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

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC.

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

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

Contract No. DE-AC36-08GO28308

Feasibility Study of Economics 

and Performance of Solar 

Photovoltaics at the Santo 

Domingo Pueblo in Sandoval 

County, New Mexico

Jesse Geiger, Lars Lisell, and Gail Mosey

Produced under direction of U.S. Environmental Protection Agency 

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

Interagency Agreement IAG-11-1836 and Task No. WFM2.1001. 

Technical Report

NREL/TP-6A10-58844

July 2013
NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC.

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

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

Contract No. DE-AC36-08GO28308

National Renewable Energy Laboratory

15013 Denver West Parkway

Golden, CO 80401

303-275-3000 • www.nrel.gov

Feasibility Study of Economics 

and Performance of Solar 

Photovoltaics at the Santo 

Domingo Pueblo in Sandoval 

County, New Mexico 

Jesse Geiger, Lars Lisell, and Gail Mosey

Prepared under Task No. WFM2.1001

Technical Report

NREL/TP-6A10-58844

July 2013
NOTICE

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

16560, photo by Dennis Schroeder, NREL 17613, photo by Dean Armstrong, NREL 17436, photo by Pat Corkery, NREL 17721.

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

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at www.nrel.gov/publications.

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 Kenneth Pin and the facility operators for 

their generous assistance and cooperation. 
iv

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National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

Executive Summary

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

America’s Land initiative, selected the Pueblo of Santo Domingo in Sandoval County, New 

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

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

assess specific areas on the site for potential installation of photovoltaic (PV) systems and to 

estimate the cost, performance, and site impacts of different PV options. The report also 

recommends financing options that could assist in the implementation of these PV systems. This 

study did not assess environmental conditions at the site. 

The Santo Domingo Pueblo is an American Indian reservation located in New Mexico 40 miles 

northeast of the City of Albuquerque. The site has an 8.7-acre industrial site, a 3.95-acre landfill, 

and a number of government buildings (administrative areas) that are being evaluated for PV 

systems. The industrial site, referred to as the CC Housing Site by the EPA, was originally used 

as a lumber yard, particle board manufacturing facility, and modular housing manufacturing 

plant from the 1950s until it was abandoned in 1986. The industrial site is owned by the Santo 

Domingo Pueblo Tribe. The current plan for the site is to renovate and offer building space to 

starting companies and artists to build up the Tribal economy. 

The feasibility of installing a PV system on a Resource Conservation and Recovery Act (RCRA) 

site is highly impacted by the available area for an array, solar resource, distance to transmission 

lines, and distance to major roads. In addition, the remediation status, ground conditions, and 

restrictions associated with redevelopment of the RCRA site also impact the feasibility of a PV 

system. Based on an assessment of these factors, the Santo Domingo Pueblo is suitable for 

deployment of a large-scale PV system. Roofs are unaffected by the ground contamination, but 

they do require structurally sound buildings. 

The Pueblo industrial site is approximately 8.7 acres, and there is a high potential to renovate the 

site with roof-mounted PV but limited potential to build out the site with a ground-mounted PV 

system due to the limited land space. There are currently 0.44 acres available for a groundmounted PV system at the site, without additional demolition and debris removal. There are 

7.25 acres potentially available for a ground-mounted PV system on the landfill nearby. 

Calculations performed for this analysis are based on the total feasible area being developed. 

However, installations can be staged as area(s) and/or funding become available. It should be 

noted that the purpose of this report is not to determine how to develop the site but to investigate 

options and present the results in an unbiased manner. 

Of the nine scenarios considered, eight had a positive net present value (NPV), and all had a 

payback in the analysis period. The economic feasibility of potential PV systems on the Santo 

Domingo Pueblo depends greatly on the price of electricity from Public Service Company of 

New Mexico (PNM). The economics were analyzed using $0.123219/kWh, which is a weighted 

average of middle-tier rates provided by PNM. This value is also used for the PV production sale 

price through the net-metering policy, which the site is assumed able to use for all energy 

produced on site. Table ES-1 shows the current incentives considered.
v 

This report is available at no cost from the 

National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

Table ES-1. Summary of Incentives Evaluated

Applicable to 

Tribe-Owned 

System Incentive Title Modeled Value Expected End 

Federal Investment Tax Credit 30% of total investment 12/31/2015

Advanced Energy Tax Credit 6% of total investment, must 

be over 1 MW

$60 million

X Net Metering Net meter up to 80 MW - 

Renewable Energy Production 

Tax Credit (Corporate) 

Average $0.027/kWh, 

10 years

- 

Sales Tax Incentive 100% of receipts - 

X REC Payment from PNM $0.04/kWh, system sizes 

under 10 kW, 8 years

$0.05/kWh, system sizes 

10 kW – 1 MW, 8 years

12/31/2013,

Restructured each 

year

The net metering applies to 80-MW and smaller cases, so each case in this analysis has applied 

the net-metering policy. The study did not consider other incentives for which the Santo 

Domingo Pueblo was not clearly eligible. The Santo Domingo Pueblo does qualify for funding 

opportunities through grants and the Reduce Your Use program from PNM, but these grants are 

expected to pay for the modeled cost.

Table ES-2 summarizes the performance and economics of potential systems that would use all 

available areas that were surveyed at the Santo Domingo Pueblo. All values represent Tribe 

ownership except for forecasted power purchase agreement (PPA) price, which is through a solar

investor. The table shows the annual energy output from the systems along with the number of 

average American households that could be powered off of such a system and estimated job 

creation. All spaces evaluated at the Santo Domingo Pueblo can be developed with PV systems.

The roof systems for the Santo Domingo Pueblo municipal buildings have good paybacks that 

could be taken advantage of immediately. The largest government building roof system, at 

16 kW, would generate 26,951 kWh of electricity and have an NPV of $5,537 with 10.5 years to 

pay back. This includes the current cost of energy, expected installation cost, site solar resource, 

and existing incentives for the proposed PV system. The industrial site, once renovated, would 

benefit from installing PV systems that would match the projected energy use of the renovated 

industrial site. The landfill was also investigated for both offsetting energy use at the renovated 

industrial site as well as leasable land to a solar developer. The savings and payback are deemed 

reasonable, and as such, a solar PV system represents a viable reuse for the landfill under 

analyzed conditions. 
vi 

This report is available at no cost from the 

National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

Table ES-2. Santo Domingo Pueblo PV Systems Summary
vii 

This report is available at no cost from the 

National Renewable Energy Laboratory (NREL) 

at www.nrel.gov/publications.

