&EPA
United States
Environmental Protection
Agency
Evaluating Renewable Energy Opportunities
THE APACHE POWDER SUPERFUND SITE, BENSON, ARIZONA
U.S. Environmental Protection Agency
Superfund Redevelopment Initiative
February 2011
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Table of Contents
This document summarizes the renewable energy pre-
feasibility analysis conducted at the Apache Powder
Superfund Site.
Introduction p. 1
Renewable Energy Analysis p. 2
Step One: Evaluate Renewable Energy Resources p. 3
Step Two: Assess Site Suitability p. 4
Step Three: Consider Technology-Specific Criteria p. 6
Step Four: Review Market and Incentives p. 8
Summary of Findings p. 10
Resources p. 12
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ntroduction
For over 10 years, the United States Environmental
Protection Agency (EPA) has been working with
communities to better understand how Superfund sites can
be returned to beneficial uses and supporting Superfund
site reuse nationwide. EPA also strongly supports the
evaluation of sites for reuse through renewable and
sustainable energy production. Through efforts such
as the Superfund Redevelopment Initiative and Re-
Powering America's Lands Initiative, EPA is providing
resources to encourage alternative and renewable energy
generation at these sites.
In 2008, the Apache Powder Superfund Site, located near
Benson, Arizona, presented a unique opportunity for EPA
to support the evaluation of renewable energy generation.
Ground water and soil contamination from prior disposal
practices was addressed by Apache Nitrogen Products,
Inc. (ANP) with EPA oversight, and construction of
the remedy was completed in 2008. ANP continues to
manufacture chemical products on portions of the site
and expressed interest in exploring opportunities for
renewable energy generation on remaining areas of the
site.
With the support of EPA's Superfund Redevelopment
Initiative, EPA Region 9 began to look at the site's
potential for renewable energy development. A
preliminary screening identified the following key assets:
• Excellent solar power generation potential
• A large tract of available land ready for reuse
• Significant federal, state and local incentives for
solar energy projects
• A willing and enthusiastic site owner
Based on these assets, EPA conducted a Renewable
Energy Pre-Feasibility Analysis to provide ANP with
information on the site's potential for renewable energy
development that could be compatible with the site's
remedy and the on-going manufacturing operations at the
ANP facility. The process and findings of this analysis are
summarized in this document.
Top: Example of solar arrays installed at Nellis Air Force Base, Nevada. Bottom: ANP facilities at the Apache Powder Superfund Site, 2008.
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Renewable Energy Analysis: A Four-Step Process
A renewable energy pre-feasibility analysis assists site owners, stakeholders and EPA in determining whether a site may
be a candidate for renewable energy technologies. Following the analysis, site owners may develop a more detailed
feasibility study for a particular renewable energy technology or identify development partners and move forward with
renewable energy development. At the site, the four-step process for the analysis included:
Evaluate Renewable Energy Resource: Determine
the availability of renewable energy resources
and identify the renewable energy opportunities
requiring further analysis.
2 Assess Site Suitability: Identify site-specific
considerations such as access, topography and slope,
remedial components, infrastructure, the existing
uses and facilities.
3 Consider Technology-Specific Criteria: Identify
technology-specific considerations such as
infrastructure requirements (including space and size
requirements), energy generation and storage capacity,
and costs for installation, operation and maintenance.
4 Review Market and Incentives: Assess the current
renewable energy market and identify the federal, state
and local incentives available to promote renewable
energy generation.
Site Background
Since 1922, ANP (formerly the Apache Powder
Company) has manufactured industrial chemicals and
explosives. Historically, these operations produced
both solid and liquid wastes which were disposed of
on the property owned and operated by ANP, resulting
in ground water and soil contamination.
Following initial investigations at the Site in the
1980s, ANP removed all contaminated soils, with the
exception of sediments and soils in several evaporation
ponds, which were covered, re-graded and capped
in 2007. Deed restrictions in the form of a State of
Arizona Declaration of Environmental Use Restriction
(DEUR) were also placed on the ponds.
