BROWN
&ER&
United States
Environmental Protection
Agency
Solar Power on
Closed Landfill in Houston
Sustainability Pilot Background
TEXAS
EPA's Brownfields Sustainability Pilots provide technical assistance to assist
communities in achieving greener, more sustainable results when redeveloping
brownfields. These pilots also provide models for other communities across
the country.
EPA provided the City of Houston with technical assistance for the redevelopment of \
a 300 acre former landfill located near downtown. EPA provided an analysis of the
environmental, engineering and regulatory considerations associated with building
a ten megawatt solar plant on the former landfill. EPA support also helped the
city analyze the potential level of solar energy production and review the financial v"~^>
feasibility of the solar project. This project is expected to spur a local market for solar energy systems and create jobs
in the renewable energy field. In addition, project implementation will reduce the city's greenhouse gas emissions by
providing an alternative source of power for municipal operations.
Holmes Road Landfill Background
The City of Houston closed the Holmes Road Landfill in the 1970s, and a state mandated cap was installed. Over
the past 30 years the site remained idle, even as potential redevelopment plans—including at one point a municipal
golf course—materialized and faded. Ultimately, Houston's abundant sunshine and the former landfill's location near
existing power distribution lines led to recognition of the site's potential for a solar power generation project. To assist
their efforts, the city requested technical assistance from EPA.
Project Highlights
EPA's technical assistance to the City of Houston included an analysis of environmental conditions, preliminary
engineering designs, solar photovoltaic (PV) system conceptual design and specifications, solar farm turn-key costs,
estimates of solar system output potential, and economic valuations. These analyses provided the city with current
and accurate information on the associated costs, benefits, and regulatory requirements for building a solar farm on a
former landfill owned by the city.
The technical assistance included:
• An on-site photovoltaic project assessment
• Regulatory assessment
• Site engineering assessment
• Determination of PV system size, conceptual design
Development of installed cost estimates for the
solar farm
Economic analysis of the proposed solar
farm's characteristics
elements, and specifications
The City of Houston conducted a request for proposals and received bids from 11 companies. In September 2009,
the city selected NRG Energy Inc. to develop the solar farm. After designing and building the solar power farm, NRG
will enter into a long term power purchase agreement with the city to sell the solar generated power.
Based on the modeled output derived from the technical assistance, the solar farm will generate over 12.5 million
kilowatt hours (kWh) annually accounting for approximately one percent of the city's annual energy purchases. The
system itself will have a lifespan of 30 years and carries with it an operational and maintenance cost of approximately
$0.005 per kWh. The city is working with the U.S. Business Council for Sustainable Development to assist with the
development of a project master plan. Current plans are for completion of the ten megawatt solar farm by 2010.
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Challenges and Lessons Learned
Overgrowth and Cap Depth Inconsistency
Since the landfill cap was installed in the mid
1970s, the site became overgrown with large
trees and brush. In addition to the added cost of
clearing the site of this growth, the cap depth is
variable, complicating construction, tree removal,
and site grading as consideration must be taken
to ensure the cap's integrity. This may require,
for example, that tree roots extending into the
subsurface landfill waste be left in place and
covered. Approaches include moving soil from
areas where cap depth is greater or to bring in
additional soil to make the overall cap depth
more consistent.
Distribution Line Capacity
Utility distribution lines are located adjacent to the landfill on three sides. Studies determined that the most
viable location for the solar farm would be on the south side, which has the highest utility distribution capacity.
However, further investigation into the actual carrying capacity of these south side distribution lines needs to
be conducted.
Constant Communication Among All Stakeholders
For this project, frequent communication among all stakeholders—the city, state, EPA, and consultants—was
essential to achieving positive results. The open communication maintained through multiple stages of technical
assistance and analysis made successful completion of the solar plant more likely.
The Holmes Road Landfill site before renovation.
Sources for Additional Information
For more information on this project, please see the full Houston Solar project technical assistance report at:
http://www.epa.gov/brownfields/sustain_plts/factsheets/houston_solar.pdf
Additionally, please see:
Action Plan for the Beatty Area, Nye County, Nevada, Renewable Energy Power Park
www. epa. gov/aml/revital/msl/pdfs/beatty. pdf
Regional Contact Information
For more information on the Houston Solar Brownfields Sustainability Pilot project, please contact:
Rob Lawrence
EPA Region 6
214-665-6580
lawrence.rob@epa.gov
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