CARIBOU — Construction of a $351,000, 280-kilowatt, cogeneration facility at Cary Medical Center is expected to be complete by May, Cary officials announced Wednesday. Ground breaking for the facility was held Feb. 19.

The hospital received a $165,000 matching grant on April 14, 1989, from the Maine Office of Energy Resources. Hospital officials predicted that the cost for construction would be recovered in about 2 1/2 years, resulting in a 30 to 40 percent reduction in energy costs at Cary, now budgeted at $240,000 a year.

The plant will provide 50 percent of the heat and electricity for the hospital and the nearby Veterans Home, hospital officials said.

Dennis Drew, plant engineer at the hospital, submitted the grant application in December 1988, with the help of Brian McDougal, an energy audit consultant. The grant required special legislation to complete the project, according to Bill Flagg, community relations and development director at Cary.

Enabling legislation sponsored by state Rep. John Lisnik and state Sen. Donald Collins was passed in the spring of 1989. Before the legislation, the state had denied energy conservation funding to schools and hospitals that were constructed after April 1, 1978. Cary opened its doors in July 1978, Flagg said.

Persistence and aggressiveness to pass the legislation paid off with Cary experiencing “one of the most dramatic cost-reduction projects we have ever done,” according to Flagg.

Drew said energy requirements would increase significantly at the hospital as a result of the 34,000 square feet of new construction. The cogeneration will allow Cary to assume the demands of the new space at a reduced expense, Drew said.

Cogeneration is the simultaneous generation of electrical energy and low-grade heat from the same fuel. The project at Cary involved installation of a 280-kilowatt generator which will produce power nearly equivalent to the total electrical power demand at the hospital. This will reduce the hospital’s peak load electrical requirement, hospital officials said.

The process of cogeneration also involves the recapturing of waste heat that is normally lost through conventional exhaust discharge. The recaptured heat is used to produce steam by means of a heat exchanger. The steam then is used to replace or supplement the existing steam-heating system for the hospital. Cooling water from the 280-kilowatt generator will be used to preheat domestic hot water for the hospital.

Facilities Management Co. of Waltham, Mass., is the primary contractor. Local and state subcontractors will be utilized to furnish materials and to complete the project, enabling Cary to confine 60 percent of the funded money to Maine contractors. Included were County Electric, Industrial Heating and Piping Co., Northeast Mechanical Sales of Portland, Dragon Products Co., Soderberg Construction, Paul Robertson (masonry), Jordan Milton of Bangor, Sheridan Corp. of Fairfield, and McDougal.