 10–25 years. Projects with irregular modules and 

shading issues usually benefit from micro-inverters. 

With string inverters, small amounts of shading on a solar panel will significantly affect 

the entire array production. Instead, it impacts only that shaded panel if micro-inverters 

are used. Figure 5 shows a string inverter.
9 

Figure 5. String inverter

Source: NREL PIX 07985 

3.2.3 Balance-of-System Components

In addition to the solar modules and inverter, a solar PV system consists of other parts 

called balance-of-system components, which include: 

• Mounting racks and hardware for the panels 

• Wiring for electrical connections. 

3.2.3.1 Mounting Systems 

The array has to be secured and oriented optimally to maximize system output. The 

structure holding the modules is referred to as the mounting system. 

3.2.3.1.1 Ground-Mounted Systems

For ground-mounted systems, the mounting system can be either directly anchored into 

the ground (via driven piers or concrete footers) or ballasted on the surface without 

ground penetration. Mounting systems must withstand local wind loads, which range 

from 90–120 mph for most areas or 130 mph or more for areas with hurricane potential. 

Depending on the region, snow and ice loads must also be a design consideration for the 

mounting system. For landfill applications, mounting system designs will be primarily 

driven by these considerations coupled with settlement concerns. 

Typical ground-mounted systems can be categorized as fixed tilt or tracking. Fixed-tilt 

mounting structures consist of panels installed at a set angle, typically based on site 

latitude and wind conditions, to increase exposure to solar radiation throughout the year. 

Fixed-tilt systems are used at many landfill sites. They have lower maintenance costs but 

generate less energy (kWh) per unit power (kW) of capacity than tracking systems. 

Tracking systems rotate the PV modules so they are following the sun as it moves across 

the sky. This increases energy output but also increases maintenance and equipment costs 

slightly. Single-axis tracking, in which PV is rotated on a single axis, can increase energy 

output up to 25% or more. With dual-axis tracking, PV is able to directly face the sun all 

day, potentially increasing output up to 35% or more. However, depending on underlying 

soiling conditions, single- and dual-axis trackers may not be suitable due to potential 

settlement effects, which can interfere with the alignment requirements of such systems. 
10 

Settlement concerns combined with the higher cost typically limits the economic 

feasibility of dual-axis tracking systems for landfill applications. 

 

Source: NREL PIX 17394 Source: NREL PIX 15280 

Figure 6. 2-MWp PV system with fixed tilt on former landfill in Fort Carson, Colorado

Table 1. Energy Density by Panel and System

System Type Fixed-Tilt Energy 

Density (DCWatts/ft2

) 

Single-Axis 

Tracking Energy 

Density

(DC-Watts/ft

2

)

Dual-Axis Tracking 

Energy Density 

(DC-Watts/ft2

) 

Crystalline 

Silicon

4.0 3.5 3.0

Thin Film 3.3 2.7 2.5

Hybrid HE 4.8 3.9 3.5

The selection of mounting type is dependent on many factors, including installation size, 

electricity rates, government incentives, land constraints, latitude, and local weather. 

Contaminated land applications may raise additional design considerations due to site 

conditions, including differential settlement. 

Selection of the mounting system is also heavily dependent on anchoring or foundation 

selection. Further, the mounting system design will need to meet applicable local building 

code requirements with respect to snow, wind, and seismic zones. Selection of mounting 

types should also consider frost protection needs, especially in cold regions such as 

Wisconsin. 

3.2.3.1.2 Wiring for Electrical Connections

Electrical connections, including wiring, disconnect switches, fuses, and breakers are 

required to meet electrical code (e.g., NEC Article 690) for both safety and equipment 

protection. 
11 

In most traditional applications, wiring from (1) arrays to inverters and (2) inverters to 

point of interconnection is generally run as direct burial through trenches. In landfill 

applications, this wiring may be required to run through above-ground conduit due to 

restrictions with cap penetration or other concerns. Therefore, developers should consider 

noting any such restrictions, if applicable, in requests for proposals in order to improve 

overall bid accuracy. Similarly, it is recommended that PV system vendors reflect these 

costs in the quote when costing out the overall system. 

3.2.3.2 PV System Monitoring 

Monitoring PV systems can be essential for reliable functioning and maximum yield of a 

system. It can be as simple as reading values such as produced AC power, daily kilowatthours, and cumulative kilowatt-hours locally on an LCD display on the inverter. For 

more sophisticated monitoring and control purposes, environmental data such as module 

temperature, ambient temperature, solar radiation, and wind speed can be collected. 

Remote control and monitoring can be performed through various remote connections. 

Systems can send alerts and status messages to the control center or user. Data can be 

stored in the inverter’s memory or in external data loggers for further system analysis. 

Collection of this basic information is standard for solar systems and is not unique to 

landfill applications.

Weather stations are typically installed in large-scale systems. Weather data such as solar 

radiation and temperature can be used to predict energy production, enabling comparison 

of the target and actual system output and performance. It can also identify underperforming arrays. Operators may use this data to identify required maintenance, shade 

on panels, and accumulated dirt on panels, for example. Monitoring system data can also 

be used for outreach and education. This can be achieved with publicly available, online 

displays, wall-mounted systems, or even smartphone applications. 

3.2.4 Operation and Maintenance

PV panels typically have a 25-year performance warranty. The inverters, which come 

standard with a 10-year warranty (extended warranties available), would be expected to 

last 10–15 years. System performance should be verified on a vendor-provided website. 

Wire and rack connections should be checked annually. This economic analysis uses an 

annual O&M cost computed as $20/kW/yr, which is based on the historical O&M costs 

of installed fixed-axis grid-tied PV systems. Single-axis tracking system analysis uses an 

estimated annual O&M cost of $22/kW/yr, and dual-axis tracking system analysis uses an 

estimated annual O&M cost of $25/kW/yr. 

3.3 Siting Considerations

PV modules are very sensitive to shading. When partially or fully shaded, the panel is 

unable to optimally collect the high-energy beam radiation from the sun. As explained 

above, PV modules are made up of many individual cells that collectively produce a 

small amount of current and voltage. These individual cells are connected in series to 

produce a larger current. If an individual cell is shaded, it acts as resistance to the whole 

series circuit, impeding current flow and dissipating power rather than producing it. 
12 

The NREL solar assessment team uses a Solmetric SunEye solar path calculator to assess 

shading at particular locations by analyzing the sky view where solar panels will be 

located. By finding the solar access, the NREL team can determine if the area is 

appropriate for solar panels. 

After the NREL team collects data and determines a site is adequate for a solar 

installation, they need to decide on ideal system size, which depends on the average 

energy use of the facilities on the site, PPAs, incentives available, and utility policy. 
13 

4 Proposed Installation Location Information

This section summarizes the findings of the NREL solar assessment site visit on 

May 30, 2012. 

4.1 Sky Park Landfill Site PV System

As discussed in Section 1, the Sky Park Landfill site is owned and managed by the City 

of Eau Claire. 

