Page 233 - Sustainable On-Site CHP Systems Design, Construction, and Operations

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reactive organic gases (ROG) that lead to the formation of ambient ozone that can affect
public health, biological resources, and property. CHP systems also emit sulfur oxide
(SO ), carbon monoxide (CO), and microscopic particulate matter (PM) that lead to
x
health impacts, property damage, and regional haze. The operation of CHP systems
also releases hazardous air pollutants such as acrolein, xylenes, and aldehydes and are
known to increase the risk of cancer in addition to chronic and acute health risks in
humans. Finally, CHP systems emit large amounts of greenhouse gases such as carbon
dioxide (CO ) and uncombusted methane (CH ) that are believed to contribute to global
2 4
warming. As noted in previous chapters, CHP still has an environmental benefit due to
the high overall system efficiencies and the reduction of fuel combustion for thermal
requirements. Table 12-1 includes a summary of pollutants that are typically emitted
from combustion-based CHP systems.
The permit application for a CHP system should quantify the air pollutants resulting
from the proposed project and also assess their potential impacts on the environment
and health. It should also assess how regulations apply to the project and how the
project will comply with those regulations. This section provides additional details of
the types of regulations affecting air quality impacts that may apply to CHP projects.
This chapter attempts only to provide a general regulatory framework that the project
engineer or developer may expect to encounter, regardless of the facility location. The
specific air quality regulations that may apply to any single project cannot be effectively
addressed within a single chapter.

Technology and Emission Standards
In almost any instance, the engineer or developer will have to demonstrate that the
proposed project meets minimum technology and emission standards. Generally, these
environmental performance standards reflect reasonably available and current tech-
nology. In the case of lean burn reciprocating internal combustion engines, environ-
mental performance standards typically reflect the use of modern engine technology,
but do not necessarily require post-combustion emission control devices. For example,
the United States Code of Federal Regulations specifies standards, known as New Source
Performance Standards (NSPS) for reciprocating internal combustion engines. For natural
gas–fired reciprocating internal combustion engines, NSPS presently specify that the
engine must be a lean burn engine that can meet 1.0 to 2.0 g/bhp-h NO , 2.0 to 4.0 g/
x
bhp-h CO and 0.7 to 1.0 g/bhp-h VOC (bhp-h is brake horsepower-hour). Although
modern engine technology is needed to meet these standards for lean burn engines, the
NSPS are lenient enough to allow operation without selective catalytic reduction sys-
tems (SCR) or oxidization catalysts. Rich burn engines have higher uncontrolled emission
rates, but their emissions can be controlled with relatively low-cost three-way catalyst
technology. The NSPS for rich burn engines incorporate the low-cost control technol-
ogy. For prime power diesel fueled engines, NSPS requires the use of SCR systems or
oxidization catalysts, only if engine manufacturers are also required to integrate the
emission control technologies into the base engine packages. The integration of emission
control technology into new diesel engine packages are scheduled to be implemented
in the years 2009 through 2014.
Minimum standards also exist for combustion turbines. As with lean burn recipro-
cating internal combustion engines, the minimum standards typically mandate the use of
current engine technology, but do not necessarily mandate the use of post-combustion