Search results

A recent paper by Searchinger highlighted that Annex-1 nations do not count CO2 emissions due to combustion of biomass in their commitments. This is because it is assumed that emissions from use of biomass are accounted for in the land use sector, where they should appear as reductions in carbon stocks. However, if the biomass comes from a non-Annex 1 country, these reductions are not counted within the Kyoto Protocol. Indeed, even Annex 1 countries do not necessarily fully account for carbon stock losses associated with bioenergy. This results in overestimating the mitigation benefits of bioenergy. - The problem can be rectified by modifying the accounting system, adopting new policy measures or a combination of both. In the paper, we describe possible options and policy measures to improve the accounting of emissions from bioenergy. The pros and cons of the identified solutions are also discussed.

In the course of the transformation to a greenhouse gas-neutral society in the second half of the 21st century, the use of synthetic energy carriers based on renewable electricity or biomass is under discussion. This project evaluates the environmental impacts of technical and logistical options for the generation of such energy carriers on the basis of environmental impact categories such as global warming potential, acidification or land use. The production of five products (Fischer-Tropsch fuels, methanol, synthetic natural gas, biomethane and hydrogen) was examined based on various process steps/procedures and their current and future technical data. By using regional factors for Germany, Europe, and the Mediterranean region - like the availability of renewable energy carriers such as wind or PV and of raw materials such as carbon or water as well as transport routes to Germany - these processes were combined to form supply paths for these energy carriers. Using the method of life cycle assessment, the environmental effects were analysed for today and 2050. In addition, the costs for plant construction and operation were estimated. The results show that synthetic energy carriers generally have a significantly lower global warming potential than today's fossil reference products due to the use of renewable energies. However, the production of electricity generation plants and associated economic processes - such as steel and cement production - can still make a relevant contribution to the global warming potential if they are not also greenhouse neutral. At the same time, it is this production of the necessary plants that leads to (sometimes significantly) increased burdens compared with the fossil reference in almost all other impact categories, most notably in terms of water and land use. This study therefore also provides indications of which environmental impacts must be further reduced in the future.