The Sky Park Landfill site is sufficiently flat, with a maximum slope estimated to be 

under 2%. Closed in 1965, the site does not currently experience differential settlement at 

high enough levels for concern. Approximately 3 acres of the site is free of vegetation 

and associated shading. The remainder of the site has dense vegetation that would need to 

be removed to facilitate the installation of a solar PV system. The site owner has 

indicated a willingness to remove necessary vegetation and provide basic grading of the 

site in preparation for a solar installation. 

Approximately one-half acre of land still experiences settlement likely beyond acceptable 

levels, due to the landfilling of downed trees and branches following a storm in the 

1980s. This settlement would need to be mitigated before being appropriate for the 

installation of a solar PV system. For the purposes of this report, it is not considered a 

feasible area. 

In order to get the most out of the ground area available, it is important to consider 

whether the site layout can be improved to better incorporate a solar system. If there are 

unused structures, fences, or electrical poles that can be removed, the un-shaded area can 

be increased to incorporate more PV panels. 

Figure 7 shows an aerial view of the Sky Park Landfill site taken from Google Earth; the 

total area of the site is approximated in brown. The green area, inclusive of the blue area, 

demonstrates the potentially feasible area with removal of vegetation. The blue area 

approximates the area available without significant vegetation removal. As shown, there 

are large expanses of relatively flat available land, which makes it suitable for a PV 

system. 

The total site area is 26.41 acres, shown in brown, and the feasible area shown in green is 

approximately 23 acres. Reasonable setbacks from property lines and adjacent shading 

elements, as well as other functional exemptions, were considered in determining the 

total feasible area. The area currently free of trees is approximately 3 acres. 
14 

Figure 7. Aerial view of the feasible area (green) for PV at the Sky Park Landfill site

Illustration done in Google Earth 

PV systems are well-suited to the Eau Claire, Wisconsin, area, where the average global 

horizontal annual solar resource—the total solar radiation for a given location, including 

direct, diffuse, and ground-reflected radiation—is 4.49 kWh/m2/day. 

Figure 8 shows various views of the Sky Park Landfill site. 
15 

Figure 8. Views of the feasible area for PV at the Sky Park Landfill

Photos by Google Maps (top and bottom) & Ned Noel, City of Eau Claire (middle) 

4.2 Utility-Resource Considerations

The expected electrical tie-in point and inverter for the PV system at the Sky Park 

Landfill site is expected to be located along the southern portion of the site, near the 

adjacent industrial development. As the site is surrounded by significant development and 

the system is expected to occupy a majority of the available land, the final location of the 

tie-in point is not expected to have a significant effect on the overall estimated cost of the 

system. The exact location will be dependent on the utility infrastructure in place and 

final design of any proposed system. 
16 

As a landfill on the site closed in 1965, there is not an existing tie-in location already on 

the site, but the location adjacent to industrial properties indicates sufficient capacity for 

the proposed solar system. Coordination with the local utility, Xcel Energy of Wisconsin, 

will be necessary to determine the capacity of the transmission lines. This information 

will be determined during the interconnection application process and system design. 

The allowable trenching of electrical service to and throughout the site will also need to 

be considered. Any limitations on typical trenching installations may adversely affect the 

expected cost of development. When developing a ground-mounted system, an electrical 

tie-in location will need to be identified to determine how the energy would be fed back 

into the grid. 

4.3 Useable Acreage for PV System Installation 

Typically, a minimum of 2 useable acres is recommended to site commercial-scale PV 

systems. Useable acreage is typically characterized as "flat to gently sloping," with 

southern exposures that are free from obstructions. This acreage would get full sun for at 

least a 6-hour period each day. For example, eligible space for PV includes under-utilized 

or unoccupied land, vacant lots, and/or unused paved area (e.g., a parking lot, industrial 

site space, or existing building rooftops). 

4.4 PV Site Solar Resource

The Sky Park Landfill site has been evaluated to determine the adequacy of the available 

solar resources, using both on-site data and industry tools. 

The assessment team for this feasibility study collected multiple Solmetric SunEye 

datapoints and found a solar access of 97% in the presently un-shaded area. Some 

peripheral shading is expected due to remaining trees and adjacent facilities to the site but 

is expected to be minimal. All data gathered using this tool is available in Appendix C.

Even following complete removal of trees on the site in preparation for a solar 

installation, the maximum assumed solar access for the area is approximately 98% due to 

peripheral shading and shading from other panels and equipment. Assuming that 

necessary clearing would occur, the financial analysis uses a 98% solar access factor. 

The predicted array performance was found using PVWatts Version 21 for Eau Claire, 

Wisconsin. Table 2 shows the station identification information, PV system 

specifications, and energy specifications for the site. For this summary array performance 

information, a hypothetical system size of 1 kW was used to show the estimated 

production for each kilowatt so that additional analysis can be performed using the data 

indicated below. It can be scaled linearly to match the proposed system size. 

 

1 http://www.nrel.gov/rredc/pvwatts/.
17 

Table 2. Site Identification Information and Specifications

Station Identification

City Eau Claire

State Wisconsin

Latitude 44.87° N

Longitude 91.48° W

PV System Specifications

DC Rating 1.00 kW

DC to AC Derate Factor 0.8 

AC Rating 0.8 kW

Array Type Fixed-Tilt 

Array Tilt 44.9° 

Array Azimuth 180°

Energy Specifications

Cost of Electricity $0.08/kWh

Table 3 shows the performance results for a latitude-matched fixed-tilt PV system in Eau 

Claire, Wisconsin, as calculated by PVWatts. 

Table 3. Performance Results for 45-Degree Fixed-Tilt PV

Month Solar Radiation

(kWh/m2

/day)

AC Energy

(kWh)

Energy Value

($)

1 3.29 89 7.12

2 4.63 110 8.80

3 5.24 134 10.72

4 4.84 114 9.12

5 5.42 125 10.00

6 5.61 121 9.68

7 5.67 127 10.16

8 5.31 118 9.44

9 4.68 103 8.24

10 3.82 92 7.36

11 2.46 58 4.64

12 2.33 60 4.80

Year 4.44 1,253 100.24

Table 4 shows the performance results for a zero-tilt single-axis tracking PV system in 

Eau Claire, Wisconsin, as calculated by PVWatts. 
18 

Table 4. Performance Results for Zero-Degree Single-Axis PV

Month Solar Radiation

(kWh/m2/day)

AC Energy

(kWh)

Energy Value

($)

1 3.77 102 8.16

2 5.44 130 10.40

3 6.28 162 12.96

4 6.02 144 11.52

5 7.23 172 13.76

6 7.47 166 13.28

7 7.82 174 13.92

8 6.91 157 12.56

9 5.86 131 10.48

10 4.53 110 8.80

11 2.76 66 5.28

12 2.62 68 5.44

Year 5.53 1,584 126.72

Table 5 shows the performance results for a two-axis tracking PV system in Eau Claire, 

Wisconsin, as calculated by PVWatts. 

