Published in the ECHO Journal, October 2007
The Pacific Heights Towers Association is a 127-unit condominium in a 20-story high-rise in San Francisco. After the association experienced a 40 percent increase in its electrical costs during California’s deregulation fiasco in 2001, the association got serious about the cogeneration system that they had been considering for years. About the same time as the electricity cost increase, along came a new cogeneration technology called a “MicroTurbine” that promised to be quieter and more maintenance free than some earlier cogeneration system designs.
Cogeneration is the simultaneous production of energy from one fuel source. In this case, natural gas is ignited in a small turbine engine, which generates electricity as it rotates while its exhaust is used to heat hot water at the same time. This gives the cogeneration technology a high 80 percent efficiency. This is much better efficiency than typical central natural gas power plants that do not utilize the waste heat they generate, and they operate at efficiencies in the low 30-40 percent range.
The association’s Energy Committee members flew to Southern California to see a Capstone MicroTurbine for themselves. They visited two operational Capstone installations with which they were very impressed.
Another factor in their decision to install cogeneration was a $60,000 incentive program, called the Self-Generation Incentive Program, developed by the California Public Utilities Commission and administered by PG&E. The association received its $60,000 check for the cogeneration system, which began operation in March 2005. The project is expected to have a 6-year simple payback.
Hot water from the cogeneration unit heats both the domestic hot water and the building’s hydronic heating water (hydronic heating is the heating of a building by radiation from panels containing hot water). The electricity from the unit provides light and power to the building’s common areas such as the corridors, lobby, and garages. The cogeneration unit is located in the building’s rooftop boiler room. The Capstone unit, about the size of two refrigerators, sits next to the hot water storage tank and hot water boilers. In a PG&E power failure, the MicroTurbine continues to power critical electrical circuits such as lighting in the corridors and garages and power to garage doors.
Pacific Heights Towers is helping the environment by utilizing natural gas at very high efficiency, self-generating its own hot water, and taking a significant electrical load off of California’s stressed power grid.
This sort of electrical “distributed generation” will play an increasing role in supplying California’s electrical needs. It provides high-efficiency generating power at the location where the electricity is utilized and thus takes a load off the power grid for the benefit of all Californians on power-short summer days.
Brian Hines of North Coast Solar Resources in Santa Rosa, who has served as energy consultant to Pacific Heights Towers for 15 years, was the Project Manager for the cogeneration project.
John Stevens is a resident at Pacific Heights Tower Owners Association, an ECHO member association in San Francisco.