The Climate Report - Winter 2011
Under EPA's May 2010 " Tailoring Rule," greenhouse gas emissions from the largest industrial sources became subject to the Clean Air Act's "prevention of significant deterioration," or "PSD," preconstruction permit program and the Act's Title V operating permit program on January 2, 2011. With the PSD program applicable to greenhouse gas emissions, federal, state, and local permitting authorities must now determine what constitutes the "best available control technology," or "BACT," for such emissions.
On November 10, 2010, U.S. EPA issued
draft guidance to assist permit writers in making such
determinations. In its proposed guidance, EPA makes clear that it
is not changing its established "top-down" process for
selecting BACT on a case-by-case basis for greenhouse gas
emissions. Rather, EPA stresses that permit writers have discretion
to determine BACT for greenhouse gases using the same five-step
process it has recommended in the past for other types of
emissions. These steps are: (1) identify all available control
technologies; (2) eliminate technically infeasible options; (3)
evaluate and rank remaining control technologies; (4) evaluate cost
effectiveness of controls and energy and other environmental
impacts; and (5) select BACT.
Throughout its discussion of these five steps, EPA emphasizes
energy-efficiency as a primary consideration in any greenhouse gas
BACT analysis. In particular, EPA
states that "BACT for a new combustion source should
include the consideration of methods that increase the overall
energy efficiency of the source. In general, a more energy
efficient technology burns less fuel than a less energy efficient
technology on a per unit of output basis." The draft guidance
also identifies carbon capture and sequestration ("CCS")
as a technology that should be considered an "available
technology" for new large combustion sources, although EPA is
skeptical that CCS will ultimately be selected as BACT due to its
limited commercial availability and high cost.
EPA also provided industry-specific information on the sectors that
emit the highest amounts of greenhouse gases in
several white papers that the Agency issued in connection with
its BACT guidance. These white papers summarize available control
measures to reduce greenhouse gases from electric generating units
("EGUs"), large industrial/commercial boilers, the pulp
and paper industry, the portland cement industry, the iron and
steel industry, petroleum refineries, and nitric acid plants.
While the white papers provide information for use in making BACT
determinations, they do not prescribe BACT for any of the covered
industries. EPA's
EGU white paper, for example, states that there is "no one
best available coal-fired EGU technology universally applicable to
all EGU projects." EPA defines an EGU as a solid fuel-fired
steam generating unit that serves a generator that produces
electricity for sale to the electric grid.
Carbon dioxide is identified as the primary greenhouse gas
emitted by EGUs. According to EPA, the primary factors affecting
carbon dioxide emissions are the type of coal burned, the overall
efficiency of the power generation process, and the use of air
pollution control devices.
EPA discusses options for increasing energy efficiencies on EGUs,
along with the benefits and drawbacks of numerous technologies for
carbon dioxide control, including CCS, use of supercritical and
ultra-supercritical boilers, coal drying, and oxygen combustion.
Although bituminous coal is identified as the type of coal with the
lowest carbon dioxide emissions per unit of heat input, EPA does
not believe that requiring EGUs to exclusively use this type of
coal would necessarily reduce overall greenhouse gas emissions, in
light of the methane (another greenhouse gas) released during
mining and other releases associated with mining, processing, and
transporting coal.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
