Photo of VT Department of Environmental Conservation
Tom Powers, retired Air Force technical sergeant and member of Peruvian City Council, is monitoring a wide range of issues affecting this city in northeastern New York: zoning issues, local water supply, Road maintenance. In the past two years, one of the main items in his diary was the smoke plumes from a dozen wooden boilers in the backyard of the city.
A number of these wooden boilers are located in the hamlet of Peru, about 750 houses along the banks of the Little Ausable River. The others are scattered around the city, a sample of 80 square miles of rolling woods, farms and apple orchards about 10 miles south of Plattsburg. On a cold and matte gray day earlier this winter, all seemed to be in the process of operating, the lazy spiral in the descending clouds.
These exterior boilers burn wood – and almost anything else – and usually provide heat to one or more buildings at much less cost than it takes to heat a house or barn or greenhouse with Oil or propane, a growing disparity The cost of oil is increasing.
Smoke, however, is a very serious problem. Most exterior wood boilers are paramount from an engineering point of view – simply metal boxes surrounded by a small water jacket. The wood burns in the box and heats the water, which is distributed to the building. If it is inconvenient for the owner to cook the boiler, he can charge it with fuel every 12 to 24 hours or so and adjust the thermostat so that it produces a constant heat wire all day.
Burned in this way, the fire only crosses paper during much of its burning cycle, sending smoke out of the pile. The piers are usually fairly short, roughly half the height of the roof line of a two-storey house, which means that the smoke can form a hug near the ground. If there are neighboring neighbors, their homes may be invaded by smoke. The problem is exacerbated when operators burn green or wet wood or, worse, things like garbage cans or old tires that some do.
At the same time, potentially external boilers are a very cost-effective way to use firewood, which has enormous supply, particularly in the heavily forested areas of the northern US. In addition, burning wood for fuel is sustainable because wood, unlike coal or oil, is a renewable resource. Replacing these fuels with wood reduces the user’s carbon footprint and thus reduces global warming. And these boilers can be burned cleanly. Some producers have developed boilers with considerably reduced emissions and increased efficiencies. It is more expensive to install, but the savings from more efficient use of fuel help to reduce the initial investment.
These factors – the threat of low wood smoke, the prospect of significant financial savings and potential environmental benefits – have combined to constitute a highly controversial public issue. Some states, including Vermont and Maine, and later Michigan and Washington, have established strict constraints on boiler emissions. New York is currently developing a state-wide regulation. Meanwhile, many municipal governments, particularly New York and Massachusetts, have moved alone to regulate outdoor boilers.
In response, the boiler industry has mounted an aggressive campaign to protect its right to continue producing boilers of all types, including poorly designed and wetter units.
Heating with wood
For a process whose roots have fallen back into prehistory, burning wood to generate heat can be surprisingly complex. In this country we started with chimneys, where much of the heat went directly into the chimney, and then we moved to various types of stoves inside. The generation of wood stoves that appeared in the mid-1960s was not much more efficient than chimneys. The fact that they can be mitigated – deprived of a filling of air – meant that an owner could load them, stifle the flow of air, and then obtain a more or less stable heat flow for hours.
The choking of the air supply, however, is an inefficient way to get out of the heat from the fuel and also very dirty: these stoves generated a lot of smoke and pollution, and that was a major problem. In a city like Waterbury, Vermont, which is in a bowl of hills along the Winooski River, a winter inversion of temperature could trap the smoke near the ground and make the city almost uninhabitable.
In response to the public breathlessness on this issue, Environment (EPA) issued rules in 1988 obliged manufacturers of wood stoves to improve their products. Older cookers, pre-EPA certification, generally emit 40 to 60 grams of fine particles in the air every hour. Once manufacturers were required to meet EPA standards, the allowable limit was first set at 8.5 grams per hour; In 1990, this limit was cut to 7.5 grams per hour (4.1 grams for catalytic stoves). So to stay in business, manufacturers have completely redesigned wood stoves with catalytic converters or improved airflow to burn wood efficiently and cleanly.
These regulations, however, have exempted wood-fired central heating appliances, including outdoor wood boilers. When manufacturers have recently begun to accelerate the production of these devices, many of them have used the same inefficient box technology as forbidden interior stoves, which is simpler and cheaper to manufacture – and as smoked as Prohibited wood pits.
