The Impact of Air Quality Regulations on Distributed ... - NREL

3.2.2 Texas
On May 23, 2001, the Texas Natural Resource
Conservation Commission (TNRCC) approved
new air emissions standards 29 for small electric
generating units. <strong>The</strong> standards are divided
between east and west Texas. <strong>The</strong> rule also
addresses system size and capacity factors.
Parts <strong>of</strong> East Texas have the worst air quality in
the nation and therefore already have very
stringent limits for emissions from all sources.
For units 10 MW or less installed in east Texas
29 http://www.tnrcc.state.tx.us/permitting/airperm/nsr_permits/fi
les/segu_final.pdf
27
prior to 2005 and operating more than 300
hours per year, the limit is 0.47 lb
NOx/MWh. This is slightly lower than the
2003 CARB certification standard and can
currently be met only by very low-emitting
gas engines, microturbines, and fuel cells.
<strong>The</strong> 2005 limit <strong>of</strong> 0.14 lb/MWh can only be
met today by fuel cells. A market study is
being performed to see whether the 2005
standard is appropriate. For units operating
less than 300 hours per year, the limit is 1.65
lb/MWh, declining to 0.47 lb/MWh in 2005.
Table 3-5
Texas NOx General Permit Limits for Units less than 10 MW
Installed Prior to 2005 Installed In 2005 or Later
East Texas
Operates more that 300 hrs/yr 0.47 lb/MWh 0.14 lb/MWh
Operates less than 300 hrs/yr 1.65 lb/MWh 0.47 lb/MWh
West Texas
Operates more than 300 hrs/yr 3.11 lb/MWh 3.11 lb/MWh
Operates less than 300 hrs/yr 21 lb/MWh 21 lb/MWh
<strong>The</strong> west Texas requirements for units 10 MW
or less are not as stringent. <strong>The</strong> limit <strong>of</strong> 21
lb/MWh for units operating 300 hours per year
or less can be met by diesel engines and most
other DG technologies. <strong>The</strong> 3.11 lb/MWh limit
for higher-capacity-factor units can be met by
combustion turbine technologies and many
lean-burn gas engines.
<strong>The</strong> Texas rule allows a DG project that
employs CHP to take a credit based upon the
amount <strong>of</strong> heat recovered. <strong>The</strong> credit is 1
MWh for each 3.4 MMBtu <strong>of</strong> heat
recovered. <strong>The</strong> thermal output must be at
least 20% <strong>of</strong> the total output.
<strong>The</strong> Texas and California rules are
examples <strong>of</strong> new approaches to DG
regulation that <strong>of</strong>fer simpler treatment but
set limits that are not achievable by
today’s conventional DG technology.