Fuel Storage for Biomass Heating. Fuel Storage UK

What is the boiler’s size (output)?

A boiler’s size will depend on the heat load it must satisfy. The load pattern must be taken into account as well as the absolute load at any one time. Depending on the particular project, different information will be available from which to work out the heat load. Well sized boilers will usually use around 2.1MWh of energy per year for each kW of installed out put.

What is the boiler’s fuel consumption?

A boiler’s fuel consumption depends on heat load and so is proportional to boiler size. As part of determining the size of a boiler, an estimate is made of fuel consumption and this is used in sizing the fuel sture.

How often will the store require filling?

People often ask what size the fuel store should be. This depends on the boiler’s fuel consumption and the required period between fills. In general, the target period is between 1 and 2 months. In certain situations clients are happy to reduce this period, perhaps where fuel can be transferred into the store on a more regular basis using on site handling equipment. Where fuel is being delivered by a third party supplier it is important that reasonable delivery volumes can be accepted in order for the cost effectiveness of fuel deliveries to be maximised.

As boiler output increases, the size of fuel store to achieve a given delivery period increases in turn. Where larger boilers are installed (e.g. >500kW), fuel delivery periods often drop as very large storage volumes can be less cost effective. In these situations, it is important to ensure full, bulk deliveries can be made, minimising delivery costs and time.
 

How will the fuel be delivered?

Woodchip is likely to be delivered in bulk, perhaps in a lorry, tractor and trailer or via a fork-lift bucket from an on site storage building.

Wood Pellets can be delivered in 15kg bags, often delivered on a pallet, in bulk bags or blown into a store from a delivery tanker. This type of delivery is similar to that of heating oil.

For more fuel storage examples please see the fuel storage gallery.
 

Is it possible to achieve a satisfactory delivery interval of woodchip, based on the access and storage restraints of the site?

It is critical, in woodchip installations, to ensure sufficient space is available for fuel storage. The fuel storage must be configured such that delivery is simple and associated costs are kept to a minimum. Where these conditions can not be met or the achievable delivery interval is too short, one solution is to opt for a wood pellet system.

Wood Pellets not only have a higher calorific value than woodchip, but also have a much higher bulk density. See below:
 

This fuel store feeds a 900kW boiler. It is a 100 tonne store which requires filling around once a month.