Understanding the Bigger Energy Picture: DESERTEC and Beyond

This book focuses on the global cycles of energy, water and carbon, which are not only the essentials of our main energy carriers, the fossil fuels, but are also the building blocks of life. The book offers an overview of the basic scientific facts and relationships that are needed to understand today’s energy generation and use, how they relate to global climate, the water cycle and other resources, and the complexities of energy policy. Building on the work of the Desertec project, it presents the main technological options that we will have in a world after the “Energiewende” and presents the possible future solutions for a sustainable world. The book is written in an engaging, descriptive style that can be understood by those without specific knowledge of science or economics and allows readers to form their own conclusions. Controversy rages over energy problems, climate change and their possible solutions. Expressions like “climate deniers”, “renaissance of nuclear energy”, “stop the war on coal”, and “Energiewende now” represent a diversity of opinions that divide our society and political leaders. This book shows the reader the whole energy picture and how it is part of the wider global problems of overpopulation and uncontrolled economies in a world of limited resources

Early stages of phase selection in MOF formation observed in molecular Monte Carlo simulations

Metal-organic frameworks (MOF) comprising metal nodes bridged by organic linkers show great promise because of their guest-specific gas sorption, separation, drug-delivery, and catalytic properties. The selection of metal node, organic linker, and synthesis conditions in principle offers engineered control over both structure and function. For MOFs to realise their potential and to become more than just promising materials, a degree of predictability in the synthesis and a better understanding of the self-assembly or initial growth processes is of paramount importance. Using cobalt succinate, a MOF that exhibits a variety of phases depending on synthesis temperature and ligand to metal ratio, as proof of concept, we present a molecular Monte Carlo approach that allows us to simulate the early stage of MOF assembly. We introduce a new Contact Cluster Monte Carlo (CCMC) algorithm which uses a system of overlapping "virtual sites" to represent the coordination environment of the cobalt and both metal-metal and metal-ligand associations. Our simulations capture the experimentally observed synthesis phase distinction in cobalt succinate at 348 K. To the best of our knowledge this is the first case in which the formation of different MOF phases as a function of composition is captured by unbiased molecular simulations. The CCMC algorithm is equally applicable to any system in which short-range attractive interactions are a dominant feature, including hydrogen-bonding networks, metal-ligand coordination networks, or the assembly of particles with "sticky" patches, such as colloidal systems or the formation of protein complexes.</p

Polarized lepton nucleon scattering - summary of the experimental spin sessions at DIS 99

This paper summarizes the contributions to the experimental sessions on polarized lepton nucleon scattering at the DIS 99 workshop. Results are reported about the flavor decomposition of the quark polarization, a first direct measurement of a positive gluon polarization, the observation of a double-spin asymmetry in diffractive rho production, the polarization of lambda hyperons, the observation of transverse single-spin asymmetries and the measurement of the Gerasimov-Drell-Hearn sum rule. Prospects of future fixed target and collider facilities are discussed.Comment: 8 pages, 5 figures, Proc. of the 7th Int. Workshop on Deep Inelastic Scattering and QCD (DIS99), Zeuthen, Germany, April 19-23, 1999, to appear in Nucl. Phys. B (Proc. Suppl.

Understanding the Bigger Energy Picture: DESERTEC and Beyond

climate change; renewable energy; sustainable development; water; water-energy-carbon nexu

Understanding the kinetic and thermodynamic origins of xylene separation in UiO-66(Zr) via molecular simulation

