Archive for the ‘Fuel consumption’ Category

Home heating and the environment

Monday, August 23rd, 2010

Eighty percent of the #2 heating oil burned in the U.S. is burned in the Northeast.  We have adapted well to a fuel that was plentiful, easy to distribute, and easy to consume.  Much of the world, and a growing number in the Northeast,  have recognized that the patterns we’ve grown accustomed to are unsustainable. Roughly 85% of the energy we use in our homes in the Northeast is used for heat and domestic hot water.

Pellet-fired central heating has some distinct economic advantages for our region.  Retaining money spent on home heating energy in the region can only mean good things for employees in our region.  In truth, the economic possibilities for our region from a significant shift from fossil fuels to renewable, biomass heating are breathtaking.

Thoughtful people looking at conversion from fossil fuel heating to wood pellet heating quickly ask three  questions:  what about atmospheric carbon, what about combustion emissions, and could our forest sustain more home heating with wood and remain healthy?

Let’s look at those questions.

What about atmospheric carbon?

Nearly everyone is concerned with the increase in atmospheric carbon that has occurred in recent decades.  While some argue that the Earth’s populations will be in trouble if atmospheric carbon concentrations exceed 360 ppm, current carbon concentration is approximately 390 ppm.  The rapid, dramatic increases in atmospheric carbon concentration have arisen largely from human combustion of fossil fuels which releases carbon that has been “stored away” in fossil form for millenia.

The prevailing wisdom has held for some time that burning wood does not significantly increase greenhouse gas carbon dioxide because the carbon stored in the trees is part of the active carbon cycle.  That is, the carbon emitted from burning wood as carbon dioxide was removed from the atmosphere by the growing tree and will return to the atmosphere whether the tree is cut and burned or dies and decomposes. Green plants will again take up the carbon and the cycle will repeat.

Recognizing that fossil fuels are utilized in harvesting and transporting the wood and pellets has led to the widely accepted claim of  70-75% carbon neutrality for the combustion of wood pellets for heating. The US Environmental Protection Agency made the following statement in 2010:

“Although the burning of biomass also produces carbon dioxide, the primary greenhouse gas, it is considered to be part of the natural cycle of the earth. The plants take up carbon dioxide from the air while they are growing and then return it to the air when they are burned, thereby causing no net increase.”

What about emissions?

There is no sulfur and little nitrogen in biomass. During combustion AutoPellet boilers produce no sulfur oxides,  less nitrogen oxides and less carbon monoxide than oil or gas boilers. They also produce very little particulate matter but a bit more than oil or gas boilers (oil boiler .007 lb/million BTUs, AutoPellet .019 lb/million BTUs).  This performance has the AutoPellet systems achieving the very demanding standards that the EPA is proposing for biomass boiler systems.

Could our forest sustain more home heating with wood and remain healthy?

Currently Maine alone has the mill capacity to produce over 300,000 tons of pellets per year.  Many of those pellets leave the state because there is not a sufficiently large local market for their consumption.  300,000 tons of pellets would heat more than 33,000 typical New England homes, so, if the pellets stayed in the State, 7.5% of Maine’s oil-burning homes could be heated now with today’s local pellet manufacturing capacity.

The Northeast is heavily forested and traditional consumers of harvested wood have been consuming less and less material for decades.  In 2009, following a substantial 2008 run-up in oil prices, Maine Governor John E. Baldacci commissioned a task force to study the issues surrounding greater use of wood for thermal energy in Maine.

The Wood to Energy Task Force considered a 10% conversion of residential heating in Maine to pellet heating over the decade.  In looking at longer term forest products implications, the Task Force drew on the “Maine Forest Service Assessment of Sustainable Biomass Availability: Absolute Supply is not the Issue” in concluding “…there can be enough wood in Maine in 20 to 30 years to eventually make a significant proportion of Maine’s homes and businesses independent of imported oil without a demand induced scarcity of forest-based raw material and thus without a demand induced price rise even if the pulpwood demand remains constant.”

The answers to the three conscientious questions are all well-considered and positive answers.

  • Atmospheric carbon emissions will be substantially reduced by those who switch from fossil fuel burning to pellet-fired central heating.
  • High quality pellet boilers have very favorable emissions profiles reducing sulfur and nitrogen oxides and meeting, or exceeding, very stringent EPA proposed rules for particulate emissions.
  • There is an ample pellet supply in Maine today to convert more than 30,000 Maine homes to clean, renewable, locally produced pellet fuel.

The author is the managing director of Maine Energy Systems, which imports and assembles OkoFEN pellet boiler systems.  He can be reached at dutch@maineenergysystems.com

Posted in Environmental issues, Fuel consumption, Pellet burners, Pellet fuel, Uncategorized, Wood pellet boiler | No Comments »

Heating fuel prices

Tuesday, May 4th, 2010

There are all sorts of strategic, environmental, and regional economic reasons for large segments of the population in the Northeast to switch from fossil fuels to renewable wood pellet heating for their homes and businesses. Reasons like

  • reducing dependency on foreign oil,
  • reducing carbon footprints, and,
  • spending heating dollars for our own products.

