Reduced rate of VAT on the installation of wood-fuelled boilers
From 1st January 2006 the reduced rate of VAT (5%) for energy-saving material has been extended to include the installation of boilers fuelled solely by wood, straw or similar vegetable matter in homes and certain residential and charity buildings.
This measure is intended to encourage the use of microgeneration using sustainable energy sources, promote household energy efficiency and contribute to the Government’s commitment to reduce carbon dioxide emissions.
Solid Biomass is basically a solid fuel that is formed from a product that has grown as a tree or crop. This is as opposed to a solid mineral fuel that is a solid fuel that is, or is processed from, a mineral that has been extracted from the ground (such as coal or smokeless fuels) Currently this fuel is used more on the continent but it is becoming more popular in the UK and the technology to do so effectively and efficiently is being imported.
Since the basic fuel i.e. wood can be grown in the UK and acts as a carbon dioxide 'sink', it is considered renewable and can take from one to thirty years to regenerate depending on the type of crop used. When these crops grow they absorb more Carbon Dioxide from the atmosphere (and produce oxygen in the process) than is created when burning in an efficient appliance so these fuels is less damaging.
The main product used as a solid biomass is wood in a variety of forms, this is not the only product and below is a summary of the products that currently fall into this category.
This is the most popular form of solid biomass but in a large majority of cases is used simply as a decorative or supplementary heat source, e.g. a wood burning stove to heat one room. Advanced log boilers from 20 kW upwards, now allow very high combustion efficiencies above 80% using fan controlled combustion and 'gasification' where the boiler is remotely located away from the combustion zone.
This is wood dust such as sawdust, that is processed by high pressures into a small pellet around 6 to 8 mm. diameter. This process gives a degree of conformity and ensures that the fuel is consistent when used and hence is easier to using mechanised feed screws. There is a European standard for this fuel but as yet there is no test house in the UK providing certification against this standard. The small size of the fuel allows a controlled delivery and high combustion quality. A kg. of wood pellets can produce nearly 5 kWh of heat.
This is the chippings caused when forestry is cleared for timber and the small branches and bark are removed from the tree and so is another waste products. This is less consistent is size and type but is small enough to be handled and fed into a combustion unit mechanically on demand. Not often found in domestic applications.
This has been used in the UK for some time with a number of straw bail burners having been installed for many years. This requires large bulk storage and handling as well as a large combustion chamber and so this type of fuel is often used on farms for process heat. The fuel is quickly grown and cropped and so has a very short recycle life. Not often found in domestic applications.
The main market is the occasional use wood burning stove (4.5 – 18 kW), this market has been increasing constantly over the last five years and is by far the largest sector. There are still a number of users of wood logs on open fires (the output from these is up to 3kW) but with the increasing trend towards energy efficiency this has reduced in popularity. The use of wood logs for central heating using batch fired log boilers (12 – 50 kW domestically but up to 250kW for commercial boilers) has now begun to take a foot hold but is a small market compared with the occasional use stove. The wood pellet burners are a new market in the UK. The use of wood chip is not currently used in any numbers in the domestic sector and is likely to be used in the commercial sector in greater numbers (outputs from 15kW up to 500kW +). The cost of the plant to handle this fuel and the space required limits its application in houses but could become popular in schools, community halls or group heating schemes.
In the UK the less technical units are the most popular and as yet there are few engineers that understand the technology in the more sophisticated units but this is slowly changing. The scope is from a relatively simple wood burning stove (from 4.5 – 18 kW )to full heating systems that are capable of delivering the fuel from a remote store to the boiler on demand and then modulate the boiler output to suit the heating demand (12 – 50kW). A big factor in the effectiveness of these systems is the design of the heat storage and distribution system as well as the ability to accommodate heat from more than one boiler and even solar heat collectors.
These appliances need a vertical flue or chimney and so the existence of one, or the ability to provide one, are key factors. In the case of the more sophisticated systems the space to store fuel, for the sighting of the heat accumulators and the boiler itself must be considered and this is not likely to be available in a small home. There are many properties with flues that can be opened up and adapted to use by a stove or boiler and if the client is happy to provide the effort for manual refuelling etc then the scope is widened considerably
One of the major issues limiting the adoption of this type of appliance and technology is the current regulations in the UK. The use of solid fuels (such as wood and wood products) and the development of efficient and sophisticated solid fuel appliances have been hampered by the availability of cheap oil and gas in the UK. On parts of the continent where these fuels are not cheap the regulations and policies have been developed alongside the appliances and systems and reflect the requirements and abilities of the market and the installation skills.
The building regulations in the UK are written in a way that makes the economical and effective installation of the continental appliances difficult but the installations in the UK will have to reflect these Regulations and maintenance procedures until these units are specifically written into these Regulations. An additional difficulty is the UK clean air act that requires the testing of appliances in ways that these units are not intended to operate and so is causing difficulties for install in smoke control areas.
The Regulations that have to be considered in the installation of these appliances in the UK include Building Regulations Approved documents F, J and L. Any installation that is carried out by a none registered competent person (see competent persons page) will come under Building Control and must not be undertaken until building control permission has been obtained. Standards.
As with the regulations the British Standards for fireplaces, installation and chimneys all reflect the use of solid mineral fuels rather than wood or solid biomass fuels and so these again place restrictions on the installation techniques used in the UK. The standards to be considered are BS 6461 for the construction of masonry chimneys. BS 7566 for the installation of prefabricated steel chimneys (due to be replaced in 2005 by a BS EN, European normative standard) and BS 8303 for the installation of solid fuel appliances.
Currently the competent persons scheme covering the installation of a solid fuel appliance is the HETAS scheme. HETAS provide training courses that covers the regulations and standards for the installation of the appliance and the lining and construction of chimneys. In its basic registration the scheme provides self certification for the installation of none boiler appliances, service and maintenance and the installation of flexible stainless steel liners for solid fuels with an additional courses being required to cover the installation of boiler models and other chimney lining types.
HETAS limited
PO Box 37
Bishops Cleeve
Gloucestershire
GL52 9TB
Tel 0124 673257
Or www.HETAS.co.uk
Training resources
HETAS run a number of courses throughout the UK and details of these can be obtained from the above web site. In addition to this there are a number of organisations, including the IDHEE and The Centre of Alternative Technology www.cat.org.uk that run specialist courses.