Last week I wrote that Illinois Attorney General Lisa Madigan accused Edison Mission Energy of perpetuating suspicious electricity trading patterns that Edison had told regulators it ceased in April 2006. Combing through bid/offer data kept by PJM Interconnection, the Mid-Atlantic grid, Madigan and consultant Robert McCullough identified plants they said were Edison's that seemed to be withholding power from the market in a possible attempt to drive up prices. They couldn't be sure because PJM's data masks plants' identities.

Edison Mission denied the plants were theirs.

"These are not our units," said company spokesman Doug McFarlan."We can't tell whose units they are, but we can tell you emphatically that they are not ours," said Edison Mission spokesman McFarlan.

Now, says McFarlan via email, PJM has confirmed that the plants do not belong to Edison. "Wanted to advise that today PJM contacted us and confirmed, at our request, that the specific units and bids cited in Mr. McCulloch's [sic] affidavit are not Edison Mission's," he said late Monday.

So I called PJM to double check. But PJM spokesman Terry Williamson wouldn't confirm what Edison Mission says PJM said, citing confidentiality rules. And my followup question -- "If the plants doing the suspicious bidding aren't owned by Edison Mission, whose are they?" was going nowhere with Williamson, either.

“I’m still bound by the confidentiality rules," he said.

Great. So there is prima facie evidence that somebody in the system that serves Maryland and a dozen other states is gaming the system. And PJM won't say anything about it -- not to exonerate a company that was publicly alleged to have continued doing something irregular, and not to identify the real suspect. There's your open, transparent wholesale electricity market for you. The only recourse consumers and state regulators have to pry this can open is the Federal Energy Regulatory Commission, which seems to be very happy with the way things are. FERC didn't even get to the bottom of Edison Mission's original irregular trading -- settling the case with a small fine for what it said was EM's lack of candor and misleading responses in the investiation.

What a mess. When electricity is ultimately reregulated, generation companies and pro-market policymakers will have only themselves to blame.