CIEMAT
In most Mediterranean countries, there is a major market for solid biofuels used in residential heating applications. In these countries, in addition to pellets and wood chips, a large number of solid biofuels derived from typical Mediterranean biomass are used, most importantly the olive stone. In general, however, use of these biofuels is not taken into consideration by any quality standards (standard ISO 17225:2014 does not include olive stone or nut shell in its classification) and appliances that have not been designed for their combustion are often used.
In Spain in recent years, specific standards for classifying the quality of olive stone and certain kinds of nut shell have been implemented. At the same time, various manufacturers have developed appliances that have been tested and may be suitable for use with Mediterranean biofuels. All of this is promoting the use of these fuels, especially in countries where the market is more developed. Nevertheless, new elements exist, such as the Ecodesign Directive, which will come into force in the coming years for all EU countries and introduce new challenges that must be addressed for small combustion installations.
In the present context, this guide has several aims. The first is to determine the capacity of small-scale biomass combustion technologies currently on the market that use typical Mediterranean biofuels in terms of operating conditions, efficiency and the emission requirements of the Ecodesign Directive. The second is to identify possible improvements for combustion appliances in order for them to comply with the Directive. The guide also has the aim of assessing the suitability of certain Mediterranean biofuels with high potential for use in domestic combustion appliances.
