The Building Tradesman Newspaper

Friday, February 08, 2013

Renewable energy capability to transform NMU plant

By Marty Mulcahy, Editor

MARQUETTE – Northern Michigan University’s Ripley Heating Plant is getting a new look and a new purpose.

Johnson Controls and the building trades are moving toward completion of the Ripley Combined Heat and Power Renewable Energy Project. Under construction is a new biomass-fueled cogeneration combined heat and power plant.

According to NMU, a new addition to the plant will utilize a solid fuel stoker boiler rated at 40,000 pounds per hour, capable of burning wood chips with natural gas as a backup fuel. The new plant will be capable of meeting 87 percent of thermal needs on campus. Plus, a new back-pressure steam turbine generator will produce up to 645 kilowatts of electricity, which amounts to about 16 percent of the university's electrical load.

The plant’s existing natural gas boilers will supplement the biomass plant for peaking duty. Electricity will continue to be purchased, as needed, from the Marquette Board of Light and Power.

“Johnson Controls Inc.  coordinated their subcontractors very well, staging deliveries and scheduling work to maximize task achievement safely and efficiently at numerous locations on site at any given time,” said Gisele Duehring, NMU’s associate director facilities/heating plant.  “This took a great deal of continuous communication, especially when some equipment delivery schedules changed. In addition to JCI, subcontractors’ foremen provided valuable input and leadership in that process.”

Duehring added that it was “a pleasure” to see workers on the project “really enjoying their work and taking pride in it, being committed to teamwork, quality and safety.” 

The Ripley Plant first came on line in 1966, producing steam heat to the NMU campus. Throughout its history the plant has had three boilers that have been powered by natural gas, with fuel oil backup. The plant also acts as the primary distribution point for electricity purchased from the Marquette Board of Light & Power. Growth of the NMU campus resulted in the upgrade of two of the original three boilers and replacement of all the switchgear in 2006.

For fuel, the new biomass-burning boiler will utilize wood chips and wood by-products of the Upper Peninsula’s logging industry, such as tree tops, sawdust, and bark. The goals of the project are to reduce operating costs, provide greater fuel flexibility and protection from volatile gas pricing, use a renewable resource and create local jobs.

The project, NMU says, will also address several long-term maintenance issues at the plant, including the installation of a fire suppression system throughout the existing facility, and the replacement of the original water softeners and brine system.  Other energy optimization improvements include the interconnection of the New Science chiller to the Learning Resource Center chilled water system and the replacement of the existing single-stage unit in Cohodas Hall with a two-stage absorption chiller.

WORKING AT NORTHERN Michigan University’s Ripley Combined Heat and Power Renewable Energy Project is Brian Engstrom of IBEW Local 1070.

THE NEW $16.4 MILLION Ripley plant addition, at right, will utilize a solid fuel stoker boiler rated at 40,000 pounds per hour, capable of burning wood chips with natural gas as a backup fuel.

SETTING UP A WELDING job at the Ripley Plant are (l-r) Ben Eichhorn and Drew Parovisti of Plumbers and Pipe Fitters Local 111. They’re employed by Tweet/Garot Mechanical. Photos by Jack Deo/Superior View Photography