Even the cleanest wood stove emits pollutants, which can include soot, fly ash, creosote and heavy metals. These chemicals can be very dangerous in themselves, but perhaps the greatest danger of wood smoke is that the particles produced can be very small, smaller than 2.5 microns. One micron is one millionth of a meter and 2.5 microns is about one-20th of the diameter of human hair. When a person breathes these tiny particles, they penetrate deep into the lungs, bypassing the normal respiratory tract structures that catch larger particles. All particles less than one micron in size do not penetrate only the deepest part of the lungs but also directly into the bloodstream. A growing body of medical research shows that these particles are carcinogenic and dangerous to human health.
It does not necessarily have to be that way. There are outdoor boilers on the market that can burn wood with negligible emissions and a minor health hazard, producing even cleaner smoke than the new EPA certified wood stoves. One is the Garn Boiler, produced by the Dectra Corporation of St. Anthony, Minnesota. The Garn, which stands out in the air, resembles a miniature tank car, constructed of solid steel and well insulated. The main combustion chamber is a fairly small box that is inside a large pool of water that acts as a heat sink.
The air is sucked into the unit by a constant rotating fan and is divided into two streams before it enters an insulated combustion chamber. The lower stream passes through the burning logs and generates a very hot fire. The second flow passes over the combustion chamber and collects the volatile gases released by the combustion logs. This stream enters a secondary combustion chamber, where these gases are themselves burnt. The remaining exhaust, most of the water vapor, passes through a serpentine exhaust system that flows through the water basin, enveloping even more heat.
This kind of wood gasification boiler solves the problem of emissions by addressing the fundamental physics of the issue, namely that wood burning and heat storage must be treated in two distinct stages. In order for the wood to be burned efficiently, it requires a well insulated chimney with plenty of air circulation for high temperature combustion. For the resulting heat to be used effectively, it requires a large storage tank that can hold heat between the tie rods. Rather than burning, therefore, a Garn is burned warmer (and less frequently) than low-tech smoke boilers, whose design places a small tank of cold water directly against the chimney.
For comparison, the water tank in Garn boilers range from 1,400 to 3,200 gallons depending on the model. Those in the smoke variety range from 140 to 400 gallons. Efficiency ratings for both types of boilers confirm the Garn approach. According to the New York State Department of Environmental Conservation, the efficiency of the old outdoor wood boilers currently operating in the state varies from 28 to 50 percent, with an average of 43 percent hundred. This means that for every two logs you put on the fire, the heat of at least one full newspaper goes up the chimney. On the other hand, EPA-certified wood stoves increased from 68 to 72 percent, obviously much better. The efficiency of the Garn Outdoor boiler exceeds the EPA standard for wood burning stoves.
The friction, of course, is the price. According to Eric Johnson, Editor-in-Chief of Northern Logger magazine and moderator of an on-line discussion forum on wood-fired boilers, wood-burners range from less than $ 5,000 at the lower end to more than $ 10,000 for A Garn. “Keep in mind that there are significant installation costs for these boilers as well as the relatively high initial purchase price,” Johnson said. “You need to consider things like piping, a chimney or chimney, optional hot water storage, heat exchangers and other equipment and parts needed to assemble a wood gasifier to your existing home heating system . ” Johnson added that hot water storage is already included in the Garn design.
Since the 1970s, the air quality divisions of the six New England states plus New York and New Jersey have worked together as a group on solutions to emission problems. This group, called NESCAUM (Northeastern States for Co-ordinated Air Use Management) drew attention to wood boilers and developed a model rule that recommends that any government agency control outdoor boilers .
In essence, the rule is to make boilers approximately as clean as domestic EPA approved stoves. However, the appliances are not quite comparable, and NESCAUM and others interested in the outdoor wood boiler industry have developed a different set of measurement standards: internal wood stove emissions are measured in Grams of fine particles per hour, while outdoor boilers are evaluated in terms of Pounds Per Million BTU (British Thermal Units) of heat produced inside the boiler.