Table 5. Performance Results for Two-Axis PV

Month Solar Radiation

(kWh/m2

/day)

AC Energy

(kWh)

Energy Value

($)

1 4.03 109 8.72

2 5.64 135 10.80

3 6.40 165 13.20

4 6.30 151 12.08

5 7.94 189 15.12

6 8.40 187 14.96

7 8.33 192 15.36

8 7.36 168 13.44

9 6.00 135 10.80

10 4.59 111 8.88

11 2.83 68 5.44

12 2.80 73 5.84

Year 5.89 1,682 134.56

4.5 Sky Park Landfill Energy Usage

When considering a site for a PV installation, it is important to understand the energy use 

of the site to enable a full analysis that considers whether energy produced would need to 

be sold or if it could offset on-site energy use.
19 

4.5.1 Current Energy Use

The Sky Park Landfill site does not have any energy-consuming facilities or electric 

service on-site at this time. Since closure, the site has not been utilized for any energyconsuming purpose. The site does contain, however, several ground-monitoring wells 

along the perimeter of the site. The site is not currently served by the local utility, Xcel 

Energy, but it would likely be considered a commercial property should a significant PV 

installation be proposed. 

Current information on the Eau Claire electric rates was supplied by an Xcel Energy 

analysis of the average blended rate the city pays. Published rates are also available on 

the Xcel Energy website.2 The serving utility, Xcel Energy of Wisconsin, is operated by 

the Northern States Power Company-Wisconsin and is regulated by the Public Service 

Commission of Wisconsin. 

4.5.2 Net Metering

Net metering is an electricity policy for consumers who own renewable energy facilities. 

"Net," in this context, is used to mean "what remains after deductions"—in this case, the 

deduction of any energy outflows from metered energy inflows. Under net metering, a 

system owner receives retail credit for at least a portion of the electricity the system

generates. As part of the Energy Policy Act of 2005, under Sec. 1251, all public electric 

utilities are required upon request to make net metering available to their customers:

(11) NET METERING.—Each electric utility shall make available upon 

request net metering service to any electric consumer that the electric 

utility serves. For purposes of this paragraph, the term ‘net metering 

service’ means service to an electric consumer under which electric energy 

generated by that electric consumer from an eligible on-site generating 

facility and delivered to the local distribution facilities may be used to 

offset electric energy provided by the electric utility to the electric 

consumer during the applicable billing period. 

In 2009, the Wisconsin Public Utility Commission considered whether and how to 

expand the availability and use of advanced renewable tariffs, also known as feed-in 

tariffs, in Wisconsin. The commission concluded that federal and state law limited 

authority to order any Wisconsin utility to offer an advanced renewable tariff and 

recommended that tariffs only be voluntarily offered by willing utilities. 

Renewable energy certificates (RECs),

3 also known as green certificates, green tags, or 

tradable renewable certificates, are tradable commodities in the United States that 

represent proof of electric energy generation from eligible renewable energy resources 

(renewable electricity). The RECs that are associated with the electricity produced and 

are used on-site remain with the customer-generator. If, however, the customer chooses 

to receive financial compensation for the REC remaining after a 12-month period, the 

utility will be granted the RECs associated with only that surplus they purchase. 

 

2 Current electric rates: http://www.xcelenergy.com/My_Account/Understand_Bill/Bill_Details/WI_Rates. 3 For a description of RECs, see http://apps3.eere.energy.gov/greenpower/markets/

certificates
20 

4.5.3 Virtual Net Metering

Some states and utilities allow for virtual net metering (VNM). This arrangement can 

allow certain entities, such as a local government, to install renewable generation at one 

location within its geographic boundary and to generate credits that can be used to offset 

charges at one or more other locations within the same geographic boundary. 

Often, separate allowances for VNM can be made for government facilities. Local 

government can be defined to include cities, counties, school districts, special districts, 

political subdivisions, or other local public agencies that are authorized to generate 

electricity. Because the subject site is owned by the City of Eau Claire, it may qualify for 

VNM, should the utility choose to enable such an installation. The Xcel Energy customer 

representative for the site should be asked if VNM is an option. For the purposes of this 

analysis, it is assumed that some form of VNM was acceptable and that the cost of 

electricity offset by the installed PV system is the city’s average blended commercial rate 

of $0.08/kWh. 

If Xcel Energy were to allow VNM, energy use for the entire site could be offset by a 

larger system. This would also allow all generated energy to be fed into the closest Xcel

connection point and would avoid the need to determine a PPA with Xcel. A new 

transformer would be required. A “feed-in” meter would be installed and would credit the 

other meters on-site. 

4.5.4 Community Solar

The concept of “community solar” is one in which the costs and benefits of one large 

solar project are shared by a number of participants. A site owner may be able to make 

the land available for a large solar project, which can be the basis for a community solar 

project. Ownership structures for these projects vary, but the large projects are typically 

owned or sponsored by a local utility. 

Community solar gardens are distributed solar projects wherein utility customers have a 

stake via a pro-rated share of the project’s energy output. This business model is targeted 

to meet demand for solar projects through customers who rent/lease homes or businesses, 

do not have good solar access at their site, or do not want to install solar systems on their 

facilities. Customer pro-rated shares of solar projects are acquired through a long-term 

transferrable lease of one or more panels or through subscription to a share of the project 

in terms of a specific level of energy output or the energy output of a set amount of 

capacity. 

Under the customer lease option, the customer receives a billing credit for the number of 

kilowatt-hours their pro-rated share of the solar project produces each month; it is also 

known as VNM. Under the customer subscription option, the customers typically pay a 

set price for a block of solar energy (i.e., 100 kWh per-month blocks) from the 

community solar project. Other models include monthly energy outputs from a specific 

investment dollar amount or from a specific number of panels. 

Community solar gardens and customer subscription-based projects can be solely owned 

by the utility, solely owned by third-party developers with facilitation of billing provided 
21 

by the utility, or be a joint venture between the utility and a third-party developer leading 

to eventual ownership by the utility after the tax benefits have been absorbed by the thirdparty developer. 

There are some states that offer solar incentives for community solar projects, including 

Washington (production incentive) and Utah (state income tax credit). Community solar 

is known as solar gardens depending on the location (e.g., Colorado). 

Xcel Energy recently offered a community solar program in Colorado called 

Solar*Rewards Community4 that proved to be extremely popular. It became fully 

subscribed within 30 minutes of release. The system was set up so that subscribing 

customers could purchase an interest in a solar garden developed by the community and 

benefit from the production of that system. The subscriber organization was able to install 

a system and receive production incentives from Xcel energy. The popularity of this 

system may increase interest in supporting this type of development in states such as 

Wisconsin in the future. At this time, however, community solar is not offered by Xcel 

Energy in Wisconsin. If this is a solution of interest to the site, interested parties should 

develop potential purchasers and the overall structure of the system before presenting 

interest to the local utility. 

