Commercial Wood Fuel Boilers

Wood fired heat, steam and electricity generation is becoming an increasingly attractive option within the commercial and industrial sectors. Buildings or processes requiring large and often constant demand for heat allow biomass boilers to operate efficiently and cost effectively.

This section contains information on:


Commercial / Industrial wood fired boilers and CHP

Modern boilers burn high quality wood fuels such as wood chips, pellets or uniform agricultural and industrial residues, automatically, free of any sign of smoke and with emissions comparable to modern oil fired systems. By pelleting residues from wood and crop processing, a possible disposal problem is turned into a high quality fuel. High energy content and easy handling make trade over longer distances economically feasible.

wood fired boilerwood chip fuel store and stirrermodular energy cabin
Wood Fired Boiler
Wood Chip Fuel Store and Stirrer
Modular Energy Cabin

Modern woodchip and pellet boilers retrieve the wood fuel automatically from the storage area and burn it, meeting high environmental standards. Modern wood boilers use up to 90% of the energy contained in the wood for heating, similar to good oil and gas boilers. State of the art models include automatic ignition and heat exchanger cleaning, automatic ash removal and ash compression (wood has a very low ash content, so ashes only have to be removed a few times a year). Some manufacturers even offer remote monitoring and boiler control.

Small scale

Heat only boilers with capacities up to 1MW are available "off the shelf" from a number of manufacturers based throughout Europe. The most commonly used boilers are in the range of 100kW to 600kW although domestic sized boilers are available for smaller commercial applications. Typical applications include:

  • Hotels
  • Leisure Centres
  • Offices
  • Hospitals
  • Schools
  • Universities

Selecting the right capacity for the boiler is very important if its operation is to be economical and trouble-free. If wood heating is to replace a system, the previous fuel consumption is the best basis for calculating the future requirements and the heat load. When replacing an existing heating system, it is strongly advised to consider improving the building's insulation as the new system could then be designed to the lower requirements following renovation. If a system is installed in a new building, an accurate calculation of the heat load is highly recommended.

It often makes sense to use the biomass boiler as a base load system by under sizing the boilers and using a fossil fuel boiler as a peak load / backup system. In this way it is normally possible to provide 90%-95% of annual heat demand using a much smaller biomass boiler thus reducing capital investment costs considerably and reducing economic payback.

Fuel supply infrastructures have developed considerably in recent years. Pellets are available nationwide through Balcas based in Northern Ireland and a number of importers. Wood chips are often available locally and equipment suppliers are often able to offer a wood chip supply contract if required ensuring security of supply.

Medium and large scale
Graingers CHP plant
Grainger Sawmill Biomass CHP Plant, Co. Cork

Larger scale biomass boilers are suitable for heat, steam or electricity production.

Designs are normally bespoke with boilers ranging in size from 1 MW upwards. Larger scale plants can be of the order 50-100 MW but these larger systems are mainly confined to the electricity power generation industry.

Heat is used within industry in a variety of ways. The simplest systems use boilers to produce heat as with smaller commercial and domestic boilers. The heat might be used within the process or more commonly for space heating purposes.

Boilers are often used to produce steam which is extensively used within industry processes. Examples include kiln drying of wood and provision of heat dairy produce processing.

The final category is that of CHP. This involves the production of high pressure steam. A proportion of the steam is used in a turbine to produce electricity. The remaining steam and low temperature steam exiting the turbine can then be used for process or space heating. For CHP systems the proportions will vary depending on the requirements of the industrial site and practical considerations with regard to technical feasibility.

High efficiency makes economic sense

Wood boilers use the latest technology to control the amount of fuel and air released to the burner. The standard size and quality of pellets ensure an extremely efficient and clean heating system. The lower cost of the fuel competes well with similar oil systems.

Coillte HQ
Wood chips/pellets boiler at Coillte Office, Wicklow

Your checklist for selecting a wood boiler

  • Efficiency of 85% or higher
  • CO2 Emissions less than 200 mg/m3
  • After sales service contract
  • Automatic cleaning
  • Good quality burn-back protection
Details on funding can be found in the 'Policy and Funding' section. Alternatively visit the Grants section of our website.

EN 303-5Heating boilers for solid fuels, hand and automatically stoked, nominal heat output of up to 300 kW

This standard is applicable to solid fuel boilers (including chip and pellet boilers). The solid fuels covered include chips, pellets, briquettes and sawdust. A boiler needs to meet a number of pre-set criteria to pass the standard. The main criterion include:

  • Minimum nominal efficiency
  • Operator / Installation manual covering minimum requirements
  • CO emissions must be below pre-defined thresholds
  • Dust emissions must be below defined thresholds
  • Organically bound carbon emissions must be below defined thresholds

It is strongly recommended that any boilers or stoves you consider purchasing have been tested to the appropriate EN standard. In this way a degree of quality can be assured.

The above standards can be downloaded from

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