Table of Contents

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

2 Development of PV Systems on Brownfield Sites ............................................................................ 3

3 PV Systems ........................................................................................................................................... 4

3.1 PV Overview................................................................................................................................. 4

3.2 Major System Components........................................................................................................... 5

3.2.1 PV Module ....................................................................................................................... 5

3.2.2 Inverter............................................................................................................................. 7

3.2.3 Balance-of-System Components...................................................................................... 8

3.2.4 Operation and Maintenance ........................................................................................... 10

3.3 Siting Considerations .................................................................................................................. 10

4 Proposed Installation Location Information.................................................................................... 12

4.1 Santo Domingo Pueblo PV Systems........................................................................................... 12

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

4.3 Useable Acreage for PV System Installation .............................................................................. 15

4.4 PV Site Solar Resource ............................................................................................................... 15

4.5 Santo Domingo Pueblo Energy Usage ........................................................................................ 17

4.5.1 Current Energy Use........................................................................................................ 17

4.5.2 Net Metering .................................................................................................................. 17

5 Economics and Performance............................................................................................................ 18

5.1 Assumptions and Input Data for Analysis................................................................................... 18

5.2 SAM-Forecasted Economic Performance ................................................................................... 20

5.2.1 Solar Investor vs. Tribe Owned...................................................................................... 21

5.2.2 Fixed-Axis vs. Single-Axis Tracking............................................................................. 22

5.3 Job Analysis and Impact ............................................................................................................. 22

5.4 Financing Opportunities.............................................................................................................. 23

5.4.1 Owner and Operator Financing ...................................................................................... 23

5.4.2 Third-Party Developers with Power Purchase Agreements........................................... 24

5.4.3 Third-Party “Flip” Agreements...................................................................................... 24

5.4.4 Hybrid Financial Structures ........................................................................................... 24

5.4.5 Solar Service Agreement and Operating Lease.............................................................. 25

5.4.6 Sale/Leaseback............................................................................................................... 25

5.4.7 Community Solar/Solar Gardens ................................................................................... 25

6 Conclusions and Recommendations ............................................................................................... 27

Appendix A. Provided Site Information .................................................................................................. 28

Appendix B. Assessment and Calculations Assumptions................................................................... 29

Appendix C. Solar Access Measurements ............................................................................................. 32

Appendix D. Results From the System Advisor Model......................................................................... 33

Appendix E. Results of the Job and Economic Development Impact Models ................................... 39
viii

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at www.nrel.gov/publications.

List of Figures

Figure 1. Generation of electricity from a PV cell ...........................................................................4

Figure 2. Ground-mounted array diagram .......................................................................................5

Figure 3. Mono- and multi-crystalline solar panels .........................................................................6

Figure 4. Thin-film solar panels installed on (left) landfill geomembrane cover and 

(middle/right) fixed-tilt mounting system ..................................................................................6

Figure 5. String inverter ...................................................................................................................8

Figure 6. Aerial view of the feasible areas for PV at the Santo Domingo Pueblo industrial site 

(ground-mounted in dark blue and roof-mounted in light blue) ..............................................12

Figure 7. Aerial view of the feasible areas for PV within the Santo Domingo Pueblo (no 

ground-mounted PV potential exists; existing municipal buildings with potential roofmounted PV in blue) ................................................................................................................13

Figure 8. View of utility building suitable for roof-mounted PV ..................................................14

Figure 9. View of industrial site area feasible for ground-mounted PV. Water tower is to the 

north .........................................................................................................................................14

Figure 10. Location of PNM Substation in relation to the landfill and industrial site ...................15

Figure C-1. Solar access measurement for Senior Center PV site .................................................32

Figure D-1. 16-kW roof-mounted monthly production projection ................................................33

Figure D-2. 76-kW ground-mounted fixed-axis monthly production projection ..........................34

Figure D-3. 63-kW ground-mounted single-axis monthly production projection .........................35

Figure D-4. 16-kW roof-mounted annual cash flow ......................................................................36

Figure D-5. 76-kW ground-mounted fixed-axis annual cash flow ................................................37

Figure D-6. 63-kW ground-mounted single-axis monthly annual cash flow ................................38

List of Tables

Table ES-1. Summary of Incentives Evaluated ...............................................................................v

Table ES-2. Santo Domingo Pueblo PV Systems Summary ......................................................... vi

Table 1. Ground-Mounted Energy Density by Panel and System ...................................................9

Table 2. Rooftop Energy Density by Panel .....................................................................................9

Table 4. Performance Results for 20-Degree Fixed-Tilt PV .........................................................16

Table 5. Performance Results for 20-Degree Single-Axis PV ......................................................17

Table 6. Installed System Cost Assumptions .................................................................................19

Table 7. Summary of Incentives Evaluated ...................................................................................19

Table 8. Summary of SAM Results ...............................................................................................21

Table 9. JEDI Analysis Assumptions ............................................................................................23

Table A-1. Utility Rates Provided by PNM Contact .....................................................................28

Table B-1. Cost, System, and Other Assessment Assumptions .....................................................29

Table B-2. Modeling Assumptions ................................................................................................30

Table E-1. Photovoltaic Project Data Summary 16-kW Roof-Mounted System ..........................39

Table E-2. Local Economic Impacts – Summary Results .............................................................40

Table E-3. Detailed PV Project Data Costs ...................................................................................41

Table E-4. PV System Annual Operating and Maintenance Costs ................................................42
1 

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at www.nrel.gov/publications.

1 Study and Site Background

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

America’s Land initiative, selected the Santo Domingo Pueblo, Sandoval County, New Mexico, 

for a renewable energy production feasibility study. Under the Region 6 Contract, EPA provided 

funding to the National Renewable Energy Laboratory (NREL) to support a feasibility study of 

solar renewable energy generation at the Santo Domingo Pueblo. NREL provided technical 

assistance for this project. The purpose of this report is to assess various sites at the Pueblo for a 

possible photovoltaic (PV) system installation and to 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 Santo Domingo Pueblo is approximately 1 hour northeast of Albuquerque, New Mexico,

and 1 hour south of Santa Fe, New Mexico. The site is home to approximately 5,000 residents 

and is approximately 115 square miles in area. The site experiences summers that are warm and 

dry with high temperatures typically in the low 90oF range. The winters are cold and mostly dry 

with low temperatures in the 19oF to 25oF range. The site has on average over 250 days of 

sunshine each year. PNM is the utility providing electricity to the site. 