The NESCAUM emission standard was set at 0.44 pounds of particulate matter per million BTUs produced in the boiler (not delivered at home). The EPA has established a guideline (unlike a standard, a directive is not enforceable) for outdoor boilers of 0.60 pounds per million BTUs. Most of the regulations in force or adopted in the region use either of these two numbers. By 2010, the NESCAUM model also calls for an even stricter standard: 0.32 pounds per million BTUs.
These emission-level provisions are at the heart of the issue and controversial because once they have been passed by a state they would force a traditional smoke-furnace manufacturer to redefine its units or withdraw from the field .
As important as these NESCAUM constraints are, an equally important feature of the model rule is that it applies to manufacturers, not to those who buy and operate boilers. As with wood stoves, no one expects a government employee to examine the volume of smoke coming out of a garden pile. The rule provides that governments will put in place certification schemes to which manufacturers will have to comply in order to sell their units in that jurisdiction.
A rule incorporating much of the NESCAUM model comes into force in Vermont on March 31, 2008. The emission standard will be 0.44 pounds per million BTU and will improve to 0.32 pounds in 2010 The Maine law comes into force at the same time, but using the EPA emission standard of 0.60 pounds rather than 0.44. Maine, however, also goes to 0.32 pounds in spring 2010. Both states have shrinkage provisions and pile height.
Many cities in other Northeastern states, meanwhile, impose their own restrictions; These vary greatly in detail and efficiency. At least 20 cities in Massachusetts have instituted at least some controls. Several cities in the eastern Adirondack are among the more than 50 communities in New York who have already done so or are considering it. In early January 2008, for example, the City of Essex in New York passed a rigorous and multidimensional law for their community.
Ron Jackson, the City of Essex administrator, said the issue had been very controversial, but after several public discussions there was a strong consensus that something had to be done. The final ordinance was one of the strictest adopted by a single community.
In the countryside, any new boiler will have to meet the standard of 0.44 pounds per million BTUs. This will eliminate many units currently on the market. The operator will have to burn seasoned wood or other high quality fuels such as corn, wheat, soybeans or wood pellets. In the historic district, a hamlet surrounding the ferry dock on Lake Champlain, the boilers are completely prohibited; The reason, says Jackson, is that the houses are very close and at a low altitude, so that temperature inversions cause the presence of smoke in homes.
In the rest of the hamlet and running along the shore north and south of the ferry dock, there are withdrawal requirements. Any neighbor within 500 feet of a proposed boiler should agree in writing not to object. Finally, in this district – between open farmland and the historic district, most of the time, along the shore of the lake – the operation of the boiler would be prohibited from May to September.
Other cities continue to fight the problem. In Jay, a small town in the high peaks of the Adirondacks, Randy Douglas, the city’s administrator, said his community held a public hearing on the issue but did not decide what to do. They set up a committee to seek a compromise between supporters and opponents of regulation.
“One of the problems is what people burn in them,” Douglas said on the boilers. “You are supposed to burn dry wood … I saw with my own eyes that the black smoke was circulating out of them, and that led me to believe that they were burning something other than wood – construction debris or Rubbish, rubbish, rubbish, rubbish, rubbish, rubbish, rubbish, rubbish, rubbish or anything else.
The fact is that the development of regulations at the local level is particularly difficult, socially and politically. Tom Powers in Peru, New York, is very aware of this every day. There were half a dozen boilers in town in 2007, when Peru promulgated a moratorium on outdoor boilers and created a committee to work on it.
“I do not think the city wants to ban them,” he said. “I would not want to see them in the hamlet, but if they were in the backwoods, it would not matter.”
Members of the Town Hall know all the residents who operate the boilers in town, including in the hamlet. In a small town, it’s hard to say no to your friends and neighbors. This is true even if Peru is unusual in the local book law requiring that every Peruvian resident obtain a city permit before installing a heater even in the house. Of the dozen boilers now in town, only one has such a license. Will the city council oppose these illegal boilers? The powers simply do not know.
The battle gets warmer
Estimates of the number of boilers operating nationwide range from 150,000 to 200,000, with very rapid growth. There are dozens of manufacturers, many of them represented by a national trade association, Hearth, Patio and Barbeque, which has put in place a global defense of the right of its members to continue producing and selling even the More smoky. Lawyers for regulation, they charge, just try to prevent people from heating with wood.