Xcel Energy also recently offered the “Experimental Advanced Renewable Energy 

Purchase Service”5 tariff program, wherein distributed generation facilities are offered an 

advanced renewable energy tariff for the purchase of electricity produced. The service 

did reference some “community-based projects” for biomass/biogas and wind 

developments; however, community systems were not offered for solar, and the 

maximum system size for solar was listed as 10 kW. Due to the scale of the site, this 

tariff program is not feasible for the Sky Park Landfill site. 

If interested in this option, the site will need to work with the state public service 

commission and the local utility to develop an approach that meets local requirements 

and expectations. 

 

4 Xcel Energy Colorado Solar*Rewards Community: 

http://www.xcelenergy.com/Save_Money_&_Energy/For_Your_Home/Renewable_Energy_Programs/Sola

r*Rewards_Community_2_-_CO. 5 Sheet No. E54.2: http://www.xcelenergy.com/staticfiles/xe/Regulatory/2We_Section_3.pdf. 
22 

5 Economics and Performance

The economic performance of a PV system installed on the site is evaluated using a 

combination of the assumptions and background information discussed previously, as 

well as a number of industry-specific inputs determined by other studies. In particular, 

this study uses the NREL System Advisor Model (SAM).6 

SAM is a performance and economic model designed to facilitate decision making for 

people involved in the renewable energy industry, ranging from project managers and 

engineers to incentive program designers, technology developers, and researchers. 

SAM makes performance predictions for grid-connected solar, solar water heating, wind, 

and geothermal power systems and makes economic calculations for projects that buy 

and sell power at retail rates and power projects that sell power through a PPA. 

SAM calculates a system's energy output on an hourly basis (sub-hourly simulations are 

available for some technologies). The financial model calculates annual project cash 

flows over a period of years for a range of financing structures for residential, 

commercial, and utility projects. 

SAM makes performance predictions for grid-connected solar, small wind, and 

geothermal power systems and provides economic estimates for distributed energy and 

central generation projects. The model calculates the cost of generating electricity based 

on information provided about a project's location, installation and operating costs, type 

of financing, applicable tax credits and incentives, and system specifications.

5.1 Assumptions and Input Data for Analysis

Cost of a PV system depends on the system size and other factors, such as geographic 

location, mounting structure, and type of PV module. Based on significant cost 

reductions seen in 2011, the average cost for utility-scale ground-mounted systems have 

declined from $4.80/W in Q1 2010 to $3.20/W in Q4 2011. With an increasing demand 

and supply, further cost reduction is expected as market conditions evolve. Figure 9 

shows the cost per watt of a PV system from 2010 to 2011 for utility-scale projects.

 

6 For additional information on the NREL Solar Advisor Model, see https://sam.nrel.gov/cost. 
23 

Figure 9. Solar market insight 2011 year-end summary of PV costs7

NREL recently released the Residential, Commercial, and Utility-Scale Photovoltaic 

(PV) System Prices in the United States: Current Drivers and Cost-Reduction 

Opportunities report, which cites the 2011 benchmark price at $2.79/W for utility 

ground-mounted fixed-axis systems. 8

As the system for this site is not expected to be installed until Q4 2012 at the earliest, and 

the trends in price reduction have continued, the assumed installed cost for a fixed-tilt 

ground-mounted system is assumed to be $2.232/W. The installed cost of single-axis

tracking was assumed to be $3.348/W. 

The estimated increase in cost from this baseline for a ballasted system is 25%. This 

increased cost is due to limitations placed on design and construction methods due to the 

ground conditions at the site. Such limitations include restrictions on storm water runoff, 

weight loading of construction equipment, inability to trench for utility lines, additional 

engineering costs, permitting issues, and non-standard ballasted racking systems. The 

installed system cost assumptions are summarized in Table 6. 

Table 6. Installed System Cost Assumptions

System Type Fixed-Tilt 

($/Wp) 

Single-Axis 

Tracking 

($/Wp)

Dual-Axis Tracking 

($/Wp)

Baseline 

system

2.232 2.67 2.944

With ballast 0.558 0.678 0.736

Total installed 

cost

2.79 3.348 3.68

 

7 Data and figure drawn from the Solar Energy Industries Association “SEIA/GTM Research U.S. Solar 

Market Insight” 2011 year-end report. See http://www.seia.org/cs/research/SolarInsight. 8 Forecast of U.S. solar pricing: http://www.nrel.gov/docs/fy12osti/53347.pdf. 
24 

These prices include the PV array and the balance-of-system components for each 

system, including the inverter and electrical equipment as well as the installation cost. It 

covers estimated taxes and a national-average labor rate but does not include land cost. 

The economics of grid-tied PV depend on incentives, the cost of electricity, the solar 

resource, and panel tilt and orientation. For this analysis, the cost of electricity was 

assumed to be $0.08/kW, increasing at 2% annually, as indicated earlier with the 

assumption that a VNM agreement could be established with Xcel Energy to use the 

installed system to offset other city energy use. 

An alternative scenario to VNM could be to develop a lease agreement with an adjacent 

industrial property to provide a behind-the-meter solar electric system. If the City of Eau 

Claire were able to develop a scenario where electricity produced by a solar system 

located on the Sky Park Landfill could be sold through a PPA to an adjacent facility to 

offset electricity already being used, a favorable economic situation could result. In this 

scenario, the value of the electricity produced by the system would correlate to the energy 

price being paid by the industrial facility. As indicated previously, the average blended 

rate for the City of Eau Claire is approximately $0.08/kWh. A small industrial property 

may have a higher blended rate and may pay based on the peak demand charge. If the 

facilities peak usage is correlated to a time of day when solar production is expected, the 

peak demand charge may be reduced significantly, often leading to a very significant 

savings compared to typical use, adding value to the renewable energy system. 

While not established by the public service commission (PSC) or the utility at this time, 

VNM or community solar gardens are considered the most economically feasible solution 

for the site. A PPA with the utility would not be expected to result in an economically 

favorable installation. If the city is subject to time-of-use rates or peak demand charges, 

the economic feasibility of the system will likely become more favorable. If annual 

electric rate changes for the city increase faster than the 2%/annum assumed for this 

analysis, the system becomes significantly more favorable. 

It was assumed for this analysis that relevant federal incentives are received. It is 

important to consider all applicable incentives or grants to make PV as cost-effective as 

possible. If the PV system is owned by a private tax-paying entity, this entity may qualify 

for a federal tax credit and accelerated depreciation on the PV system, which can be 

worth about 15% of the initial capital investment. The total potential tax benefits for the 

tax-paying entity can be as high as 45% of the initial system cost. Because state and 

federal governments do not pay taxes, private ownership of the PV system would be 

required to capture tax incentives. 