This study assesses: (1) installation of roof-mounted PV systems on existing government 

buildings within the Pueblo administrative area; (2) installation of roof-mounted PV systems on 

existing buildings at the 8.7-acre industrial site; and (3) installation of ground-mounted PV 

systems on the industrial site and adjacent 3.95-acre landfill. The industrial site, referred to as the

CC Housing Site by EPA, was originally used as a lumber yard, particle board manufacturing 

facility, and modular housing manufacturing plant from the 1950s until it was abandoned in 

1986. The industrial site currently has abandoned buildings on it, and renovations or completely 

new construction is required for future utilization of the site. The adjacent landfill was used for 

the disposal of construction debris from the industrial site operations and contains primarily 

particle board chips. The industrial site analysis focuses on the use of PV arrays to primarily

offset energy costs for future businesses and/or an artisan market on the site. 

The major contaminants at the industrial site are related to years of manufacturing of housing 

materials and related components by lessees of the Atchison Topeka & Santa Fe Railroad, 

including CC Housing Company. These contaminants include low levels of polycyclic aromatic 

hydrocarbons (PAHs), total petroleum hydrocarbons (gasoline and motor oil range), metals, and 

polychlorinated biphenyls (PCBs). The contamination is primarily found in surface and shallow 

subsurface soil.1

 

Rooftop PV systems evaluated for the four government buildings in the administrative area will 

be able to tie directly into the existing meter at the building. However, PV systems for the

industrial site (if unable to tie in at the site itself), will have to tie in at the substation located 

across the street. Having a substation within 1,000 feet makes the industrial site an ideal location 

for a large PV system. A detailed interconnection study will need to be performed through the 

 

1

“Historical Summary/Recommendations Report,” Santo Domingo Pueblo Former CC Housing Site, Targeted 

Brownfields Assessment, USACE, January 2011.
2 

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at www.nrel.gov/publications.

local electric utility, PNM, to determine the feasibility of utilizing the substation as a tie-in point 

for a large PV system. 

Feasibility assessment team members from NREL and the Santo Domingo Pueblo Tribe

conducted a site visit on Monday, December 10, 2012, to gather information integral to this 

feasibility study. The team considered information, including solar resource, transmission 

availability, community acceptance, roof conditions, and ground conditions. 
3 

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at www.nrel.gov/publications.

2 Development of PV Systems on Brownfield Sites 

EPA Region 6 has identified several benefits for siting solar PV facilities on Resource 

Conservation and Recovery Act (RCRA) sites, noting that they:

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

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

residential redevelopment

• Could be adequately zoned for renewable energy 

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

infrastructure

• Could 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 Santo Domingo Pueblo Tribe owns all of the sites investigated and is interested in potential 

revenue flows and cost savings for the tribe. This site development is community driven and will 

be developed and managed by community leaders. The purpose of this study is to analyze all PV

options so that an informed decision can be made on how to best utilize the Tribe’s funds 

and property. 

The industrial site at the Santo Domingo Pueblo has 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. The

current vision is to renovate and repurpose the buildings on the industrial site for startup 

community business and incubators. 

There are many compelling reasons to consider moving toward renewable energy sources for 

power generation instead of fossil fuels, including: 

• Renewable energy sources offer a reliable and 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 longterm PPAs linked to renewable energy systems

• Generating energy without harmful emissions or waste products can be accomplished 

through renewable energy sources.
4 

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at www.nrel.gov/publications.

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 stimulating electrons (negative charges) in a 

layer in the cell 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 on the 100+ MW scale. 

Electricity from utility-scale systems is commonly sold back to the electricity grid. 

(-)

(+)

-

- -

-

Electron

Current flow

-

Solar cell

- - -

Load
5 

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at www.nrel.gov/publications.

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 (BOS) 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 utility-scale 

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 the supply (silicon industry) and product sides. This technology has 

30 years of demonstrated consistency and high efficiency in the field. The performance 

degradation, a reduction in power generation due to long-term exposure, is under 1% per year. 

Silicon modules have a lifespan in the range of 25–30 years but can keep producing energy 

beyond this range. 
6 

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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 multi-crystalline 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-crystalline installed on 

tracking mounting systems. 

Figure 3. Mono- and multi-crystalline solar panels. Photos from (left) SunPower Corporation, 

NREL 23816 and (right) SunPower, NREL 13823

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 such applications as 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 for 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.

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

fixed-tilt mounting system. Photos from (left) Republic Services, Inc., NREL 23817; (middle) Beck 

Energy, NREL 14726; and (right) U.S. Coast Guard Petaluma site, NREL 17395
7 

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at www.nrel.gov/publications.

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 power 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 gridconnected 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 micro-inverters. 

Each type has strengths and weaknesses and could 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 

between 5 and 10 years, with 10 years being the current 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 in limited use in larger systems due to potential increase in O&M cost

associated with significantly increasing the number of inverters in a given array. Current microinverters range in size between 175 W and 380 W. These inverters can be the most expensive 

option per watt of capacity. Warranties range from 10–20 years. Small projects with irregular 

modules and shading issues typically benefit from micro-inverters. 

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

entire array production. If micro-inverters are used, only the shaded panel is impacted. Figure 5 

shows a string inverter. 
8 

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at www.nrel.gov/publications.

Figure 5. String inverter. Photo by Warren Gretz, NREL 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 

BOS components, which include: 

• Mounting racks and hardware for the panels 

• Wiring for electrical connections. 

3.2.3.1 Mounting Systems

The array must 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 brownfield 

applications, mounting system designs will be primarily driven by these considerations coupled 

with potential 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 brownfield sites. Fixed-tilt systems 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 slightly increases maintenance and equipment costs. 

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. Depending on underlying soil conditions, single- and dualaxis trackers might not be suitable due to potential settlement effects, which can interfere with 

the alignment requirements of such systems. 
9 

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Table 1. Ground-Mounted Energy Density by Panel and System

System Type Fixed-Tilt Energy Density 

(DC-Watts/ft2

) 

Single-Axis Tracking Energy 

Density

(DC-Watts/ft2)

Crystalline Silicon 4.0 3.3

Thin Film 3.3 2.7

The mounting type selected depends 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. 

The mounting system selected is also heavily dependent on anchoring or foundation options. The 

mounting system design will also need to meet applicable local building code requirements with 

respect to snow, wind, and seismic zones. Mounting type should also consider frost protection 

needs, especially in cold regions, such as New England. The Santo Domingo Pueblo 

administrative area has no areas suitable for large ground-mounted PV systems due to the high 

concentration of buildings at this location. However, there is potential for ground-mounted PV 

systems on the industrial site and adjacent landfill.

