ROCKPORT — If selectmen in Camden, Hope, Lincolnville and Rockport agree, the price of the big yellow trash bags used by residents to dump garbage at the transfer station on Union Street in Rockport will increase from $1.50 to $2, each. Select Boards are due to discuss the proposal at their individual meetings over the next two weeks.

Midcoast Solid Waste Corporation is proposing a fee increase for its pay-as-you-throw program beginning May 1. The cost of a bundle of 10 small bags will rise from $9 to $12. The proposal will be presented to Camden, Tuesday, April 2; Monday, April 8, in Rockport and Lincolnville; and Tuesday, April 9, in Hope.

Currently, the 33-gallon bags are sold in packs of five for $7.50 and the 15-gallon bags are sold in packs of 10 for $9. Last year, the transfer station processed 229,000 bags of trash and sent them on trucks to PERC.

Guerra said the reason for the price increase results from anticipated tipping fee price hikes at the Penobscot Energy Recovery Company (PERC), in Orrington. That trash-to-energy incinerator facility on the banks of the Penobscot River was constructed in 1988. The four towns were charter members of a municipal committee that signed on with the private company and pledged to send their trash there until 2018. Today, there are 130 municipalities that send their trash to PERC.

"This increase is as a result of increasing tip fees at the PERC incinerator scheduled over the next five years," said Midcoast Solid Waste Manager Jim Guerra.

PERC originally set a tipping fee of $46 per ton with its charter municipalities, which was consistent for years. This year, the rate went up to $48; next year, $52; and $56 the year after. The fiscal year runs from July 1 to June 30.

At the same time 30 years ago, PERC had signed a contract with Bangor Hydro Electric Company, selling it electricity at 14 cents per kilowatt hour. The dynamics have since changed, with electricity now being sold on the market for as low as 4 cents per kilowatt hour.

To balance its books, PERC has told municipalities that it will raise its tipping fees to $90 a ton by 2018. Instead of doing it all at once that year, however, "they opted to ratchet us up," said Guerra.

Because of those anticipated rate hikes from PERC, the transfer station is raising its rates on the bags that residents are required to use.

At the Dec. 19 meeting of the quasi-municipal Midcoast Solid Waste Corporation's Board of Directors, Guerra said that 20 percent of Maine's pay-as-you-throw bag were priced at $2, "so we are in line and fair with this pricing to the consumers," meeting minutes said.

According to PERC, its facility consists of two major systems:  a front-end waste processing system and a power generation system. The former consists of two independent processing lines that shred the solid waste to a uniform particle size and separate the noncombustible material from the combustible portion of the waste.  "Noncombustible material is further separated into ferrous metal and a residue consisting of materials such as grit and glass," PERC said, at its website.  "The front-end processing residue (glass and grit) is delivered to a landfill for disposal and ferrous metals are recycled."