Heating in the Northeastern USA with a Biomass Pellet Stove: Lessons Learned in a Rural Residential Setting

Abstract

The chapter provides an overview of the carbon-neutral biomass-based alternatives for residential heating in rural areas. As with all alternatives, there are trade-offs. For example, biomass pellet stoves and gasifiers provide heat at a lower cost compared to fuel oil, but using a pellet stove or gasifier requires the installation of new equipment and often daily filling and cleaning that is not required by oil or natural gas furnaces/boilers. An overview of existing technologies for the conversion of biomass to heat and methods for preparing the biomass are discussed. The impacts to air quality differ greatly with each technology. More research is necessary to determine how to best prepare the biomass, which equipment is most efficient for burning biomass, and which combination of biomass and equipment is best at reducing negative impacts to air quality.

Questions for Critical Thinking

• (1) What is the most cost efficient method of heating residential space in the Northeastern United States today?

• (2) Which heating technology and fuel combination is responsible for the most air pollution in the United States today? Which is the cleanest burning?

• (3) With use of wood-based heat on the rise in the United States since 2004, what number of households could be sustainably heated by wood-heat?

• (4) How many acres of woods could we sustainably utilize annually to supply heat? What factors influence tree-replenishment rates?

• (5) If a 1500 square foot home could meet all winter heating needs using 2 acres of field corn, how many acres of corn would be required to provide the nation’s winter heating needs? Is this sustainable?

Glossary of Terms

B20

A mixture of 20% biodiesel and 80% conventional diesel.

Biodiesel

A biodegradable transportation fuel for use in diesel engines or heating fuel for use in specially-converted furnaces. Biodiesel, a fatty acid methyl ester, is produced through the transesterfication of organically-derived oils.

Bioenergy

Refers to biomass based production of heat, transportation fuel, or electricity to displace fossil petroleum sources.

Biofuels

Biomass converted to liquid fuels such as ethanol and biodiesel.

Biomass

Any biologically-derived organic matter. Biomass available for energy on a sustainable basis includes herbaceous and woody energy crops, agricultural food and feed crops, agricultural crop residues, wood residues.

Biomass Pellet

A biomass pellet is a cylindrical, extruded form of ground and heated biomass (usually made from wood or perennial grasses). Biomass pellets are approximately 10 times more dense than un-pelletized biomass. The pelletization of biomass improves efficiency of transportation, storage and improves fluidity of biomass feedstock in automatic feeding systems for heating units.

Carbon Dioxide (CO ₂ )

A colorless, odorless gas produced by respiration and combustion of carbon-containing fuels. Plants use it as a food in the photosynthesis process.

Carbon Monoxide (CO)

A colorless, odorless, poisonous gas produced by incomplete combustion.

Combined Heat and Power (CHP)/Co-Generation

The technology of producing electric energy and another form of useful energy (usually thermal) for industrial, commercial, or domestic heating or cooling purposes through the sequential use of the energy source.

Combustion

A chemical reaction of hydrocarbons in the presence of oxygen that produces carbon dioxide (CO₂), water (H₂O), energy (heat and light), and ash.

Feedstock

Raw materials that may be treated or converted to create fuels. Biomass feedstocks may include forestry products, crop residues, municipal waste streams, manure and food processing waste.

Gasification of biomass

A chemical reaction of hydrocarbons, but they are heated in the presence of low levels of oxygen producing a mixture of simple gaseous compounds such as carbon monoxide (CO), CO₂, hydrogen gas (H₂), and other flammable hydrocarbon gases such as methane. Other compounds produced from gasification are char and ash.

Gasifier

A device that converts solid feedstocks to gas and then burns the gas in a secondary burn-chamber. Heat can be captured and redistributed by a variety passive and active methods. Generally refers to a heating technology using thermochemical processes.

Heating oil/home heating oil/#2 heating oil

Fossil-fuel based #2 distillate from crude oil processing. Heating oil is chemically identical to diesel fuel but is dyed pink to differentiate between taxable transportation fuels and heating fuel.

Heating Value

The maximum potential energy released during complete oxidation of a unit of fuel. Includes the thermal energy recaptured by condensing and cooling all products of combustion.

New Source Performance Standards (NSPS)

Standards developed by the U.S. Environmental Protection Agency that govern the manufacture of new wood/biomass stoves and impose certain minimum standards for reduction of air pollution from biomass stoves.

Outdoor wood boiler

A biomass (wood-based) heating technology that captures heat of combustion of logs in a water-jacket and redistributes the heat through a radiator system.

Indoor wood-burning stoves

A biomass (wood-based) heating technology that captures heat of combustion of logs in metal or ceramic casing of the stove and passively redistributes heat to the surrounding airspace. Some stoves may contain a small fan that speeds distribution of heat to the surrounding space.

Particulate Matter

Fine liquid or solid particles such as dust, smoke, mist, fumes, or smog, found in air or emissions. It is usually separated into PM10 and PM2.5, which are particles of diameter equal to or less than 10 and 2.5 micrometers (μm), respectively.

Pellet

See biomass pellet.

Pellet stove

A heating device used in residential settings that utilizes biomass pellets or grains as the heating fuel source. Biomass pellets are combusted and heat is captured and distributed to the room space.

Pyrolysis

The breaking apart of complex molecules by heating in the absence of oxygen, producing solid, liquid, and gaseous fuels. a conversion method that involves heating a hydrocarbon source in the absence of oxygen to produce a black liquor liquid. The liquid can be refined and combusted in a turbine as well, for the production of heat and electricity.

Rutzke (rut-skee) Biofuel Mix

A biomass heating fuel mixture for use in pellet/grain stoves that contains a mixture of corn grain, wood or grass pellets and cherry pits.

Seasoned wood

Wood that is aged and dried over time (6 months to 2 years, depending on wood type and environmental conditions) through exposure to wind, rain, sun and natural drying conditions to remove moisture from newly harvested (green) wood. Seasoned wood produces less creosote and burns more cleanly than green wood.

Syngas

Syngas, short for synthesis gas, is a mixture of carbon monoxide (CO) hydrogen (H₂) and methane. It is the product of high temperature gasification of organic material such as biomass. Following clean-up to remove any impurities such as tars, syngas can be converted to liquid biofuels such as synthetic diesel (via Fischer–Tropsch synthesis).

Thermochemical Gasification

A process operated at elevated temperature that converts a solid feedstock into a gaseous fuel, while maximizing the chemical energy content of the product gas.