3.2.3.1.2 Roof-Mounted Systems

The Santo Domingo Pueblo administrative area and industrial site have great potential for roofmounted PV systems on existing and future buildings. Installing PV on rooftops entails many of 

the same considerations as installing ground-mounted PV systems. Factors, such as available 

area for an array, solar resource, shading, distance to transmission lines, and distance to major 

roads, are just as important in roof-mounted systems as in ground-mounted systems. Rooftop 

systems can be ballasted or fixed to the roof. The roof should be relatively new (less than 5 years 

old) to avoid having to move the PV system in order to repair or replace the roof. 

The Santo Domingo Pueblo Tribe is planning to renovate existing buildings at the industrial site. 

There are many relatively easy low-cost/no-cost measures that can be taken during the design 

phase so that the buildings are optimally built for rooftop PV systems. Design strategies, such as 

orienting new buildings so that the southern exposure is maximized and reducing the amount of 

mechanical equipment on the roof, are examples of measures that can be taken to optimize 

rooftop PV systems.2

 

Table 2. Rooftop Energy Density by Panel

System Type Fixed-Tilt Energy Density 

(DC-Watts/ft2

) 

Crystalline Silicon 10.0 

Thin Film 4.3 

 

2

 A solar-ready design guide has been published in order to help design teams optimize buildings for rooftop PV 

systems. This guide can be found at http://www.nrel.gov/docs/fy10osti/46078.pdf. 
10 

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at www.nrel.gov/publications.

3.2.3.2 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. 

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

of interconnection is generally run as direct burial through trenches. In brownfield applications, 

this wiring might be required to run through above-ground conduit due to restrictions with cap 

penetration or other concerns. Therefore, developers should note any such restrictions, if 

applicable, in requests for proposals in order to improve overall bid accuracy. Similarly, PV 

system vendors should reflect these costs in the quote when costing out the overall system.

3.2.3.3 PV System Monitoring 

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

simple as reading values on the inverter LCD display, such as produced AC power, daily 

kilowatt-hours, and cumulative kilowatt-hours locally. For more sophisticated monitoring and 

control purposes, environmental data, such as module temperature, ambient temperature, solar 

radiation, and wind speed, can also be collected. Control and monitoring of these systems can be 

performed by various types of 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 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, thus enabling a comparison 

of the target versus actual system output and performance, as well as identification of underperforming arrays. Operators can use this data to identify required maintenance, shade on panels, 

and accumulating dirt on panels, for example. Monitoring system data can also be used for 

outreach and education via 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. Inverters, which come standard with a 

5-year or 10-year warranty (extended warranties available), are expected to last 10–15 years. 

System performance should be verified on a vendor-provided website. Wire and rack 

connections should be checked annually. The economic analysis in this study assumes an annual 

O&M cost of $20/kW/year, which is based on the historical O&M costs of installed fixed-axis 

grid-tied PV systems. In addition, the analysis assumes replacement of the system inverters in 

year 15 at a cost of $0.25/W. 

3.3 Siting Considerations

PV modules are very sensitive to shading. When shaded (either partially or fully), 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 all 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. 
11 

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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 collecting solar resource data using the Solmetric SunEye tool and determining that the site 

is adequate for a solar installation, an analysis of the ideal system size must be conducted. 

System size depends highly on the average energy use of the facilities on the site, power 

purchase agreements (PPAs), available incentives, and utility policy. 
12 

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4 Proposed Installation Location Information

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

December 10, 2012. 

4.1 Santo Domingo Pueblo PV Systems 

As discussed in Section 1, the Santo Domingo Pueblo Tribe owns all sites assessed in this study. 

Surface level remediation at the industrial site will need to be performed before any entities 

occupy the site. 

The entire industrial site is approximately 8.7 acres and will potentially be reused by the Santo 

Domingo Pueblo Tribe for economic development purposes. The site renovations will consider

ground- and roof-mounted PV systems for power-saving measures, with the landfill to the north 

considered for ground-mounted PV as well. In order to get the most out of the roof area 

available, it is important to consider whether the layout can be improved to better incorporate a 

solar system. If there are unused structures that can be removed, the un-shaded area can be 

increased to incorporate more PV panels. There are 0.44 acres for ground-mounted PV and 

12,000 ft2

 potentially available for roof-mounted PV systems. Calculations for this analysis 

reflect the solar potential if the total feasible area is developed. However, installations can be 

staged as area(s) and/or funding become available. It should be noted that the purpose of this 

report is not to determine how to develop the site but to investigate the PV options in an unbiased 

manner. Because the buildings will require renovations for use, they could easily be redone to 

make the buildings “solar ready,” even if the budget for a rooftop PV system is not available at 

the time of construction. 

Figure 6 shows the industrial site and the landfill just to the north of the site. The shaded area 

indicates the space available for PV development. The land west and nearest to the buildings 

should be considered for ground PV development before exploring the option of developing the 

landfill to the north. The 3.95 acres of land to the north may also be ideal to lease to a solar 

developer if the market and policy conditions are favorable for large-scale development. 

Figure 6. Aerial view of the feasible areas for PV at the Santo Domingo Pueblo industrial site

(ground-mounted in dark blue and roof-mounted in light blue) 

Illustration done in Google Earth
13 

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Figure 7 shows an aerial view taken from Google Earth of the roof areas with PV potential 

within the Santo Domingo Pueblo administrative area. The buildings with their available room 

for PV systems are:

• Utilities building: 3,948 ft2

• Recreation center: 2,975 ft2

• Mental health building: 2,682 ft2

• Senior center: 1,768 ft2. 

No feasible areas for ground-mounted PV systems exist. The existing buildings suitable for roofmounted PV are shaded in blue. Each building’s PV system would be separate from the others 

and connected to that building’s meter. 

Figure 7. Aerial view of the feasible areas for PV within the Santo Domingo Pueblo (no groundmounted PV potential exists; existing municipal buildings with potential roof-mounted PV in blue) 

Illustration done in Google Earth

The Santo Domingo Pueblo is well suited for PV systems, as the average global horizontal 

annual solar resource—the total solar radiation for a given location, including direct and diffuse

radiation—is 5.92 kWh/m2/day. Figure 8 shows a view of one building in the administrative area

where roof-mounted PV is feasible. Figure 9 shows a view of the industrial site, where groundmounted PV is feasible. 
14 

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at www.nrel.gov/publications.

