How Wood Is Used for Energy


Metapolisz Images through Wikimedia Commons

Doesn’t that fire look inviting? So what’s the scoop on firewood?

According to John Zerbe and FPL’s Mark Knaebe of the Forest Products Marketing Unit, cordwood is the most common kind of wood fuel we like to burn. The most common way of using cordwood for fuel is to burn pieces about 1–1 ½ feet long that are split from logs. We burn much of such wood in our fireplaces and wood stoves today, and, formerly, such firewood provided the main fuel source for home heating, domestic hot water, and food preparation. Wood is still used for heating some homes in industrial countries. Usually heat is not produced efficiently in fireplaces, but some fireplaces are sealed with glass doors and designed to use blowers to be more effective. Stoves and furnaces burn firewood more efficiently and are getting much cleaner.

However, for some applications, wood is converted to other forms of fuel that are more convenient, waste less energy, and are less prone to emit undesirable particulates and other pollutants to the air. Examples of other kinds of fuel are manufactured fireplace logs (firelogs), which are made from waste wood and wax to provide open-hearth warmth and ambience with clean fuel. More recently, however, the main alternative to cordword is wood pellets, the main advantage of which is their dryness and their ability to be automated.

Energy from Wood: An Introduction


Wood is renewable energy, as this circle indicates.

Brrrr! Here in Madison, Wis., home to the Forest Products Laboratory, we’re having some very cold temperatures. Doesn’t a wood fire sound comforting?

And as nice as a fire sounds in this neck of the woods, what about the use of wood for fuel in other parts of the world? Sifting through the words of wisdom from FPL retiree John Zerbe, let’s delve into his overview of wood as a fuel and source of energy from the Encyclopedia of Forest Sciences.

Zerbe informs us that wood and charcoal are the predominant fuels for heat and food preparation for the majority of citizens in most developing countries. In those countries, wood fuels are also important for powering small- and medium-size industries. Moreover, energy from wood continues to be important in industrial countries.

Wood energy is consumed in a variety of forms that include fireplace lengths, chunkwood, chips, sawdust and shavings, black liquor from pulp manufacture, pellets, fireplace logs, briquettes, charcoal, gasified wood fuel, and liquefied wood fuel. Wood provides warmth and comfort to homes via burning in fireplaces and automated heating systems. And even in industrial countries, wood is used for cooking where it is burned in specially designed stoves for convenience or on grills to bring out special flavors in food.

Wood fuel is important to commercial wood manufacturing facilities where waste wood can be disposed of and used profitably for energy at the same time. Some major considerations in using wood for fuel are environmental impact, economics, convenience, reliability, and simplicity. On balance, wood is an environmentally benign fuel. It tends to be more economic than some other fuels, but may be less convenient, as anybody who has cut and stacked their own firewood knows.

Here at FPL, we love to say “Wood is good.” In future posts, we will go on to discover the many ways wood is good for producing energy.