VICINITY MAP
APACHE POWDER SUPERFUND SITE
COCHISE COUNTY, ARIZONA
Douglas
Mexico Sonora **9ua
Pneta
The Apache Powder Superfund Site encompasses approximately nine square
miles and is located in a rural area of southeastern Arizona, southeast of
Tucson
To address ground water contamination in the shallow
•r- • .1 ,1 j .1 r- .1
aquifer in the northern and southern areas of the
site, cleanup activities are underway and long-term
monitoring will continue. Cleanup activities utilizing green and renewable energy technologies include a constructed
on-site wetland system. The constructed wetland system treats nitrate -contaminated ground water twenty four hours
a day, 365 days a year. This approach avoids chemical usage, energy consumption and waste generation associated
with traditional treatment methods. During the start-up phase of the wetlands, solar power was used to circulate
water between the wetland ponds. Solar power is still used at the wetlands to power the flow meter for the system.
In September 2008, EPA completed its Construction Completion report for the site, describing all completed cleanup
activities. The site is now in the long-term operations and maintenance phase of the Superfund cleanup process.
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Step One: Evaluate Renewable Energy Resources
The renewable energy analysis for the site began with an assessment of available renewable energy resources, to
identify which renewable energy resource(s) might merit further analysis. Solar and wind were identified using readily
available information. Other renewable energy opportunities, such as biomass and geothermal energy, did not merit
further analysis, due to limited availability or other restrictions.
Regional Energy Resources
Wind Energy
In general, wind power can be well-suited to Superfund
sites because of the size of some sites and the presence
of transmission lines from previous industrial facilities.
However, the quality of wind resources varies significantly
across the United States. According to current wind resource
data from the National Renewable Energy Laboratory
(NREL), the site is not located in an area with strong wind
resources. Accordingly, the analysis concluded that the site
is likely not well-located to support a financially viable
location for a grid-connected wind turbine project.
This EPA partnership with the Department of Energy
and NREL is encouraging RE development on current
and formerly contaminated land and mine sites. The
initiative identifies the renewable energy potential
of these sites and provides useful resources for
communities, developers, industry, state and local
governments and any other parties interested in reusing
these sites for renewable energy development.
The initiative also provides the Renewable Energy
Interactive Mapping Tool (See the Resources section).
The Tool makes it possible to view EPA's renewable
energy siting information for contaminated lands and
mine sites alongside information on renewable energy
resource availability and relevant Google Earth data.
Solar Energy
Most of the United States has access to adequate-to-good quality solar resources; all of Arizona, including the site,
enjoys "excellent" quality resources, according to NREL. Arizona is also expected to rely heavily on solar energy
in order to meet future renewable energy requirements like the state's renewable portfolio standard, which requires
that electricity providers in the state obtain at minimum 15% of their power from renewable energy resources by
2025. Projections indicate that upwards of 65% of the state's renewable energy demand in 2025 will be met by solar
energy projects. Accordingly, EPA's renewable energy analysis led to the development of a Solar Energy Information
Memorandum in 2008, confirming the need to further investigate the potential for solar energy production at the site.
The Memorandum's findings indicated that
the availability of excellent solar resources and
available federal and state policies and incentives
made solar energy development a potentially
viable option at the site. Evaluating on-site energy
demands and infrastructure is another important
consideration in this first step of evaluating the
energy resource.
**
Figure 1: National solar photovoltaics (PV) resource potential
for the United States. Arizona and the Site have excellent solar
potential. Source: NREL
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Local Demand and Infrastructure
Energy Needs: ANP purchases all of its electricity from
Sulphur Springs Valley Electric Cooperative (SSVEC).
Manufacturing options at the site require a constant
supply of 1MW to meet base energy demand, with a
2MW daily peak.
Transmission Capacity: Land on ANP property is leased
by SSVEC for use by a 69kV electrical substation with a
line capacity of 40MW. While the existing substation's
capacity is adequate for current ANP operations, planned
substation and line upgrades will have a 100MW capacity.
Based on this information, EPA developed two solar
generation scenarios for further analysis:
On-site Use
• Provide ANP with an on-site energy source for all or
a portion of the facility's electrical use
• Provide on-site steam to support manufacturing
operations
Grid Use
• Generate utility scale energy for the grid with
potential energy and economic benefits to ANP
To further evaluate these energy generation scenarios, the
remaining steps of the analysis focuses on two types of
solar technologies: photovoltaic (PV) and concentrating
solar power (CSP).
