Good, Bad and the Ugly in Wood Pellet Appliances

Biomass burning heating systems inherently have several facets just like in the popular movie and expression the good, bad and the ugly. The most widely used fuel product of biomass combustion for heating is wood pellet and wood chips. The good side of the pellet stoves is worth pitting against the bad and the ugly. This exercise will give you an idea why the SEAI in their Home Energy Saving Scheme is willing to award grants up to Euro 2,500 for a Boiler installation, Euro 800 for a Stove installation and Euro 1,400 for a Stove with integral Back Boiler installation.

The good side of Wood Pellet burning appliances

Here are some interesting facts in favour of Wood Pellet appliances.

  • The pellet stove and boiler are still simple devices. There is a storage container or a hopper which feet the solid bio-mass fuel in to an auger which conveys the fuel to a burn pot. By adjusting the speed of rotation of the auger a steady and regulated fuel feed is ensured.
  • Modern units while being attractive also utilizes microprocessor controls, thermostats etc and automatic ignition and shut down, for user friendly operation. They are also therefore available as remote controlled units which recycle on the operation of a thermostat.
  • The fuel is made out of waste material and the raw material prices are cheap. Only the vendors of the final product engage in overprizing etc. most of the time in order to make a quick buck.
  • The fuel is pure bio mass and therefore has a very low carbon foot print. Naturally bio mass is a renewable fuel.
  • The efficiency of modern microprocessor controlled pellet stoves is as high as 90%. In many countries the users are provided with special incentives like tax rebates and grants even when the efficiency is anything over 75%.
  • Still the wood pellet price is reasonable while only a few months back fossil fuel prices peaked indiscriminately creating economic chaos everywhere.
  • The wastage in transit, handling and storage of wood pellets is high. The manufacturing costs too are high. In spite of this the prices are reasonable at present.
  • The raw material is a resource locally available and therefore the manufacture is not hampered greatly by external influences of petroleum producers etc.
  • Some pellet stoves can burn not only straight wood pellets but also mixtures of it with corn, sunflower seed, wheat and cherry pits.

The Bad and the Ugly of Wood Pellet burners

The bad side too is interesting.

  • Unless properly maintained and the system is well designed, the emissions of green house and toxic gases may take place. Many European countries have strict regulations regarding this.
  • The carbonaceous solid fuel produces a lot of ash and has to be cleaned regularly. This of course is dependent on the quality of fuel used as well. The use of premium grade fuel may result in less than 1% ash residue. On the other hand use of low grade wood pellets may produce up to 4% residual ash.
  • The product is hygroscopic. The European Norms specify maximum moisture content at production. However during transport and storage wood pellets may absorb moisture lowering its quality. The combustion in the stove or boiler may not be therefore complete and as a consequence inefficient while producing considerable smoke during the process.
  • The powdery nature of the raw material, wood work waste, is considered an explosion hazard like all other powders.
  • The readily perishable nature of the wood pellets makes it necessary to have a well protected storage room which makes the initial cost of installation high.
  • The total wood pellet requirement for an year is purchased in the hot season in the early parts of the year when the prices are low. This quantity runs into several tons even for an average home.
  • If the pellet stove is not cleaned and maintained regularly the tarry black, combustible, sticky substance known as creosote will accumulate in chimneys and may cause chimney fires.

Who can avail the Bio Mass Stove / Boiler Grants?

According to the terms and conditions of Home Energy Saving Scheme, the following Bio Mass burning stoves and boilers (and complying with the rest of the terms are eligible) for the grants.

  • Individuals who are home owners
  • Installing eligible products, in this instance a new wood chip / pellet, boiler or stove with back boiler or a stand alone stove (using the same fuels) and also wood gasification boilers.
  • Using installers who are registered with the SEAI for the above work.
  • Individuals intending to retrofit or install a new renewable energy heating system in an existing home built prior to July 2008.