Maine’s Public Utilities Commission should start practicing its poker face.

While staying with the ISO-New England electric grid is the poker player’s move for Maine, the PUC recommendation to do so runs counter to powerful arguments the agency and many others have made for ditching ISO altogether.

With good reason. Staying with the grid, the PUC itself has estimated, would cost Maine ratepayers some $500 million to $600 million through 2012. And chronic complaints exist about inherent unfairness and inequity in the overall ISO bureaucracy.

So why stay?

Because in this energy poker game, the PUC thinks Maine’s got a good hand.

The state has leverage over grid partners with its potential to generate new, renewable energy sources from wind and water, which ISO states need to diversify energy supplies (now mostly natural gas) and meet regional renewable benchmarks passed into law.

It’s not time to fold on ISO yet, especially since the pot is huge – maybe $1 billion in socialized ISO funding for electrical transmission projects now slated to be built across Maine.

The PUC made its choice Thursday, ending a year of study on three choices: staying with ISO, going alone, or forming an electric union with New Brunswick.

Going alone was the worst option. It would, pardon the pun, ISO-late Maine from New England and Canada and put the expense of transmission solely on in-state ratepayers, which – given the cost of maintenance – would make electricity more expensive.

Plus, this path weakened Maine’s leverage: the generation capacity on the Western mountain peaks, Aroostook County plains and the Gulf of Maine. Power from all these regions is now being explored with great haste and detail.

In gambling, though, there’s always a chance to lose. But stakes are too high for Maine for this to happen. That’s why we’re heartened by sentiments of Commissioner Jack Cashman, who is advocating that Maine also develop alternatives to staying with ISO.

Because, at its core, the New England electrical partnership is flawed and difficult to change. The PUC knows this, but still recommends staying. It’s no bluff, but no guarantee either.

It’s a gamble. And while the PUC is smart to recommend playing out Maine’s hand, it’s even smarter to tuck an ace up its sleeve.