For the purposes of this analysis, the project is expected to have a 25-year life, although 

systems can be reasonably expected to continue operation past this point. Inflation is 

assumed to be 1.5%, with the real discount rate at 5.85% and financing secured via a 15-

year loan at a 6% interest rate and 55% debt fraction. Should the site choose to own and 

operate the system itself as a city-owned entity, there may be options for lower interest 
25 

rate loans, such as the Board of Commissioners of Public Lands State Trust Fund Loan, 

fixed at a maximum level of 3.75%.9 

The panels are assumed to have a 0.5%/yr degradation in performance. The O&M 

expenses are estimated to be $20/kW/yr for a fixed-tilt system, $22/kW/yr for a singleaxis system, and $25/kW/yr for a dual-axis system. A system DC-to-AC conversion of 

80% was assumed. This includes losses in the inverter, wire losses, PV module losses, 

and losses due to temperature effects. PVWatts Version 2 was used to calculate expected

energy performance for the system. 

5.2 SAM Forecasted Economic Performance

Using the inputs and assumptions summarized in the Section 5 of this report, the SAM 

tool predicts the internal rate of return (IRR) and the levelized cost of energy (LCOE). 

For a 4-MW fixed-tilt system—assuming that VNM was permitted, the system was 

owned and operated by a tax-paying third party, and all of the energy produced would 

offset energy that the city would otherwise have used while paying a rate of 

$0.08/kWh—the system could yield an after-tax NPV of -$1,007,989.90 on first-year 

annual revenue, beginning at $387,021/yr. 

The system would be expected to produce approximately 4.8 MWh annually with an 

LCOE of approximately $0.0846/kWh. The complete results and summary of inputs for

SAM are available in Appendix E. The system would require 20 acres of land. 

Alternatively, for a 3.6-MW single-axis tracking system—assuming that VNM was 

permitted, the system was owned and operated by a tax-paying third party, and all of the 

energy produced would offset energy that the city would otherwise have used while 

paying a rate of $0.08/kWh—the system could yield an after-tax NPV of -$807,095.57 on 

annual revenue, beginning at $427,024/year. The system would be expected to produce 

approximately 5.3 MWh annually with an LCOE of approximately $0.0793/kWh. 

A potential dual-axis system was also considered. A 4-MW dual-axis tracking system 

under VNM and owned by a third party would expect an after-tax NPV of -$900,799.34 

on annual revenue beginning at $365,771, escalating thereafter. Estimated production is 

4,572,138 kWh/yr.

A summary of the results of the economic analysis and the system considered is available 

in Table 7. 

In addition, an alternate scenario wherein a PPA is established for the site was 

considered; results are summarized in Table 7. With an IRR of 8% and a PPA that 

escalates at 3.5%/annum, a 4-MW system would have an after-tax NPV of $96,991.21 

and a 3.5-MW single-axis system would have an after-tax NPV of $101,219. 

 

9 Additional information on the BCPL State Trust Fund Loan: http://bcpl.state.wi.us/.
26 

Table 7. PV System Summary

5.3 Job Analysis and Impact

To evaluate the impact on employment and economic impacts of the PV project 

associated with this analysis, the NREL Jobs and Economic Development Impact (JEDI) 

models were used.

10 The JEDI models are tools that estimate the economic impacts 

associated with the construction and operation of distributed generation power plants. 

JEDI is a flexible input-output tool that estimates, but does not precisely predict, the 

number of jobs and economic impacts that can be reasonably supported by a proposed 

facility. 

The JEDI models represent entire economies, including cross-industry or cross-company 

impacts. For example, JEDI estimates the impact that the installation of a distributed 

generation facility would have on not only the manufacturers of PV modules and 

inverters but also the associated construction materials, metal fabrication industry, project 

management support, transportation, and other industries that are required to enable the 

procurement and installation of the complete system. 

For this analysis, inputs including the estimated installed project cost ($/kW), targeted 

year of construction, system capacity (kW), O&M costs ($/kW), and location were 

entered into the model to predict the jobs and economic impact. It is important to note 

that the JEDI model does not predict or incorporate any displacement of related economic 

activity or alternative jobs due to the implementation of the proposed project. As such, 

the JEDI model results are considered gross estimates as opposed to net estimates. 

 

10 The JEDI models have been used by the U.S. Department of Energy, the U.S. Department of Agriculture, 

NREL, and the Lawrence Berkeley National Laboratory, as well as a number of universities. For 

information on the NREL Jobs and Economic Development Impact tool, see 

http://www.nrel.gov/analysis/jedi/about_jedi.html.

System Type

Financial 

Model PV System Sizea Array Tilt Annual Output

Number of 

Houses 

Poweredb

Construction 

Period Jobsc Jobs Sustainedd

(kW) (deg) (kWh/year)

Crystalline Silicon (Fixed Tilt) VNM 4,007.52 LAT 4,837,763 438.2 n/a n/a

Crystalline Silicon (Single-axis Tracking) VNM 3,506.58 n/a 5,337,797 483.5 130.9 1.4

Crystalline Silicon (Dual-axis Tracking) VNM 3,005.64 n/a 4,572,138 414.1 n/a n/a

Crystalline Silicon (Fixed Tilt) PPA 4,007.52 LAT 4,837,763 438.2 130.9 1.4

Crystalline Silicon (Single-axis Tracking) PPA 3,506.58 n/a 5,337,797 483.5 n/a n/a

Crystalline Silicon (Dual-axis Tracking) PPA 3,005.64 n/a 4,572,138 414.1 n/a n/a

System Type

Financial 

Model Annual Output

Cost of 

Electricty/PPA Pricee System Cost

Total System 

Cost

1ST Year 

Savings/Revenue After-tax NPV

(kWh/year) (¢/kWh) ($/watt) ($/year)

Crystalline Silicon (Fixed Tilt) VNM 4,837,763 8 $ 2.79 $ 11,179,632 $ 387,021 $ (1,007,989.90)

Crystalline Silicon (Single-axis Tracking) VNM 5,337,797 8 $ 3.35 $ 11,688,105 $ 427,024 $ (807,095.57)

Crystalline Silicon (Dual-axis Tracking) VNM 4,839,482 8 $ 3.68 $ 10,979,756 $ 387,159 $ (900,799.34)

Crystalline Silicon (Fixed Tilt) PPA 4,837,763 10.61 $ 2.79 $ 11,179,632 $ 513,066 $ 96,991.21

Crystalline Silicon (Single-axis Tracking) PPA 5,337,797 9.94 $ 3.35 $ 11,688,106 $ 530,635 $ 101,219.94

Crystalline Silicon (Dual-axis Tracking) PPA 4,839,482 10.35 $ 3.68 $ 10,979,756 $ 500,767 $ 95,158.14

a Data assume a maximum usable area of 23 acres was used for all arrays. Array size determined by energy density indicated in Table 1. 

b Number of average American households that could hypothetically be powered by the PV system assuming 11,040 kWh/year/household.

c Job-years created as a result of project capital investment including direct, indirect, and induced jobs.

d Jobs (direct, indirect, and induced) sustained as a result of operations and maintenance (O&M) of the system.

e Assumes a utility rate that increases at 2% per annum and a PPA that increases at 3.5% per annum. Inflation assumed to be 1.5%/year.

