Environmental Engineering Reference
In-Depth Information
2,400
2,200
2,000
1,800
1,600
1,400
1,200
1,000
Estimated Avoided Generation (2,122 MWhrs)
Sept 28-29 Actual Generation
FIGURE 2.17
Estimated avoided generation from wind event on September 28-29, 2008.
40,000
SO
2
(lbs)
30,000
20,000
10,000
NO
x
(lbs)
CO
2
(tons)
0
-10,000
-20,000
-30,000
FIGURE 2.18
Distribution of extra emissions by PSCO plant on September 28-29, 2008.
is estimated to have avoided approximately 2,122 MWh of coal-fired genera-
tion between 8:00 p.m. and 4:00 a.m.
The estimated extra emissions generated are shown in Table 2.5 using the
same three calculation methods described earlier. As with the July 2 event,
the calculation method drives the results. If the additional emissions that
occurred September 29 (after the wind fell off and coal generation resumed)
are included, this wind event resulted in 28,823 lb of SO
2
and 17,017 lb of NO
x
(18% of total SO
2
and 10% of total NO
x
generated that day) more than would
have been emitted had coal not been cycled. On the other hand, using wind
to the degree it was used on September 29 allowed PSCO to avoid generating
1,686 tons of CO
2
(3.2% of total).
Figure 2.18 shows the distribution of the emissions associated with the
Method C calculation. Virtually all the extra SO
2
and NO
X
emissions were