Figure 8. View of utility building suitable for roof-mounted PV. Photo by Jesse Geiger, NREL

Figure 9. View of industrial site area feasible for ground-mounted PV. Water tower is to the north. 

Photo by Jesse Geiger, NREL
15 

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4.2 Utility Resource Considerations

All of the roof-mounted systems (administrative area and industrial site) are expected to be able 

to connect through the existing meters at each building. Further, each of these buildings is 

expected to be an off-taker of all generated solar energy and make use of the net-metering 

incentives offered by PNM. For the potential landfill ground-mounted PV system, 

interconnection through the local substation may be required and would need to be approved by 

PNM via a detailed interconnection study. Figure 10 shows the location of the substation relative 

to the landfill and industrial site. 

Figure 10. Location of PNM Substation in relation to the landfill and industrial site 

Illustration done in Google Earth

4.3 Useable Acreage for PV System Installation 

Typically, a minimum of two useable acres is recommended to site ground-mounted PV systems. 

Useable acreage is typically characterized as "flat to gently sloping" southern exposures that are 

free from obstructions and 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 or industrial site space, as well as existing building rooftops). 

4.4 PV Site Solar Resource

The Santo Domingo Pueblo area has been evaluated to determine the adequacy of the solar 

resource available using both on-site data and industry tools. 

The assessment team for this feasibility study collected multiple Solmetric SunEye data points 

and found a solar access of 90% or higher. All data gathered using this tool is available in 

Appendix C.

The team used PVWatts Version 2 to predict array performance for the Santo Domingo Pueblo.3

Table 3 shows the station identification information, PV system specifications, and energy 

specifications for the site. For array performance information, the team used a hypothetical 

system size of 1 kW to show the estimated production for each kilowatt so that additional 

analysis can be performed using the data indicated below. It is scaled linearly to match the 

proposed system size.

 

3 PVWatts. Accessed June 5, 2013: http://www.nrel.gov/rredc/pvwatts/.
16 

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at www.nrel.gov/publications.

Table 3. Site Identification Information and Specifications

Station Identification

Cell ID 0199372

State New Mexico

Latitude 35.3° N

Longitude 106.5° 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 20°

Array Azimuth South

Energy Specifications

Cost of Electricity $0.1232/kWh

Table 4 shows the performance results for a 20-degree fixed-tilt PV system at the Santo 

Domingo Pueblo as calculated by PVWatts.

Table 4. Performance Results for 20-Degree Fixed-Tilt PV

Month Solar Radiation

(kWh/m2

/day)

AC Energy

(kWh)

Energy Value

($)

1 4.36 108 9.78

2 4.92 108 9.78

3 5.81 140 12.68

4 6.77 152 13.77

5 7.11 163 14.77

6 7.30 156 14.13

7 7.13 156 14.13

8 6.50 143 12.96

9 6.38 138 12.50

10 5.65 131 11.87

11 4.62 107 9.69

12 4.01 99 8.97

Year 5.88 1,601 197.24

Table 5 shows the performance results for a 20-degree-tilt single-axis tracking PV system at the 

Santo Domingo Pueblo as calculated by PVWatts. 
17 

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at www.nrel.gov/publications.

Table 5. Performance Results for 20-Degree Single-Axis PV

Month Solar Radiation

(kWh/m2

/day)

AC Energy

(kWh)

Energy Value

($)

1 5.59 141 12.77

2 6.23 139 12.59

3 7.58 185 16.76

4 8.92 203 18.39

5 9.49 220 19.93

6 9.80 212 19.21

7 9.18 204 18.48

8 8.48 189 17.12

9 8.22 180 16.31

10 7.44 175 15.86

11 5.87 138 12.50

12 5.11 130 11.78

Year 7.67 2,116 260.69

4.5 Santo Domingo Pueblo Energy Usage

It is important to understand the energy use of the buildings to fully determine whether or not 

energy produced would need to be sold or if it could offset on-site energy use.

4.5.1 Current Energy Use

No current monthly electricity usage or cost data was available for any of the sites evaluated for 

potential PV systems in the Pueblo. However, with the inclusion of net metering, any PV 

generation will offset current annual electricity usage. 

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 it 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. 

New Mexico’s net-metering law, which began in 1978 and was modified in 2008 to allow 

capacity up to 80 MW, requires that any qualifying system be allowed to be credited at the retail 

rate for any energy produced over the monthly use of the facility. The New Mexico law does not 

permit those who partake in the net-metering program to retain ownership of the renewable 

energy certificates (RECs) that they would own and forfeit them to their servicing utility, in this 

case PNM. Any net excess generation (NEG) in a month is carried forward into the next month’s

cycle if under $50, or paid to the system if over $50 in value. 
18 

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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).4 

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 it makes economic calculations for both projects that buy and 

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

SAM consists of a performance model and financial model. The performance model 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 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

The 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 has declined from $4.80/W in 

the first quarter of 2010 to $2.79/W in the first quarter of 2012. With an increasing demand and 

supply, the potential for further cost reduction is expected as market conditions evolve. This 

analysis assumes a baseline cost of $2.79/W for fixed-tilt roof-mounted systems. The cost for the 

fixed-axis ground-mounted systems was the same. Single-axis tracking systems were assumed in 

this analysis to have a 20% increase over the fixed-axis system cost at $3.35. Single-axis 

tracking is only available for use on the ground. Additional costs apply to systems built on 

landfills and land that requires minimal disturbance (e.g., brownfields). These systems use 

ballasting to minimize ground impact and increase the overall installation price by 25%. 

 

4 For additional information on the NREL System Advisor Model, see https://sam.nrel.gov/cost.
19 

This report is available at no cost from the 

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at www.nrel.gov/publications.

Table 6. Installed System Cost Assumptions

System Type Fixed-Tilt Roof/Fixed-Axis 

Ground ($/W)

Single-Axis Tracking 

($/W)

Baseline System 2.79 3.35

+ 25% Ballast +0.70 +0.84

Ballasted GroundMounted System

3.49 4.19

This price includes the PV array and the BOS components for each system, including the inverter 

and electrical equipment, as well as the installation cost. This includes 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. 

Santo Domingo Pueblo receives electricity through the servicer PNM. The utility retail rate used 

in the economic analysis is $0.123219/kWh. This rate is based upon correspondence with PNM 

and is the average rate received by the Tribe for commercial demand over 450 kWh per month. 

This rate is considered to be a conservative estimate of the electrical cost offset by a PV system. 

