I’ve been learning a bit about wood powered boiler heating over the last few months and I think I now have a handle on the various issues the wood biomass business faces. The two biggest? Genuine concern over particulate emissions and ... wait for it ... you know I’m going to say it ... NIMBYs.
Sad but true, it turns out that if local regulation changes or the tight wood pellet market or rising steel costs don’t do you in the blood loss from the various NIMBY’s gnawing on your ankles will.
When wood burns it isn’t really burning, it’s turning to gasses first, then they burn; particulates are the result of incomplete combustion. There has been a steady progression in technology in this area, from fireplace to Franklin stove to the current state of the art – outdoor systems that either burn wood, gasify seasoned, split hardwood, or run on wood pellets.
When I write "burning wood" what I’m talking about is a mix of green and seasoned hardwood and softwood. Systems that do this produce varying levels of particulate output, quite a bit when starting unless they’ve got oil or propane assist to get them hot, and then much less once they’re running. This is a popular option for loggers, farmers with woodlots, and other operations that have access to both types of wood and the equipment to handle it. This is also the worst, environmentally speaking.
Wood gasifiers are clean, cleaner than a small, indoor, EPA rated pellet stove. They’re also the most demanding to operate – nothing but dry, split hardwood. If you’ve got a good supply of oak or ash these are the type of machine to get. As you can see from this truckload the gasifier units in front, Central Boiler ECL 2300s, are literally crowding the older wood boiler models out.
Pellet boilers are the easiest to operate and are rumored to be just as clean as the gasifiers; a lack of EPA standards for emissions and for how to test emissions is holding the whole field back. The ease of operation stems from the nature of the fuel itself. Any wood at all after passing through the hammer mill and extrusion process ends up being a very dense, very dry sort of "super hardwood". Unlike the wood powered systems pellet powered systems can have a large hopper or an external silo with a auger to feed the combustion chamber. Instead of a daily loading job, perhaps restarting the fire, attention is more likely to be a monthly affair. The pellets can be delivered in easily handled forty pound bags for those using a hopper or a bulk truck may deliver them directly to a silo, just as animal feed is delivered to large farming operations. These Wood Master outdoor pellet boiler units can handle a large house and a sizeable shop or garage with ease.
Given what is going on in the oil market this is going to need attention sooner rather than later. There are massive biomass resources available in New England and the Pacific Northwest but right now a municipality can blanket ban anything that goes outdoors and burns anything, killing off dozens of clean pellet systems over one badly behaved wood boiler. This has to be handled in an orderly, professional fashion at the federal level, with defined standards for emissions, defined testing procedures, and perhaps we’ll be seeing new systems with electrostatic precipitators and retrofit kits for existing systems in the field. We, as a nation, are in a time when much needed moves away from fossil fuels must not be blocked by a handful of misguided actvists.