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Glossary · Energy industry & energy transition

Biomass

Biomass Bioenergy renewable energies controllable generation sustainability

Biomass refers to organic material of plant, animal or microbial origin that can be used for energy. In the power system, this mainly includes solid biomass such as wood residues or landscape management material, gaseous energy carriers such as biogas and biomethane, and the biogenic fractions of waste. Biomass does not produce electricity directly. First, a fuel or a combustible gas is obtained from it. This is then converted in a power plant, a combined heat and power unit or a gas engine into electricity and, usually at the same time, heat. Biomass can be thought of as a kind of natural battery: plants store solar energy chemically, and this energy can later be released again at a chosen time.

Which quantity matters depends on the level of analysis. For the resource, the relevant figures are tonnes of fresh or dry matter, calorific value, methane content or the available quantities of residues. For electricity generation, kilowatt-hours and megawatt-hours count. For the system, the installed electrical capacity in kilowatts or megawatts is also important, as are the speed at which a plant can change its output and the length of time for which fuel or gas can be stored. Biomass is thus at once a resource, a fuel, a generation technology and part of an agricultural, forestry or waste-management value chain.

Legal definition in Germany

For support under the Renewable Energy Sources Act (EEG), the Biomass Ordinance (Biomasseverordnung) specifies which substances count as biomass. Accordingly, biomass comprises energy carriers from phyto- and zoomass, that is, from plant and animal matter. This also includes by-products, secondary products, residues and wastes whose energy content derives from such matter. Expressly named are, among others, plants and plant components, residues from agriculture, forestry and fisheries, biowaste, and gas produced from biomass by gasification or pyrolysis. Biogas generated by anaerobic digestion also counts, although with restrictions on the material used.

The ordinance's negative list is important. Not regarded as biomass within the meaning of the ordinance are, among others, fossil fuels, peat, mixed municipal waste, waste wood with the exception of industrial residual wood, paper, sewage sludge, certain animal by-products, spent liquors from pulp production, and landfill gas and sewage gas. This yields a correction to a common simplification: sewage gas, landfill gas and the biogenic fraction of waste are often counted as biomass in energy statistics. Within the meaning of the Biomass Ordinance, however, they are not biomass. The EEG treats landfill gas and sewage gas separately. For figures and legal questions, it must therefore always be stated which definition is meant.

In addition, there are sustainability requirements based on the European Renewable Energy Directive. The German Biomass Electricity Sustainability Ordinance of 2021 makes the EEG payment entitlement conditional on proven sustainability and minimum values for greenhouse gas savings. It applies to solid biomass fuels in plants with a total rated thermal input of 20 megawatts or more, to gaseous ones from 2 megawatts, and to liquid bioliquids. Under this version, smaller plants are not subject to the verification requirement.

Distinction from bioenergy, biogas and renewable electricity

Biomass is not the same as bioenergy. Biomass is the material; bioenergy is the energy obtained from it in the form of electricity, heat or fuel. Biogas is produced by the fermentation of organic matter and consists predominantly of methane and carbon dioxide. Biomethane is upgraded biogas of natural gas quality. It can be fed into the gas grid and converted into electricity at another location.

Electricity from biomass is counted among renewable energies because the feedstocks regrow or arise anyway as residues. However, it is not automatically climate-neutral. For the climate balance, what counts are origin, cultivation, fertilisation, transport, drying, methane losses, competing uses and the time until the carbon removed is sequestered again. Residual wood from sustainable management is to be assessed differently from energy crops grown on a large scale on land that is also important for food, nature conservation or carbon storage.

Significance in figures

According to data from the Working Group on Renewable Energy Statistics (AGEE-Stat) at the German Environment Agency (Umweltbundesamt), a total of 47.8 terawatt-hours of electricity was generated in Germany from biomass, including the biogenic waste fraction, in 2025, compared with 49.7 TWh in 2024. This corresponds to about 9 percent of gross electricity consumption. Around two thirds of this came from biogas and biomethane, and about 5.4 TWh from the biogenic fraction of waste. Its significance is even greater in the heat sector: in 2025, biomass provided around 84 percent of renewable heat, which is about 175 TWh, predominantly from wood. Other statistics sometimes give differing values because of different definitions.

Technical role in the power system

Unlike wind energy and photovoltaics, biomass is a chemically stored energy carrier. A gas store at the biogas plant, a wood chip storage facility or biomethane in the gas grid can shift generation in time. Many plants operate in combined heat and power, thus producing electricity and heat at the same time. The electrical efficiency therefore describes their benefit only incompletely. If the heat is used in a heating network, a business or a municipal property, overall efficiency rises significantly. If it remains unused, a large part of the energy benefit is lost.

