VERNON -- Settlement talks are planned in a complex, long-running dispute over the value of two local hydroelectric stations.

Representatives of Vernon, Rockingham and energy giant TransCanada will engage in a mediation session -- possibly in May -- in an attempt to avoid an expensive, time-consuming trial to resolve big differences in appraisals of the Vernon and Bellows Falls dams.

While a TransCanada spokesman said the company hopes for "a mutually agreeable resolution," an attorney representing Vernon said he was "not optimistic" for such an outcome.

"We will see what happens at mediation," attorney Richard Coutant said. "I don't know how flexible the company is going to be in terms of a settlement, but we'll find out."

TransCanada Hydro Northeast is appealing an "increase in property taxes" on four Vermont generating stations -- Bellows Falls, Vernon, Comerford and McIndoes, said Davis Sheremata, a spokesman for the Calgary, Alberta-based company.

"The appeals are on similar schedules and raise similar issues because each appeal relates to the values assessed by the towns as of April 1, 2012, and because each of the towns rely on the same appraisal report prepared for the state of Vermont," Sheremata said.

Coutant summed it up this way: "Their value and the town's are very different." For the Vernon dam, the town/state appraisal is $39.78 million, while TransCanada thinks the facility should be worth $20.9 million, Coutant said.

The Bellows Falls station's numbers are much bigger but similarly far apart: A state appraisal set the value at $108 million in 2012, but TransCanada is arguing for a $62 million value, said Montpelier-based attorney Richard Saudek, who represents Rockingham in the appeal.

"The dam that goes across at Bellows Falls is mostly in New Hampshire," Saudek said. "But the lion's share of that generating station is in Vermont. And that's one reason that it's critical to Rockingham, because it's such an expensive piece of property."

The appeal also is of no small consequence in Vernon, where TransCanada's tax bill is $448,374, according to the town listers' office. In 2012, after mediation, Vernon and TransCanada reached a tax agreement for the 2011 tax year -- but the company never has agreed with the town's appraisal of the property.

"TransCanada is paying in a timely fashion all taxes assessed by the towns while the court actions proceed," Sheremata said. "Recently, TransCanada resolved a property tax dispute with the town of Vernon via mediation."

He added that "TransCanada is cooperating with the parties in a mediation process related to pending appeals and hopes a mutually agreeable resolution can be achieved."

That's a reference to a planned sit-down that may involve Vernon, Rockingham and also the town of Barnet. Coutant initially had said the session might happen next month, but that's now been pushed to late May -- and no firm date has been set.

Saudek said mediation -- or some sort of alternative dispute resolution -- is "required as a precondition of going to trial in most civil cases." And Coutant said it makes sense to have as many parties as possible involved in the court-ordered meeting with TransCanada and an independent mediator.

"We're trying to combine as much of this as possible to keep the expense down," Coutant said. "It doesn't make any sense to have three or more separate mediations with the same attorneys and the same people involved on the same issues."

A meeting of the minds, however, does not necessarily mean a resolution of their differences. Coutant told Vernon Selectboard members that TransCanada "has never been terribly flexible or terribly cooperative. So I'm not optimistic that it's going to get settled in mediation for a reasonable value."

Vernon Selectboard member Janet Rasmussen was selected to attend the mediation. A member of the listers' office also is expected to participate.

"If there is a tentative agreement reached at the mediation, everybody understands that that agreement is not binding unless it's ratified by the full Selectboard," Coutant said.

If the matter is not resolved in mediation, however, Coutant expects a date to be set later this year for a trial in Windham Superior Court Civil Division.

He added that the state-hired appraiser who set the dams' values -- New Hampshire-based George Sansoucy -- "has been appraising these facilities for a long time" and "feels pretty comfortable that his value is a reasonable, conservative value that will stand up in court."

Mike Faher can be reached at mfaher@reformer.com or 802-254-2311, ext. 275.