Step Two: Assess Site Suitability
After determining resource availability and demand,
EPA assessed the suitability of different site areas
for solar development. First, the effort mapped
existing site conditions. As illustrated in Figure 2,
the site includes several large, flat contiguous areas
unrestricted by natural or constructed features.
Areas shown in green represent land with a slope
of less than 5%. Paved roads are shown in grey
and internal site roads are shown in tan. Remedial
components are indicated in yellow and were
excluded from the assessment due to potential
regulatory conflicts. Additional infrastructure such
as rail lines and site facilities are also shown.
Figure: 2 Existing Conditions Suitability Analysis
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Potential Solar Development Zones
Based on site features, six potential solar zones were identified (see Figure 3 below). Zone criteria included:
• Contiguous areas greater than 15 acres
• Areas with less than 5% slope
• Road access
• Proximity to infrastructure
• Areas with washes, remedy components and facilities excluded
At 25+ acres, Zones A, B and C were all large enough to support CSP technology. All six zones could support PV
technology, which could be installed on areas as small as 15 acres. The resulting area with potential for either CSP or
PV development totalled 185 acres (see
table below for zone acreages).
I
^
Potential Solar Zones
CSP Potential
Zone A 70 acres
Zone B 25 acres
Zone C 35 acres
130 Total Acres
PV Potential
Zones A-C 130 acres
Zone D 15 acres
Zone E 20 acres
Zone F 20 acres
185 Total Acres
Net PV/CSP Potential
185 Total Acres
SITE FEATURES
| Paved Public Road
Internal Site Roads
Major Railroad
Internal Rail Spurs
Buildings
Major Washes
25'Contour
5'Contour
C 3 Remedy Component
Figure 3: Potential Zones for Solar Development
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Step Three: Consider Technology-Specific Criteria
The analysis next evaluated each solar technology based on technology-specific opportunities and constraints. PV
systems use solar electric panels to directly convert the sun's energy into electricity. CSP systems generate electricity
through the use of long mirrors that focus light on a tube of fluid. The concentrated rays boil the fluid (usually water),
and the resulting steam drives turbines, generating electricity. Facilities at the site already rely on steam in production
processes and could potentially use the steam produced by CSP systems to meet on-site production demand. PV
systems and CSP systems could both take advantage of the abundant solar resources available at the site. However,
each technology has specific requirements that may make it more or less suitable for use at the site. The table below
summarizes some of the key differences in technology requirements for CSP and PV systems. CSP systems, for example,
require large, contiguous land areas, use significant amounts of water, and can store energy. PV systems, in contrast, can
be located on smaller land areas, do not use much water, and do not have any storage capacity.
Concentrating Solar Power (CSP) and Photovoltaic (PV): Key Differences
Solar
Technology Type
CSP
PV
Acres per MW
3-8
acres / MW
4-10
acres / MW
Minimum Practical
Acreage
40 - 50 acres
N/A
Site Needs
Large, contiguous,
level area
Flexible
Storage
Capacity
Yes
No
*Estimates can vary based on specific technology
Estimated Annual
Water Usage*
Significant
Negligible
/
Inverter
and
Transformer
Solar Tracking Array
Photovoltaic systems make use of highly purified
silicon that functions to convert sunlight directly
into electricity, which can be used in place or
supplied and distributed to the power grid, as
depicted above.
Image Source: U.S. EPA
Steam condenser
Concentrating solar power systems indirectly
generate electricity and essentially consists of
two parts: one part that collects solar energy and
converts it to heat and the other that converts
the heat energy to electricity (see image to the
right). This system can generate power around
the clock through the use of its thermal storage
capabiliies, not just when the sun is shining.
Receiver
Generator
Turbine'
Parabolic Troughs
Image Source: U.S. Department of Energy
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Comparative Analysis
To further understand the implications of CSP and PV systems for solar power generation at the site, EPA conducted a
comparative analysis of capital and operations costs for a 5MW PV installation and a 10MW CSP installation. Findings
from the analysis are presented in the table below.
