Callidus Design Consulting Engineers

Designers, engineers, consultants and technical specialists covering a wide range of building and process services.


Renewables - Biomass

Biomass, in the context of a fuel for heating buildings, is the burning of organic matter, usually in the form of wood, grass or straw. The vast majority of Biomass installations burn wood which can be used in a variety of forms. Wood chips and pelletised wood are the most common options.

Wood chips are most commonly produced by chipping the waste timber and bark from newly felled trees and during routine thinning and maintenance. The chips are dried naturally before use and the size of the wood chips can vary. The useful energy which can be extracted from the wood chip varies considerably depending on the moisture content and species of the wood chip.

Wood pellets are manufactured predominantly from joinery waste and are produced in a uniform size, with an inherently low moisture content. The size and shape of the pellets allow them to be easily packaged, transported, stored and finally introduced into the firebed of a biomass boiler.

Due to the manufacturing costs, wood pellets are generally a more expensive fuel source than wood chip. The actual cost comparison is highly dependent on a number of factors, including the availability of the wood chip or pellets local to the Biomass boiler installation and the transportation costs which will be applicable. In addition to cost factors, the space which is available for fuel storage, access for fuel deliveries and the method of delivery are key considerations which need to be addressed before opting for a Biomass fuel source.

The use of Biomass has been increasing in recent years as it is deemed as being a low carbon technology, particularly if the fuel is sourced in a sustainable manner where the fuel consumption either matches or is less than the rate at which replacement trees are planted. The emissions from Biomass installations are deemed to be less harmful to the environment than from an equivalent oil or gas fired boiler plant and typically the fuel costs are also lower. The capital cost of a biomass installation is, however inevitably much greater due to the added complications associated with fuel storage, fuel deliveries, fuel feed mechanisms, greater spatial requirements and the associated increase in maintenance considerations.

To combat the high capital cost, the UK Government has, in recent years introduced an RHI (Renewable Heat Incentive) scheme which allows for annual inflation adjusted payments to owners/operators of Biomass Installations which meet all the necessary qualification standards.

On all potential Biomass projects, it is important to consider all the aforementioned factors to determine if the installation is commercially viable. Callidus Design have completed a number of projects incorporating Biomass installations. Please get in touch if Callidus Design can be of assistance with the design of your new Biomass installation.

Some examples of our Biomass design experience can be seen in these examples from our project profile section of this website.