While there is a lower rate for electrical consumption up to 450 kWh per month, the actual usage 

for each building is expected to be much higher. Any energy that a PV system offsets in the 

highest rate tier will bring an even greater benefit.

This analysis assumes that relevant federal and state incentives are received for taxable entities. 

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

possible. The full list of incentives used in this study can be found in Table 7. 

Table 7. Summary of Incentives Evaluated

Applicable to 

Tribe Owned 

System Incentive Title Modeled Value Expected End 

Federal Investment Tax Credit 30% of total investment 12/31/2015

Advanced Energy Tax Credit 6% of total investment, 

must be over 1 MW

$60 million

X Net Metering Net metering up to 

80 MW

- 

Renewable Energy Production 

Tax Credit (Corporate) 

Average $0.027/kWh, 

10 years

- 

Sales Tax Incentive 100% of receipts - 

X REC Payment from PNM $0.04/kWh, system 

sizes under 10 kW, 

8 years

$0.05/kWh, system 

sizes 10 kW–1 MW, 

8 years

12/31/2013,

restructured 

each year
20 

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

systems can be reasonably expected to continue operation past this point. A full list of standard 

assumptions can be found in Appendix B-1. The modeling assumed PV could cover 80% of the 

rooftop and ground space available. PVWatts Version 2 was used to calculate expected energy 

performance for the system. 

5.2 SAM-Forecasted Economic Performance

Using varied inputs and the assumptions summarized in Section 5.1 of this report, SAM predicts 

net present value (NPV), PPA, and levelized cost of energy (LCOE). Nine scenarios total were 

run for the Santo Domingo Pueblo. Four cases were used to model filling the available roof 

spaces on municipal buildings with PV arrays. Three cases were done to investigate installing 

PV systems on the industrial site if the site were to be renovated, including a roof-mounted 

system. Two cases investigated the landfill for a large-scale system to possibly lease or use as a 

power source for the industrial site. All cases were run with applicable incentives to show the 

maximum benefit available to each system. 

There are multiple factors that go into choosing the most appropriate scenario(s) beyond NPV, 

PPA, and LCOE; however, Table 8 shows the different options and their results. It is important 

to note that the economic models used the assumptions found in Appendix B-2, and further 

investigation is suggested before investing in a PV system. All roof systems have the same 

expected payback period of 10.45 years. The best municipal system from an NPV point of view 

is the utilities building, but all municipal buildings are expected to be favorable. The only 

unfavorable model for the industrial site is the fixed-axis ground system on the landfill. The 

benefits of the PV systems at the industrial site will not be realized until the site is repurposed 

and using significant amounts of electricity. All systems have a payback within the 25-year 

evaluation space and all are less than 15 years. 
21 

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Table 8. Summary of SAM Results

5.2.1 Solar Investor vs. Tribe Owned

While ownership of the system is profitable for the Santo Domingo Pueblo, it will require hiring 

the contractors to permit, install, and maintain the system. A solar investor assumes the risk and 

profit, and the Santo Domingo Pueblo in turn will receive power from the PV system at a rate 

determined by the investor. A solar investor will also be able to take advantage of federal and 

state tax benefits, which will lower the cost of the system. Solar investors also usually have a 

size threshold that they require before they will develop a site. Roof systems are typically not 

attractive sites for investors and were not considered in the study. 

The recommendation of the feasibility team is for the Santo Domingo Pueblo Tribe to develop 

and own all roof systems (administrative area and industrial site) and the industrial site groundmounted system and not pursue a PPA for those systems. For the landfill, however, the 

feasibility team recommends the Tribe pursue a PPA because an investor may be interested in 

building a PV system at that location. The model currently shows a PPA of $0.1145/kWh, with a 

15% internal rate of return for the investor, for a single-axis PV system on the landfill area. The 
22 

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at www.nrel.gov/publications.

PPA price is lower than what is expected to be paid to the utility and could potentially save the 

Tribe more than if they were to install and own the system. 

5.2.2 Fixed-Axis vs. Single-Axis Tracking 

The primary difference between fixed and single-axis tracking is the tradeoff between energy 

production and capital costs. The single-axis tracking system is able to gather a significantly 

greater portion of the sun’s energy but costs more per watt and covers a greater amount of land 

than a fixed-axis system of the same size. The fixed-axis system gathers less solar energy but 

costs less, can be put on roofs, and more panels can be packed together than single-axis tracking. 

The single-axis tracking system is the more economically attractive ground system. 

For this site, the feasibility team recommends pursuing single-axis tracking for the groundmounted systems. If the fixed-axis installed price were to be $0.99 less than the single-axis 

installed price, the fixed-axis tracking system would become more favorable on an NPV basis. 

All roof systems must be fixed axis. 

The entire results and summary of inputs to the SAM is available in Appendix E.

5.3 Job Analysis and Impact

To evaluate the employment and economic impacts of the PV projects associated with this 

analysis, the NREL Jobs and Economic Development Impact (JEDI) models are used.

5 JEDI 

estimates the economic impacts associated with the construction and operation of distributed 

generation power plants. It 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 the 

proposed facility. 

JEDI represents the entire economy, 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 on 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 JEDI 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 results are considered gross estimates 

as opposed to net estimates. 

For demonstrating the impact of constructing a single system in the Santo Domingo Pueblo, the 

system values in Table 9 were assumed. 

 

5

 JEDI has 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 JEDI, see 

http://www.nrel.gov/analysis/jedi/about_jedi.html. 
23 

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at www.nrel.gov/publications.

Table 9. JEDI Analysis Assumptions

Input Assumed Value

PV System Capacity 16 kW

Placed in Service Year 2013

Installed System Cost $44,054

Location Santo Domingo Pueblo, NM 

Using these inputs, JEDI 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, full-time equivalent 

(FTE) position. An FTE is defined as 40 hours per week for one person 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 analysis provided in Appendix D, the total proposed 

system is estimated to support 0.5 direct and indirect jobs per year for the duration of the 

procurement and construction period. Total wages paid to workers during the construction period 

are estimated to be $19,800, and total economic output is estimated to be $480,700. The annual 

O&M of the new PV system is estimated to support zero FTEs per year for the life of the system. 

The jobs and associated spending are projected to account for approximately $300 in earnings 

and $500 in economic activity each year for the next 25 years. 

5.4 Financing Opportunities

The procurement, development, construction, and management of a successful utility-scale 

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 

each owner’s/operator’s assets and equity in the project. In addition, private entities can utilize 

any of 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 stand-alone tax credit bond; through a tax-
24 

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at www.nrel.gov/publications.