Estimated Est|mated Estimated Annual Estimated Annual
_ . _ . _ Acres per _ .... _. Land Area Estimated Capita «».. r. m *
Solar Technology Type MJ Facility Size Cost ($ 1000)* O&M Cost Water Usage
(MW) (acres) ($ 1000)* (gallons)
MW
CSP Trough
No Storage
No Storage Air Cooled
With Six-hour Storage
Linear-Fresnal
Reflector
PV
Thin Film
(fixed axis)
10
10
10
10
50
50
80
30
$45,000 -
60,000
$65,000 -
70,000
$50,000 -
65,000
$30,000 -
35,000
$1,250- 1,500
$1,250- 1,500
$1,400- 1,600
20,000,000
2,300,000
$1,300-1,600 25-30,000,000
30-40 $25,000-30,000 $400-600
20,000,000
Negligible
Crystalline Silicon
(fixed axis)
4-5
20-25 $30,000-36,000 $450-600
Negligible
PV Tracking
40-50 $35,000-40,000 $900-1,100
Negligible
*Estimates based on 2009 cost approximations to provide a relative comparison of the two different technologies.
As outlined in the table above, minimal capital investment anticipated for solar
technology ranges from approximately $25 million for a 5MW PV facility to up to $70
million for a 10MW CSP facility. In general, CSP systems can generate more power
on less land but require significant amounts of water in comparison with PV systems.
Additional technology-specific considerations include:
• CSP economic viability is most likely achieved at 200-3OOMW facilities.
However, the potential for re-purposing the steam produced by CSP technology
could increase the viability of a smaller facility at the site.
• Facilities larger than 5MW would also require substation and line upgrades that
could be met as part of planned upgrades.
Top: Tracking PV panels follow the
sun to allow for increased solar
capture. Bottom: Fixed axis PV
panels aligned to be south facing.
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Step Four: Review Market and Incentives
Finally, EPA's renewable energy analysis looked at market conditions and the availability of federal, state and local
incentives to help make solar development at the site viable. The analysis found that the site is located in a growing
solar market and ANP could benefit from both policy-based and financial incentives.
Solar Energy Market
In general, Arizona has excellent solar resources statewide and there are expectations for a growing market for renewable
energy development, based on several factors:
• The state's dependence on natural gas as a source of electricity, given the price volatility of natural gas
• The state's proximity to large potential solar markets
• Intellectual capital resources at in-state universities and research centers
Across the state, the amount of installed grid-tied solar capacity has steadily increased:
• PV system installations quadrupled in Arizona between 2008 and 2009
• In 2009, 23MW of PV capacity was installed in Arizona. This capacity is expected to increase significantly in
coming years, with large projects like the proposed 280MW Solana solar thermal project in Gila Bend
• Arizona ranked fourth nationally in installed solar energy capacity in 2009 (behind California, New Jersey and
Colorado)
Generation and Sale of Electricity
Utilities or their affiliates provide power generation, high-voltage transmission lines and low-voltage distribution.
Energy providers can sell their power in two primary ways: wholesale and retail. Power sold at "wholesale" is
primarily done for large-scale utility providers. Power sold at "retail" is usually done for individual customers
or facilities.
Two types of purchasing agreements are commonly used by energy generators and utilities:
• Retail Purchasing Agreement: May be advantageous for the provider and the buyer if an individual facility owner
(such as ANP) can provide inexpensive land access to an energy developer in exchange for cheaper utility rates
for a set number of years. Additionally, this option may work well if there are too many costs associated with the
developer's ability to access the utility grid. In this case, the individual facility may benefit from consuming all
energy generated on site.
• Wholesale Purchasing Agreement: May be more economically beneficial to a landowner/energy developer if a
utility company is looking to increase its overall power generation.
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Renewable Energy Incentives
The analysis found that, in Arizona, there are significant incentives available to facilitate the development of renewable
energy projects for solar energy. Incentives are available at the local, state and federal levels and include both policy-
based incentives (e.g., renewable portfolio standards) and financial incentives (e.g., tax credits and rebates). The
incentives identified by the analysis are presented below.
