Biomass: striking a balance between energy and climate policies

Strategies for sustainable bioenergy use

Bioenergy is the most versatile of the renewable energy sources and provides more energy than wind and hydroelectric power, solar energy and geothermal energy combined. A coherent bioenergy policy must ensure that bioenergy use has no negative social and environmental impacts, and makes the greatest possible contribution to climate protection.

The “Bioenergy” working group of the Academies’ Project ESYS has investigated how bioenergy can contribute to climate protection and how to make system-beneficial use of it.

OVERVIEW OF THE RESULTS

In a nutshell

  • There is little risk associated with putting residues and waste materials to use as energy. Germany has major potential in terms of timber residues, straw and animal excrement. Converted into energy, these could cover up to 17 per cent of Germany’s future primary energy demand.
  • In order to be sustainable, bioenergy must be put to system-beneficial use: it can assume those functions in the energy system for which other renewables are unsuitable. Bioenergy could, for example, power ships and aircraft or provide heat for industrial processes.
  • Climate models have shown that CO2 will in the future have to be removed from the atmosphere in order to achieve the Paris climate targets. There are various options for producing such “negative emissions”, one of which is to capture carbon dioxide in bioenergy plants and put it into permanent underground storage (BECCS). This approach should be considered in
    relation to future bioenergy applications.
  • Certification systems and a sufficiently high CO2 price are ways of ensuring that bioenergy is beneficial to the climate. They are most effective if they cover not just bioenergy, but rather all agricultural products.

Greenhouse gas balance of bioenergy

Bioenergy is already providing one tenth of Germany’s energy requirements. Biomass is, however, not only needed for supplying energy, but also for producing materials, food and feedstuffs. Since the global population is continuing to grow, so too is demand for biomass, and thus also competition for limited land area.

Any further expansion or intensification of human land use increases the pressure on the environment and nature. It is therefore absolutely essential for bioenergy to be generated and used in such a way that it produces the least amount of greenhouse gas emissions possible, and neither jeopardises biodiversity nor degrades the quality of soils and water resources.

Nitrous oxide emissions from nitrogen fertilisation are the greatest source of emissions from cultivating crop plants. However, changes in land use can also contribute considerably to climate change, in particular when forests are replaced by agricultural land. This is because forests store much more carbon in vegetation and soil than do arable and pasture land. Indirect land use changes occur when the cultivation of energy crops results in the area of agricultural land being expanded in other regions, often in non-European countries. Since the extent of such changes is disputed, reliable estimates of the greenhouse gas emissions caused by bioenergy are extremely difficult to obtain.

Putting forest wood and agricultural commodities to use for producing energy is thus associated with major environmental risks. Bioenergy should instead primarily be produced from residues and waste materials. If unexploited potential from timber residues, cereal straw and animal excrement were tapped and primary energy consumption were reduced to 2,000 terawatt-hours per year by 2050, as targeted by the federal government, residues and waste materials could provide 13 to 17 per cent of primary energy. Designing bio-based materials to be low in pollutants and readily recyclable enables repeated use and energy recovery at the end of the product’s life (cascade use).

Global potential

Biomass is traded on international markets. Bioenergy use in Germany thus has global consequences. Estimates of future sustainable global bioenergy potential range from between fifty exajoules per year, or roughly today’s level of consumption, and several hundred exajoules per year. The range is so large because it is unclear to what extent agricultural yields can be raised and how much unused, degraded agricultural and pasture land on which energy crops could be cultivated is available.

Future dietary habits have a major influence on available land area. For instance, given a purely plant-based diet, the world could feed approximately twice as many people from the same land area as today. Consuming less meat and dairy products would mitigate conflicts between food security, bioenergy and nature conservation.

CO2 removal technologies

Intergovernmental Panel on Climate Change (IPCC) scenarios show that even a very rapid and far-reaching reduction in greenhouse gas (GHG) emissions will not alone be enough to achieve the Paris climate targets. “Negative emissions” will also be necessary. One such option for reducing the CO2 content of the atmosphere is to use bioenergy with carbon dioxide capture and storage (BECCS): if biomass is put to use for producing energy, the resultant carbon dioxide is captured and put into permanent underground storage.