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 tax-exempt entities, public entities are 

unable to benefit directly from the various tax-credit-based incentives available to private 

companies. This has given way to the now 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, they often 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 is typically 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 receiving either 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 term of a PPA typically 

varies 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 investors would begin with the majority ownership. Eventually, the ownership would flip to 

the developer once each investor’s return is met.

5.4.4 Hybrid Financial Structures

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

to finance solar projects. A particular structure, nicknamed “The Morris Model” 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 
25 

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very attractive PPA price for the site hosts. New Markets Tax Credits have been combined with 

PPAs and public debt in other locations, such as Denver, Colorado, and Salt Lake City, Utah. 

5.4.5 Solar Service Agreement and Operating Lease

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

predominately used in the municipal and cooperative utility markets due to their treatment of tax 

benefits and the rules limiting federal tax benefit transfers from non-profit to for-profit 

companies. Under Internal Revenue Service (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 as a workaround for 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 nonprofit utility typically purchases the solar services with either a one-time up-front 

payment equal to the turn-key system cost minus the 30% federal tax credit or may purchase the 

services in annual installments. The municipality can 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., the SSA 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 results 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.” 

5.4.6 Sale/Leaseback

In the widely accepted sale/leaseback 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, the public or private entity

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 public or 

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

are exhausted. 

5.4.7 Community Solar/Solar Gardens

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 projects are distributed solar projects wherein 

utility customers have a stake via a prorated share of the project’s energy output. This business 

model is targeted to meet demand for solar projects by customers who rent/lease homes or 

businesses, do not have good solar access at their site, or do not want to install a solar system on 

their facilities. Customers acquire pro-rated shares of solar projects through a long-term 

transferrable lease of one or more panels, or they subscribe 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 
26 

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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 “virtual net

metering.” Under the customer subscription option, the customers typically pay a set price for a 

block of solar energy (i.e., 100 kWh/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 billing facilitated by the utility, or a joint 

venture between the utility and a third-party developer that leads to eventual ownership by the 

utility after the tax benefits have been absorbed by the third-party developer. 

Some states offer solar incentives for community solar projects, including Washington State 

(production incentive) and Utah (state income tax credit). Community solar is sometimes known 

as solar gardens depending on the location (e.g., Colorado). 
27 

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6 Conclusions and Recommendations 

The Santo Domingo Pueblo Tribe should consider installing small PV units on the roofs of 

government buildings at the Pueblo administrative area because they could be economically 

beneficial. Once the industrial site is renovated, both ground- and roof-mounted PV should be 

installed at the site to offset energy costs. Obtaining grants from PNM and other sources will 

help improve the economic benefits of these systems. Leasing the landfill space to a solar 

developer could be economically beneficial for the Tribe if the extra PV is needed for the 

renovated industrial site. 

This analysis found that the installation of all roof- and ground-mounted PV systems for the 

administrative area, industrial site, and landfill is economically feasible, potentially generating 

1,326,628 kWh annually. 

The single-axis net-metering PV system on the industrial site has the best NPV and payback of 

$56,252 and 9.1 years, respectively, according to the SAM economic analysis summarized in 

Section 5. If the landfill PV system was developed under a solar investor/PPA arrangement, the 

best possible PPA price is $0.1145/kWh, which could potentially save the Tribe a larger sum of 

money than the Tribe owning the system on the landfill.

The administrative area has enough rooftop space available for four PV systems totaling 45 kW. 

These systems would potentially produce 77,649 kWh of energy annually, enough to power 

14 homes.

Once the industrial site has been renovated, PV panels (roof- and ground-mounted) should be 

installed that could potentially offset 224,428 kWh/year from on-site production and up to 

1,248,979 kWh/year if the landfill is developed. The economics for a larger PV system at the 

Santo Domingo Pueblo landfill should be more thoroughly studied to determine the practicality 

of leasing the land to a solar developer for either lease revenue or lower electrical rates.

The Santo Domingo Pueblo is a good site to pursue PV to offset energy use, and any grants 

available for PV development should be pursued. The modeled values in this feasibility study are 

also conservative in regards to financing the system and could potentially be better than 

modeled. If bonds were able to be obtained, the value of the system could potentially double. A 

more thorough study of available grants and potential funding sources should also be considered 

during an investigation of potential installers.
28 

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Appendix A. Provided Site Information

Table A-1. Utility Rates Provided by PNM Contact

In the Billing Months 

Of: 

June, July, and August All Other Months

Customer 

Charge: 

$5.00/Bill x Per Metered 

Account)

$5.00/Bill x Per Metered 

Account)

Energy Charge:

First 450 kWh per Month 

Next 450 kWh per Month 

All Additional kWh per Month 

$0.0906237/kWh 

$0.1373455/kWh 

$0.1576960/kWh 

$0.0906237/kWh 

$0.1185101/kWh 

$0.1283520/kWh 

Table A-1 lists the utility rates, dependent on month of the year, for each service location.

6 Net 

utility rate is dependent upon total power purchased from each tier shown above. 

All kilowatt-hour usage under this tariff will be subject to a Fuel and Purchase Power Cost 

Adjustment Clause (“FPPCAC”) factor calculated according to the provisions in PNM’s 

Rider 23. The rider allows for tariffs to change up or down according to changes in fuel and 

purchased power prices.7

 

 

6 Newby, C. Email, PNM Governmental Affairs, 1 January 2013.

7 Public Service Company of New Mexico. “2nd Revised Rider No. 23,” 30 December 2011. Accessed July 15, 

2013: http://www.pnm.com/regulatory/pdf_electricity/rider_23.pdf. 
29 

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Appendix B. Assessment and Calculations 

Assumptions

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

Cost Assumptions

Variable Quantity of 

Variable

Unit of Variable

Cost of Site Electricity 0.123219 $/kWh

Annual O&M (fixed) 20 $/kW/year

System Assumptions

System Type Annual Energy 

kWh/kW

Installed Cost 

($/W)

Energy Density 

(W/sq. ft.)

