Wood pellets, ecological fuel or eco marketing?

Pellet is a heating product from the group of biofuels. It began to be produced at the end of the 20th century, became popular at the beginning of the 21st century, but it has been present on the Polish market for a relatively short time. Its most popular form is wood pellets, made of compressed sawdust produced during various types of work related to wood processing (hardwood, coniferous, exotic or mixtures). In order to use the full energy potential of this fuel, it is necessary to burn it in appropriate devices adapted to this type of heating products. Otherwise, it may turn out that most of the heat escapes through the chimney in the form of very hot exhaust gases, or we emit high-energy, unburnt gases into the atmosphere. Is it worth investing in special heating devices adapted to burn pellets? Is it an investment in ecology, or only in the efficient marketing of the lobby of pellet producers?

Is pellet an ecological fuel?

Each combustion process emits heat (which we care about), but also by-products: solid waste (ash) and volatile waste (exhaust gas). Of course, the less by-products, the better. Let's compare how wood pellets compare to other fuels.

Ash emission:

Wood pellet - burning one ton of pellets, we get from 6 to 10 kg of ash; ash obtained from pure wood pellets can be used in the garden as a high-quality mineral fertilizer;

Eco-pea coal - by burning one ton of eco-pea coal, we obtain from 60 to 120 kg of ash; ash requires proper disposal - it cannot be used by us and should be handed over to a specialized waste disposal company;

Walnut hard coal - by burning one ton of walnut hard coal, we obtain from 100 to 150 kg of ash; all ash must be disposed of (similarly as in the case of eco-pea coal);

Coke - by burning one ton of coke, we obtain from 80 to 120 kg of ash; all ash must be disposed of (as in the case of eco-pea coal and hard coal);

Natural gas - by burning one cubic meter of natural gas we will not have any solid residues.

To sum up: the amount of ash obtained after burning pellets is 10-25 times lower than in the case of other popular fuels. The exception is natural gas, which has no solid by-products when burned.

Exhaust emissions:

Exhaust gases (in other words: flue gases) are a mixture of gases produced in the process of combustion of various types of fuels. What amounts of undesirable and environmentally hazardous compounds are emitted into the atmosphere during the combustion of particular types of heating products?

Wood pellet - when burning one ton of pellets (e.g. from coniferous trees), we get 15-19 GJ of energy, and we emit:

• 0.02 kg of sulfur oxides SOx
• 0.8 kg of nitrogen oxides NOx
• 11 kg of carbon monoxide CO
• 2.50 kg of particulate matter

Eco-pea coal - by burning one ton of eco-pea coal (obtained from hard coal), we get 20 - 25 GJ of energy (slightly more than in the case of pellets), and we emit:

• 9.6 kg of sulfur oxides SOx (nearly 500 times more than in the case of pellets);
• 3.2 kg of nitrogen oxides NOx (4 times more than in the case of pellets);
• 10 kg of carbon monoxide CO (comparable to pellets);
• 10 kg of particulate matter (4 times more than pellets);
• 0.003 kg of benzo(α)pyrenes (when burning pellets, these substances are not emitted at all).

Walnut hard coal - by burning one ton of hard coal, we obtain approx. 20 GJ of heat (the amount is comparable to the amount of heat obtained from burning one ton of pellets), and we emit into the atmosphere:

• 14 kg of sulfur oxides SOx (700 times more than in the case of pellets)
• 2.1 kg of NOx (2.5 times more than pellets);
• 50 kg of carbon monoxide CO (almost 5 times more than in the case of pellets);
• 10 kg of particulate matter (4 times more than pellets);
• 0.015 kg of benzo(α)pyrenes (when burning pellets, these substances are not emitted at all).

Coke - by burning one ton of coke, we obtain approx. 24 GJ of thermal energy (slightly more than in the case of pellets), and we emit into the atmosphere:

• 12.8 kg of sulfur oxides SOx (nearly 640 times more than in the case of pellets);
• 1.1 kg of nitrogen oxides NOx (almost 1.5 times more than in the case of pellets);
• 25 kg of carbon monoxide CO (2 times more than in the case of pellets);
• 12 kg of particulate matter (5 times more than pellets);
• 0.0001 kg of benzo(α)pyrenes (when burning pellets, these substances are not emitted at all).

