Green Hearth Products Fuels

An Introduction

Green hearth products (fireplaces and stoves) can use a large variety of fuels or energy sources. These fuels can be used in a more environmentally friendly manner, or used wastefully. Hearth product fuels are not unlike gasoline that can be used in smaller, more efficient vehicles, or used wastefully. Also, each fuel provides a different mixture of environmental characteristics, unique to that fuel. The overall environmental impact of a particular fuel is a combination of the environmental characteristics of the fuel and of how the fuel is used. Hearth products fuels include the following:

Natural Gas
Propane
Cordwood
Wood Pellets
Fireplace Firelogs
Wood Stove Firelogs
Coal
Oil
Electricity

Natural Gas

Natural gas is the most environmentally friendly of all the fossil fuel energy sources. Additionally, it has a relatively small carbon footprint from its processing and transportation. Natural gas also produces less CO2 per unit of energy produced than other fossil fuels. Natural gas turns out to be a very efficient heating source when burned in a high efficiency fireplace or stove, relative to most ducted central heating systems. The overall efficiency of a typical gas fireplace can be 70% or more, while a typical ducted, central heating system is 50% to 60% due to duct losses and due to heating rooms not in use.

Many times natural gas is burned in open fireplaces that have “gas logs”. This use of natural gas is not green, but it is primarily for entertainment, not heating. Natural gas logs can be considered green however, when they are used with glass doors to replace burning wood in a typical open, wood burning fireplace. Without gas logs and glass doors, burning wood in these fireplaces produce huge amounts of particulate matter and typically make houses colder than when the fireplace is not used at all.

Propane

Propane is essentially the same as natural gas in many environmental features. There are some differences however. Being a distillate of oil, propane has a larger carbon footprint from its manufacturing and processing than natural gas does. Additionally, propane has a larger carbon footprint from its transportation than natural gas does.

Cordwood

Cordwood is a unique fuel in that it can be very environmentally friendly or not, depending on how it is used. Wood, like any other biomass material is both a renewable and sustainable energy source. Additionally, it is essentially carbon neutral, producing no net increase in greenhouse gas emissions. It also has a very low carbon footprint from processing and transportation. Wood also is renewable, sustainable; essentially carbon neutral producing no net global warming and has a small carbon footprint from processing... wow it’s a wonder fuel! But, there is a catch. Wood is not a practical heating energy source for homes on small lots and in larger cities because of availability and storage requirements. Additionally, burning wood in open fireplaces and old, uncertified stoves wastes much energy, which is seen in the volumes of particulate matter that come from chimneys. There are some rural air sheds where this may not be an issue, but their heavy amounts of PM10 particulate matter is a big problem in most areas and is unacceptable in green homes. Wood however, can be burned in certified, clean burning stoves, inserts and fireplaces and produce no visible smoke. In fact, the rate of particulate matter that comes from a good certified wood stove is about equal to the amount of particulate matter that wears off the tires of a full sized car traveling at 55 mph.

So, the key issue is that in green homes, only certified clean burning appliances should be used when wood is the fuel. Additionally, wood must be used properly. Wood, like automobiles is susceptible to operator error. It’s important that wood be dried for a year and always kept covered before it is used. Also, these certified clean burning appliances should always be operated with sufficient combustion air in accordance with owner’ manuals.

Wood Pellets

Like cordwood, pellet fuel is a renewable, sustainable, clean burning, essentially carbon neutral producing no net global warming heating energy source. They are a cost stable home heating alternative currently used throughout North America. Pellets are a biomass product made of renewable substances – generally recycled wood waste. There are approximately 800,000 homes in the U.S. using wood pellets for heat, in freestanding stoves, fireplace inserts and even furnaces. Pellet fuel for central heating can also be found in such large-scale environments as schools and prisons. North American pellets are produced in manufacturing facilities in Canada and the United States, and are available for purchase at fireplace dealers, nurseries, building supply stores, feed and garden supply stores and some discount merchandisers. In short, pellet fuel is a way to divert millions of tons of waste from landfills and turn it into energy. Wood pellets have a much lower moisture content than cord wood and are burned in appliances with forced combustion, resulting in higher efficiencies and cleaner burning than wood stoves. Pellet fuel also has a great, green future in that it can be manufactured from forest thinning and from other kinds of biomass materials. The above information is provided in part by the Pellet Fuels Institute.

