As New Zealanders, most of us are familiar with the concept of lugging the firewood off the trailer, stacking it inside the garage wall, and when you need to fill up the basket beside your fireplace darting into the cold garage to fill up your arms with wood…all in the efforts of keeping your lounge toasty warm.
While the way we burn biomass remains the same, the efficiency of the system producing the heat energy has evolved. There are now highly efficient systems that harness the whole burning process of the biomass fuel and output energy for central heating systems that heat the whole house, not just the lounge.
Biomass is a renewable energy source generated from wood, plants, and other organic matter. It releases carbon dioxide (CO2) when burned but vastly less than fossil fuels. With the demand in New Zealand for carbon-neutral heating options growing, biomass boilers provide a renewable fuel alternative for areas in the market where fossil fuel would have been previously considered.
Central Heating New Zealand offers two types of biomass boilers; the Attack Log gasification boiler and the Attack pellet boiler.
Gasification boilers, like the Attack 45, are cleaner and more efficient than traditional wood-burning appliances due to their controlled burn process that releases and burns gases within the wood. The boiler can regulate its temperature by control of the fan and air damper. Gasification boilers can only burn wood fuel and ideally with a moisture content of less than 20%.
The Attack pellet boiler burns wood pellets that have become so popular over the past 15 years. The boiler automatically starts and stops and provides all the convenience of regular central heating boilers with little hands-on maintenance.
What do biomass boilers burn?
Log boilers are batch fed in the same way a log fireplace is. They hold a lot more wood in the combustion chamber and produce a lot of energy that is transferred into the water of the central heating system to go to the radiators. Log boilers are ideal if you have a lifestyle block or access to plenty of wood.
Wood pellet boilers are automatically operated and stoked, making them more convenient for the end-user and more suited to underfloor heating as well as radiators. They have a hopper for the storage of pellets which are then augured into the boiler in precise regulation. Wood pellet fuel is readily available in bulk or in bags and is very stable in price. Wood pellets are a popular sustainable fuel because they are made from waste sawdust and wood shavings.
Wood chip boilers are mainly for small to large commercial applications. These are the most sophisticated due to the wide variation in the wood chip, quality, and moisture content. They are automatically operated and require more space for the hopper.
Renewable and sustainable
Biomass fuels are known as contemporary carbon which means when they are combusted, they release the same carbon levels that were consumed by the growing tree, meaning that the carbon levels are consistent and sustainable. Biomass is only considered renewable if it comes from a sustainable source, such as where new trees are grown in place of those that are harvested.
Biomass systems are highly recommended to assist New Zealand to achieve lower carbon emissions sustainably.