In addition to BECCS, there are further CO2 removal technologies, including:

  • Afforestation: trees absorb CO2 and store the carbon. Storage potential can be increased if wood is harvested and transformed into long-lasting products.
  • Biochar: carbonised biomass is stored in the soil. Carbonisation prevents the carbon from being released as CO2.
  • Direct air capture: Technical installations capture carbon dioxide from the ambient air with chemical binding agents. The carbon dioxide is then compressed and stored underground.

While afforestation, biochar and BECCS require cultivated land, direct air capture is more costly, energy-intensive and logistically complex. Both BECCS and direct air capture entail using CCS technology, which is controversial in Germany. A mix of technologies will probably be the only way to meet the overall requirements for negative emissions. If BECCS is to contribute to climate protection, it must be borne in mind that not all bioenergy technologies are equally well suited to CO2 capture.

Climate policy tools

A comprehensive bioenergy policy must view energy, resource and land use as an integrated whole. If, in the future, residues and waste materials are to a greater extent put to use for producing energy, close links with waste management will also develop. The various tools in individual policy areas will thus have to be much more closely coordinated with one another than in the past.

Given a uniform, sufficiently high CO2 price, it will be possible to regulate CO2 emissions from
bioenergy over the entire life cycle. This price will have to include all greenhouse gases in all sectors of the economy, in particular also emissions from agriculture.

Alternatively, or in addition, these tools can help to ensure that bioenergy is of benefit to the climate:

  • National or EU-wide statutory regulations can ensure that biomass produced in Germany is produced sustainably.
  • All biomass imports could be certified. In addition to greenhouse gas emissions, certification should also include social and environmental sustainability criteria.
  • In order to treat domestic and imported biomass equally, the greenhouse gas emissions of imports could be subject to a border tax adjustment.

However, regulating bioenergy only is largely incapable of preventing further deforestation, since only a small proportion of agricultural production is put to use for producing energy. In order to ensure effective protection of forests, these tools would therefore have to be applied equally to all agricultural and forestry products.

Bioenergy technologies

The energy system of the future will probably put bioenergy to different uses than in the past. Given the limited potential of biomass, bioenergy should primarily be used in applications where other renewable energies come up against their limits. By offsetting the weaknesses of wind and hydroelectric power, photovoltaics and geothermal energy, biomass can make a valuable contribution to the energy transition.

  • In the long term, it makes sense to use biomass predominantly for producing motor fuels in applications in which purely electric powertrain systems are impractical, for instance in aviation, shipping or heavy goods vehicles.
  • Another major application is the provision of process heat in industry, since biomass and biogas can also be combusted at high temperatures.
  • In power generation, bioenergy should primarily be used to provide flexibility, while for heating, priority should be given to use in efficient CHP plants.

If bioenergy is to be able to contribute to climate protection in both the short and the long term, on the one hand, existing technologies such as biomethane production and combined heat and power generation should be further developed, and on the other hand, new technologies such as BECCS and biorefineries should be researched and successfully demonstrated.

Development pathways

The areas in which bioenergy is used in the future will primarily be determined by three developments.

  • A first deciding factor is the acceptance or otherwise of CCS as part of the climate protection strategy. If it is rejected by society, it will not be possible to use either BECCS or direct air capture for CO2 removal. If society consents to using CCS, infrastructure for the transport and storage of carbon dioxide must be put in place in the near future.
  • Secondly, it is uncertain how successful the commercial introduction of liquid biofuels made from lignocellulose (e.g. wood or straw) will be. If manufacture is to be competitive, the technology for industrial-scale biorefineries will have to be further developed. Another decisive factor is how the respective markets develop for fuels and raw materials, and for secondary and co-products. In many cases, producing fuel from lignocellulose is only economically viable in large plants, which is inconsistent with today’s pattern of decentralised bioenergy use.
  • Thirdly, expanding infrastructure for combined heat and power generation (CHP) can assist with putting bioenergy to flexible use for electricity and heat generation, not only in small, more decentralised, but also in large, centralised plants. If combined heat and power generation is to be able to develop to its full potential, however, district heating grids need to be expanded and supported by energy policies.