U.S. Energy Information Administration. http://www.eia.doe.gov/ask/electricity_faqs.asp#electricity_use_home. Accessed November 2, 2010.
27 

For the Sky Park Landfill site, the values in Table 8 were assumed using the single-axis 

tracking system example. 

Table 8. JEDI Analysis Assumptions

Input Assumed Value

Capacity 4,007 kW

Placed In Service Year 2013 

Installed System Cost $11,688,105

Location Eau Claire, WI

Using these inputs, the JEDI tool estimates the gross direct and indirect jobs, associated 

earnings, and total economic impact supported by the construction and continued 

operation of the proposed PV system. 

The estimates of jobs associated with this project are presented as either construction 

period jobs or sustained operations jobs. Each job is expressed as a whole or fraction fulltime equivalent (FTE) position. An FTE is defined as one person working 40 hours per 

week for the duration of a year. Construction period jobs are considered short-term 

positions that exist only during the procurement and construction periods. 

As indicated in the results of the JEDI model analysis provided in Appendix D, the total 

proposed system is estimated to support 111.9 direct, indirect, and induced FTE jobs for 

the duration of the procurement and construction period. Total wages paid to workers 

during the construction period are estimated to be $4,784,400, and total economic output 

is estimated to be $14,465,700. The annual O&M of the new PV system is estimated to 

support 1.4 FTEs per year for the life of the system. The jobs and associated spending are 

projected to account for approximately $65,600 in earnings and $123,400 in economic 

activity each year for the next 25 years. 

5.4 Financing Opportunities

The procurement, development, construction, and management of a successful utilityscale distributed generation facility can be owned and financed a number of different 

ways. The most common ownership and financing structures are described below. 

5.4.1 Owner and Operator Financing

The owner/operator financing structure is characterized by a single entity with the 

financial strength to fund all of the solar project costs and, if a private entity, sufficient 

tax appetite to utilize all of the project’s tax benefits. Private owners/operators typically 

establish a special purpose entity (SPE) that solely owns the assets of the project. An 

initial equity investment into the SPE is funded by the private entity using existing funds, 

and all of the project’s cash flows and tax benefits are utilized by the entity. This equity 

investment is typically matched with debt financing for the majority of the project costs. 

Project debt is typically issued as a loan based on the owners’/operators’ assets and 
28 

equity in the project. In addition, private entities can utilize any federal tax credits 

offered. 

For public entities that choose to finance, own, and operate a solar project, funding can be 

raised as part of a larger, general obligation bond; as a standalone tax credit bond; 

through a tax-exempt lease structure, bank financing, grant and incentive programs, or 

internal cash; or some combination of the above. Certain structures are more common 

than others and grant programs for solar programs are on the decline. Regardless, as taxexempt entities, public entities are unable to benefit directly from the various tax creditbased incentives available to private companies. This has given way to the common use 

of third-party financing structures such as the PPA. 

5.4.2 Third-Party Developers with Power Purchase Agreements

Because many project site hosts do not have the financial or technical capabilities to 

develop a capital-intensive project, many times they turn to third-party developers (and/or 

their investors). In exchange for access to a site through a lease or easement arrangement, 

third-party developers will finance, develop, own, and operate solar projects utilizing 

their own expertise and sources of tax equity financing and debt capital. 

Once the system is installed, the third-party developer will sell the electricity to the site 

host or local utility via a PPA—a contract to sell electricity at a negotiated rate over a 

fixed period of time. The PPA typically will be between the third-party developer and the 

site host if it is a retail behind-the-meter transaction or directly with an electric utility if it 

is a wholesale transaction. 

Site hosts benefit by either receiving competitively priced electricity from the project via 

the PPA or land lease revenues for making the site available to the solar developer via a 

lease payment. This lease payment can take on the form of either a revenue-sharing 

agreement or an annual lease payment. In addition, third-party developers are able to 

utilize federal tax credits. For public entities, this arrangement allows them to utilize the 

benefits of the tax credits (low PPA price, higher lease payment) while not directly 

receiving them. The terms of a PPA typically vary from 20–25 years. 

5.4.3 Third-Party “Flip” Agreements

The most common use of this model is a site host working with a third-party developer 

who then partners with a tax-motivated investor in an SPE that would own and operate 

the project. Initially, most of the equity provided to the SPE would come from the tax 

investor and most of the benefit would flow to the tax investor (as much as 99%). When 

the tax investor has fully monetized the tax benefits and achieved an agreed-upon rate of 

return, the allocation of benefits and majority ownership (95%) would “flip” to the site 

host (but not within the first 5 years). After the flip, the site host would have the option to 

buy out all or most of the tax investor’s interest in the project at the fair market value of 

the tax investor’s remaining interest. 

A flip agreement can also be signed between a developer and investors within an SPE, 

where the investor would begin with the majority ownership. Eventually, the ownership 

would flip to the developer once investors’ return is met. 
29 

5.4.4 Hybrid Financial Structures

As the solar market evolves, hybrid financial solutions have been developed in certain 

instances to finance solar projects. One particular structure, nicknamed “The Morris 

Model”11 after Morris County, New Jersey, combines highly rated public debt, a capital 

lease, and a PPA. Low-interest public debt replaces more costly financing available to the 

solar developer and contributes to a very attractive PPA price for the site hosts. 

In addition, new markets tax credits, which were established by Congress in 2000 to 

encourage investments in low-income communities, can be leveraged in combination 

with PPAs and public debt to reduce the overall tax liability. The credit, claimed over 

7 years, totals 39% of the original investment amount. New markets tax credits have been 

combined with PPAs and public debt in other locations, such as Denver and Salt Lake 

City. Additional information on new markets tax credits has been compiled by NREL12

and the Department of the Treasury Community Development Financial Institutions 

Fund.13 

5.4.5 Solar Services Agreement and Operating Lease

The solar services agreement (SSA) and operating lease business models have been 

predominantly used in the municipal and cooperative utility markets due to their

treatment of tax benefits and the rules limiting federal tax benefit transfers from nonprofit to for-profit companies. Under IRS guidelines, municipalities cannot enter capital 

leases with for-profit entities when the for-profit entities capture tax incentives. As a 

result, a number of business models have emerged to circumvent this issue. 

One model is the SSA, wherein a private party sells “solar services” (i.e., energy and 

RECs) to a municipality over a specified contract period (typically long enough for the 

private party to accrue the tax credits). The non-profit utility typically purchases the solar 

services with either a one-time up-front payment equal to the turnkey system cost minus 

the 30% federal tax credit or may purchase the services in annual installments. The 

municipality may buy out the system once the third party has accrued the tax credits, but 

due to IRS regulations, the buyout of the plant cannot be included as part of the SSA (i.e., 

it cannot be used as a vehicle for a sale and must be a separate transaction).

