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Biomass ¹⁾, a renewable energy source, is biological material derived from living, or recently living organisms, such as wood, waste, and alcohol fuels. Biomass is commonly plant matter grown to generate electricity or produce heat. For example, forest residues (such as dead trees, branches and tree stumps), yard clippings and wood chips and garbage may be used as biomass. However, biomass also includes plant or animal matter used for production of fibers or chemicals. Biomass may also include biodegradable wastes that can be burnt as fuel. It excludes organic materials such as fossil fuels which have been transformed by geological processes into substances such as coal or petroleum.

Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, and a variety of tree species, ranging from eucalyptus to oil palm (palm oil). The particular plant used is usually not important to the end products, but it does affect the processing of the raw material.

Although fossil fuels have their origin in ancient biomass, they are not considered biomass by the generally accepted definition because they contain carbon that has been “out” of the carbon cycle for a very long time. Their combustion therefore disturbs the carbon dioxide content in the atmosphere.

Carbon Cycle in which CO₂ is captured by plants that release it later during combustion or decompositon.

The carbon cycle ²⁾ is the process through which carbon is cycled through the air, ground, plants, animals, and fossil fuels. Large amounts of carbon exist in the atmosphere as carbon dioxide (CO2). Carbon dioxide is cycled by green plants during the process known as photosynthesis to make organic molecules (glucose, which is food). This is where the nourishment of every heterotrophic organism comes from. Animals do the opposite of plants–they release carbon dioxide back into the air as a waste product from respiration. (Note: Plants also undergo respiration to make food, but the majority of the carbon dioxide in the air comes from heterotrophic respiration). Decomposers, when they break down dead organic matter, release carbon dioxide into the air also. Decomposers are essential because without them, all of the carbon on the planet would eventually become locked up in dead carcasses and other trash. Decay permits carbon to be released back into the food web. Carbon is also stored in fossil fuels, such as coal, petroleum, and natural gas. When these are burned, carbon dioxide is also released back into the air. Carbon dioxide can dissolve in water, where some of it is later returned back into the atmosphere. The rest can be taken to form calcium carbonate, which builds up shells, rocks, and skeletons of protozoans and coral.

• The heating system is installed safely (WETT Certified Professional)
• Fuel is harvested sustainably
• The fuel is burned efficiently with little or no visible smoke

Different stoves models and wood furnace.

A wood stove is the most popular, flexible and economical wood heating option. A stove can be located almost anywhere there is enough space and where its chimney can be properly routed. A perfect installation has the stove located centrally in the main floor living area of the house and the flue pipe running straight up into the chimney. This installation design will provide the best performance and need the least amount of maintenance.

Different type of stoves:

• Wood Stoves
• Wood Fireplaces
• Wood Inserts
• Wood Furnaces

Fireplace Insert

Fireplace Inserts sit partially inside the fireplace, and are equipped with an outer shell to deliver heated air into the room and minimize heat loss to the masonry. Surround panels cover the fireplace opening, and a stainless steel liner extends to the top of the chimney.

Catalytic and non-catalytic stove design Wood stoves

Advanced combustion wood stoves expand on the concept of a simple box stove that has been in use for over 100 years. Simple stoves allow the heat and smoke of the resulting fire to travel in a direct path up the the chimney. The advanced combustion stove places an “air injection” tube into the smoke path. Secondary inlet air is drawn in through the tube increasing the oxygen content of the smoke, causing it to burn. The smoke then travels through a labyrinth path, radiating heat before exiting via the chimney ³⁾.

Stove manufacturers have improved their combustion technologies over the years, and now some newer stoves have certified emissions in the 1 to 4 grams of smoke per hour range.

The two general approaches to limit smoke emissions are catalytic and non-catalytic combustion. Both approaches have proved effective, but there are performance differences.

• The smoky exhaust is passed through a coated ceramic honeycomb inside the stove where the smoke gases and particles ignite and burn.
• Catalytic stoves are capable of producing a long, even heat output.
• All catalytic stoves have a lever-operated catalyst bypass damper which is opened for starting and reloading.
• The catalytic honeycomb degrades over time and must be replaced, but its durability is largely in the hands of the stove user.
• The catalyst can last more than six seasons if the stove is used properly, but if the stove is over-fired, garbage is burned and regular cleaning and maintenance are not done, the catalyst may break down in as little as two years.

