Pellets are made from compressed wood by-products
e.g. sawdust, wood shavings. They have a higher energy content and
are much less bulky than wood chips, and so need less storage
space. They are also easier to handle.
Other benefits of wood pellets are their consistent heat content
and size (6-8 mm for domestic/small scale, 10-12 mm for larger
systems) and their low moisture content (8% to 10%).
However, they are more expensive than wood chips since their
manufacture requires more energy and the capital cost for
production plant is high. Several pellet producers are
manufacturing and supplying pellets in Scotland, made from Scottish
wood.
Pellets are used in stoves and boilers, fuelling a variety of
heating systems from small domestic scale to large industrial scale
heating for schools and hospitals.
For the domestic user, pellets offer the most user-friendly form
of wood heating. Some suppliers in Scotland can deliver wood
pellets in specialised tankers, otherwise they can be bought in
bags of varying size individually or as bulk loads.
Compressed sawdust or wood shavings are also used to produce
briquettes which are larger blocks of woodfuel,
suitable for either open fires or log boilers, but less commonly
used.
Briquettes are similar to wood pellets, but physically larger.
Widths vary from around 50 mm to 100+ mm. Briquettes are usually
between 60 mm and 150 mm in length. They can offer a cleaner, more
consistent alternative to firewood logs, offering higher energy
density and steady combustion.