Sep. 10--Matanuska Electric Association is eager to build a coal-fired power plant outside Palmer. The Matanuska-Susitna Borough has passed a power-plant siting ordinance that says, "Slow down. We need a thorough look at the pollution and other side effects from such a big project."

The borough made the right call. Better for all concerned if MEA uses its members' money to comply with the ordinance rather than fight it in court. MEA's urge to build a coal plant has implications far beyond the co-op and its customers. The borough's new rules offer a process for engaging all those affected in finding an environmentally acceptable, affordable long-term supply of electricity. For MEA management, coal is literally a quick and dirty solution. Coal is easy to get, from the Usibelli mine in Healy, while natural gas prices are rising as local supplies dwindle. Diversifying the region's electrical fuel sources has some appeal.

But those who look beyond MEA's institutional self-interest have good reason to be concerned about a coal plant. Coal is the most polluting of the fossil fuels. Emissions from any MEA coal plant will drift over the entire Southcentral region. Modern technology does a good job of capturing the dirty, smog-inducing pollutants: fly ash, nitrogen oxides and sulfur diodide. But emissions of mercury and fine particulates are a different story. When mercury hits water, it enters the aquatic food chain -- a change that will sully Alaska's reputation for sparkling clean fisheries. Fine particles from coal combustion can do long-term harm to even healthy lungs, let alone asthmatic kids and the elderly.

The particles also carry trace amounts of harmful heavy metals like arsenic and cadmium. But the biggest problem with coal today is a relatively new concern: Burning it produces roughly double the greenhouse gases that natural gas does. Because of that, the long-run cost of burning today's "cheaper" coal is sure to escalate. Coal-burning utilities Outside realize that they will soon have to pay for the privilege of pumping huge amounts of carbon dioxide into the atmosphere. MEA's coal today uses an optimistically low estimate of future costs for carbon emission controls. MEA's move to coal will also likely undermine efforts to bring a natural gas pipeline to Southcentral.

The more big customers for the gas, the better the economics of a line from the huge fields on the North Slope. MEA management has locked onto the idea it must build its own electrical plants. MEA officials desperately want to stop buying power from the region's largest supplier, Chugach Electric. Until 2014, the two utilities are stuck in a bad marriage that went sour years ago. Members of MEA endorsed "local generation" in an election where MEA management spent a lot of money to produce that outcome. But agreeing MEA should pursue locally produced power is hardly an endorsement of management's current rush to build a coal plan .

As with any big project that has a high potential for pollution, building a new power plant in the Mat-Su Borough raises many legitimate questions. The Borough is right to insist on a process that involves the entire community in finding the answers. BOTTOM LINE: The MEA coal plant plan raises lots of concerns.