150 federal buildings found to be candidates for pellet boilers

Wood pellet boilers should be considered at all hot-water heated
federal facilities where natural gas is unavailable, particularly in
northern regions, according to the U.S. General Services
Administration.  The GSA’s Green Proving Ground just released a study of
the retrofit done at the Ketchikan Federal Building in Ketchikan,
Alaska, that installed a state-of-the-art pellet-fired biomass boiler.

GPG commissioned researchers from the National Renewable Energy
Laboratory to evaluate the efficiency, cost-effectiveness, and
operational functionality of the 1-million Btu boiler. NREL gauged the
technology’s deployment potential by combining information from GSA’s
Energy Usage and Analysis System with independent research to locate
wood-pellet biomass sources, estimate delivered costs, and identify
additional candidate facilities. After one full year of boiler
operation, researchers performed a measurement and verification
assessment over the course of one day in January 2012 to ascertain
biomass boiler operational efficiency.

Because weather conditions were mild on that day and the boiler is
oversized, it was operating at only 45 percent of load, but still
maintained 85 percent efficiency, the report said. Payback for
Ketchikan, in which the retrofit included the replacement of the entire
legacy heating system, is estimated at 30 years. In part, that is due to
the oversizing of the boiler, the report said. “Over the course of a
year, the boiler installed at Ketchikan is capable of generating 8,760
million Btu but estimated use in 2011 was 1,150 million Btu, or 13
percent of full capacity. Under more favorable conditions, including but
not limited to appropriate system sizing, simple payback can be less
than five years.” A table in the report reported the payback periods for
various pellet prices and differently sized systems. Paybacks are less
than three years at prices between $200 and $250 per ton for systems
ranging from 1 million Btu per hour to 4 million Btu per hour.

The report listed several benefits of pellet boilers, summarizing
them as having high operational functionality and low operating and
maintenance costs. Of the more than 1,500 GSA-owned buildings across the
U.S., researchers identified approximately 150 as potential candidates
for biomass heating. “Wood-pellet- fired biomass boilers should be
considered at all hot-water-heated facilities where natural gas is
unavailable. Deployment should target facilities that have an extended
heating season and where pellet fuel is available within 50 miles.”