Similar to the SSA, there are a variety of lease options that are available to municipalities 

that allow the capture of tax benefits by third-party owners, which result in a lower cost 

to the municipality. These include an operating lease for solar services (as opposed to an 

equipment capital lease) and a complex business model called a “sale/leaseback.” Under 

the sale/leaseback model, the municipality develops the project and sells it to a thirdparty tax equity investor who then leases the project back to the municipality under an 

operating lease. At the end of the lease period, and after the tax benefits have been 

absorbed by the tax equity investor, the municipality may purchase the solar project at 

fair market value. 

 

11 For more information on the Morris Model: http://www.co.morris.nj.us/improvement/renewable.asp. 12 New markets tax credits NREL fact sheet: http://www.nrel.gov/docs/fy10osti/49056.pdf. 13 Community Development Financial Institutions Fund: 

http://www.cdfifund.gov/what_we_do/programs_id.asp?programid=5.
30 

5.4.6 Sale/Leaseback

In this widely accepted model, the public or private entity would install the PV system, 

sell it to a tax investor, and then lease it back. As the lessee, they would be responsible 

for operating and maintaining the solar system as well as have the right to sell or use the 

power. In exchange for use of the solar system, the public or private entity would make 

lease payments to the tax investor (the lessor). The tax investor would have rights to 

federal tax benefits generated by the project and the lease payments. Sometimes, the 

entity is allowed to buy back the project at 100% fair market value after the tax benefits 

are exhausted. 
31 

6 Conclusions and Recommendations 

The site locations considered for a solar PV system in this report are reasonable areas for 

the implementation of solar PV systems. Installing a 3.6-MW single-axis tracking PV 

system on the Sky Park Landfill with VNM for the city could offset approximately 

$427,024 in energy costs during the first year of operation for the city. It would represent 

a significant distributed generation facility for the area. 

Additionally, reusing land that cannot be used for other purposes would minimize the 

environmental impact of the site. While the net present value for a VNM installation 

would be negative, the value to the City of Eau Claire towards meeting its 25% by 2025 

renewable energy goal, positive press, or other non-financial benefits may exceed this

cost. If electricity rates were to increase faster than the 2%/annum used in this analysis, 

the feasibility of the system would increase. 

As summarized in Section 5, the economic analysis completed using SAM predicts a 

negative net present value for fixed, single-axis, and dual-axis tracking systems installed 

at the site when using the average blended city cost of electricity of $0.08/kWh, should 

VNM with other city properties be allowed. 

It should be noted that, as the site does not have significant energy use without VNM or 

community solar, the site would need to establish a PPA with the local utility to sell the 

electricity generated or establish a lease agreement with an adjacent facility to develop a 

behind-the-meter system wherein the site is leased to a developer who develops the 

system and sells the resultant energy to the adjacent consumer through a PPA. In order to 

earn an IRR of 8%, a PPA of about $0.10/kWh increasing at 3% annually would need to 

be established. This represents the expected minimum allowable IRR for a third-party 

developer and is therefore considered the breakeven price for this type of system. If the 

utility, or adjacent energy consumer, were willing to purchase electricity at this rate, the 

system would be considered feasible. This analysis also assumes that a third party owns 

and operates the system, enabling it to take advantage of tax credits. The fee for using the 

site would be negotiated through the city as the owner of the land and the site developer. 

Due to the low blended cost of electricity paid by the city, low cost of electricity 

produced by Xcel Energy, limited interest in VNM on behalf of the utilty, and lack of onsite energy use, opportunities for solar system development at the Sky Park Landfill site 

are limited. Potential opportunities may exist if a behind-the-meter system could be 

developed in partnership with an adjacent industrial consumer, if the Wisconsin PSC 

establishes a market for RECs or requires utilities to purchase distributed generation solar 

electricity at a higher rate, or if the cost of electricity increases significantly. 

When reviewing proposals for a PV system to be installed at this site, evaluation criteria 

should include the annual output (kWh/yr) as well as PPA price per kilowatt-hour for the 

electricity produced. Ideally, the price should be below the current cost of energy for the 

purchaser to ensure a positive return. A design-build contract can enable vendors to 

optimize system configuration, including slope and tracking requirements, or a specific 

system design can be required of the vendor. 
32 

As the cost of energy increases, the cost of PV continues to decline, and increased 

opportunities for distributed generation are developed with the local utility, the 

opportunity for successful development of a PV system on the Sky Park Landfill site will 

become more favorable. A PV system may be a reasonable use for the site if an 

appropriate opportunity to sell the electricity produced is developed—either through 

development of community solar, VNM, a PPA, or a behind-the-meter application for an 

adjacent consumer of electricity. 
33 

Appendix A. Provided Sky Park Landfill Site 

Information

Figure A-1. High resolution plan, available from City of Eau Claire, Wisconsin

Map provided by Ned Noel, City of Eau Claire 
34 

Appendix B. Assessment and Calculations 

Assumptions

Table B-1. Cost, System, and Other Assessment Assumptions

Cost Assumptions Quantity of Unit of Variable

Variable Variable

Cost of site electricity 0.08 $/kWh

Annual O&M (fixed) 20 $/kW/year

Annual O&M (single) 22 $/kW/year

Annual O&M (dual) 25 $/kW/year

System Assumptions

System Type Annual energy 

kWh/kW

Installed Cost 

($/W)

Energy Density 

(W/sq. ft.)

Ground fixed, ballasted 1,253 $3.49 4.0

Ground single-axis, ballasted 1,584 $4.19 3.5 

Ground dual-axis, ballasted 1,682 $4.62 3.0

Other Assumptions

1 acre 43,560 ft2

1 MW 1,000,000 W

Ground 

utilization

23 acres
35 

Appendix C. Solar Access Measurements 

Figure C-1. Solar access measurements for Sky Park Landfill PV site
36 

Appendix D. Results of the JEDI Model

Table D-1. Summary Results of the NREL JEDI Model

Photovoltaic (project data summary based on model default values)

Project Location WISCONSIN

Year of Construction or 

Installation 2013

Average System Size - DC Nameplate Capacity (KW) 4,008

Number of Systems Installed 1

Total Project Size - DC 

Nameplate Capacity (KW) 4,008

System Application Utility

Solar Cell/Module Material Crystalline Silicon

System Tracking Single-axis

Base Installed System Cost 

($/KWDC) $3,348

Annual Direct Operations and Maintenance Cost ($/kW) $22.00

Money Value - Current or 

Constant (Dollar Year) 2012

Project Construction or 

Installation Cost $11,668,105

 Local Spending $8,024,549

Total Annual Operational 

Expenses $1,664,558

 Direct Operating and 

Maintenance Costs $88,165

 Local Spending $81,112

 Other Annual Costs $1,556,393

 Local Spending $0

 Debt Payments $0

 Property Taxes $0

Local Economic Impacts - Summary Results

Jobs Earnings Output

During construction and 

installation period $000 (2012) $000 (2012)