Residues and waste materials can already be put to greater energy use in the short to medium term. Technical adjustments will have to made to the plants to increase the efficiency with which they can be processed.

If biogas is upgraded to biomethane, it can be fed into the natural gas grid and flexibly used in any sector. The environmental footprint can be improved by using residues and waste materials as well as ecologically beneficial crops (e.g. grasses), instead of conventional energy crops.

Comprehensive bioenergy strategy

Since there is not enough biomass available for all conceivable applications, various areas of use will compete for the biomass potential. A comprehensive bioenergy strategy must ensure that bioenergy makes the greatest possible contribution to climate protection and to a secure and affordable energy supply, places no burden on the environment and nature, and at the same time, is accepted by society.

  • Integrated models of energy and land use systems make it possible to evaluate different biomass scenarios and to assess how far they can help to achieve climate protection targets. The models should in the future also include CO2 removal technologies such as BECCS. Systematic research into the opportunities and risks presented by CO2 removal technologies is required
    in order to be able to develop the models appropriately.
  • A platform for discussing transformation pathways could help to shed light from various perspectives on bioenergy development pathways and to rank them. The platform should bring together all of the relevant stakeholders around one table: from energy, agriculture and forestry industry associations to environmental interest groups and consumer advice centres, to representatives of local authorities, civil society and the general population.
  • Systematic monitoring using suitable indicators could be applied to the different development pathways, ideally taking into account the insights into the different aspects of evaluation gained from the discussion platform. The system knowledge created in this way could assist in further developing bioenergy use in a system-beneficial direction.

In this discussion, it is vital to focus on and communicate the huge urgency for climate policy action. CO2 removal technologies such as BECCS are accordingly not in any way an alternative, but rather are complementary to ambitious CO2 mitigation strategies. Should Germany entirely dispense with CCS and CO2 removal technologies, minimising the climate impact of industrial processes in particular and offsetting unavoidable emissions from agriculture will become more difficult.

In a nutshell
  • There is little risk associated with putting residues and waste materials to use as energy. Germany has major potential in terms of timber residues, straw and animal excrement. Converted into energy, these could cover up to 17 per cent of Germany’s future primary energy demand.
  • In order to be sustainable, bioenergy must be put to system-beneficial use: it can assume those functions in the energy system for which other renewables are unsuitable. Bioenergy could, for example, power ships and aircraft or provide heat for industrial processes.
  • Climate models have shown that CO2 will in the future have to be removed from the atmosphere in order to achieve the Paris climate targets. There are various options for producing such “negative emissions”, one of which is to capture carbon dioxide in bioenergy plants and put it into permanent underground storage (BECCS). This approach should be considered in
    relation to future bioenergy applications.
  • Certification systems and a sufficiently high CO2 price are ways of ensuring that bioenergy is beneficial to the climate. They are most effective if they cover not just bioenergy, but rather all agricultural products.

Greenhouse gas balance of bioenergy

Bioenergy is already providing one tenth of Germany’s energy requirements. Biomass is, however, not only needed for supplying energy, but also for producing materials, food and feedstuffs. Since the global population is continuing to grow, so too is demand for biomass, and thus also competition for limited land area.

Any further expansion or intensification of human land use increases the pressure on the environment and nature. It is therefore absolutely essential for bioenergy to be generated and used in such a way that it produces the least amount of greenhouse gas emissions possible, and neither jeopardises biodiversity nor degrades the quality of soils and water resources.

Nitrous oxide emissions from nitrogen fertilisation are the greatest source of emissions from cultivating crop plants. However, changes in land use can also contribute considerably to climate change, in particular when forests are replaced by agricultural land. This is because forests store much more carbon in vegetation and soil than do arable and pasture land. Indirect land use changes occur when the cultivation of energy crops results in the area of agricultural land being expanded in other regions, often in non-European countries. Since the extent of such changes is disputed, reliable estimates of the greenhouse gas emissions caused by bioenergy are extremely difficult to obtain.