The largest US manufacturer is Central Boiler, Inc., of Greenbush, Minnesota. Rick Kezar, director of sales and marketing for Central, refused to disclose the company’s conventional boiler emissions figures, one of the most popular units on the market, but he refused to believe he Was a problem. He also acknowledged that Central Classic boilers could not meet the 2008 Vermont or Maine emission standards.
Regulatory lawyers are saying that the enhanced standards will lead to very advanced technology improvements and that air quality will benefit. In fact, Dick Valentinetti, Director of the Air Pollution Control Division of the Vermont Environmental Conservation Department, notes that Central Boiler has designed a boiler that would qualify for certification under the new Law of Vermont. At the time this story was pressed, there was a question as to whether Central Boiler’s “E-Classics” were still available for purchase.
Valentinetti said he did not think there would be government action to eliminate former smokers who are already in place. Instead, they would be integrated. Adam Sherman, an analyst with Biomass Energy Resource Center (BERC) in Montpelier, Vermont, is concerned that manufacturers are dumping as many of their first boilers on consumers as possible before regulations take effect.
Phil Etter, Environmental Analyst for the Vermont Air Pollution Control Division, stated that there are a number of technical problems with emission testing and efficiency of wood boilers in full Air, but are being resolved. Once these are resolved, he says, there will be no problem in delineating high-quality boilers, with advanced technology, old smokers.
One of the most striking demonstrations that it is possible to generate heat in a sustainable and clean way with an outdoor wood boiler can be found at a place called Cobb Hill in Hartland, Vermont, a 270-acre farmhouse located in a hillside bowl A few miles west of the Connecticut River. Cobb Hill is a co-housing project, made up of about 20 families, about 20 adults and 20 children. On the valley floor, residents operate a farm that produces vegetables, turkeys, broilers, honey, maple syrup and a herd of Jersey cows that support a successful cheese company. Additionally, on the site is the Institute of Sustainability, which does research on system problems.
Residents live in a collar of houses climbing a steep coastline from Cobb Hill northwest of the bottom of the valley. The organization and ethics that guide the group reflect the vision of the late Donella Meadows, Systems Analyst at Dartmouth College, who was one of the co-founders of the project.
Roughly halfway up the hill, roughly in the middle of the dwellings, both duplexes and single family homes, is a low-rise building that houses a Garn wood exterior boiler and 60 cords of firewood. This boiler provides 85 percent of annual heat and hot water requirements for 19 single-family homes, three apartments and a community home. The remaining heat is supplied by the propane. A background calculation indicates that the annual cost is about $ 400 per family. By contrast, the federal energy information agency estimates that the typical heating cost per family in the northeast to winter 2008 will exceed $ 2,000. A fifth of the cost, and of course, the Garn produces minimum emissions.
The Cobb Hill boiler does exactly one social cost that could not be met by the ordinary residential boiler operator. The co-hosting group assigns a resident to monitor maintenance needs of the machine, checking for items such as its joints and other mechanical parts and watching the use of the fuel. The current instructor is a retired physician, Alan Keitt; He is supported by his predecessor, Phil Rice, an analyst at the Sustainability Institute.
In very cold weather, Cobb Hill residents add fuel to the boiler every hour for 19 hours a day, which is part of shared responsibility. The loading of the boiler, however, is very simple. Open the door, throw two or three pieces of firewood 30 inches on the bed of coal, close the door and you’re done. And the only boiler heats 23 family units.
“We could have got a pellet boiler (with automatic feed),” said Rice. “But the wood in pieces is local and it has much less energy embodied than wood pellets. You have to be careful what you do,” he continued. “If you simply want to turn on a thermostat, do not heat it with wood.When you handle the wood that heats your house, it closes a cycle in your mind. I think it’s critical. “
Rice said that getting the five-A.M. Change enriches his life. “It’s my time to see Orion, the great winter constellation, I see it at night when it arrives, then at 5 o’clock in the morning I see it fall, I see glorious things.”
That the outdoor wood boiler industry will also see glorious things remains an open question. The next few years will see more states and cities adopting regulations, while manufacturers will find new models to try to comply with these regulations. Outdoor wood boilers can still become the right answer to the best way to heat a home in the northeast – an area where these homes are surrounded by the fuel that heats them.
Hamilton E. Davis is a writer from Burlington, Vermont.