Think about storage and delivery access

So, you need to assess how much storage you need, what space is available, and how accessible that space is to delivery vehicles.

Storage should be as close to the boiler as possible, to minimise the complexity of system needed to transfer woodfuel to the boiler. The system should be designed to minimise fuel handling - poor design can add substantially to your fuel costs. It also needs to be a watertight space. Have a look at the types of storage available.

How much wood fuel storage space is needed?

You can estimate how much woodfuel you'll need to store based on:

• boiler size (output in kWh)
• operating hours
• boiler efficiency
• energy content of the fuel - see typical calorific values of fuels (Biomass Energy Centre website)

The Biomass Energy Centre have produced a tool, Estimating Fuel Requirement, to help you do this calculation.

Some points to bear in mind when estimating storage space:

• Fuel requirements will vary between summer and winter - the size of the store needs to minimise deliveries during the heating season. However, the maximum size will be mainly be constrained by cost and the space available on site.
• For wood chip and pellet systems, unless your delivery system is very flexible, you should be able store enough fuel for at least 10 winter days.
• For wood chip systems your fuel store should be about 25% larger than the fuel is contains to reduce potential condensation problems.
• With automated systems, approximately half a meter is required at the bottom of the store to accommodate walking floors or spring loaded agitators.
• If you have limited storage space, wood pellets may be the best option.

Delivery access

Do you have convenient access for the size of vehicle your delivery needs? If not, is there the potential for delivery access to be part of the project design?

The tipping or transfer of wood fuel should be quick and simple to minimise your costs.

There are a number of fuel delivery options available. Delivery type will depend on:

• The proposed fuel type for the wood fuel boiler.
• The area available and any other physical access constraints at the site (e.g size of gate).
• The area required for the delivery vehicle to access the fuel store.
• The proposed delivery vehicles available from prospective fuel supplier

Generally the fuel supplier's vehicle needs direct access to the fuel store. However, wood chips can be blown a limited distance. Where access is problematic, wood pellets may be the best solution.

Further information

• Biomass heating - a practical guide for potential users (Carbon Trust) - this is a PDF to download, see pages 26-31
• Storing biomass (Biomass Energy Centre)
• Delivery of biomass into the storage facility (Biomass Energy Centre)