Putting forest wood and agricultural commodities to use for producing energy is thus associated with major environmental risks. Bioenergy should instead primarily be produced from residues and waste materials. If unexploited potential from timber residues, cereal straw and animal excrement were tapped and primary energy consumption were reduced to 2,000 terawatt-hours per year by 2050, as targeted by the federal government, residues and waste materials could provide 13 to 17 per cent of primary energy. Designing bio-based materials to be low in pollutants and readily recyclable enables repeated use and energy recovery at the end of the product’s life (cascade use).

Global potential

Biomass is traded on international markets. Bioenergy use in Germany thus has global consequences. Estimates of future sustainable global bioenergy potential range from between fifty exajoules per year, or roughly today’s level of consumption, and several hundred exajoules per year. The range is so large because it is unclear to what extent agricultural yields can be raised and how much unused, degraded agricultural and pasture land on which energy crops could be cultivated is available.

Future dietary habits have a major influence on available land area. For instance, given a purely plant-based diet, the world could feed approximately twice as many people from the same land area as today. Consuming less meat and dairy products would mitigate conflicts between food security, bioenergy and nature conservation.

CO2 removal technologies

Intergovernmental Panel on Climate Change (IPCC) scenarios show that even a very rapid and far-reaching reduction in greenhouse gas (GHG) emissions will not alone be enough to achieve the Paris climate targets. “Negative emissions” will also be necessary. One such option for reducing the CO2 content of the atmosphere is to use bioenergy with carbon dioxide capture and storage (BECCS): if biomass is put to use for producing energy, the resultant carbon dioxide is captured and put into permanent underground storage.

In addition to BECCS, there are further CO2 removal technologies, including:

  • Afforestation: trees absorb CO2 and store the carbon. Storage potential can be increased if wood is harvested and transformed into long-lasting products.
  • Biochar: carbonised biomass is stored in the soil. Carbonisation prevents the carbon from being released as CO2.
  • Direct air capture: Technical installations capture carbon dioxide from the ambient air with chemical binding agents. The carbon dioxide is then compressed and stored underground.

While afforestation, biochar and BECCS require cultivated land, direct air capture is more costly, energy-intensive and logistically complex. Both BECCS and direct air capture entail using CCS technology, which is controversial in Germany. A mix of technologies will probably be the only way to meet the overall requirements for negative emissions. If BECCS is to contribute to climate protection, it must be borne in mind that not all bioenergy technologies are equally well suited to CO2 capture.

Climate policy tools

A comprehensive bioenergy policy must view energy, resource and land use as an integrated whole. If, in the future, residues and waste materials are to a greater extent put to use for producing energy, close links with waste management will also develop. The various tools in individual policy areas will thus have to be much more closely coordinated with one another than in the past.

Given a uniform, sufficiently high CO2 price, it will be possible to regulate CO2 emissions from
bioenergy over the entire life cycle. This price will have to include all greenhouse gases in all sectors of the economy, in particular also emissions from agriculture.

Alternatively, or in addition, these tools can help to ensure that bioenergy is of benefit to the climate:

  • National or EU-wide statutory regulations can ensure that biomass produced in Germany is produced sustainably.
  • All biomass imports could be certified. In addition to greenhouse gas emissions, certification should also include social and environmental sustainability criteria.
  • In order to treat domestic and imported biomass equally, the greenhouse gas emissions of imports could be subject to a border tax adjustment.

However, regulating bioenergy only is largely incapable of preventing further deforestation, since only a small proportion of agricultural production is put to use for producing energy. In order to ensure effective protection of forests, these tools would therefore have to be applied equally to all agricultural and forestry products.

Bioenergy technologies

The energy system of the future will probably put bioenergy to different uses than in the past. Given the limited potential of biomass, bioenergy should primarily be used in applications where other renewable energies come up against their limits. By offsetting the weaknesses of wind and hydroelectric power, photovoltaics and geothermal energy, biomass can make a valuable contribution to the energy transition.

