With FERC’s blessing, MISO will synchronize its generator replacement process with its generation suspension and retirement process to give interconnection customers more flexibility when they decide to replace, retire or suspend a generating unit.  

MISO received a favorable decision on a tariff change from FERC on March 29 and now will allow owners hoping to replace their generation with the option to simultaneously request to be evaluated for retirement or suspension if their plans for a replacement facility don’t pan out (ER24-1055). 

MISO’s current generator replacement process requires an interconnection customer seeking to replace its generating facility with a new facility to submit a request for replacement at least a year before the existing facility halts commercial operations. MISO completes a replacement impact study on the new generation to figure out whether its addition will adversely impact the system and completes a reliability study to see if the system will suffer violations without the existing generation while the replacement generation is being built. If the project can proceed, MISO drafts a replacement generation interconnection agreement (GIA).  

However, that roughly yearlong process bumps up against MISO’s generation suspension and retirement requirements, which expect generation owners to make a request to retire or suspend more than a year before the generating unit idles.  

MISO said its generation owners often begin the process unsure of whether a replacement, suspension or retirement is the best decision for their generation and have only the results of MISO’s reliability and impact studies for replacement once the notification deadline to retire or suspend the unit has passed. That leaves owners who find that their replacement plan is not viable in a bind, MISO said, and beholden to a process “entirely driven by procedural timing requirements rather than engineering or economic considerations.”  

Now generation owners will be able to request a suspension/retirement equivalency study alongside their option for MISO to perform generation replacement studies. If owners elect the equivalency study at the time of their replacement request, MISO will waive the yearlong lead time for suspensions and retirement requests and require only 30 days’ notice to begin suspension/retirement studies. 

MISO said the rule change will allow generation owners whose replacement plans fall through and have elected the equivalency study to seamlessly transfer units to suspension status, “which will allow the interconnection customer to make the proper plans for the future of its unit.”  

FERC said the change should allow MISO to process suspension, retirement and replacement requests more efficiently and give interconnection customers better data to make informed business decisions.  

“We find that MISO’s proposal will integrate and harmonize its retirement and suspension processes with its generator replacement process by aligning the timeline for an interconnection customer with an existing generating facility to be considered for a suspension and/or retirement request with a replacement generating facility request,” the commission wrote.   

FERC said the revisions will allow owners more freedom to pursue suspension and retirement decisions if their replacement facility requests are denied by MISO and lessen the risk that they miss deadlines to cease operations.  

MISO also said it will apply its new process to partial replacement of generation facilities, where some interconnection rights are left over after a replacement facility is planned. In those cases, interconnection customers can make additional replacement generating facility requests for the remaining capacity of an existing generating facility up until the first GIAs are struck for some of the interconnection rights.  

The Mississippi and Arkansas public service commissions, Entergy and WEC Utilities protested the filing, arguing that MISO’s plan would deprive generator owners of their residual interconnection capability by prohibiting additional interconnection requests of already-paid-for interconnection rights after the first GIA is signed.  

FERC brushed those concerns aside, saying interconnection customers still have the opportunity to replace an existing generating facility up to the same level of interconnection service.