System Comparison of Storable Renewable Energy Sources (SYSEET)

Within the framework of the European climate policy and the Paris Agreement, Germany has committed itself to reducing the emission of CO2 and other greenhouse gases by up to 95 percent by 2050. The most efficient way to eliminate these emissions is to directly use electricity from renewable sources. In some sectors, though, such as air traffic and international shipping, this is virtually impossible to achieve. Additionally, some parts of the industry will continue to require liquid or gaseous energy carriers as raw materials, reducing agents and fuel. In future, this demand could be satisfied by so-called Power-to-X energy carriers (PtX). These are either synthetic gases (hydrogen, methane) or liquid hydrocarbons (diesel, gasoline, kerosene, methanol) that can be produced with electricity from renewable sources.

The aim of the SYSEET project is to determine the environmental impact of the production of these storable energy carriers - today and in the transformation process until 2050. Even with 100 % electricity from renewable sources, the construction of the facilities and the transport infrastructure require raw materials and cause emissions into air and water. The carbon needed for the synthesis of hydrocarbons must be recovered as CO2 from exhaust gases, air or biomass. This can in turn result in environmental pollution – from eutrophication to acidification of soil and water.

The results of this study will allow a systematic and comprehensive assessment of the supply of gaseous and liquid fuels based on renewable electricity and biomass. The basis for the comparison is the life cycle assessment (LCA) of these substances, which takes all relevant environmental impacts and resource needs into account.


March 2017 – November 2018


Umweltbundesamt (UBA)


Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

JOANNEUM RESEARCH Forschungsgesellschaft mbH


Download the study (in German)

Press release on the publication of the study (in German)