Biomass

Wood Chips

In general, the use of wood chip heating systems becomes economical at sizes above 500kW. With smaller heat requirements, the capital investment often does not balance the fuel savings. The exception are situations in which heat generation is required all year round.

The choice of boiler type is entirely dependent on the quality of fuel available and on the required power. This choice has to be right from the beginning; compromises are not possible. We differentiate between three types of grate in automatically-stoked wood-chip boilers:

• Underfed grate for dry material
• Stepped grate for wet material
• Fluidised bed combustion for systems above 1MW

Wood chips (like pellets) are stored in fuel silos or bunkers close to the boiler and are transported automatically to the boiler via a feed system. The feed systems delivers the correct quantity of fuel to the combustion chamber, based on current energy needs. Wood-chip systems can be run between 20 and 100% of their nominal power output through the controlled supply of fuel.

A biomass power station of any type always requires long-term contracts with fuel suppliers. In our experience, there is great interest on the part of potential suppliers in using wood residues which would otherwise remain unused, provided the remuneration is right. Of course, the ecological advantages of using fuels from renewable sources are easily undone if the fuel is transported over long distances. We always consider the availability of wood chips close to the installation in order to ensure that the overall energy balance is positive.

Related Case Studies

• 3MW wood chip heating plant
• French village switches to biomass heating
• District heating system with remote supervision
• Wood chip heating system in container form
• Wood chip heating for greenhouses
• Energy from cherry stones