RE-Powering America's Land:
Siting Renewable Energy on Potentially Contaminated Land and Mine Sites
Solar Technologies
What is the RE-Powering America's Land initiative?
Demand for renewable energy is increasing in the United States. However,
renewable energy facilities often require large amounts of land and could
contribute to energy sprawl if developed on greenfield sites. Through
its RE-Powering America's Land: Siting Renewable Energy on Poten tially
Contaminated Land and Mine Sites initiative, the U.S. Environmental
Protection Agency (EPA) identified more than 11,000 EPA tracked sites
and nearly 15 million acres that have potential for developing solar,
wind, biomass and geothermal facilities. Using potentially contaminated
land and mine sites to develop renewable energy facilities can preserve
greenfields; provide developers with access to existing infrastructure;
create jobs; and enable potentially contaminated property to return to a
productive and sustainable use.
What is solar energy?
Solar technologies generate electricity from the sun's energy. The following
types of solar production technologies were evaluated by EPA.
Utility scale concentrating solar power (CSP) - Uses the sun's thermal
energy to heat a liquid that drives a generator to produce electricity. CSP
technology is constructed at the megawatt (MW) or multi-MW scale and
electricity generated is typically exported
to the grid. Three types of utility scale CSP
technologies were evaluated by EPA:
• Trough system - Uses long rectangular,
curved (U-shaped) mirrors that
concentrate sunlight on tubes that run
the length of the mirrors. A fluid heated
inside the tubes boils water for a
conventional steam-turbine generator
to produce electricity.
• Power tower system - Uses a large field
of flat, sun-tracking mirrors known
as heliostats to concentrate sunlight
onto a receiver on top of a tower. A
fluid heated in the receiver generates
steam for a conventional steam-turbine
generator to produce electricity.
• Stirling engine system - Uses a
mirrored dish to concentrate sunlight
onto a thermal receiver. A fluid heated
inside the receiver moves pistons
and creates mechanical power, which
runs the Stirling engine to produce
electricity.
A CSP Stirling engine system in Boulder, CO
TheSolar Two CSPpowertower
system near Barstow, CA
How much solar potential exists
on contaminated sites?
Utility scale concentrating solar power (CSP)
Trough and power tower systems - 60 sites
Stirling engine system - 85 sites
Direct normal solar resource availability > 6 kWh/m2/day
Distance to transmission lines < 10 miles
Acreage (trough and power tower systems) s 250 acres
Acreage (Stirling engine system) s 40 acres
Distance to graded roads < 25 miles
Utility scale photovoltaic (PV) - 470 sites
Direct normal solar resource availability > 5 kWh/m2/day
Distance to transmission lines < 10 miles
Acreages 40 acres
Distance to graded roads < 25 miles
PV policy driven -1,355 sites
This category only includes sites in states with an RPS solar
set-aside, solar multiplier or distributed generation incentive.
The criteria are the same as utility scale PV, except that resource
availability is not considered.
Non-grid connected PV-11,384sites
There are no formal screening criteria as PV technology can be
sited at all properties.
EPA tracked sites with PV policy driven and utility scale PV potential
Estimating total technical potential
Solar technical potential for EPA tracked sites:
almost 920,000 MW
Market potential - The portion of the
economic potential that could be achieved
given current costs, policies and
technical constraints.
Economic potential - The portion of the
technical potential that is economically
viable, but requires additional policies to
break down market barriers.
Technical potential - Potential that is
technically possible, without consideration
of cost or practical feasibility.
For more information on solar technologies, visit:
www. nrel.gov/learni ng/re_solar. h tml
-------
Solar Technologies
A PV array at Fort Carson, CO
Photovoltaic (PV) - Converts the sun's light energy directly into electricity. PV technology is scalable; the amount of electricity
generated is directly related to the number and efficiency of installed panels. It can technically be sited anywhere, though the
economics may make a project unfeasible in lower resource areas. Three types of PV production were evaluated by EPA:
• Utility scale PV- Uses PV technology at the MW or multi-MW scale at sites with the greatest resource and acreage availability.
Electricity generated is typically exported to the grid.
• PV policy driven - Represents sites that may have development potential due to state
policies, including sites in areas with lower resource availability. One of the most
important state policies affecting the development of electricity from solar energy is
a renewable portfolio standard (RPS) that includes a solar set-aside, which requires
a certain percentage of the state's electricity be generated from solar resources. An
RPS can also include a solar multiplier that gives additional credit for solar projects
that contribute toward meeting the RPS, or a requirement for distributed generation
(i.e., electricity generation close to the point of use). Most states allow electric power
providers to meet RPS solar requirements by purchasing solar renewable energy certificates from non-utility producers. These
incentives may help to make PV projects financially viable in areas with lower solar resource availability.
• Non-grid connected PV - Uses PV technology at a smaller scale, typically to power the energy needs of a single property.
What are some examples of solar facilities being successfully sited on contaminated land?
The RE-Powering America's Land Web site highlights several solar facilities developed on
contaminated land. At the Fort Carson Army Base in El Paso County, Colorado and the Nellis
Air Force Base near Las Vegas, Nevada, solar panels were mounted on former Resource
Conservation and Recovery Act (RCRA) landfills to provide power to base facilities. Fort
Carson's 2 MW PV solar array generates 3,200 MW-hours of power annually. This is enough
to supply 2.3% of Fort Carson's energy consumption, which is the equivalent of 540 homes.
Nellis' 14 MW PV system is estimated to generate at least 25 million kilowatt-hours annually.
This is enough to power 2,350 homes and save $1 million on electricity and 24,000 tons
of carbon dioxide annually. In Richmond, California, a 1 MW solar PV system was developed partially on a site that was previously
used as a sludge-drying pond and is now used for storm water management; it provides 30% of the wastewater treatment
facility's electricity needs.
There are several cases in which PV solar facilities have been used to power ground water remediation on Superfund sites, such as
the Frontier Fertilizer site in Davis, California, the Pemaco site in Maywood, California, the Apache Power site near Benson, Arizona
and the Lawrence Livermore National Laboratory near Livermore, California. These solar projects provide significant energy cost
savings and, in some cases, support ground water treatment in remote areas that would otherwise require the installation of
costly power lines or generators.
PV roof panels in Pemaco, CA
For more information, visit www.epa.gov/renewableenergyland or contact cleanenergy@epa.gov
------- |