Dive Brief:

• Ameren Illinois has filed comments with FERC, asking regulators to examine a controversial capacity planning auction in the Midcontinent ISO that resulted in Zone 4 prices more than 40 times higher than other zones.
• Ameren filed intervening comments last week, joining the Illinois Attorney Genera, Southwestern Electric Cooperative and Public Citizens, Inc., in demanding answers surrounding the auction's results.
• The groups want FERC to halt significant rate increases they allege are tied to Dynegy Inc.'s manipulation of the auction; the company responded saying it bid all available megawatts and followed all auction rule.

Dive Insight:

Ameren is now the latest in a growing list of concerned parties — energy companies, advocates and law enforcement — who want FERC to take a hard look at MISO's recent capacity planning auction.

“Since the auction results were announced, we have been in discussions with MISO officials to explore any available avenue to provide our customers with relief from this unexpected surge in capacity prices,” Richard Mark, President of Ameren Illinois, said in a statement. 

Ameren said that the capacity price for Zone 4, which includes its customers, was more than 40-times the price than compared to other MISO zones during the recent auction. Fierce Energy has the details: 
While eight of MISO's nine zones cleared at prices less than $3.50/MW-day, Zone 4 priced at $150/MW-day.

But Ameren also confirmed that the grid operator will be refunding approximately $84 million to load serving entities in Zone 4, and on average, a typical residential customer who takes power supply from Ameren Illinois will save about $2 per month.

In its comments to FERC, Ameren Illinois also asked regulators for a review of the market rules that will be utilized in future capacity auctions. 

Dynegy, under scrutiny from Illinois Attorney General Lisa Madigan and public advocates, has defended its actions in the auction. The company issued a statement saying it "offered all of its megawatts into the MISO auction with no physical or economic withholding in accordance with MISO tariffs and as approved by the Independent Market Monitor."

Dynegy "follows and respects all the rules, tariffs, and obligations in the markets," the Houston-based company said.