• Energy Research
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To satisfy national sustainability targets in Germany, both bioenergy and organic farming claim a growing area of farmland. Analyses with a land use model and ac-companying expert interviews show, how the competition for land is growing in certain regions. A restricted area potential for energy crops – even with an ever intensifying farming opposes targets for an increasing share of land for organic agriculture and nature conservation. Thus there is a need for policy action, to discuss and solve this goal conflict. An ongoing study currently develops strategies for two selected German regions for a more ecologically compatible bioenergy production.

Forest biomass plays a crucial role in the quantification of the terrestrial carbon budget. Today, forest biomass is poorly quantified across most parts of the Earth surface due to the great difficulties in measuring biomass on the ground and consistently aggregating measurements across scales. SAR satellites can provide the required information globally and frequent in order to quantify current biomass state and the changes. Tandem-L is a German mission proposal for an innovative interferometric L-band radar mission that enables the systematic monitoring of dynamic Earth processes using advanced techniques and technologies. The mission is science driven aiming to provide a unique data set for climate and environmental research, geodynamics, hydrology and oceanography. Important application examples are global forest height and structure and the derivation of forest biomass. The Tandem-L mission concept consists of two cooperating satellites flying in close formation. The 3 D structure mode provides a unique data source to observe and quantify changes in forest biomass. This paper provides an overview of the potential of using multi-parametric SAR for forest structure estimation with the derivation of forest biomass and suggests a mission for a global acquisition.

In 2011 the German Advisory Council for Global Change (WBGU) published a remarkable policy document entitled ‘World in Transition: A Social Contract for Sustainability’ in which the authors proclaim the need for a great social transformation at the global scale in order to address climate change. This article builds on and critically discusses the central messages of the report that emphasizes the necessity to pro-actively shape the change of our values and worldviews that underpin our lifestyles and consumption patterns. By arguing for a transdisciplinary approach to implement this challenging vision the report identifies urbanization as a significant dimension in these processes thus shifting away from the dominant focus on socio-technical solutions. This puts the field of urban planning and development and related disciplines at the centre of the climate change adaptation and mitigation debate raising profound questions as to how these professionals, academics and practitioners could respond to the ideas brought forward in the report. The author considers this an opportunity for hitherto largely neglected integral approaches to gain more importance in mainstream urban planning practice and theory. The concluding part sketches out an initial research programme based on the previous discussion in order to illustrate at a more concrete level the implications of an integrative, transdisciplinary framework for planning.

The transformation of the electricity system upon condition of sustainable development and an accelerated nuclear phase-out is one of the crucial challenges currently facing the German economy. Due to effective policy support to date, electricity generated by renewable energies already accounts for a relevant share - 20.1% - of the German electricity supply. As a result, enforced market integration and a more demand-oriented feed-in of electricity from renewable energies are considered crucial next steps in the process of transformation. In the process, recent years have seen the development and discussion of new regulation mechanisms aimed at facilitating a smooth transition for renewable energy power plant operators from guaranteed feed-in tariffs to a deregulated electricity market. A variety of actors have been involved, both in this development process and in the actual process of market integration. These actors’ goals, strategies and options have formed the focus of two interdisciplinary research projects1. The goal of the projects is the development of an agent-based simulation model as an instrument to analyse possible actions and interactions of the relevant stakeholders, as well as their effects on the overall system under different regulatory frameworks. An important prerequisite for the set-up of the agent-based model was the thorough analysis of the relevant actors: how are they influenced by the regulatory framework? How do they develop business models and routines, and how have they tried to reshape formal institutions in order to meet their goals? This actor analysis and its results will be presented in this paper. We will present the agent-based simulation model AMIRIS (Agent-based Model for the Integration of Renewables Into the Power System), which can be used as a policy analysis and design tool to foster the integration of renewable energy sources into the electricity market. Additionally, we show some results of first simulation runs for the assessment of the ‘optional market premium’ in Germany until 2020.

