Wood pellets are becoming more popular, and that trend is good news for the environment. These small cylindrical pieces are usually made from recycled wood and serve as an alternative to fossil fuels for heating. Biomass fuels also include wood, chips, waste paper, and many other agricultural by-products that can be used for energy.
Pellets come from by-products from furniture manufacturing, agriculture, and other wood-using activities. They are not waste; they are raw materials that can heat homes in winter without purchasing firewood.
According to Ecoinventos’ portal, many pellet producers take wood waste and refine it into pencil-sized, uniform pellets with consistent size, shape, moisture, density, and energy content.
1.- Why is it better to burn pellets than to use regular firewood?
First, the moisture content of pellets is much lower, typically between 4% and 8%, compared with 20% to 60% in raw biomass. Less humidity means higher BTUs and easier handling, especially in the cold conditions associated with green biomass materials.
Second, pellet fuel density is higher than that of raw biomass. More fuel fits in a truck cavity, and more energy can be stored in the field.
Third, pellets offer easier and more predictable handling. Their uniform shape and size enable a smaller, simpler feeding system that lowers costs. The high density and uniform form allow storage in standard silos, transport in wagons, and delivery in truck containers.
2.- What are wood pellets used for?
As an alternative to fossil fuels, wood pellets provide an environmentally friendly option for heating. They are used in biomass boilers to generate heat and hot water in homes.
They also serve as a zero-emission fuel for heat generation and industrial production in commercial and industrial settings.
Pellet fuel helps divert millions of tons of waste that would otherwise go to landfills and turn it into energy.
The exceptional consistency and combustion efficiency of pellet fuel produce a fraction of the particulate emissions of crude biomass. Pellet burners typically emit fewer particulates than other solid-fuel burners.
With sustainable forestry initiatives and efficient farm management, biomass remains a virtually limitless resource with relatively stable prices compared to fossil fuels.
Locally produced wood pellets from sustainably managed forests are ideal when available.
3.- How to identify a good quality pellet?
When purchasing wood pellets, look for ENplus A1 and DIN Plus certifications. The Ecoinventos portal is a useful reference for guidance.
ENplus A1 signifies the highest quality and safety standard for premium wood pellets. Low-quality pellets can damage boilers and cost more in the long run.
Humidity should be low (around 6%) to ignite stoves quickly, and drier pellets produce less smoke.
You should also consider ash content, ideally at or below 6%, because higher ash requires more frequent cleaning of the burner.
Calorific value is a key criterion, indicating heat output. A target around 18 MJ/kg (about 5 kWh/kg) aligns with quality standards.
Pellet composition matters: softwood pellets, known for bright colors, generate more heat than hardwood pellets when moisture stays under 10%.
4.- How do pellet stoves work?
Pellet stoves gained rapid popularity due to their efficiency and ease of use. Their fuel economy helps widen their market reach.
The operation is simple and affordable. The stove stores fuel in a hopper. When activated, a screw feeds pellets into the combustion chamber at a rate set by the electronic control system. The pellet burns, producing heat and exhaust that travels through a flue connected to an external chimney.
This arrangement boosts indoor temperature by venting exhaust from the room while directing heat inward.
Pellet stoves are ventilated, meaning they have a built-in fan that draws room air, heats it, and returns it at a higher temperature, differentiating them from traditional wood stoves.
Two heat transfer processes occur in a pellet stove: convection from the fan-driven hot air and radiation from the flame. Convection can warming the room faster than radiant heat alone, which is a notable advantage over traditional stoves.
Not everything is perfect with pellet stoves. The air needed for combustion is drawn from the surrounding environment, and once combustion ends, exhaust is expelled through the chimney, releasing some heated air outside. This can slightly reduce room air and require a small inflow of cooler outdoor air.
If air intake is drawn from outside, some models improve performance by bringing combustion air from outdoors, but they require additional installation. This often means drilling two openings in the building exterior—one for the chimney and one for the outdoor air intake.
In any case, the practical trade-offs depend on the stove design and installation specifics.
Aside from these points, the overall environmental impact depends on sourcing, forestry practices, and end-use efficiency. The information above reflects general characteristics and common industry guidance cited for reference in the biomass and pellet sectors.