Biomass pellets as a mean of encountering climate change threats

The successful encounter of humanity with climate change is among the greatest challenges that biomass to energy systems are called to implement.

The addiction of western economies to fossil fuel and their huge consumption for energy purposes has been widely recognized as the main reason for the enhancement of the global warming, with all its notorious consequences (e.g. sea water level uprising, extreme weather effects).

Biomass pellets neutrality regarding their carbon emissions is not a matter of a non-emitting carbon dioxide emissions combustion; this is inevitable for any substance which contains carbon. The environmental benefits of biomass pellets arise from the fact that during their production from natural resources they absorb about the same quantity of carbon dioxide (photosynthesis process). Thereby, the total mass balance of carbon dioxide to atmosphere is close to zero. But then, of course there are various parameters that must be taken into account in order to fulfill a stricter calculation of carbon mass balance, like the pellets combustion system efficiency or the energy consumption of the pellet producing facility.

A lot of research have been conducted during the last decade so as to clarify the question whether biomass pellets consist a more friendly to environment alternative comparing to the conventional fossil fuels. A relative study of the UK Department of Trading and Industry (2003) where carbon emissions resulting from various fuels combustion was calculated in a life cycle analysis study, it was concluded that biomass pellets emit less than 5% of the relevant emissions per MWh than oil. In comparison to natural gas (which is usually promoted as a more “clean” fuel) the same study showed that carbon emissions from pellets are equal to about 5.5% of those from natural gas utilization. In any case, both oil and natural gas are by definition non-renewable energy resources whereas biomass is.

The Environmental Protection Agency of the USA (USEPA) refers to biomass pellets as a renewable fuel which derives from compressed, dried wood or other biomass. In addition, the Agency argues that pellet stoves pollute so slightly that their certification from US EPA is not necessary (unlike the conventional wood log stoves).

Similarly to the abovementioned, a study from the Salzburger Institute for Urbanization and Housing has resulted to the fact that an average Austrian household can reduce the carbon emissions to about 10 tonnes annually, just by converting its oil consuming central heating to a pellet consuming one.

The examples from official, well respected Organizations worldwide which prove the contribution of biomass pellets to the elimination of greenhouse gases emission are numerous. But carbon dioxide is not the only headache; it is necessary to examine also carbon monoxide and particulate matter emissions.

Between the period 1980-2000 there had been a tremendous drop in the emitted amounts of carbon monoxide from household pellet heating systems; a fact that can be fully attributed t the technical evolution of those systems. Similarly, the amount of produced PM10 during the combustion of biomass pellets in new, highly developed combustion systems has decreases drastically. It is estimated that due to the quality of the majority of modern combustion systems the PM10 concentration in the exhaust gases is less than 1% than it used to be twenty years ago. It must be noticed also, that PM10 emissions from biomass pellets combustion are more than 5% less than thosw which are emitted from conventional wood log fireplaces.

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