  • In the long term, it makes sense to use biomass predominantly for producing motor fuels in applications in which purely electric powertrain systems are impractical, for instance in aviation, shipping or heavy goods vehicles.
  • Another major application is the provision of process heat in industry, since biomass and biogas can also be combusted at high temperatures.
  • In power generation, bioenergy should primarily be used to provide flexibility, while for heating, priority should be given to use in efficient CHP plants.

If bioenergy is to be able to contribute to climate protection in both the short and the long term, on the one hand, existing technologies such as biomethane production and combined heat and power generation should be further developed, and on the other hand, new technologies such as BECCS and biorefineries should be researched and successfully demonstrated.

Development pathways

The areas in which bioenergy is used in the future will primarily be determined by three developments.

  • A first deciding factor is the acceptance or otherwise of CCS as part of the climate protection strategy. If it is rejected by society, it will not be possible to use either BECCS or direct air capture for CO2 removal. If society consents to using CCS, infrastructure for the transport and storage of carbon dioxide must be put in place in the near future.
  • Secondly, it is uncertain how successful the commercial introduction of liquid biofuels made from lignocellulose (e.g. wood or straw) will be. If manufacture is to be competitive, the technology for industrial-scale biorefineries will have to be further developed. Another decisive factor is how the respective markets develop for fuels and raw materials, and for secondary and co-products. In many cases, producing fuel from lignocellulose is only economically viable in large plants, which is inconsistent with today’s pattern of decentralised bioenergy use.
  • Thirdly, expanding infrastructure for combined heat and power generation (CHP) can assist with putting bioenergy to flexible use for electricity and heat generation, not only in small, more decentralised, but also in large, centralised plants. If combined heat and power generation is to be able to develop to its full potential, however, district heating grids need to be expanded and supported by energy policies.

Residues and waste materials can already be put to greater energy use in the short to medium term. Technical adjustments will have to made to the plants to increase the efficiency with which they can be processed.

If biogas is upgraded to biomethane, it can be fed into the natural gas grid and flexibly used in any sector. The environmental footprint can be improved by using residues and waste materials as well as ecologically beneficial crops (e.g. grasses), instead of conventional energy crops.

Comprehensive bioenergy strategy

Since there is not enough biomass available for all conceivable applications, various areas of use will compete for the biomass potential. A comprehensive bioenergy strategy must ensure that bioenergy makes the greatest possible contribution to climate protection and to a secure and affordable energy supply, places no burden on the environment and nature, and at the same time, is accepted by society.

  • Integrated models of energy and land use systems make it possible to evaluate different biomass scenarios and to assess how far they can help to achieve climate protection targets. The models should in the future also include CO2 removal technologies such as BECCS. Systematic research into the opportunities and risks presented by CO2 removal technologies is required
    in order to be able to develop the models appropriately.
  • A platform for discussing transformation pathways could help to shed light from various perspectives on bioenergy development pathways and to rank them. The platform should bring together all of the relevant stakeholders around one table: from energy, agriculture and forestry industry associations to environmental interest groups and consumer advice centres, to representatives of local authorities, civil society and the general population.
  • Systematic monitoring using suitable indicators could be applied to the different development pathways, ideally taking into account the insights into the different aspects of evaluation gained from the discussion platform. The system knowledge created in this way could assist in further developing bioenergy use in a system-beneficial direction.

In this discussion, it is vital to focus on and communicate the huge urgency for climate policy action. CO2 removal technologies such as BECCS are accordingly not in any way an alternative, but rather are complementary to ambitious CO2 mitigation strategies. Should Germany entirely dispense with CCS and CO2 removal technologies, minimising the climate impact of industrial processes in particular and offsetting unavoidable emissions from agriculture will become more difficult.

Infographic

What use can the energy system of the future make of bioenergy?

Bioenergy can perform many different functions in the energy system but potential supplies are limited. How it is used in future depends on decisions made by society and on technological developments. The infographic shows possible development pathways for the future of bioenergy use.

Please choose how the context for making use of bioenergy might develop.