Xylene isomers are precursors in many important chemical processes, yet their separation via crystallization or distillation is energy intensive. Adsorption presents an attractive, lower-energy alternative and the discovery of adsorbents which outperform the current state-of-the-art zeolitic materials represents one of the key challenges in materials design, with metal-organic frameworks receiving particular attention. One of the most well-studied systems in this context is UiO-66(Zr), which selectively adsorbs ortho-xylene over the other C8 alkylaromatics. The mechanism behind this separation has remained unclear, however. In this work, we employ a wide range of computational techniques to explore both the equilibrium and dynamic behavior of the xylene isomers in UiO-66(Zr). In addition to correctly predicting the experimentally-observed ortho-selectivity, we demonstrate that the equilibrium selectivity is based upon the complete encapsulation of ortho-xylene within the pores of the framework. Furthermore the flexible nature of the adsorbent is crucial in facilitating xylene diffusion and our simulations reveal for the first time significant differences between the intracrystalline diffusion mechanisms of the three isomers resulting in a kinetic contribution to the selectivity. Consequently it is important to include both equilibrium and kinetic effects when screening MOFs for xylene separations

Import options for chemical energy carriers from renewable sources to Germany

Import and export of fossil energy carriers are cornerstones of energy systems world-wide. If energy systems are to become climate neutral and sustainable, fossil carriers need to be substituted with carbon neutral alternatives or electrified if possible. We investigate synthetic chemical energy carriers, hydrogen, methane, methanol, ammonia and Fischer-Tropsch fuels, produced using electricity from renewable energy sourceses as fossil substitutes. Renewable energy sourceses potentials are obtained from GIS-analysis and hourly resolved time-series are derived using reanalysis weather data. We model the sourcing of feedstock chemicals, synthesis and transport along nine different energy supply chains to Germany. and compare import options for seven locations around the world against each other and with domestically sourced alternatives on the basis of their respective cost per unit of hydrogen and energy delivered. We find that for each type of chemical energy carrier an import option with lower costs compared to domestic production in Germany exists. The lowest cost import options for energy and hydrogen are by hydrogen pipeline from Denmark, Spain and Western Asia and North Africa at 40.6 to 46.8 EUR per MWh (LHV) (1.4 to 1.6 EUR per kg H2) in 2050 assuming 5% p.a. capital cost. For complex energy carriers like methane, ammonia, methanol or Fischer-Tropsch fuel, imports from Argentina by ship to Germany are attractive even compared to closer European Union or Western Asia and North Africa exporters. For meeting hydrogen demand, direct hydrogen imports are more attractive than indirect routes using methane, methanol or ammoniaimports and subsequent decomposition to hydrogen because of high capital investment costs and energetic losses of the indirect routes. We make our model and data available under open licenses for adaptation and reuse

Import options for chemical energy carriers from renewable sources to Germany

Import and export of fossil energy carriers are cornerstones of energy systems world-wide. If energy systems are to become climate neutral and sustainable, fossil carriers need to be substituted with carbon neutral alternatives or electrified if possible. We investigate synthetic chemical energy carriers, H2, CH4, MeOH, NH3 and Fischer-Tropsch fuels (FTF), produced using electricity from RES as fossil substitutes. [...] We model the sourcing of feedstock chemicals, synthesis and transport along nine different Energy Supply Chains to Germany (DE) and compare import options for seven locations around the world against each other and with domestically sourced alternatives on the basis of their respective cost per unit of H2 and energy delivered. We find that for each type of chemical energy carrier, there is an import option with lower costs compared to domestic production in DE. No single exporting country or energy carrier has a unique cost advantage, since for each energy carrier and country there are cost-competitive alternatives. This allows exporter and infrastructure decisions to be made based on other criteria than energy and cost. The lowest cost means for importing of energy and H2 are by H2 pipeline from Denmark, Spain and Western Asia and Northern Africa starting at 36 EUR/MWh$_{LHV}$ to 42 EUR/MWh$_{LHV}$ or 1.0 EUR/kg$_{H2}$ to 1.3 EUR/kg$_{H2}$ (in 2050, assuming 5 % p.a. capital cost). For complex energy carriers derived from H2 like CH4, NH3, MeOH or FTF, imports from Argentina by ship to DE are lower cost than closer exporters in the European Union or Western Asia and Northern Africa. For meeting H2 demand, direct H2 imports are more attractive than indirect routes using CH4, MeOH or NH3 imports and subsequent decomposition to H2 because of high capital investment costs and energetic losses. We make our model and data available under open licenses for adaptation and reuse