Roof Fixed 1,601 $2.79 4.00

Ground Fixed w/ Ballast 1,601 $3.49 4.00

Ground Single-Axis w/ Ballast 2,116 $4.19 3.30

Other Assumptions

1 acre 43,560 ft2

1 MW 1,000,000 W

Ground 

utilization

90% of available 

area
30 

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Table B-2. Modeling Assumptions

Item PPA/Investor Tribe Purchase Notes

Analysis Period

(years) 25 25

Inflation 2.50% 2.50%

Real Discount 

Rate 5.85% 5.85%

Federal Tax Rate 35% 0%

State Tax Rate 8% 0%

Insurance (% of 

installed cost) 0.50% 0.50%

Property Tax 0 0

Construction Loan 0 0

Loan Term 15 15

25-year bonds would greatly 

improve the economics

Loan Rate 6% 6% May be lower for bonds

Debt Fraction 55% 55%

45%–60% PPA, 

100% municipal ownership, 

DSCR of ~1.3 (>1.2)

Minimum IRR 15.00% N/A

PPA Escalation 

Rate 1.50% N/A

Fed Depreciation

5-year MACRS with 

50% first-year 

bonus N/A N/A for municipal ownership 

State Depreciation 5-year MACRS N/A N/A for municipal ownership

Fed ITC 30% N/A N/A for municipal ownership

Payment 

Incentives 0 0

Degradation 0.50% 0.50%

Availability 100% 100%

Cost – Fixed-Axis 

per kW $2.79–$3.20 $2.79–$3.20

Cost – Single-Axis 

Tracking per kW $3.35–$3.84 $3.35–$3.84

Cost - Landfill 

Ballasted per kW $3.49–$4.00 $3.49–$4.00

Grid 

Interconnection 

Cost $ - $ - 
31 

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Land Cost $ - $ - 

O&M

$30/kW/yr first 

15 yrs and 

$20/kW/yr 

yrs 16-25

$30/kW/yr first 

15 yrs and 

$20/kW/yr 

yrs 16-26

Derate Factor 0.8 0.8

Fixed-Tilt 20° 20°

Single-Axis Tilt 0° 0°

Acres per MW 

Fixed 5.74 5.74 

Acres per MW 

Tracking 6.96 6.96 
32 

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Appendix C. Solar Access Measurements

All sites had greater than 90% solar access. Below is a representation of the sites.

Figure C-1. Solar access measurement for Senior Center PV site
33 

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Appendix D. Results From the System Advisor Model

Figure D-1. 16-kW roof-mounted monthly production projection
34 

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Figure D-2. 76-kW ground-mounted fixed-axis monthly production projection
35 

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Figure D-3. 63-kW ground-mounted single-axis monthly production projection 
36 

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Figure D-4. 16-kW roof-mounted annual cash flow
37 

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Figure D-5. 76-kW ground-mounted fixed-axis annual cash flow
38 

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Figure D-6. 63-kW ground-mounted single-axis monthly annual cash flow
39 

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Appendix E. Results of the Job and Economic 

Development Impact Models 

Appendix E shows the JEDI results from installing a 16-kW roof-mounted system. Other PV 

system sizes will be relative to this.

Table E-1. Photovoltaic Project Data Summary 16-kW Roof-Mounted System

Project Location New Mexico

Year of Construction or Installation 2013

Average System Size - DC Nameplate Capacity (kW) 16.0

Number of Systems Installed 1 

Project Size - DC Nameplate Capacity (kW) 16.0

System Application

Small 

Commercial

Solar Cell/Module Material

Crystalline 

Silicon

System Tracking Fixed Mount

Total System Base Cost ($/kWDC) $2,853 

Annual Direct Operations and Maintenance Cost 

($/kW) $25.00

Money Value – Current or Constant (Dollar Year) 2012

Project Construction or Installation Cost $45,645

 Local Spending $29,953

Total Annual Operational Expenses $5,588

 Direct Operating and Maintenance Costs $400

 Local Spending $364

 Other Annual Costs $5,188

 Local Spending $9

 Debt Payments $0

 Property Taxes $0
40 

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Table E-2. Local Economic Impacts – Summary Results

Jobs Earnings Output

During Construction and Installation Period $000 (2012) $000 (2012)

 Project Development and On-Site Labor Impacts

 Construction and Installation Labor 0.1 $4.0

 Construction and Installation Related Services 0.1 $5.2

 Subtotal 0.2 $9.3 $16.2

 Module and Supply Chain Impacts

 Manufacturing Impacts 0.0 $0.0 $0.0

 Trade (Wholesale and Retail) 0.0 $1.9 $5.8

 Finance, Insurance, and Real Estate 0.0 $0.0 $0.0

 Professional Services 0.0 $1.2 $3.9

 Other Services 0.0 $2.2 $7.5

 Other Sectors 0.1 $2.3 $4.5

 Subtotal 0.2 $7.6 $21.7

 Induced Impacts 0.1 $3.0 $10.1

 Total Impacts 0.5 $19.8 $48.0

Annual Annual

Annual Earnings Output

During Operating Years Jobs $000 (2012) $000 (2012)

 On-Site Labor Impacts

 PV Project Labor Only 0.0 $0.2 $0.2

 Local Revenue and Supply Chain Impacts 0.0 $0.1 $0.2

 Induced Impacts 0.0 $0.0 $0.1

 Total Impacts 0.0 $0.3 $0.5

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 

might not add up due to independent rounding.
41 

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Table E-3. Detailed PV Project Data Costs

NEW MEXICO Purchased Manufactured

Installation Costs Cost

Locally 

(%) Locally (Y or N)

Materials and Equipment 

 Mounting (rails, clamps, fittings, etc.) $1,765 100% N 

 Modules $14,159 100% N 

 Electrical (wire, connectors, breakers, etc.) $1,136 100% N 

 Inverter $2,555 100% N 

 Subtotal $19,615 

Labor 

 Installation $4,024 100% 

 Subtotal $4,024 

Subtotal $23,639 

Other Costs 

 Permitting $5,646 100% 

 Other Costs $2,305 100% 

 Business Overhead $13,050 100% 

 Subtotal $21,001 

Subtotal $44,640 

Sales Tax (materials and equipment purchases) $1,005 100% 

Total $45,645 
42 

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Table E-4. PV System Annual Operating and Maintenance Costs

Cost Local Share

Manufactured 

Locally 

(Y or N)

Labor

 Technicians $219 100%

 Subtotal $219

Materials and Services

 Materials and

Equipment $181 100% N

 Services $0 100%

 Subtotal $181

Sales Tax (materials and

equipment purchases) $9 100%

Average Annual Payment 

(interest and principal) $5,178 0%

Property Taxes $0 100%

Total $5,588

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) 0%

 Local Property Taxes $0 100%

 Local Sales Tax Rate 5.13% 100%

 Sales Tax Exemption 

(percent of local taxes) 0%

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%