A significant requirement for the further development of floating wind turbines is the reduction of cost and fabrication time. This can be achieved through a universally applicable anchor design, that can be utilized in almost all use cases and that enables decentralized and industrialized mass production. For this reason, a universal modular and scalable gravity anchor system was developed and is presented within this paper. The gravity anchor system consists of reinforced concrete modules which can be combined with each other by a connector system in order to scale the mass and bearing surface. Each module weighs approximately 1000 tons. A “module kit” of several modules for the various functions of a gravity anchor structure was developed. This enables a wide range of adaption of the structure to fit the specific requirements of the case. The modules can be produced decentralized and transported to a dry dock, where a time and cost-efficient assembly takes place. The installation process of the anchor is fast and cost efficient and almost independent of the water depth. The modules of the anchor are hollow inside and therefore buoyant. During installation process the modules are filled with water. Transport and installation of the anchor can be done by simple tug boats. The anchor is suitable for almost all seabed types, environmental impact during installation is kept to a minimum. Due to modularity the anchor system can be optimally adapted to all types of floating structures, mooring configurations and seabed conditions and can be used both as a single-point and as a multi-point anchor in a wind farm.

In order to tap the world wide offshore wind resources above deep waters, cost efficient floating platforms are inevitable. Tension-Leg Platforms (TLPs) could enable that crucial cost reduction in floating wind due to their smaller size and lighter weight compared to spars and semi-submersibles. The continuous development of the GICON®-TLP is driven by computer-aided engineering. So-called aero-hydro-servo-elastic coupled simulations are state-of-the-art for predicting loads and simulating the global system behavior for floating offshore wind turbines. Considering the complexity of such simulations, it is good scientific praxis to validate these numerical calculations by use of scaled model testing. This paper addresses the setup of the scaled model testing as carried out at the offshore basin of the École Centrale de Nantes, as well as the numerical model for the GICON®-TLP. The results of dedicated decay tests of the scaled model are used to validate the computational model at the first stage and to determine the natural frequencies of the system. Besides different challenges to the scaled model during the survey, it was possible to take these difficulties into account when updating the numerical model. The results show good agreements for the tank tests and the numerical model.

The paper deals with new technical solutions for outdoor cultivation systems for microalgae production. Various types of algae cultivation systems and materials applied for reactors are described. The characteristics and performance of a novel closed photobioreactor system with “Christmas tree” design (brand name: GICON-PBR) consisting of a silicone double-wall tubing-system, developed in collaboration between the companies GICON and Wacker Chemical corporation, are discussed. Special attention is paid to the issue of temperature control for closed cultivation systems. The performance of the chilling system stabilizing the temperature of algae cultivation, which applies a thermal energy storage filled with Phase Change Material (PCM). Two kinds of the systems are considered: free cooling and with compressor units. The lumped-model equations were developed to analyze heat-transfer dynamics inside the installation and some results are presented here. The model equations describe energy balances for the chiller, PCM thermal storage and heat receiver. Influence of the heat transfer, fluid-flow-rate control, heat capacity of the system components as well as heat losses to ambient were taken into account. The results of PCM storage application are compared with reference water-filled buffer-tank. The study shows a great potential of PCM storage unit to stabilize the temperature of the algae cultivation system.

Microalgae are often heralded as a miracle cure to solve future questions concerning energy and food supply of the world's population. This is due to their vastly superior area productivity compared to terrestrial plants and the feasibility of cultivating them independently of arable land and fresh water. Algal biomass can be used as food and feed as well as a source for a plethora of biofuels and high value products such as nutraceuticals and pharmaceuticals. This review article seeks to shed light on recent advances in microalgal technology and their potential for the production of biofuels.

Offshore wind farms will play an important role in supplying the increasing energy demand while considering ecological and economic aspects. Especially floating foundations which have a great potential for offshore wind farms in water depths between 40 m up to 200 m and more, will be a major factor. The objective of this paper is to focus on the design of a TLP substructure including the anchoring in the seabed by considering the economic and ecological aspects. One main focus is on economic challenges and the approaches for reduction of the investment costs and the Levelized Cost of Energy. A second focus is on the cumulative energy demand as well on the expected CO2-emissions during the fabrication process. (C) 2018 The Authors. Published by Elsevier Ltd.