• Stoves do not use a catalyst, but have three internal characteristics that create a good environment for complete combustion. These are
  • Firebox insulation,
  • A large baffle to produce a longer, hotter gas flow path
  • Pre-heated combustion air introduced through small holes above the fuel in the firebox.

Non-catatytic stoves cannot match the even heat output of catalytic stoves, but their owners love watching the beautiful fire they create. The baffle and some other internal parts of a non-catalytic stove will need replacement from time to time as they deteriorate with the high heat of efficient combustion.

Although most of the stoves on the market are non-catatytic, some of the most popular high-end stoves use catalytic combustion. Because they are slightly more complicated to operate, and the best of them do produce exceptional performance, catalytic stoves are suited to people who like technology and are prepared to maintain it properly so it continues to operate at peak performance.

Both options have their pros and cons, and most users of either type seem satisfied with the performance of their stoves.

Biomass Stove and Cut-a-way diagram of a pellet stove

Pellet stoves utilize biomass and wate wood by-products from manufacturers of furniture, lumber and other wood products. The waste material is ground and pressed together using naturally occuring resins and binders to hold the pellets together.

As a waste product, biomass fuel pellets offer excellent synergy, heating buildings while reducing landfill waste at the same time. Pellets are convenient as they are supplied in neat and compact dog food sized bags, which can be stacked somewhere ready to use. Simply scoop a bunch in the hopper of the stove about once per day and the controlled feeding unit will automatically deliver the rigth amount of uel to the burner. The only down side is no electricity, no fire.

A pellet stove will specifically burn wood pellets. Biomass stoves are typically sealed units manufactured from either cast iron or steel. They operate at around 75% efficiency whereas an open fire operates at only 15% to 20% efficiency ⁴⁾. Biomass stoves are able to burn multifuel pellets. Current fuels include:

Different pellets types used in Biomass stoves

• Corn
• Wheat
• Barley
• Bark Pellets
• Agri-Waste pellets
• Switch Grass Pellets

There are free-standing stoves designed to heat a room or large space (much like a cord-wood burning stove), fireplace inserts and larger pellet-burning furnaces that can replace or supplement a home's existing furnace. These larger solutions heat either air or water, connect to the home's existing heating system and can be placed in the utility closet or basement.

Although there will be many small design differences across the various manufacturers, biomass stoves share many similarities. Almost all feature a hopper, which is filled with the fuel. Hopper size can depend on stove size. Bigger stoves or furnaces might have bigger hoppers, but they also might burn more fuel. Hoppers will need to be refilled, and this frequency also depends on usage although a once-a-day filling is the average. Most of these units run on electricity, which powers the auger or feeding system. Electricity also powers the blowers that distribute warmed air into the room.

Fine Particulate Emission from different sources

Biomass fuel burns cleaner than cord-wood, which is one reason why a homeowner might consider switching to it. Particulate emissions, which is measured in pounds/million BTUs, is significantly lower in a wood pellet stove when compared to a traditional wood stove or fireplace. Pellet stoves measure about .49 while a wood stove is 1.4 and a fireplace is 28. Biomass stoves are also more efficient than traditional wood stoves. The biomass fuels are uniform, consistent and drier than wood.

Advanced technologies offer several advantages, including:

• Much higher efficiency
• Much less smoke pollution
• Greater safety because less creosote is formed
• Burn less wood for more heat. Five acres of wood can support a home forever

• Web site on Wood stoves technologies
• CANBIO is interested in the development, promotion and use of bioenergy
• Brad Leonard Biomas introduction / April 2009 «How-to workshop for homeowners» recorded with camera
• Alan Gibson Biomass presentation / April 2009 «How-to workshop for homeowners» recorded with camera
• Biomass part 1 / YouTube Video / «How-to workshop for homeowners» March 2009/ Brad Leonard
• Biomass part 2 / YouTube Video / «How-to workshop for homeowners» March 2009/ Brad Leonard
• Introduction to Biomass / June 2009 «How-to workshop for homeowners» PowerPoint presentations (pdf format) / SWITCH web site
• Biomass / June 2009 «How-to workshop for homeowners» PowerPoint presentations (pdf format) / SWITCH web site