Wood-Chip Heating Systems - Biomass Energy Resource Center

Q: Will wood smoke cause acid rain?
A: The major sources of acid rain are sulfur dioxide
and nitrogen compounds in combustion
reactions (known as SOx and NOx). Unlike
fossil fuels, wood has practically no sulfur and
so produces virtually no SOx when it burns.
Wood combustion does create NOx, but at levels
comparable to fossil fuel combustion.
Q: Aren’t oil and natural gas so cheap that it doesn’t
make sense to burn wood?
A: Depending on local market conditions, this is
sometimes true for cordwood - but it is not true
for wood chips. Wood chips generally cost about
half as much as natural gas and no. 2 fuel oil,
even at very low bulk prices for oil. Most dollars
spent on oil and gas leave the Northeast, while
wood dollars stay in the state economy, creating
an additional economic benefi t.
Q: If everybody starts burning wood chips, won’t
the price go up sharply?
A: The price of all fuels can be expected to go up
over time. However, wood-chip prices are not
directly connected to the world energy market.
Wood is also a locally produced renewable fuel.
For these reasons, it can be expected to increase
less in price than the other fuels. Wood prices
paid by schools have increased gradually at about
1% a year over the last fi fteen years.
Q: Is there enough wood to heat this facility in the
long term?
A: All 11 states of the Northeast have a large excess
capacity of biomass available now, with an even
larger reserve of unmanaged woodland that
could be tapped on a renewable basis for energy
production.
fi lled by a mechanical engineer or a project manager
experienced in boiler installations. In many cases the
installation of the wood system will be done under a
general contract that will also include either mechanical
work or building construction or both. These cases
will already involve a project architect or mechanical
engineer who will be able to oversee the wood system
installation in addition to having other responsibilities.
Structuring a Typical Conversion
A typical conversion from electric heat to a
biomass system might be structured as follows. A
mechanical engineer is hired by the owner to design
the boiler room equipment and the distribution
piping throughout the building. This engineer is also
responsible for advising the owner in the selection of
the wood system manufacturer, and for designing the
piping and controls connections between the woodchip
boiler and the backup boilers.
After the system manufacturer is selected, an
architect is hired to work with the engineer and
manufacturer to design the boiler room and the
storage bin. There may also be a structural engineer,
as a subcontractor to the architect, to design the
concrete work (drainage, footings, slabs, walls, and
reinforcement) for the fuel storage bin and boiler
room. An electrical engineer will usually be involved in
the overall project, and may have some responsibility
associated with the biomass system.
If the biomass conversion is from an oil, gas, or
coal system with hot water or steam distribution,
there will be little mechanical design work outside the
boiler room. In this case the mechanical engineer’s
role will focus more on the selection and installation
of the biomass system. In new construction or in cases
where there is an expansion of the existing building,
the architect is likely to be in the lead role, with the
mechanical engineer acting as a subcontractor.
If a biomass specialist is on the project team, that
person will either work directly for the owner or be a
subcontractor to the architect or mechanical engineer.
It will be the specialist’s responsibility to oversee the
wood system specifi cation and selection, as well as
to work with the engineer and architect in putting
together the pieces associated with the system: the
piping and controls interface between the wood and
backup systems, and the design and construction of the
boiler room and storage bin.
In smaller, simpler jobs where an architect and a
mechanical engineer would not normally be employed,
such as an installation in a small commercial
greenhouse, all elements of the design work can be
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