The Midwest ISO (MISO) projects more than sufficient resources to meet this summer’s peak demand, if peak demand occurs in July or August.
If system peak occurs in June, however, MISO’s reserve margin will erode due to higher planned outages and lower designated resources to serve load, the RTO said in its 2012 summer resource assessment.
MISO has a planning reserve margin of 27.4% or 24,608 MW of installed capacity resources prior to shedding firm load for the 2012 summer peak.
Furthermore, MISO said it does not expect any transmission-related issues to occur throughout the summer period. By the beginning of the summer season, 112 miles of new transmission lines, upgrades or rebuilds will have come to service, including four 230-kV lines and one 345-kV line. There will also be one new bulk transformer and two transformer upgrades, the RTO said.
“There are no concerns in meeting target in-service dates of transmission identified,” MISO said. “MISO does not anticipate any existing, significant transmission lines or transformers being out of service through the summer season. MISO does not have any transmission constraints that could significantly impact reliability.”
Demand, capacity forecasts for summer
Overall, the region’s demand and capacity forecasts are lower than they were for the summer of 2011, which MISO attributes to the respective departures from the RTO of FirstEnergy (NYSE:FE), Duke Energy Ohio and Duke Energy Kentucky.
MISO’s nameplate capacity has decreased by 5.5% to 127,493 MW, of which 5,719 MW comes from the Duke Energy (NYSE:DUK) subsidiaries’ exit.
This year’s projected capacity available to serve load during summer peak conditions is 114,475 MW, including 3,462 MW of external resources and 3,523 MW of behind-the-meter generation. MISO also expects 765 MW of wind capacity to serve load during this period, representing 7% of the region’s wind resources’ nameplate capacity.
“Although MISO’s overall capacity resources are reduced from last year’s levels, MISO expects the reserve margin to be relatively unchanged,” the RTO said.
A 26.6% actual reserve margin occurred on July 20, 2011. The 2012 projected planning reserve margin is 0.8% higher at 27.4%, exceeding the 16.7% MISO system planning reserve margin for 2012, MISO said.
The projected net internal demand during the summer peak is 89,867 MW. The Duke Energy subsidiaries’ exit lowers net internal demand by 4.23% from 2011. Unrestricted non-coincident peak demand for the summer is 98,957 MW, MISO said.
According to a load forecast uncertainty (LFU) value, which is used to determine how likely actual load will be from forecasted load, MISO could experience a high load scenario of 99,792 MW for the summer. For the LFU, MISO compared four years of real-time load data to its forecasts for June, July and August.
Excluding Duke Energy Ohio and Duke Energy Kentucky, current MISO membership has seen a 1% increase in demand from 2011, the RTO said.
During the July 20, 2011 peak, MISO operated under normal operating conditions, without having to use emergency operating procedure (EOP) resources, and experienced 2% reserves prior to EOP. For 2012, MISO expects 5% and -0.5% planning reserves prior to EOP given a mid load, or 50/50 forecast, and high load, or 90/10 forecast, respectively, the RTO said.
A 50/50 forecast is the mean value in the normal probability distribution, meaning there is a 50% chance the actual load will be higher and a 50% chance actual load will be lower. The 90/10 forecast follows the same pattern.
Impact of weather, EPA regulations on generation fleet
MISO indicated its generation fleet could see some effects from abnormally dry weather conditions, which contributed to severe drought in the Upper Midwest and Northern Plains. This could have an impact on the availability of water to cool generating facilities in these areas, MISO said. The RTO is collaborating with stakeholders to assess the potential magnitude of this issue.
EPA regulations are not expected to have a significant impact on reliability during this year’s summer period, MISO said.
“We do anticipate that recently finalized and/or developing EPA regulations will impact the MISO region in the future but the recent delay in the implementation of the Cross-State Air Pollution Rule (CSAPR) has pushed those impacts out beyond the 2012 summer season, we believe,” MISO said.
According to MISO, the Duke Energy subsidiaries’ departure removed 6.7%, or 4,659 MW, of coal generation from the 70 GW of its 2011 coal fleet. Another 1,663 MW of subtracted capacity last year are from unit retirements, comprising 49% gas and oil facility retirements, or 823 MW; 43% coal generator retirements, or 722 MW; and 8% of other resources retirements, or 120 MW.
Of the capacity additions, 75%, or 2,904 MW, are attributable to new units and/or facility upgrades. The majority of new units, or 1,906 MW, comprise wind.