[caption id="attachment_51137" align="alignright" width="350" caption="Dale Withers, director of facilities at Pacific Union College (left), Gayle Grove, co-generation manager and Associate Co-Gen Plant Manager Raulton Haye monitor the Kawasaki Gas Turbine Power Plant at Pacific Union College in Angwin producing 1.5 megawatts of energy -- enough power for the entire campus community."][/caption]
ANGWIN – The ability to generate mechanical energy, megawatts of electricity and heat in the same engine using a process called co-generation is increasing in popularity due to skyrocketing fuel prices and continued uncertainty over the future availability of global oil supplies.
At Pacific Union College (PUC) in Napa County, facilities managers anticipated this trend years ago and installed a $12 million gas turbine power plant that went into 24/7 continuous operations on Feb. 18, 2006.
Today PUC is more than half way toward realizing a complete return on its investment. This plant saves the college approximately $1 million a year in energy costs.
“During the past decade we experienced a series of rolling blackouts and sharply rising electricity rates,” said Dale Withers, director of facilities at PUC.
“By using 20 percent more natural gas than was historically used in our boiler to supply steam for our campus, PUC is able to supplement 90 percent of its electrical needs while also covering the campus’ steam use.”
The college installed a Kawasaki GPB-15X natural gas turbine, capable of generating 1.5 megawatts (MW) of power (1,490 kW).
This is enough energy to satisfy the needs of a campus with more than a million square feet of building space. These facilities include dormitories, classrooms, laboratories, offices, a cafeteria, library, gymnasium, and auditoriums, along with a student center and church occupied by more than 1,200 students, faculty and the administrative staff.
The gas turbine is similar in function to engines used in turbo prop airplanes that service Charles M. Schulz Sonoma County Airport. However, instead of a propeller, an electric engine is used on the gas turbine.
The gas turbine system is designed to last 30 to 35 years. The engine is overhauled every three years to keep the power plant operating at peak efficiency.
The exhaust from the turbine has temperatures approaching 1,000 degrees Fahrenheit. Hot air is captured in a heat recovery system that produces 10,000 pounds of steam per hour used in a variety of applications.
“With current utility grid prices, PUC could be paying 14 to 17 cents per kilowatt hour (kWh). However, using co-gen technology, our cost is about nine cents per kWh to produce electricity and six to seven cents per kWh for steam -- when you consider the steam we are using for heat is a byproduct of co-generation,” according to Gayle Grove, co-generation manager at PUC.
Mr. Grove said when considering co-gen, it is important to sign up for an extended service agreement as well as long-term natural gas supplier contracts to fix maintenance and operating costs.
“The cost of natural gas can go up from 10 to 20 cents per decatherm, (1,000 square feet of natural gas equivalent to 100,000 BTUs, or British Thermal Units of heat energy). However, current natural gas prices are among the lowest in years and the U.S. has huge onshore reserves.”
This single, unified power system operating at 80 percent efficiency provides over 90 percent of the energy required for the entire campus when it comes to producing heat, hot water, steam, chilled water (for ventilation and air conditioning), lighting, as well as the steam needed to heat PUC’s indoor swimming pool and sanitize cafeteria equipment.