@unpublished{KaulBoellmannThemaetal., author = {Kaul, Anja and B{\"o}llmann, Andrea and Thema, Martin and Kalb, Larissa and St{\"o}ckl, Richard and Huber, Harald and Sterner, Michael and Bellack, Annett}, title = {Identification of Robust Thermophilic Methanogenic Archaea and Packing Material for High Liquid Hold-Up at Low Volumetric Gas Flow Rates for Use in Trickle-Bed Reactors for Biological Methanation}, series = {SSRN Electronic Journal}, journal = {SSRN Electronic Journal}, doi = {10.2139/ssrn.3940878}, abstract = {he hydrogen gas-to-liquid mass transfer is the limiting factor in biological methanation. In a trickle-bed reactor, mass transfer can be increased by high flow velocities in the liquid phase, by adding a packing material with high liquid hold-up, or by choosing methanogenic archaea with a high methane productivity. This study analyzed various packings and methanogenic strains from a hydrodynamic and microbial perspective. By analyzing twelve pure cultures of thermophilic methanogens for their ability to produce high quality methane and to form biofilms on different packings, strains of Methanothermobacter were found to perform better than thus of the genus Methanothermococcus. Best methane production and adherence was observed on DuraTopĀ®, Bioflow 9, and filter foam. DuraTopĀ® and Bioflow 9 had also a high dynamic liquid hold-up, but the maximum hold-up was determined for expanded clay. The ideal combination for use in the ORBIT-trickle-bed reactor was identified as Methanothermobacter thermoautotrophicus IM5 and DuraTopĀ®.}, language = {en} } @unpublished{HeberlWithelmKauletal., author = {Heberl, Michael and Withelm, Christian and Kaul, Anja and Rank, Daniel and Sterner, Michael}, title = {Prospective Life Cycle Assessment of Biological Methanation in a Trickle-Bed Pilot Plant and a Potential Scale-Up}, publisher = {SSRN}, doi = {10.2139/ssrn.4635066}, abstract = {In this study, a pilot-scale trickle-bed reactor for biological methanation and various scale-up scenarios for 2023 and 2050 were investigated using LCA. A best- and worst-case scenario for technology development until 2050 was evolved using cross consistency analysis and morphological field, based on which the data for the ecological models were determined.The results show that the plant scale-up has a very positive effect on the ecological consequences of methanation. In the best-case scenario, the values are a factor of 23-780 lower than those of the actual plant today. A hot-spot analysis showed that especially electrolysis operation has a large impact on total emissions. The final Monte-Carlo simulation shows that the technology is likely to achieve a low GWP with a median of 104.0 kg CO2-eq / MWh CH4.}, language = {en} } @unpublished{MeisingerHofrichterBaueretal., author = {Meisinger, Alexander and Hofrichter, Andreas and Bauer, Franz and Sterner, Michael}, title = {Unlocking Potential Energy Partnerships in Europe: a Case Study on the Way to a Franco-German Energy Transition}, publisher = {SSRN}, doi = {10.2139/ssrn.5251699}, pages = {23}, abstract = {Global warming is already causing global destabilization. Geopolitical challenges fuel this instability and highlight the need for trusted energy partnerships to ensure energy security. To limit global warming and increase energy security, it is essential to take joint action on an international and global scale. The European Green Deal contributes to this. However, specific national actions are still needed. This research presents a way forward for a Franco-German energy transition and unlocks the potential of energy partnerships within Europe, using a cost-based, sector-coupled optimization model. Both countries are coupled via an isolated country optimization approach. Thus, the focus is on the development of each national energy system. The results highlight the increase of energy security in line with the European Green Deal. The main pillars of the energy transition are solar energy (32- 33\%), wind energy (25-38\%) and biogenic energy sources (13-27\%). Nuclear power is being phased out in Germany and France. The results show that a Franco-German energy partnership has great potential. Overall, France can cost-effectively cover 25\% of Germany's hydrogen import needs (122 TWh) in 2050. At the same time, France can also benefit from the energy partnership in terms of economic growth and joint action to mitigate climate crisis.}, language = {en} } @unpublished{SchummAbdelKhalekBrownetal., author = {Schumm, Leon and Abdel-Khalek, Hazem and Brown, Tom and Ueckerdt, Falko and Sterner, Michael and Fioriti, Davide and Parzen, Max}, title = {The impact of temporal hydrogen regulation on hydrogen exporters and their domestic energy transition}, publisher = {Research Square Platform LLC}, doi = {10.21203/rs.3.rs-4285425/v1}, abstract = {As global demand for green hydrogen rises, potential hydrogen exporters move into the spotlight. However, the large-scale installation of on-grid hydrogen electrolysis for export can have profound impacts on domestic energy prices and energy-related emissions. Our investigation explores the interplay of hydrogen exports, domestic energy transition and temporal hydrogen regulation, employing a sector-coupled energy model in Morocco. We find substantial co-benets of domestic climate change mitigation and hydrogen exports, whereby exports can reduce domestic electricity prices while mitigation reduces hydrogen export prices. However, increasing hydrogen exports quickly in a system that is still dominated by fossil fuels can substantially raise domestic electricity prices, if green hydrogen production is not regulated. Surprisingly, temporal matching of hydrogen production lowers domestic electricity cost by up to 31\% while the effect on exporters is minimal. This policy instrument can steer the welfare (re-)distribution between hydrogen exporting firms, hydrogen importers, and domestic electricity consumers and hereby increases acceptance among actors.}, language = {en} }