    • In the world outside the heating industry, these are good, noble ideas that would be nice to embrace if there were ways to adopt them that made personal financial sense.

    The good news is the spread between pellet pricing and heating oil pricing is growing as oil in Maine rests somewhere near $2.80/gallon and bulk delivered pellet prices have been reduced to $220/ton delivered. $220/ton pellets are the cost equivalent of $1.83/gallon heating oil. At today’s prices, a home using 1,000 gallons of oil a year would save approximately $960/year on heating and domestic hot water.

    Maine Energy Systems, a regional distributor of bulk pellets, has reduced its delivered price to $220, and has reversed last year’s policy of setting prices for the year. Last year’s effort to assure users of pellet availability and price stability had MESys hold onto its $280/ton price into the spring. As mill prices dropped, it became clear to us that despite our intention to reassure the market about stable pellet pricing, this practice was not in the best interest of the market.

    Going forward, we plan to adjust prices periodically to reflect the mill prices we pay for the pellets. With ample production capability in the region and a somewhat depressed international pellet market, we don’t anticipate significant changes in bulk pellet prices over the coming months.

    The picture continues to improve for those who seek financial justification for doing the “right thing” on so many other fronts.

    The graph linked below has fascinated me for some time. Whether it’s precisely correct or only conceptually correct, we were born into the single period in world history when all of the petroleum will be consumed.

    longperiodgraph

    Dutch Dresser

    In the interest of disclosure, the author is the Managing Director of Maine Energy Systems, in Bethel, Maine


    Posted in Fuel consumption, Pellet fuel, Uncategorized, Wood pellet boiler | No Comments »

    Lessons along the way…

    Wednesday, February 3rd, 2010

    In the interest of full disclosure, the author is a Director of Maine Energy Systems, in Bethel, Maine.

    As one of the leading developers of the residential biomass heating industry in the United States, we’ve learned a lot of lessons along the way. As the owner and operator of a pellet-fired residential boiler system, I’ve learned a lot of lessons along the way as well. Following are a few of the lessons we’ve learned.

  • Sizing of boilers is still a bit mysterious, but the picture is clarifying somewhat. It is the American practice to oversize boilers because cost differentials between boiler sizes are relatively small and contractors don’t want to risk “I don’t have enough heat” phone calls. We have been told by Europeans since we began this venture to size boilers smaller than heat loss calculations would suggest are necessary. That’s a hard sell. However, we are routinely seeing boilers sized to match calculated heat loss running on shorter cycles than are ideal suggesting that smaller sizing was, in fact, in order. We will try to quantify the size reduction that would lead to most efficient use of this technology. In my own case, a purposefully undersized boiler (51,000 BTU/hr vs heat loss calculations of 106,000 BTU/hr) carries the house’s heat and DHW needs until the temperature gets down to 0 fahrenheit. When that point is reached, I can either accept a boost from my old oil boiler or accept the fact that 65 Fahrenheit is the best I can do in my kitchen. One of these days I’ll change my pellet boiler to a 25KW unit (85,000 BTU/hr)
  • Pellet durability is fundamentally important to the success of bulk pellet installations. The pellet mills with which we’ve worked along the way have been very good about ensuring durability of pellets in excess of 98%. This improvement has made a tremendous difference in fuel system dependability.
  • Ash removal cycles result from the complex relationship among boiler efficiency, pellet ash content, and quantity of pellets consumed. Different burner types also create different amounts of waste. Whether ashes are removed from the boiler directly, as with more basic systems, or from ash storage containers, as with more modern systems, the remove cycle calculus must include all of those elements to be at all predictive.
  • Burner system modulation results in reasonably stable boiler temperatures and reduces fuel consumption. The well-established pattern of having burner output follow heat demand provides the same efficiencies that “highway driving” affords automobiles. Cold starts are not part of the picture with modern pellet boilers.
  • Pellet deliveries smell good!

    • Posted in Fuel consumption, Pellet boiler maintenance, Pellet burners, Pellet fuel, Wood pellet boiler | No Comments »

    Needing more heat

    Thursday, January 7th, 2010

    As I’ve reported in earlier blogs, my large, old farm-style house in Bethel, Maine, was heated experimentally last winter with a four-section pellet-fred boiler. The Janfire-fired system is rated at 23 kilowatts, about 51,000BTU/hour. The system heated the house to our satisfaction pretty well last winter with the exception of a few “design days” when outside temperatures dropped below zero. On those days, we were faced with a house at, or below, 60 degrees F, or burning a bit of oil to support the pellet boiler.

