The use of C&D wood as a fuel product is a common end market for mixed C&D recyclers, and an underpinning to the economic feasibility of many an operation. The use of the wood is also environmentally sound for a variety of reasons, including those outlined in a study performed by the University of New Hampshire. One of the best of those reasons is the fact that by using the wood, there is a net loss of emissions of greenhouse gases because the wood fuel replaces oil, gas or coal as the energy source. It is true the wood will emit GHG when used as fuel, but it would have let that gas go anyway if left in the forest when a tree dies. By replacing the fossil fuel, the greenhouse gases those would emit stay sequestered with the mineral in the ground. Plus it just makes common sense. I mean, what do you burn in your fireplace? This makes C&D wood a raw product, one that should not be defined as a waste.

But there is great resistance in the environmental movement for incineration of waste for use as fuel. It is complicated, but there are two basic objections: The use of waste as fuel hurts local recycling programs because it deverts some materials that could end up recycled into higher end uses away from that option, and there is concern about emissions, not just GHGs but other substances, into the atmosphere. In Europe, waste-to-energy (WTE) is pretty common. Other factors help bring that around, including high tipping fees, very robust recycling programs that remove more from the waste stream before the fuel stage, strong national government support and strict emission control standards that require the top technology on the stacks from the power plants.

So while the waste as fuel debate is going on in North America, unfairly or not, C&D wood fuel is being lumped in as just another WTE subplot. That really should not be, if only because of the higher Btu value kiln-dried wood brings. Of course, emissions can be an issue, but today’s emissions control technology renders that point moot, very little is emitted when using the proper technology.

Despite its advantages and differences from traditional WTE, C&D wood is getting a bum rap by being considered the same. It should be recognized differently. One promising development for the use of C&D wood, and which may be more acceptable to environmental groups, is the rise of gasification systems. Different people have different definitions of gasification, but basically if it uses heat on the fuel, it isn’t gasification. Many of these systems are still on the drawing board or in other stages of development, but because they can take a diversity of materials, even perhaps post processing residue from C&D facilities.

The bottom line is C&D wood should be considered a preferable biomass fuel, especially by those who supposedly espouse pro-recycling views. Otherwise, the economic viability of many mixed C&D plants is threatened.

William Turley
C&D World Associate Publisher & Editor
CMRA Executive Director
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