Provide your organization’s comments on the ISO’s proposal to withdraw the T-30 WEIM base schedule functionality:
NV Energy appreciates the opportunity to comment on the ISO’s proposal to withdraw the T-30 EIM base schedule timeline that was approved on December 2, 2020. This is the type of change that should come back to the stakeholder process if there were issues with the implementation that may result in a policy change from a Board approved proposal. NV Energy does not support the ISO’s proposed change because this functionality is important to manage the new uncertainty from recent Flexible Ramping Product (“FRP”) changes.
New Uncertainty from the Nodal FRP Implementation:
Since the introduction of the new FRP nodal process we have observed that the test is more difficult to pass due to changes that occur in the requirement between the T-75 and T-40 test horizon. Prior to the nodal deployment and the new Mosaic calculation the requirements for the flex ramp RSE test were know 24 hours in advance. The prior calculation being so far in advance also provided EIM entities with the ability to calculate the diversity benefit in order to estimate the amount that would be needed to pass the test for each hour.
With the introduction of the Mosaic calculation that was part of the nodal FRP deployment the advisory calculation is not complete until T-75 and the final calculation is completed at T-55. This adds another layer of difficulty in passing the tests. This has resulted in an increase of the requirement of 10 MW from the T-75 to T-55 requirement calculations for 8% of the upward tests with the largest increased requirement of 196 MWs. This unknown variation makes it difficult for EIM Entities that are trying to pass the test with last minute changes and the magnitude of the variation is unacceptable. NV Energy was looking forward to the implementation of the T-30 test to help manage the uncertainty that has been added to the Resource Sufficiency test requirement with the additions of the Mosaic approach and the implementation for the Nodal FRP. Therefore, NV Energy is not supportive of the ISO’s proposal to remove the approved T-30 base schedule functionality unless CAISO can implement changes that would help manage this uncertainty.
Alternatives and the need for additional information:
First, NV Energy requests that CAISO provide alternative proposals to either help mitigate the uncertainty described above or alternative proposals to help maintain the approved T-30 functionality. It might be helpful for stakeholders to be able to see additional information regarding the RTPD performance in order to provide additional counter proposals or other ideas.
Possible performance improvements:
During the stakeholder call, CAISO provided a short period of time showing the performance prior to the new FRP nodal software and after the nodal FRP software. Along with that short period of time it did not include any analysis on which process was affected with the increased run times. For example, it is important to know if the Network Application or power flow (“NA”) process is now running longer or the security constrained unit commitment (“SCUC”) process is now running longer in order to provide feedback. This additional information could be useful for understanding any possible improvements that could help increase performance. Additionally, the CAISO stated that the RTPD4 process cannot move its timeline because it is already running within a 7.5 minute time window. The proposed timeline for the RTPD5 run was 7.5 minutes. Therefore, NV Energy, would like to know if there have been performance issues with the RTPD4 process.
To reiterate, NV Energy does not support the ISO’s proposal to withdraw the T-30 EIM base schedule run because this functionality is important for our BA operations. Instead, NV Energy offers the following counter proposal for CAISO and stakeholders to consider to maintain the approved T-30 timeline:
- Move the T-30 test timeline up to T-35. Five minutes is a very short time to make adjustments, however, it is better than removing the test all together. Additionally, the T-40 test was also moved to kick off later than that exact time, around T-38. NV Energy proposes to move this run back to the original time so that there is time for the additional run to be adjusted and time for the execution of the test.
- Could other process be adjusted to start earlier so that there is more time for the additional test to run? For example, the T-40 test start say at T-50. We recognize that RTPD 6 would possibly have to start earlier as well. This would provide additional time for the last test and could provide the room for the RTPD5 process to run.
Finally, NV Energy believes it is worthwhile to take time to consider additional options through this stakeholder process before eliminating the approved functionality because the T-30 functionality would have been a useful tool in managing this new uncertainty.