BANGOR, Maine – Penobscot County commissioners on Tuesday signed a three-year contract with Bangor Gas Co. to supply natural gas to the courthouse, jail and the 3rd District Court building.

The conversion from heating oil to natural gas is expected to save county taxpayers between $100,000 and $160,000 a year depending on the price of oil and natural gas, according to County Treasurer Dan Tremble.

The conversion at the District Court building is expected to be completed in about four weeks. A gas line on Franklin Street will be tapped to bring gas into the building. It is expected to take about eight weeks to bring a gas line down from Union Street to Hammond Street so the Penobscot County Courthouse and Jail can begin using natural gas.

The gas company will pay the expense of bringing the lines to the buildings, and the county will spend at least $37,000 to convert to a dual system that could burn either natural gas or heating oil.

The buildings have used an average of 85,000 gallons of oil a year, according to Tremble. The recent installation of energy-saving devices is expected to save about 10,000 gallons.

Commissioners also asked for figures to be presented later this month on the estimated increase in electricity costs. Last week the Public Utilities Commission approved standard offer rate increases for medium- and large-business customers to help offset increasing natural gas and oil costs. This translates to an overall bill increase of about 13 percent, a spokesperson for Bangor Hydro-Electric Co., said in an earlier Bangor Daily News story.

In other business, commissioners signed a three-year contract with secretaries and custodians. They agreed to a 3 percent raise that will be retroactive to Jan. 1. The new contract affects about 20 people and also increases the employees’ contributions to the cost of health care.

Two other bargaining units, the supervisors and line units, are working without contracts, according to County Administrator Bill Collins. The line unit includes corrections officers and patrol officers.