NATIONAL REPORT—Combined heat and power (CHP), the simultaneous production of electricity and thermal energy from a single heat source, is increasingly being used by companies such as Starwood Hotels & Resorts Worldwide Inc. and Host Hotels & Resorts Inc. to alleviate rising energy costs.
CHP, also known as cogeneration, is generated onsite by a plant powered by any number of systems: fuel cells, reciprocating engines, turbines, or microturbines. Electricity generated is used to meet a portion of the hotel’s needs and byproduct heat is used to heat hot water or steam.
Cogeneration plants are much more efficient than coal-powered or other types of plants that supply most of America’s electric power. Typical power plants waste 74 percent of the energy they produce, but a cogeneration plant will lose only about 17 percent and use another 49 percent for heating and the remaining 34 percent for electricity generation.
At the 336-room Ritz-Carlton, San Francisco, a PureComfort combined cooling, heating and power (CCHP) system from UTC Power has been generating electricity and helping to meet the hotel’s heating and cooling needs since late 2005. About 240 kW of electricity is generated by the system that includes four 60-kW microturbines and a double-effect chiller from Carrier Corp., UTC Power’s sister company.
The microturbine’s exhaust is collected in a manifold and used to drive the double-effect absorption chiller, enabling the PureComfort system to achieve an overall fuel utilization rate of more than 80 percent. The power plant, which has a footprint of approximately 22 feet long, 21 feet wide, and 16 feet high, saves enough electricity to light 220 homes every day.
Payback in Just Three Years
“The installation was a big success for our company,” says Randy Gaines, Senior Director, MEP/Systems, Design & Construction, for Bethesda, Md.-based Host Hotels & Resorts. “We purchased the system outright. It will have a payback of less than three years. The system is exceeding expectations.”
Gaines says cogeneration plants make sense where fuel costs are reasonable.
“We put them in markets where we can lock in a long-term natural gas rate,” says Gaines, who adds that his company is currently considering locations in New York City for cogeneration. “You also need a good footprint—a large enough area to put the equipment, and the system needs to fit the mechanics of the building.”
Utility company incentives are important when considering cogeneration systems. Gaines says Connecticut, New York and California are examples of states that offer rebate programs.
It is no coincidence that Starwood and Host Hotels & Resorts are both pursuing cogeneration. At the Sheraton San Diego Hotel & Marina, for example, the two companies worked together on the installation of several Direct FuelCell power plants. Those plants now generate 1.5 MW of electricity and provide waste heat to help meet domestic hot water demands. (Click here to read article.)
Starwood Commits to CCHP in Kauai
In addition to its five properties that currently have Direct FuelCell power plants, Starwood is pursuing continuous-duty, diesel-driven CCHP EnviroGen Energy Modules for its Sheraton Kauai property in Kauai, Hawaii. Starwood will not own the plants but will purchase the power from BluePoint Energy Inc. (See article.) The plants are expected to be up and running by early 2008.
“While the Hawaiian island of Kauai is one of the most beautiful and remote places on Earth, it presents special challenges with respect to accessing reliable and cost-efficient energy,” said John Lembo in a press release announcing the BluePoint venture.
Whereas natural gas would be the fuel of choice on the mainland, in Kauai diesel fuel will be used to power the EnviroGen Energy Modules. At the hotel, a back-up generator also will be installed. Heat produced by the plants will help meet 20 to 30 percent of the property’s domestic hot water needs.
“We will be saving $350,000 a year without any out-of-pocket cost,” Lembo says.
Lembo says Starwood currently is considering cogeneration plants for hotels in New York City and may also implement the technology outside the United States.
Glenn Hasek can be reached at editor@greenlodgingnews.com.
