Integrating Southwest Power Pool Wind to Southeast Electricity ...

Table 3-5 shows the contingency reserve values used for each of the regions as modeled for the
scenarios. For scenarios 3 and 4 where the regions in effect operate as a single balancing area,
the contingency reserve was assumed to be the highest value from each of the regions. Here, only
the single largest contingency is counted towards contingency reserve across the entire footprint;
this reduction is not due to wind but the fact that only one contingency is now examined.
Another approach would have been to count the two largest contingencies, as there would be a
higher probability of multiple simultaneous outages. This would tend to lessen the aggregation
benefit as the reduction in the aggregate reserve requirement would be less.
Table 3-5
Contingency reserves
Scenario Area Spin Non-spin
SPP 800 800
1 and 2
Entergy
Southern
1020
650
1020
600
TVA 300 1300
3 and 4 All 1020 1020
For all scenarios, a load regulation requirement of 1.5% of the hourly load was included in the
total regulation requirement (load and wind).
Figure 3-12 shows the average regulation (load and wind) for all scenarios (with the bars
representing maximum). Figure 3-13 and Figure 3-14 show the average total reserves
(regulation, spin and supplemental) without and with contingency reserves included,
respectively. The whiskers on the plots show the maximum values.
In scenario 1, SPP receives the greatest possible wind aggregation benefit since all of the wind is
aggregated into a single pool. However, SPP only benefits there are no load aggregation benefits
in this scenario since the regional loads have not been combined.
In scenario 2, there are slightly less wind aggregation benefits because the wind has been
allocated to the individual regions for balancing. Since the wind is being netted with a much
larger pool of load the net regulation for the overall footprint is decreased. The reduction in
regulation is offset by a higher spin and supplemental to make the total reserves nearly the same
for scenarios 1 and 2. Regulation is reduced in the footprint by 206 MW while spin and
supplemental are increased by 118 MW and 235 WM, respectively, leading to a 147 MW
increase in total reserves for the footprint in scenario 2.
Scenarios 3 and 4 are identical for the reserve requirements and are labeled as scenario 4 on the
graphs. These scenarios see a reduction in regulation and total requirements due to the
aggregation of all load and wind into a single balancing area. The overall footprint regulation
requirement is reduced about 190 MW over scenario 2 and 395 MW over scenario 1. The wind
related spin and supplemental components of the reserves are based on the aggregated wind
making these components the same for scenarios 1 and 4. There is a reduction of 118 MW and
235 MW for spin and supplemental from scenario 2 to 4. The reduction in total reserves is 542
MW in the same scenarios.
3-13