Usage pathways:CHP strategy implementedCombined heat and power generation (CHP) is the simultaneous production of mechanical energy and thermal energy for heating purposes or industrial processes. It enables efficient electricity and heat generation from biogas, wood or waste. If greater use is to be made in future of CHP with bioenergy, heating networks will have to be expanded. Although CHP plays a major part in many energy scenarios, support for investment in combined heat and power generation and heating networks is currently patchy.

Usage pathways:Technology for liquid fuels from lignocelluloseBiofuels have so far been produced from oil crops such as oilseed rape (biodiesel) or starch crops such as maize (bioethanol). However, growing these crops requires farmland, fertilisers and pesticides and therefore has a negative impact on both the environment and biodiversity. It would be more sustainable to produce biofuels in future from forest wood residues, straw or other waste and residues, but this will require special conversion processes. Existing plants for producing liquid fuels and biogas plants cannot process lignocellulose.

Usage pathways:CCS is part of the climate protection strategyClimate protection scenarios show that carbon dioxide will have to be removed from the atmosphere within a few decades. One possible way of achieving this is bioenergy with carbon (dioxide) capture and storage (BECCS). This works by plants capturing carbon dioxide from the air and using it to form energy-rich compounds. If the plants are then used for energy production, the resultant carbon dioxide is captured and put into underground storage. Carbon dioxide storage is a highly controversial issue in German society.

Usage pathways

CHP strategy implemented

Technology for liquid fuels from lignocellulose

CCS is part of the climate protection strategy

Main applications

Further development of current systems

Small CHP

Small CHP and advanced motor fuels

Advanced motor fuels

Industrial process heat + CCS

H2 as motor fuel

Large CHP plants

Large CHP und H2 as motor fuel

Main applications:Further development of current systemsWood is today mainly used for heating. Biogas is combusted in small combined heat and power plants to generate electricity and heat. These technologies will be capable of providing climate-friendly heat and electricity in the future too. If, however, heating networks are inadequate, it is often not possible to make full use of the heat generated in CHP plants. A heating network moreover provides buffer capacity which means that the heat and power supply from CHP plants can be somewhat decoupled. In the absence of heating networks, CHP plants are less capable of compensating fluctuating feed-in from wind and solar power systems.

Biogas could in future be upgraded to biomethane. Biomethane can be transported via the existing natural gas grid and put to flexible use for heat and power generation and in natural gas vehicles. Instead of being obtained from maize as previously, biogas could in future be obtained in a more environmentally friendly way from residues and waste materials, grass mixtures and bee-friendly flowering crops.

Main applications:Small CHPCHP plants are the most efficient way of generating heat and electricity from bioenergy. There is a need for a CHP strategy to give some impetus to the expansion of heating networks and create a favourable economic framework in the energy sector for CHP plants. This usage pathway permits the use of small, decentralised plants which are preferred by the population. In addition to biogas plants, small wood gasifiers are another important technology here.

Connecting large heat storage systems, solar thermal energy and power-to-heat plants to the heating network in addition to CHP plants assists with stabilising electricity supplies: when the sun is shining and the wind blowing, power-to-heat plants convert excess power into heat. CHP plants, on the other hand, bridge power supply gaps during calm spells with low light.

Main applications:Small CHP and advanced motor fuelsMotor fuels from biomass are more valuable to the energy system than electricity or heat from this energy source since the latter can be easily and efficiently generated using wind and solar power. Producing motor fuels from electricity, in contrast, is lossy and expensive. Biorefineries for producing motor fuel are, however, large-scale plants which demand appropriate logistics for sourcing biomass. Biomass, which is today mainly produced, traded and used locally or regionally, would have to be transferred into supra-regional supply structures. Impacts on local biomass suppliers and users should be taken into account here.

Biomass which will continue to be put to decentralised use can be most efficiently used for electricity and heat generation in CHP plants.

Main applications:Advanced motor fuelsMotor fuels will continue to be required even in the long term for aviation, shipping and some heavy goods transport. While fuels can indeed be produced from wind and solar power using "power-to-X" processes, this approach is costly and energy-intensive. If motor fuels from residues and waste materials containing lignocellulose can be successfully commercially introduced, they might provide an inexpensive alternative. Achieving this will, however, require further development of the associated processes. In particular, there is a need to develop biorefineries on a large industrial scale, achieve high plant availability and cut costs.