Incentive Description
Federal
Incentives
Business Energy Tax Credits: 30% tax credit to partially offset the upfront installed cost
of a solar system. Also known as Investment Tax Credits (ITCs)
Modified Accelerated Cost Recovery: Current method of accelerated asset depreciation
required by the United States income tax code
Clean Renewable Energy Bonds (CREBs): Bonds to provide a federal tax credit for the
bond owner in lieu of interest payments from the issuer.
State
Incentives
Renewable Energy Standard (RES): Arizona has legislated a 15% RES by 2025.
Investor-owned utilities serving retail customers will be subject to the standard. Further,
by 2011, 30% of renewables must come from distributed generation sources such as
commercial and residential projects. The 15% RES goal is mandatory for investor-
owned utilities, energy cooperatives must also meet renewable energy goals.
Renewable Energy Credits (RECs): RECs are tradable commodities decoupled from
electricity generation. An REC is equal to IMWh of power generated in the course of
one year from a renewable source. RECs can amount to 30-70% of a solar project's
anticipated revenue stream. Market prices for RECs can vary significantly, Arizona's
RES allows RECs to be banked and withdrawn at a later date.
Solar Energy Property Tax Exemption: Applies to "solar energy devices and any other
device or system designed for the production of solar energy for onsite consumption."
Commercial/Industrial Solar Energy Tax Credit Program: 10% of the installed cost of
a solar device, not to exceed $50,000 per business per tax year.
Local Utility
Incentives
Upfront incentives (purchase price incentives): One-time, upfront incentive or rebate
based on the size of the solar system. SSVEC offers both commercial and residential
solar rebates.
Production-based incentives: An incentive paid out based on actual kWh production of
a renewable energy system over time instead of an initial, upfront incentive payment.
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Summary of Findings
The Renewable Energy Pre-Feasibility Analysis for
the Apache Powder Superfund site yielded several key
findings, including:
• The site could potentially support direct use and
utility-scale solar development (PV preferred)
• Solar energy development could be compatible
with the site's existing characteristics
• A project would face high upfront capital costs
for both CSP and PV systems (approximately $25
million for PV and $35 million for CSP)
• The ability to use incentives and obtain a long-
term power purchase agreement would likely be
critical for the economic viability of a utility-scale
project at the site
Land Availability
The site has sufficient acreage in areas with appropriate
slope and infrastructure access to support a solar energy
project. Analysis identified 100-130 acres of contiguous
land and up to 185 acres of non-contiguous land that could
be suitable. Analysis did not include remedy component
areas, since sufficient acreage was available elsewhere on
the site. The available acreage could support a 15-45MW
PV facility. Alternatively, the acreage could support a
20MW CSP facility that includes a storage capacity of up
to six additional hours or a 40MW facility with no storage
capacity.
Potential solar energy generation scenarios include on-
site use and grid use. On-site use will not cover all of
ANP's energy needs but could provide ANP with an on-
site energy source to reduce peak electricity demand.
Grid use could generate utility-scale energy for the grid
with potential energy use and economic benefits for ANP.
Solar Technologies
Analysis of solar technologies focused on a 5MW PV
installation and a 10MW CSP installation. Currently,
the economic viability of a CSP system is most likely
achieved at 200-300MW facilities, although the potential
for repurposing the steam produced by CSP technology
could increase the viability of a smaller facility at the site.
However, water resource availability and cost challenges
in the southwest could make the technology difficult
to implement due to its significant water requirements.
The minimal capital investment anticipated for solar
technology at the site range from approximately $25
million for a 5MW PV facility to up to $70 million for a
10MW CSP facility. Facilities larger than 5MW would
also require substation and line upgrades.
In conclusion, the site could potentially support both CSP
and PV technologies. Given the large amount of acreage
available, solar energy development would be compatible
with the site's existing characteristics. However, there
are high-upfront capital costs for installation of both CSP
and PV technologies. ANP's ability to use incentives and
obtain a long-term power purchase agreement is likely
critical to the economic viability of a utility-scale project
at the site.
5MW r
4MW
3MW
2MW
1 MW
I | December
Q June
I | Annual Average
' Apache Peak Demand
1 Apache Baseload Demand
12
18
24 Hours
Hypothetical daily generation for a 5MW PV array demonstrates
how an on-site facility could help reduce peak electricity demand.
