Wood Chip Boiler Would Add $4-5 Million
24 February 2009
For Immediate Release
Media Contact: Kevin Robinson
BENNINGTON, Vt. — As the hospital continues work to create its modernization project, officials now have more information on the feasibility of burning wood chips to provide steam for heat, laundry, cooking, and medical sterilization. The hospital recently received the results of a feasibility study it commissioned with input from the Bennington Energy Committee and the Bennington County Regional Commission. Hospital officials said it was unlikely that the project could be added to the upcoming modernization plans.
"The study provides a thorough analysis of everything that is involved in burning wood to heat the hospital," explained Kevin McDonald, Vice President of Marketing and Planning. "In looks at the investment required to install several types of wood-burning boilers, and includes calculations on payback. The study examines reliability and sizing, too. Importantly, it also looks at the supply chain, and what is required to provide enough fuel for a system like this to operate. However, the investment required to build such as system will likely be more than SVMC can absorb in our modernization project."
The study looked at six different options for wood-burning boilers: direct burn wood chip, wood chip gasification, and wood pellet, each in 500 and 1000 horsepower. After calculating the peak steam requirements and other variables, the study demonstrates that the most viable options were for either a 500-hp wood chip gasification or direct-burn system. The costs of this capability would add $4 to $5 million to the modernization project. In each case, the system would pay for itself in a little more than seven years.
"The payback time is shorter than we expected," McDonald said. "But we still have to have the money to build the system."
McDonald explained that financial analysis shows that the modernization project will require SVMC to borrow about $30 million. "That is about the limit of what we will be able to borrow," he said. "In fact, we already had to trim back some of our goals for the project to fit within $30 million. Everything in this project is a patient care necessity. We simply can't cut patient care areas to add the ability to burn wood. We hope the community understands that we've thoroughly studied the issue, but can't trade a better hospital for a wood-fired boiler."
Any wood-burning system would require significant construction of enough storage to handle fuel for three days of peak operation. The type of storage varies according to the fuel type. Burning wood also requires an automated system for feeding the burner. These also vary according to the type of fuel. However, using wood-chips as fuel would require an underground storage facility, to keep the chips from freezing, and a system of hydraulic scrapers, augers, and conveyors to feed the boiler. In addition, any wood-burning system requires a method for removing ash both from the burner area and from the exhaust.
Wood-chip boilers require more regular maintenance than other types of boilers. In fact, trained operators must be available round-the-clock. Wood boilers require weekly ash removal, cleaning, and inspection. They also require constant adjustment of fuel feed rates and combustion air. Lastly, staff need to be able to clear fuel jams from the feeding system. SVMC would need to hire additional staff to support these needs.
The study also revealed that a single wood-chip system would require more than three 53-foot delivery trucks per day during the peak heating season. These trucks come equipped with a snorkel that allows for automatic unloading. Unloading the trucks is much louder than other fuels. It also must be done during the day because it usually requires more than one operator.
"This exhaustive study provides us with a wealth of information about the feasibility of burning wood to provide steam for the hospital," McDonald explained. "It answers numerous questions about what is required to run such a system and what the costs and benefits are. The determining factor is the cost."