 Project Development and OnSite Labor Impacts

 Construction and Installation 

Labor 19.7 $1,273.1

 Construction and Installation 

Related Services 29.7 $1,074.7

 Subtotal 49.3 $2,347.8 $4,410.6

 Module and Supply Chain 

Impacts

 Manufacturing 0.0 $0.0 $0.0

 Trade (Wholesale and 

Retail) 11.8 $599.0 $1,870.2
37 

 Finance, Insurance, and 

Real Estate 0.0 $0.0 $0.0

 Professional Services 9.0 $240.6 $1,166.6

 Other Services 9.1 $537.7 $2,044.7

 Other Sectors 18.9 $411.4 $1,193.7

 Subtotal 48.8 $1,788.7 $6,275.1

 Induced Impacts 32.8 $647.9 $3,780.0

 Total Impacts 130.9 $4,784.4 $14,465.7

Annual Annual

Annual Earnings Output

During Operating Years Jobs $000 (2012) $000 (2012)

 On-site Labor Impacts

 PV Project Labor Only 0.8 $49.1 $49.1

 Local Revenue and Supply 

Chain Impacts 0.3 $12.2 $47.2

 Induced Impacts 0.2 $4.3 $27.1

 Total Impacts 1.4 $65.6 $123.4

Notes: Earnings and Output values are thousands of dollars in year 2012 dollars. Construction and

operating period jobs are full-time equivalent for one year (1 FTE = 2,080 hours). Economic impacts "During 

operating years" represent impacts that occur from system/plant operations/expenditures. Totals may not 

add up due to independent rounding.

Detailed PV Project Data Costs

Purchased Manufactured

Installation Costs Cost Locally (%) Locally (Y or N)

Materials & Equipment

 Mounting (rails, clamps, 

fittings, etc.) $585,970 100% N

 Modules $4,865,708 100% N

 Electrical (wire, connectors, 

breakers, etc.) $410,906 100% N

 Inverter $878,201 100% N

 Subtotal $6,740,785

Labor

 Installation $1,273,069 100%

 Subtotal $1,273,069

Subtotal $8,013,854

Other Costs

 Permitting $1,452,736 100%

 Other Costs $592,954 100%

 Business Overhead $3,357,633 100%

 Subtotal $5,403,323

Subtotal $13,417,177

Sales Tax (Materials & 

Equipment Purchases) $0 100%

Total $13,417,177
38 

PV System Annual Operating 

and Maintenance Costs Cost Local Share

Labor

 Technicians $52,899 100%

 Subtotal $52,899

Materials and Services

 Materials & Equipment $35,266 100%

 Services $0 100%

 Subtotal $35,266

Sales Tax (Materials & 

Equipment Purchases) $0 100%

Average Annual Payment 

(Interest and Principal) $1,556,393 0%

Property Taxes $0 100%

Total $1,644,558

Other Parameters

Financial Parameters

Debt Financing

 Percentage financed 80% 0%

 Years financed (term) 10

 Interest rate 10%

Tax Parameters

 Local Property Tax (percent of 

taxable value) 0%

 Assessed Value (percent of 

construction cost) 0%

 Taxable Value (percent of 

assessed value) 0%

 Taxable Value $0

 Property Tax Exemption 

(percent of local taxes) 100%

 Local Property Taxes $0 100%

 Local Sales Tax Rate 5.00% 100%

 Sales Tax Exemption (percent 

of local taxes) 100.00%

Payroll Parameters Wage Per Hour Employer Payroll Overhead

 Construction and Installation 

Labor

 Construction Workers/ 

Installers $21.39 45.6%

 O&M Labor

 Technicians $21.39 45.6%
39 

Appendix E. Results of the Solar Advisor Model

Table E-1. Summary Inputs and Results for the SAM Model

SAM Results - Fixed 4-MW System - VNM

Net Annual Energy 4,837,763 kWh

LCOE Nominal $ 0.0846/kWh

LCOE Real $ 0.0734/kWh

First Year Revenue without System $ 0.00 

First Year Revenue with System $ 387,021.01

First Year Net Revenue $ 387,021.01

After-Tax NPV $ -1,007,989.94 

Payback Period 18.9125 years

Capacity Factor 13.8

First Year kWh/kW 1,208

System Performance Factor 0.79

Total Land Area 23 acres

SAM Results - Single-Axis 3.5-MW System – VNM

Net Annual Energy 5,337,797

LCOE Nominal $ 0.0793

LCOE Real $ 0.0688

First Year Revenue without System $ 0.00

First Year Revenue with System $ 427,023.79

First Year Net Revenue $ 427,023.79

Capacity Factor 17.4% 

Payback Period 17.6189 years

After-Tax NPV $ -807,095.57

First Year kWh/kW 1,522

System Performance Factor 0.80

Total Land Area 23 acres

SAM Results – Dual-Axis 3-MW System - VNM

Net Annual Energy 4,839,482 kWh

LCOE Nominal $ 0.0826/kWh 

LCOE Real $ 0.0719/kWh

First Year Revenue without System $ 0.00 

First Year Revenue with System $ 387,158.58

First Year Net Revenue $ 387,158.58

After-Tax NPV $ -900,799.34 

Payback Period 18.3924 years

Capacity Factor 18.4

First Year kWh/kW 1,611

System Performance Factor 0.8

Total Land Area 23 acres
40 

SAM Results – Fixed-Axis 4-MW System - PPA

Net Annual Energy 4,837,763 kWh

PPA Price $ 0.1061/kWh 

LCOE Nominal $ 0.1446/kWh

LCOE Real $ 0.1254/kWh

After-Tax IRR 8.00 %

Pre-Tax Min DSCR 0.60

After-Tax NPV $ 96,991.21

PPA Price Escalation 3.5%

Debt Fraction 55%

Capacity Factor 13.8%

First Year kWhac/kWdc 1,208

System Performance Factor 0.79

Total Land Area 23 acres

SAM Results – Single-Axis 3.5-MW System –

PPA

Net Annual Energy 5,337,797 kWh

PPA Price $ 0.0994/kWh 

LCOE Nominal $ 0.1356/kWh

LCOE Real $ 0.1176/kWh

After-Tax IRR 8.00 %

Pre-Tax Min DSCR 0.60

After-Tax NPV $ 101,219.94

PPA Price Escalation 3.5%

Debt Fraction 55%

Capacity Factor 17.4%

First Year kWhac/kWdc 1,522

System Performance Factor 0.80

Total Land Area 23 acres

SAM Results – Dual-Axis 3-MW System - PPA

Net Annual Energy 4,839,482 kWh

PPA Price $ 0.1035/kWh 

LCOE Nominal $ 0.1411/kWh

LCOE Real $ 0.1224/kWh

After-Tax IRR 8.00 %

Pre-Tax min DSCR 0.60

After-Tax NPV $ 95,158.14

PPA Price Escalation 3.5%

Debt Fraction 55%

Capacity Factor 18.4%

First Year kWhac/kWdc 1,611

System Performance Factor 0.79

Total Land Area 23 acres