The MidcontinentIndependent System Operator Inc. issued the final version of itsanalysis detailingpotential near-term and mid-term impacts of the U.S. EPA's Clean Power Plan.

MISO's Planning Advisory Committee discussed the analysisduring a July 20 meeting. Further internal analyses from MISO's Policy andEconomic Studies Department are "on hold" given the Feb. 9 SupremeCourt stay of theClean Power Plan, but the RTO plans to participate in a joint study withPJM Interconnection LLCsoon, MISO Director of Policy Studies J.T. Smith said during the meeting.

MISO and PJM have yet to set the scope of the joint study,Smith added. PJM's senior economic policy adviser, Paul Sotkiewicz, on June 9said the two gridoperators plan to start work on the joint study this summer and publishfindings later in the year.

The latest version is similar to a that MISO discussed during a June15 Policy Advisory Committee meeting but accounted for comments receivedthrough July on the report's executive summary.

As part of the analysis, MISO looked at the near-term andmid-term impacts of the Clean Power Plan and how the rule could alter the fuelmix of the region, which spans across 15 states from North and South Dakotasouth to Louisiana.

The near-term analysis examined how the region andindividual states can meet the rule's carbon-reduction goals using rate- ormass-based targets. The Clean Power Plan, which the EPA finalized on Aug. 3,2015, set interim targets for 2022-2029 and final carbon emission reductiontargets for 2030, but converted those targets to be either rate-based,expressed as lb CO2/MWh, or a mass-based, which are expressed in tons.

The mid-term analysis of the study looked beyond the timingof the Clean Power Plan and examined how the region's fuel mix would change tomeet various carbon-reduction scenarios. The Clean Power Plan, when finalized,was estimated to cut carbon emissions from existing power plants by 32% below a2005 baseline by 2030. But MISO also modeled an "accelerated CPP future"case that assumes a decline of 43% below the same baseline by 2030.

The mid-term analysis modeled different levels of coalretirements to estimate any impacts to system costs, which include generationproduction, capital and fixed operations, and maintenance costs. The costsexclude retirement costs and transmission and natural gas transportation costs.

In a scenario assuming a 17% carbon reduction across theregion by 2030, MISO found that between 8 GW and 11 GW of coal retirementscould keep total system costs at a low, while 24 GW to 30 GW of coalretirements would be needed to keep system costs down in the "acceleratedCPP future" case assuming a 43% reduction target, the study showed.