A good fire is an art. Not an earnest Boy Scout blaze, or a Viking pyre, it’s flame is velvety and seductive, a cobra’s mesmerizing sway. The roundabout transformation of sun and water into heat is fittingly magical and I do my best each morning to respect it.
Wood heat feels different. It’s radiant, which means heat transfers from the stove to the objects in the room, including people, without warming the air in between. The warmed objects radiate heat back out. So everything in the room feels warm. This is particularly pleasant to the body, which is radiant as well, continually losing between 500 and 1000 watts.
Wood is also a conscious heat. It’s a daily ritual of creation. It’s tactile. It’s often a shared experience that requires the collaboration of several people. In Colorado where pine beetles have ravaged the forests, it’s a local, abundant renewable resource.
While burning it creates CO2 just like burning fossil fuels, wood has lower net carbon emissions because trees absorb CO2 as they grow. Burning them is little different than letting them decompose in the forest (although we have to use trucks and chainsaws to get the wood ready to burn so it’s not perfect.) By contrast, coal, oil and gas release ancient carbon that would otherwise stay trapped in the ground.
But most interesting is wood’s efficiency in terms of energy returned on energy invested (EROEI.) EROEI is the ratio of the amount of energy acquired from a particular energy resource to the amount of energy expended to obtain it. Relatively recent research suggests that the diminishing return of EROEI is a chief cause of the collapse of complex societies, including Rome, the Mayans and Cambodians. In other words, the harder it is to get energy the more precarious the civilization becomes.
The chart below shows the EROEI of different energy sources (the tan colored parts of the bars represent the range of EROEI resulting from different source quality and processes.) Oil has been in steady decline since the 1930s, and as of the 2000s the EROEI of oil production is rarely as high as 20:1 and only going down. Wood can have an EROEI as high as 40:1 if you harvest on your own property and split with an axe. Only coal and some hydroelectric systems do better, and coal obviously has a lot of environmental downsides. (For more information on EROEI go here.)
Of course this calculation doesn’t take into account the time it takes to process the wood, which is significant. So you have to enjoy that part if you want to make wood work. Like biking to work, swinging an axe has benefits well beyond the end result of split wood. Regardless, the high human cost of wood heat makes it more appropriate as one component of a personal energy portfolio that includes wind and both hydronic and photovoltaic solar. Damnation Ranch is still working on that part.