    During this past Christmas seasons, my 86 year old mother joined us for two weeks. Our standards for suitable heating (67F, or so) didn’t work for her, so we needed to try to keep the house at 70F at a minimum. The little boiler fired at capacity much of the season to meet the demand and was generally successful. However, on days when single digit to sub-zero temperatures struck, there was no way. The boiler is just too small to fill that demand largely due to heating time lost to the ashscraping cycle of the top-fed burner. To meet the need, I set the oil boiler to fire when water temperatures dropped to 160F. All worked well; the boiler fired occasionally, generally following an ashscrape cycle when water temps would drop below the target level. My mother was warm and little supplemental oil was burned. During the past heating season, I used a total of 40 gallons of supplemental oil.

    It is my assumption that a small boiler of the same capacity of an underfed burner design that did not require lost time to ashscraping would meet my demand without support from the oil boiler. It would be fun to test the assumption.

    Because I’ve been able to use an extended ashscrape cycle due to the improvements in pellet quality, I haven’t been cleaning my boiler as often as I did last year. That’s been a mistake. In this particular Bosch/Janfire system there is ample opportunity in the cast iron boiler for ash to reduce boiler efficiency. I’ve returned to a two week cleaning cycle for this boiler to keep efficiency up and pellet consumption down.

    In the interest of full disclosure, Dutch Dresser is the Managing Director of Maine Energy Systems which sells both the Bosch/Janfire system referenced here and the more advanced AutoPellet systems made under license from OkoFEN of Niederkappel, Austria.

    Posted in Fuel consumption, Pellet boiler maintenance, Small boiler experiment, Wood pellet boiler | No Comments »

    It’s just different…

    Friday, March 13th, 2009

    In the interest of disclosure, I am a principal of Maine Energy Systems, distributors of the MESys wood pellet fired boilers.

    I’ve now been through the heart of the Maine heating season with an undersized pellet boiler in my house, and I’m always prone to reflect upon changes like that.

    In simple summary, when comparing heating with oil to heating with wood pellets, I’d say it’s just different.

    I’m a pretty typical American. I got just a little bit interested in our home heating system four years ago when it was time for a new system. The beautiful Buderus oil boiler tickled me, and I was fully impressed by the substantial savings in oil consumption I enjoyed over use of the old Burnham that it replaced. That fascination consisted more of looking at fuel bills than of looking at the boiler…it required none of my attention and got none.

    When the MESys 4000 went in my house last fall, I was fascinated with it for technical, economic, and environmental reasons. It was a mechanical thing that I could understand just by looking at it. As the winter went by, I learned about not just the little boiler, but also about our family’s heat using patterns and how they can be seen in circulating water temperature.

    Because I was intrigued by the boiler, I checked it often, noted the modulation level it was running at and the water temperature it was maintaining relative to the target. I listened to it through its various modulation levels, through start up, and through the ashscrape cycle. I got so I could tell what it was doing by opening the cellar door and listening. For me that was fun.

    I also learned about its needs relative to cleaning. I started out cleaning out the boiler pretty often, just to get an idea about how the different pellets were burning. When I decided to let it to until ash stopped it, I learned that with the pellets I had a ton of pellets burned would surely stop it. I fell into the habit of cleaning it out every other Sunday afternoon; it took a half hour, and I kind of enjoyed it.

    Over the course of the winter, I took great pleasure in looking at my small, newly lined, chimney and noticing only hot air coming from it while nothing came from the large front chimney where the oil boiler vented.

    As I’ve noted in earlier posts, my boiler is decidedly undersized for my house at 51,000 BTU/hour for a house with a calculated heat loss of 106,000 BTU/hour. My small boiler heated my house and my domestic hot water to comfortable levels all winter except the days when the temperature dropped below -5F. During those days, the oil boiler would “help out” when boiler water temp dropped below 140F, a completely arbitrary set point I chose. Today, I decided that I wouldn’t be burning anymore oil this year, so I asked my oil dealer to top up the tank while prices are low; I’m afraid they were upset to put only 41 gallons in my tank. With those 41 gallons, I received 7.4 tons of pellets and have approximately 2 tons in my bin. That puts my fuel consumption at the BTU equivalent of about 690 gallons of oil, for the October to mid-April heating season. That is lower than usual despite a cold winter. I’ll have to wait until I can compile a calendar year’s worth of data, but it appears at this time that the manufacturer’s assertion that a boiler which is working at capacity most of the time is much more efficient has proven to be the case in my situation.

    Now when I talk to people about pellet fired central heat, I always make it a point to say, “it’s just different” than heating with oil. You will have to understand your heating system a bit; you will have to clean the boiler from time to time (for me every two weeks); and, you’ll become much more aware of how your using your burning fuel.

    I like it, but it’s just different in a pleasant sort of way.

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    Posted in Fuel consumption, Wood pellet boiler | No Comments »