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Next Steps
Based on the potential opportunities highlighted in the
Renewable Energy Pre-Feasibility Analysis, ANP moved
forward with two potential solar projects: a solar awning
and canopy for existing facilities and a utility-scale solar
development.
Solar Awning and Canopy
In November of 2010, ANP completed construction of a 41
kW solar canopy. The solar canopy offsets approximately
45% of ANP's annual office energy use, saving $6,000
annually. ANP was able to construct this system utilizing
various federal, state and local tax credits, resulting in
minimal capital investment on the part of the company.
The structure does not impact the integrity of the building
and is designed to be completely free-standing on
perimeter steel beams. The beams will be covered with
stucco to blend with the existing architecture.
Utility-Scale Solar Project
Following discussions with an energy developer, the
capped ponds on site were identified as an ideal setting for
installing a solar project. The closed ponds are expected
to support a 1MW facility. Further development would
expand onto adjacent land included in the pre-feasibility
analysis.
The technology being proposed by the developer is high
concentration photovoltaic (HCPV) technology that uses
a two-axis tracking system. This technology was chosen
over CSP because of its low water use. ANP anticipates
that five or more MW of power could be generated on the
southern area of the site.
Two potential partners have been identified for the project
- a local partner interested in sponsoring renewable
energy projects and a manufacturer with a technology
well-suited to the site. The next step will be to identify
a utility interested in buying the electricity generated by
the project.
Lessons Learned
The development of renewable energy technologies is a
complex process reliant on available incentives, multiple
parties, market conditions and other factors that have
to be identified and managed throughout a project. As
the Renewable Energy Pre-Feasibility Analysis for the
Apache Powder Superfund site illustrates, contaminated
lands can provide opportunities for significant renewable
energy projects that contribute to a sustainable future.
Key lessons learned from this process that could help
guide similar projects at contaminated lands across the
country include:
• A pre-feasibility analysis, as outlined here, can
assist in determining whether a site might be a
candidate for renewable energy technologies and
merit additional evaluation.
• While utility-scale renewable energy projects can
be complex, public-private partnerships and other
resources help ensure that these complexities can
be addressed and managed.
• Solar projects can be located in many places and at
different scales
Since the inception of the Superfund program, EPA
has been building on its expertise in conducting
site characterization and remediation to ensure that
contamination is not a barrier to the reuse of property.
Today, consideration of future use is an integral part of
EPA's cleanup programs, from initial site investigations and
remedy selection through to the design, implementation,
and operation and maintenance of a site's remedy. EPA
is working nationwide with public and private partners
like ANP to encourage solar and other renewable energy
development opportunities on current and formerly
contaminated lands. Please see the Resources section on
the next page for additional information.
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Resources
Region 9 Superfund: http://www.epa.gov/region9/superfund
Superfund Redevelopment Initiative: http://www.epa.gov/superfund/programs/recycle
Re-Powering America Renewable Energy Interactive Mapping Tool: http://epa.gov/renewableenergyland/mapping_tool.htm
Solar Energy Industries Association (SEIA) and the Prometheus Institute. "US Solar Industry: Year in Review." June 2009.
U.S. Department of Energy. National Renewable Energy Lab. "Power Technologies Energy Data Book." August 2006.
U.S. Environmental Protection Agency. Office of Solid Waste and Emergency Response. "Siting Clean and Renewable
Energy on Contaminated Lands and Mining Sites." September 2008.
Solar Energy Industries Association: http://www.seia.org
Database of State Incentives for Renewables & Efficiency (DSIRE): www.dsireusa.org
EPA Renewable Energy Maps: http://www.epa.gov/renewableenergyland
DOE Solar Energy Technologies Program: http://wwwl.eere.energy.gov/solar
National Renewable Energy Lab (NREL) Solar Research: http://www.nrel.gov/solar
NREL Renewable Energy Resource Maps: http://www.nrel.gov/renewable_resources
NREL Solar Advisor Model: https://www.nrel.gov/analysis/sam
&EPA
United States
Environmental Protection
Agency
Andria Banner
Environmental Scientist and Remedial Project Manager
U.S. EPA Region 9
(415)972-3189
benner.andria@epa.gov
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