No Fuel Like an Old Fuel?
or, New Kids on the Block?
Life was so much simpler when we
didn't have to think about things like what type of fuel to use to heat our homes.
Remember the dream of "Total Electric Living" promised by Ronald
Reagan as a spokesperson for General Electric? The idea of using electricity to
heat homes now seems as outlandish as having a mini-nuclear reactor shaped like
a woodstove in your living room. Now we have to think deep and hard before choosing; a home heating fuel. Not only do we have to consider the impact
on our pocketbooks, we have to full consider the impact on the planet, too.
Thanks to www.hearth.com or providing much of this
information. --SM
Oil and
gas can be thought of as "ancient sunlight:" They are "old
fuels," highly concentrated, powerful residues of photosynthesis that took
place on the Earth's surface millions of years ago. When oil and gas are
burned, carbon that has been buried within the earth for thousands of years is released in the form of
carbon dioxide, a by-product of combustion. The result is an increase in the
atmospheric concentration of carbon dioxide, the cause of the greenhouse
effect.
If your
priority is to be kind to the planet, you
might consider a biomass, the most common of
which is wood.
Although
carbon makes up about half the weight of firewood and is released as
carbon dioxide when the wood is burned, it is part of a natural cycle. A tree
absorbs carbon dioxide from the air as it grows and uses this carbon to build
its structure. When the tree falls and
decays in the forest, or is processed into firewood and burned, the carbon is
released again to the atmosphere. This cycle can be repeated forever without
increasing atmospheric carbon. Heating with wood, therefore, does not
contribute to the greenhouse effect. And there's more good news: when the use of wood for energy displaces the use of fossil
fuels, the result is a net reduction in greenhouse gas emissions.
Wood is
not an inherently dirty fuel that causes serious air pollution. While it is
true that old technology like open fireplaces and simple heaters could not burn
the wood completely, the new generation of woodbuming appliances produce almost
no visible smoke and deliver efficiencies in the range of 70 percent. Developed since 1980, improved technology has
cut particulate emissions (smoke) by about 90 percent compared with
conventional equipment. Wood may not be the best fuel choice in densely
populated urban areas where automobile exhaust and other pollution already puts
excessive strains on the air shed. But in suburban,
small town, and rural areas, wood makes good sense.
Wood contains only a
negligible amount of sulphur, an element that leads to acid rain. In this age
of environmental awareness, a big advantage of wood over the fossil fuels is
that its main environmental impact occurs at the point of use and is visible
for all to see. In contrast, the real environmental impacts of oil and gas are
hidden from view because they occur during extraction, refining and
transportation of the fuels to market.
If the destruction of
tropical rain forests causes global warming, and if planting trees in your
community is a good strategy control greenhouse gas concentrations, then how
can using wood for home heating be justified? The answer lies in the natural
cycle of growth, maturity, decay and re- growth of trees and forests. A healthy forest is not a museum, but
a living community of plants and animals. When trees are used for energy, a
part of the forests carbon "bank" is diverted from the natural decay
and forest fire cycle into our homes to heat them.
The key
to ecologically sound and sustainable wood energy use is to ensure that the
forest remains healthy, maintains a stable level of variously aged trees and
provides a good habitat for a diversity of other species, both plants and
animals. You can do your part by insisting on firewood -that is
harvested using sustainable forestry practices. Ideally, buy your firewood from
the person who owns the woodlot because owners are less likely to damage their
forest. If that is not possible, question the seller about the origins of the
wood.
When
thousands of families turned to wood heating in the late 1970s and early 1980s
to shelter them from high energy costs and the threat of shortages; there was a
sudden increase in the number of house fires related to wood heating. Wood
heating acquired a bad reputation, mostly because neither the users nor
industry had reliable guidelines for installation safety. Since then, however,
the wood energy industry and all levels of government have worked together to
put in place the same type of safety systems as have been in place for other
heating fuels for more than 30 years.
The
product safety standards, installation codes and professional training for
installers and inspectors have resulted in a greatly improved safety record for
woodburning. Installed according to the codes and used according to the
manufacturer's instructions, woodburning appliances are no more hazardous to
use than any other form of home heating.
"The supply of firewood from
privately managed wood lots to residential users of the fuel represents an
important but neglected model of sustainable development. An increase in the
use of wood as a fuel for residential heating can occur within the framework prescribed by
current
principles of. environmental sustainability." --Dr. O.Q. Hendrickson,
"Forests are
constantly thinning themselves, and there is much evidence that tells us that we could prudently
be thinning our forests for
millennia if we attended to its rhythms and patterns." --Paul Hawkin, Author. The Ecology of Commerce.