Unlike bio-fuels like ethanol, pellet fuel is a very green heating energy source that produces a significant amount of heating energy relative to the energy used in its production and transportation. But, no fuels are perfect. Wood pellets are not good energy sources in some homes. They have some handling and storage limitations and the appliances have important maintenance requirements. Residential pellets are only available in 40 pound bags and they must be stored in a convenient, dry environment. The bags do take storage space in homes or garages. Appliances burning pellets also need more cleaning and maintenance than those burning gas or wood. Appliance cleaning and maintenance is essential in maintaining high efficiency, clean burning performance. For most residential situations, pellet handling, pellet storage and pellet appliance maintenance are not big issues. All in all, pellets remain a very desirable and affordable green heating energy source for green homes. The advantages of pellet fuel will continue to grow as fossil fuels increase in price and as consumers begin to understand the environmental advantages of pellet fuel heating.

Fireplace Firelogs

Firelogs are man made logs, designed to be burned in open, wood burning fireplaces. While open, wood burning fireplaces are not green, the conversion to using firelogs instead of wood makes a dramatic improvement in all green aspects of open fireplace operation. They also burn efficiently enough to provide some usable heat.

 

Firelogs are made of wood scrap and recycled agricultural biomass materials. They provide dramatic reductions in fireplace emissions because of their very low retained moisture. They provide dramatic reductions in carbon monoxide and hazardous air pollutants over cordwood. They are also a renewable and sustainable energy source, like wood pellets and cordwood. The best firelogs are now being made with organic wax and use no petroleum binders or additives. Good firelogs also have deep grooving in the extrusion that provides cleaner burning and quicker start-ups.

A feature that makes firelogs so environmentally beneficial over cordwood comes from their very low moisture content. This requires that the firelogs be stored in garages, sheds or homes if they are to maintain their performance advantages. But being much denser than cordwood, firelogs do take up less space than cordwood. All and all, firelogs provide a dramatic improvement in all aspects of open fireplace operation and they provide significant air quality advantages over cordwood.

Wood Stove Firelogs

Firelogs for wood stoves are a special type of firelog. They are made from pure wood waste materials and are manufactured without any additives. Firelogs that contain any wax or petroleum additives should NEVER be used in wood stoves because the additives will cause severe overheating and structural damage to wood stoves.

All the environmental and performance advantages listed above for fireplace firelogs are the same for wood stove firelogs. Storage needs are also the same in order to maintain their low moisture level.

Coal

Coal is an abundant and practical heating source in areas of America where it is available, but it is not a very green residential heating source. It’s a non-renewable fossil fuel that emits excess amounts of CO2, excess particulates and some amounts of mercury compounds, relative to natural gas when burned in stoves. Mercury and particulate emissions can be scrubbed and CO2 can be sequestered when coal is burned in advanced technology electrical power plants. So coal may become a better fuel for utility companies, but not for home use where there is the option for natural gas, cordwood or pellets as a heating source.

Oil

Oil has many of the environmental disadvantages of coal as described about coal above, in addition to it’s ever increasing cost and increased dependence on foreign sources. Oil is not a green heating source, particularly when natural gas, cordwood or wood pellets are available. Oil, like propane and coal, has the disadvantage of a relatively large carbon footprint from processing and transportation relative to greener heating sources.

Electricity

Electricity is obviously not a fuel, but an energy source. There is a significant misunderstanding about the efficiency of electric heat. While electricity is very valuable for many uses, it is not a green heating source even though the “in home efficiency” is 99%. In fact it’s a poor heating source because almost all of it comes from the combustion of coal or natural gas delivered at very low overall efficiency to residences. The US Department of Energy states that the average efficiency of our combustion based electricity delivered to a home is about 20%. Why not burn natural gas directly in a 70+% efficient hearth product. In the future, electricity could become a better heating source if the vast majority of electrical generation came from renewable or nuclear sources and not fossil fuels.