Due to the increasing number of people living and/or working in dense urban environments, the importance of city planning in consideration of human health and comfort has been continuously growing. Health and comfort factors such as thermal comfort, air quality, ventilation and UV exposure, must be considered in a future-oriented development of urban regions. For decision support, urban climate models (UCM) are applied to model the effects of existing and planned building distributions, facade and city greening, etc., based on the above mentioned factors. A highly-efficient microscale UCM, PALM-4U, has been developed allowing simulations of large cities with grid-resolved buildings and vegetation canopy, which consider a large variety of processes important for urban environments. PALM-4U is part of the PALM model system (http://palm-model.org), which is based on the large-eddy simulation code PALM. While there exist numerous UCMs that have been used for over two decades and which are well established in the scientific community, they are difficult to adapt to state-of-the-art parallel computer systems and thus often have limitations in either performance and/or possible number of grid points. PALM-4U is able to compute entire city environments like Berlin (about 1 700 km²) at building-resolving grid spacing (here 10 m) on massively parallel computers, where limitations are mainly imposed by the available computational resources. It offers several features required in urban environments, such as an energy balance solver for urban and natural surfaces, radiative transfer in the urban canopy layer, chemical reactions, biometeorological analysis products, and self-nesting to allow high resolution (e.g. 1 m) in regions of special interest. In this presentation we will focus on an overview of PALM-4U's current and planned capabilities for application in urban environments. Besides, we will demonstrate PALM-4U's performance and features based on microscale building-resolving large-eddy simulation of entire Berlin (Germany, 1700 km²) at a grid spacing of 10 m, with a nested domain of size of 1 km² at a grid spacing of 1 m. The simulation spans a simulated period of a full diurnal cycle during a selected heat wave period and is characterized by low geostrophic winds and a strong solar forcing during daytime. General features of the simulation will be visualized. This presentation is intended to be the first in a series of presentations that all have a more specific focus on single features of PALM-4U and for which abstracts are submitted separately. In this overview talk we will thus focus on the more general features of the simulation.

This paper presents some results from the EU-financed project MED-CSD in which were carried out technical and economic feasibility studies in concrete locations within selected MENA countries for water and power plants driven by concentrated solar power (CSP). If on one hand desalination helps to alleviate the problem of water scarcity and represent a valid alternative to overexploitation of underground water resources, on the other hand has to confront with energetic and environmental problems. The use of solar energy, which is typically abundant in areas affected by water scarcity, is the key for a sustainable water and power supply. Furthermore it has been shown that combined CSP-desalination plants are economically feasible and deliver energy and water at a fixed and secure price, compared with the price instability and the increasing scarcity of fossil fuels.

The design of support structures of offshore wind turbines contains high number of design variables that influence load characteristics and structural responses. These variables are stochastic and cause many uncertainties. Some of them are examined in this study. It is investigated how scattering of site conditions and load parameters affect the structural response. It is exemplified in terms of stresses that contribute to the accumulated fatigue damage within a monopile substructure. Random sampling of combinations of site conditions and load parameters is performed in order to classify the effects of parameter scattering on the stress variability by means of Sobol’ indices. Analysis shows that the highest influence on stress outputs have the variations in the load parameters. The reason is the sensitivity of the structural dynamical response to the wave height increase and decrease of distance between the wave peak frequency and the structural eigenfrequencies. © 2017 ISOPE

The Biodynamic Research Institute in Järna developed at the farm Yttereneby a two phase biogas plant. The plant digests manure of dairy cattle and organic residues originating from the farm and the surrounding food processing units containing 17,7 - 19,6 % dry matter. A new technology for continuously filling and discharging the biogas reactor was developed and implemented. Digestion residues are separated into a solid fraction for composting and into a liquid fraction. The solid fraction is suitable for aerobic composting. Initial results show that anaerobic digestion and following aerobic composting of the solid fraction improves the nitrogen balance of the farm compared to mere aerobic composting. Composted biogas plant residues and effluent together contain 70,8 % of input Ntot and 93,3 % of input NH4, merely aerobic digested manure 51,3 % Ntot and 3,9 % NH4 only. Additionally anaerobic digestion improves the energy balance of the farm producing up to 269 l biogas kg-1 VS or 1,7 kWh heat kg-1 VS.

Auf der Grundlage vorhandener Sturmflut-Messdaten aus dem Bereich der Uferlinie vor Westerland werden Gegebenheiten der Sturmbrandung am Modell resonanter Beckenschwingungen bezüglich der Ausprägung von Reflexion, Resonanz und anomaler Dispersion untersucht. Das Auftreten partiell stehender Wellen bedeutenden Ausmaßes unterstützt die These des Autors von der „Sturmwellenresonanz“. Durchschnittliche Abbruchraten von der Randdüne Westerland werden für extreme Sturmflutwasserstände zu 1,5m/h abgeschätzt. Based on existing storm surge data from the inshore and foreshore zone of Sylt island/North Sea, the circumstances of storm surf are analyzed with respect to the model of resonant basin oscillations, marked by reflection, resonance and anomalous dispersion. Partial standing waves of impressive extent support the author's finding of a „storm wave resonance“. Average sand removal rates can be estimated as 1.5m/h at heavy storm surge action.