Biomass is a popular energy source in particular for generating heat. It is the only chemically bound form of harnessing the power of the sunlight. Biogenic fuels are renewable and CO2 neutral. As such, they are an important part of attaining climate and energy policy goals.
The term biomass comprises all organic materials of biogenic origin (i.e. not fossil fuels). This includes whatever lives and grows naturally and the waste it produces.
Burning biomass does not emit more CO2 than is bound through photosynthesis when the plants grow in the first place.
Energetic use of biomass has traditionally focussed on heating. Electricity generation from biomass is negligible. Worldwide output is about 173,000 GWh and corresponds to 0.9% of overall global electricity production (cf. IEA).
For a full life cycle CO2 analysis of electricity generated from biomass, the energy invested in the growth process etc. would need to be taken into account as well (as is the case for other energy sources, too).
Generally, we distinguish between three types of electricity generation from biomass, depending on the type of biomass used.
- Solid biomass
- Liquid biomass
- Gaseous biomass
Solid biomass (e.g. wood) is combusted for electricity generation. Biomass plants either use this fuel only or co-fire with conventional fuels.
Use of solid biomass for electricity generation in Austria is normally found in the wood processing and pulp and paper industries.
Burning this type of biomass generates much more heat than electricity. This technology is optimally suited if the heat is used as well (e.g. for district heating). Combined heat and power (CHP) plants are a good use case.
Liquid biomass can be used in many different ways, fuelling transport, heat plants or CHP stations.
When discussing bioliquids, we usually distinguish between biogenic oils and alcohols. This includes e.g. bioethanol, biomethanol and plant oil. The production process of liquid biomass uses a great variety of base materials and technologies. In terms of plant oils, rape is the most important energy source by far.
Others include cooking oil and fat, and animal fat. In Austria, bioethanol is generally produced from sugar beet (for sugar) and winter wheat and potato (for starch).
Gaseous biomass results from the anaerobic microbial decomposition of organic materials (fermentation). Its main components are methane (CH4) and carbon dioxide (CO2), but it also contains hydrogen sulphide (H2S), nitrogen (N2), hydrogen (H2) and carbon monoxide (CO).
The base materials generally come from energy crops (particularly corn), but might just as well be food waste (manure or cooking oil), agricultural waste (slurry) or waste from the food production industry or landscaping (green waste, grass).
On our German pages you will find a list of websites that provide more in-depth information on power from biomass – technical details, potentials etc.