NOx Emissions Impacts from Widespread Deployment of CHP in ...

NOx Emissions Report
central station generating facility, increase the amount of fuel that must be
burnt to produce the same amount of electricity at the end-user’s site.
• CHP systems are required to meet a more stringent NOx emission limit of
0.14 lbs/MWh, which is far less than the 1.07 lbs/MWh created by central
station generators serving the Texas grid. 10
Figure 1-3: Comparison of NOx Emissions
CCGT: Combined Cycle Gas Turbine
Source: Elliott, 2001
Even though CHP systems produce an overall decrease in NOx emissions, the
technologies may still not create a viable strategy to reduce ozone in HGB. Widespread
development of CHP projects would essentially relocate the source of some of the NOx
emissions produced by the power generating sector from a few, very large point sources
outside the city to many, small point sources inside the city. Implementation of CHP
changes both the amount AND geographical distribution of NOx emissions, and the
evaluation of this trade-off is the central goal of the study.
10 NOx emissions produced by the Texas electrical grid are based on the EPA’s Emissions & Generation
Resource Integrated Database (eGRID), which is a comprehensive catalog of the air emissions (including
NOx) and environmental attributes of US electric power systems. It integrates 24 different federal data
sources on power plants and power companies, from three different federal agencies: EPA, the Energy
Information Administration (EIA), and the Federal Energy Regulatory Commission (FERC). eGRID,
which includes data for some 4,700 power plants, provides data at the plant/company, state, and power grid
region levels. The “2007 Annual eGRID (25%)” and “2007 OSD eGRID (25%)” were used to establish
utility NOx emissions in lbs per MWh consistent with protocols of the Texas Commission on
Environmental Quality (TCEQ) and EPA.
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