Natural gas - by burning one cubic meter of natural gas, we obtain approx. 30 GJ of energy (almost twice as much as in the case of pellets), and we emit into the atmosphere:

• 0.08 kg of sulfur oxides SOx (twice more than in the case of pellets, converting to the energy obtained);
• 1.65 kg of nitrogen oxides NOx (comparable to pellets);
• 0.3 kg of carbon monoxide CO (incomparably less than in the case of pellets);
• 0.0005 kg of particulate matter (combustion of natural gas practically does not emit particulate matter or emits its traces).

Greenhouse gas emissions:

Each combusted fuel emits greenhouse gases into the atmosphere, among which carbon dioxide is the leader - as a result of burning one ton of wood pellets, approx. 1330 kg of said gas enters the atmosphere. So why do most studies on pellets contain information that no greenhouse gas emissions occur when burning this biofuel? The balance is taken into account - in the case of burning fuels of plant origin, more or less as much carbon dioxide is emitted into the atmosphere as the plant previously bound from the atmosphere, i.e. theoretically the balance is zero. Fossil fuels, obtained as a result of mining activities (eg coal, natural gas or fuel oil) - are pulled "from underground" and as a result of their combustion, "new" carbon dioxide is added to the atmosphere. Of course, this zero balance in the case of pellets does not have to be equal to zero - the biofuel did not grow inside the stove! It was necessary to first obtain the wood, then crush it, and use shavings, sawdust and other waste in an energy-intensive production process to produce the eponymous wood pellet. End? Not yet! The heating product still has to be transported from the producer to the seller (intermediary) and from the seller to the end customer. As a result of all these activities, a lot of energy was used, the production of which was associated with the emission of large amounts of carbon dioxide into the atmosphere.

Some facts about absorbing and emitting carbon dioxide.

Every living organism needs energy to build its tissues and function. Trees absorb carbon dioxide from the atmosphere to produce wood (roots, trunk, stems, branches), leaves or needles, flowers, fruits, seeds, etc. It is assumed that to produce one cubic meter of wood, the plant organism needs about one tonne of carbon dioxide taken up from the atmosphere. One cubic meter of pellets is made from approximately six cubic meters of sawdust. However, in order to simplify the calculations, we can assume that one cubic meter of biofuel is equal to one cubic meter of wood and take into account only the structure of wood, and not the more difficult to measure plant metabolism. One cubic meter of pellet weighs 500-700 kg, and burning a ton of this product (i.e. about 2 cubic meters) emits about 1,330 kg of carbon dioxide into the atmosphere, while the wood from which the pellet was made (to put it simply - about two cubic meters) previously absorbed from the atmosphere from 1428 to 2000 kg of carbon dioxide. Despite the simplifications in the calculations adopted to the detriment of pellets, it is evident that the burned biofuel emits less carbon dioxide into the atmosphere than the tree originally had to absorb to produce the necessary amount of biomass. The "surplus" of carbon dioxide can be "allocated" to the production costs of this ecological heating product.

In sum:

Is wood pellet an ecological fuel?

Definitely yes! Wood pellets are unrivaled among solid fuels - the amount of ash obtained is even 25 times lower than in the case of other heating products, the emission of harmful gases is always in favor of pellets, and the emission of greenhouse gases is an area in which no other fuel of mineral origin can compete with him. Moreover, we cannot say that any other heating fuel will "grow back". While the resources of oil, gas or coal are finite (at some point they will simply run out) - wood pellets are a fully renewable source of fuel. Trees have always grown and will grow on our planet, only residues from wood processing are used to produce pellets, and the ash left after burning biofuel can be used as a natural mineral fertilizer.
Armed with the above facts, we can confidently say that wood pellets burned in a dedicated furnace is an ecological fuel, and the heat obtained in this way is environmentally friendly.

You want to protect our planet, burn pellets.

High qualitywood pellets available at distripark.com.

*This article is for informational purposes only. The presented description, in particular the use of the products, is exemplary and constitutes non-binding information about the characteristics and possibilities of their use/application. In any case, before using the product, consult a specialist whether the specific use is safe and justified. We do not bear any responsibility for the use of the proposed solutions, even in very similar situations.