Technologies and Applications
When you burn solid biomass in modern heating systems, the energy locked into the biomass is used very efficiently. The predominant source of energy is wood in the form of firewood, wood chips and pellets. Ovens and boilers fed manually, partly or fully automatically with electronically adjusted firing systems have been developed that contribute to a combustion process free from harmful substances at particularly high efficiency factors of over 90 per cent.
Solid biomass is also used to generate electricity in combined heat and power (CHP) plants. Any waste heat that arises during electricity generation is used, and supplied, for example, as heat in local and district heat grids or made available to industrial processes in the form of steam or heat. It can also be used to produce cooling, if required, for industrial purposes, for cold storage or for air conditioning in buildings.
Solid biomass is also suitable for gasification as well as burning. Fixed beds, fluidised beds and entrained gasifiers can be used depending on the characteristics of the combustion materials and the capacity of the plant. The resulting wood gas can then be used in combustion engines or gas turbines to produce electricity with high elec-tricity efficiency. Total efficiency can be enhanced significantly through the use of waste heat using CHP.
Bioenergy can be extracted from a variety of sources. These differ in their availability, their combustion properties and their possible uses. Biomass can be used to produce solid, liquid and gaseous fuels.
Solid biomass includes all dry or dried single items or bulk goods made from plants or parts of plants. It can be stored, for example, in the form of wood pellets or wood chips. This makes demand-based continuous heat and electricity generation possible.
Sustainability and bioenergy
In recent years the topic of sustainability of bioenergy has become more and more important. There are no global or European sustainability criteria. There are, however, recommendations from the European Union and in 2015 some EU countries published sustainability criteria for the first time. The EU recommendations for sustainability include the protection of ecosystems with great biological diversity and high carbon stocks as well as efficiency in energy conversion.