With high shares of wind and solar power, the mode of operation determines the value to the system. A biogas plant that feeds in evenly around the clock does displace fossil generation, but its benefit to the system is low. It rises if the plant reduces output when there is a lot of sun and wind and feeds in at times of high residual load. For this it needs larger gas stores, oversized engine capacity, heat stores, suitable permits and remuneration rules oriented towards flexibility. This flexibility is not free. A larger engine that runs only in certain hours costs more per kilowatt-hour generated. Heat supply contracts can restrict flexible operation. Gas production in the digester can also be controlled only sluggishly. Flexibility thus arises from storage, oversizing and operational reserves, not from the label "dispatchable" alone.

Support and current legal framework

The EEG has strongly shaped the expansion of biomass in Germany. Earlier fixed tariffs created incentives for continuous feed-in and for energy crops, above all maize. Later versions introduced tenders, the market premium, flexibility requirements and a cap for maize and cereal grain. With the so-called Biomass Package, the EEG 2023 was amended again in February 2025. The Act on the Flexibilisation of Biogas Plants and Securing Follow-up Support was promulgated on 24 February 2025. It took effect after state aid approval by the European Commission.

  • The tender volumes for biomass were raised to 1,300 megawatts for 2025 and 1,126 megawatts for 2026.

  • The flexibility premium rose from 65 to 100 euros per kilowatt of installed capacity per year. Follow-up support for existing plants was extended from 10 to 12 years.

  • The permissible share of maize and cereal grain in biogas plants falls from 35 to 30 percent by mass from 2025 and to 25 percent by mass from 2026.

  • For biogas plants awarded a bid in tenders, the payment entitlement is reduced at negative and even at slightly positive electricity prices (§ 51b EEG). Supported electricity volumes are also limited by operating quarter-hours. Both are intended to shift generation to hours with high prices.

These rules apply to Germany and concern mainly biogas plants. For wood-fired combined heat and power plants, biomethane plants and older plants, different provisions apply depending on the year of commissioning and the version of the EEG. In individual cases, the applicable version must therefore be checked.

Economic and institutional context

Electricity from biomass usually has higher levelised costs of electricity than electricity from new wind or solar plants. The reason: biomass must be grown or collected, transported, stored, processed and converted. For biogas, substrates, digesters, gas upgrading, engine maintenance and the handling of digestate are added. Its strength therefore lies less in large quantities of electricity than in generation targeted in time and in the link with heat supply, waste treatment and agriculture. At the same time, many areas of law meet in the case of biomass: agricultural, waste, nature conservation and emission control law, the electricity market, the gas grid and municipal heat planning. A biogas plant can reduce emissions from liquid manure and provide flexible capacity, but can also create pressure on land. A wood-fired combined heat and power plant can make use of residual wood, but causes fine particulate matter and nitrogen oxides and competes with the material use of wood.

Typical misconceptions

  • "Biomass is climate-neutral." This assumption can be roughly correct for certain residues over suitable time periods. It becomes false if emissions from fertilisation, land-use change, transport, drying or methane losses are ignored. Methane is a particularly potent greenhouse gas; even small leaks worsen the balance considerably.

  • "Biomass can replace fossil power plants on a large scale." Sustainably usable biomass is scarce. Process heat, building heat, fuels, chemicals and material use compete for the same resource. In the power system, it makes the most sense where its storability and dispatchability bring the greatest benefit.

  • "Biomass is ideal baseload." Historically, many plants ran as baseload plants because fixed tariffs rewarded this. In midday hours with a lot of solar power, however, additional feed-in aggravates negative electricity prices, curtailment and grid bottlenecks. Stored gas is then often more valuable than electricity generated immediately.

Security of supply and system costs

Biomass can contribute to security of supply because it is available independently of the weather and can be used, for example, during a Dunkelflaute (prolonged period of low wind and sun). However, its firm capacity is smaller than its installed capacity once fuel availability, maintenance, heat obligations, regulatory requirements and storage sizes are taken into account. In terms of system costs, biomass works in two directions. Its generation is comparatively expensive. On the other hand, it can avoid costs elsewhere, for example when it reduces residual load peaks, supplies heating networks, makes use of liquid manure and waste, or when fossil peaking plants are needed less often. A simple ranking by cents per kilowatt-hour overlooks this temporal value. A blanket upgrading of every biomass plant, by contrast, overlooks scarcity and ecological side effects. How much a plant is worth therefore depends on sustainable origin, efficient coupling of electricity and heat, flexible operation and clear rules on competing uses.

Sources

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Edited by eCMS on 11.11.2026 15:55

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