Many of the objections to the
burning of cordwood (safety, mess, smoke) are addressed by stoves that burn
various types of biomass pellets. Pellet-burning appliances are simpler to
operate and more convenient than other wood-burning appliances. In fact, they
are almost as easy to use as gas, oil, or electric heaters. These
stoves and inserts burn wood pellets--compressed wood which resembles rabbit
food. Some stoves can even burn feed corn or pellets made from
compressed grasses.
Typical pellet-burning
appliances rely on sophisticated computers and circuit boards to determine how
much fuel should be burned. Most models have at least two bum settings and some
use thermostats to control the fire. They also use a forced-air system to
distribute heat. Pellet-burning appliances are highly efficient and pollute
very little. Depending on the model, they may furnish between 10,000 and 60,000
Btu per hour.
Because these appliances bum
wood so efficiently, they do not typically need a standard chimney. Rather,
they exhaust fumes through a small hole in the wall to the outdoors. This pipe
is called Pellet Vent or Class L chimney, and consists of a stainless steel
interior and an aluminum or galvanized exterior. Pellet stoves and inserts can
also be vented up through existing masonry and prefab (class A) chimneys, but
the chimney typically must be relined with a smaller size of stainless steel
single wall pipe.
Pellet-burning appliances
need to be refueled less frequently than most other wood-burning appliances.
Refueling varies from once a day to twice a week, depending on the model and
your heating needs. To refuel, you simply pour the pellets into a hopper, which
holds between 35 and 130 pounds of pellets. A corkscrew-shaped device called an
auger then transfer pellets to the fire chamber.
There are two types of auger
feed systems, bottom-fed and top-fed loading systems. Some models are capable
of burning corn in addition to pellets. Others can use lower grades of pellets,
a good feature for the future when pellets may be made of materials other than
premium sawdust.
Unlike other wood-burning
appliances, pellet stoves and inserts rely on mechanical air-supply systems
(usually a forced-draft or induced-draft system) to vent air from the home. The
forced-draft system uses a fan to force air up the vent into the combustion
chamber. The induced-draft system, sometimes called the negative pressure
system, uses a fan to draw air from the combustion area through the exhaust
system.
Burning wood with a pellet
stove or insert is usually convenient, neat and safe. These devices usually
don't require refueling more than once a day and the fuel is compressed and
bagged for clean and easy storage and handling. Pellet stoves produce virtually
no smoke, and produce less odor than other
wood-burning appliances. Moreover, the exteriors of these appliances are not
used for radiating heat and stay relatively cool, preventing you from burning
yourself if you accidentally touch the stove.
Pellet-burning appliances,
however, have disadvantages. Before purchasing a pellet-burning appliance, make
sure that reliable suppliers of the fuel are in your area. To find a pellet
fuel distributor in your area, ask a local wood stove dealer or check for a
listing in your local telephone directory under Fuel or Pellet Fuel.
Pellet-burning appliances
also use several internal fans, which require about 100 KWH of electricity each
month. The need for electricity will add to your total energy bill and will also
prevent you from using your stove or insert if the power goes out (unless your
appliance has a battery pack). Moreover, there are restrictions on where you
can place a pellet-burning appliance to allow proper combustion and air
exchange. For example, you may not install a pellet stove in a new manufactured
(mobile) home according to regulations of the U.S. Department of Housing and
Urban Development.
Pellet stoves have many
moving parts and therefore require regular service and cleaning in order to
function properly. Be sure to check on the warranty and the cost for yearly
servicing. Ask your dealer if there are any major wear parts which might need
regular replacement.
If you are comparing the
price of a pellet stove or insert with a gas or wood burning appliance, you
should compare the total installed cost of both systems. If the pellet-burning
appliance doesn't need a chimney, the cost of the entire system may be less
than that of another stove. Average consumption will run from 1-2 tons for
occasional use to 6+ tons for a heavy full-time user.
Still on the horizon, but
becoming more common is biodiesel, a fuel that can be created from any number of biomass sources, most notably spent cooking
oil. Although most biodiesel is used to fuel vehicles, it can easily be used as
a substitute for home heating oil.
The
headlines in late summer/early fall inevitably involve wild fires burning out
of control throughout the West and Southwest. Peering into our energy futures
perhaps we will see a time when the energy-laden brush and chaparral are
harvested and pelletized or converted to biodiesel before going up in smoke.
Reprinted
by permission from Green Living: A
Practical Journal for Friends of the Environment; Fall
2006