The approximately 300 terawatt-hours of residues and waste materials which would be available to Germany each year if it tapped previously unused potential could, allowing for conversion losses, meet around half of future fuel demand, providing that a large proportion of transport use changes over to electromobility.

Main applications:Industrial process heat + CCSWhile heat pumps can provide heating very efficiently, this is not possible for industrial process heat at temperatures of several hundred degrees. Biomass can be an alternative combustion fuel for such applications. Biomethane is particularly straightforward to use. It has the same chemical composition as natural gas, which is widely used in industry as a combustion fuel. Natural gas can therefore be gradually replaced by biogas without requiring any changes to the industrial processes. The existing natural gas grid can be used for transport. Wood and solid residues and waste materials can, however, also be used as fuels.

Since relatively large industrial sites are possibly in any event connected to CO2 capture and storage infrastructure, bioenergy with carbon capture and storage (BECCS) could be trialled there. Some climate protection scenarios make considerable use of BECCS technologies.

Main applications:H2 as motor fuelBiorefineries can produce both carbon-containing motor fuels and hydrogen from biomass. Hydrogen in particular offers advantages if the biorefinery is to be combined with CCS (Carbon Capture and Storage) because all the carbon present in the biomass is converted into CO2 during the production of H2 and can be captured and stored. In contrast, if motor fuels such as kerosene or petrol are produced, a large proportion of the carbon remains in the motor fuel and cannot be captured and stored. Hydrogen production thus offers particularly significant potential for „negative emissions“.

The extent to which hydrogen will in future be used in the energy system depends on whether appropriate infrastructure is put in place.

Main applications:Large CHP plantsLarge CHP plants allow efficient electricity and heat generation to be combined with CO2 capture. The captured CO2 could be stored (CCS), so removing CO2 from the atmosphere.

It will be essential to expand heating networks for this development pathway because, precisely in the case of large CHP plants, it will be virtually impossible to supply the generated heat to potential consumers and make efficient use of it without heating networks.

Main applications:Large CHP and H2 as motor fuelIf society does opt for CCS (Carbon Capture and Storage) as part of the climate protection strategy, priority could be given to using bioenergy technologies which allow CO2 capture to be as complete as possible. These technologies would be firstly the production of hydrogen in biorefineries and secondly the generation of electricity and heat in large CHP plants. Widespread use of both technologies entails both expanding heating networks and building infrastructure for transporting and using the hydrogen (e.g. in fuel cell vehicles).

If the framework for both technology pathways is favourable, they will be in competition for limited biomass potential.

If you do not see an interactive infographic, please increase the size of your browser window or click on the button below for a PDF version.

Infografic as PDF

Chairmen

  • Prof. Dr. Gernot Klepper
  • Kiel Institute for the World Economy (ifw)
  • Research Area "The Environment and Natural Resources"
  • Sustainable Land Use
  • Team Leader

Publications

Position Paper

Biomass: striking a balance between energy and climate policies. Strategies for sustainable bioenergy use

Bioenergy is the most versatile of the renewable energy sources and provides more energy than wind and hydroelectric power, solar energy and geothermal energy combined. A coherent bioenergy policy must ensure that bioenergy use has no negative social and environmental impacts, and makes the greatest possible contribution to climate protection.

With the initiative “Energy Systems of the Future” (ESYS), acatech – National Academy of Science and Engineering, the German National Academy of Sciences Leopoldina and the Union of the German Academies of Sciences and Humanities provide impulses for the debate on the challenges and opportunities of the German energy transition. The Academies’ Project assembles more than 160 experts from science and research to develop policy options for the implementation of a secure, affordable and sustainable energy supply. ESYS was launched in April 2013 and will be funded by the Federal Ministry of Education and Research (BMBF) until June 2024. For this project, acatech is the lead institution.

www.acatech.de
www.leopoldina.org
www.akademienunion.de