Mikroalgen werden oft als Hoffnungsträger für die Lösung zukünftiger Fragen der Energie- und Nahrungsversorgung der Weltbevölkerung gesehen. Dies beruht auf ihrer gegenüber Landpflanzen überlegenen Flächenproduktivität und der Möglichkeit, sie unabhängig von fruchtbaren Anbauflächen und Trinkwasser zu kultivieren. Aus der Algenbiomasse kann anschließend neben Nahrungs- und Futtermitteln ein großes Spektrum an Wertstoffen und Biokraftstoffen gewonnen werden. Dieser Artikel beleuchtet neben allgemeinen Betrachtungen zur Mikroalgentechnologie ihr Potenzial zur Gewinnung von Biokraftstoffen. Microalgae are often heralded as a panacea to solve future questions concerning energy and food supply of the world's population. This is due to their vastly superior area productivity compared to terrestrial plants and the feasibility of cultivating them independently of arable land and fresh water. Algal biomass can be used as food and feed as well as a source for a plethora of biofuels and high value products such as nutraceuticals and pharmaceuticals. This review article seeks to shed light on recent advances in microalgal technology and their potential for the production of biofuels.

A crucial problem regarding the offshore electricity generation is the levelized costs of energy (LCOE). This is an even larger problem for floating substructures for offshore wind turbines. This paper highlights a substructure for floating offshore wind turbines (FOWT) for a one step installation process. It deals with the parametric study of the TLP's structure to gain hydrostatic and hydrodynamic stability during the transport and installation process of the TLP equipped with a 6 MW wind turbine. At first a hydrostatic analysis with the software tool MOSES (V7.06.062) has been performed. Hydrodynamic simulations with ANSYS AQWA (V17.2), based on 2D potential flow theory, have been conducted afterwards to get information about the motion behavior of the TLP in wind, current and waves.

Abstract The Offshore Wind Resources in deep water, but also the currently experienced issues with conventional foundations, are driving the solution requirements for new offshore wind power platforms. The latest monitoring results of German offshore wind farms show the challenges the industry is facing. Ecological impacts as well as foundation technology issues are forcing the sector to look for alternatives. The presentation will introduce a technology of a floating TLP-structure with a specific mooring line configuration as an innovative foundation concept for offshore wind turbines suited for water depths greater than 30 meters. The unique aspect of the GICON TLP is its modular, frame-work structure which allows buoyancy and load transfer functions to be decoupled from each other and instead be applied to the specific structural elements. In contrast to classic TLP designs and semi-submersible floaters, additional stabilizing effect achieved by this additional bracing minimizes the movement of the entire system. Due to this stable behavior of the TLP standard offshore turbines as currently available in the market should be usable for this platform. Furthermore results from model basin tests will be described. Also the comparison of calculated and experimental data obtained by extensive tank experiments with a scale model of an offshore turbine at Maritime Research Institute Netherlands (MARIN) in summer 2013 will be presented. These experiments include wind and wave loads that represent different sea states of the proposed location for the full scale prototype. In numerical simulations the dynamic behavior of the TLP under linked hydrodynamic and aerodynamic loading is taken into account also regarding different geometric configurations of the mooring line system and various types of anchorage systems at the sea floor. Using characteristic Campbell-diagrams structural stiffness of each component is optimized aiming at a soft-stiff design of the TLP-structure. The results of the scaled tests at MARIN have confirmed that a superposition of internal forces of the moored structure in operation for wind and wave loads can be assumed. Numerical modeling validation is confirmed by tank tests. Data and video from the tank tests will be shared as part of the presentation. GICON researchers plan to install a full-scale pilot plant in the German Baltic Sea in 2016.

A microalgae platform, consisting of four photobioreactor units incorporating a novel biomimetic design, has been installed at the Biosolar Center in Koethen, Germany. The novel photobioreactor consists of a flexible, tubular double-wall hose system (silicone based) with integrated temperature control in a closed cycle. The modular-arranged platform system (total cultivation volume 1700 L) has been designed for stable long-term cultivation of microalgae biomass in outdoor use. Cultures with Scenedesmus and Chlorella species have been grown outdoors at their optimal growth temperature (avg. 26 °C) for 145 days during spring and summer and were tested successfully for the stable production of microalgae (avg. biomass productivity 0.3 g L−1 day−1 (max. 0.75 g L−1 day−1)) with an overall photosynthetic conversion efficiency of 7.2 % based on photosynthetically active radiation. The average calorific value of the produced biomass is 23.25 MJ kg−1 with defined product quality (content relating to biomass dry weight: proteins 0.40 g g−1, lipophilic compounds 0.38 g g−1 and total carotenoids 11 mg g−1). This outdoor concept is continuously adjustable to maintain an optimal environment for microalgae cultures (in particular light entry, temperature control and limiting of oxygen levels).

Discontinuous Dry Digestion (DDD) as part of sustainable waste management systems bears high potential to reduce the amount of organics landfilled worldwide and entails twofold benefit for the reduction of global greenhouse gas emissions. Diffuse landfill gas emissions can be reduced significantly and the produced biogas substitute fossil fuels. Compared to fully mixed and plug flow wet digestion processes, mechanical pre-treatment of mixed solid waste streams is very simple for DDD comparable to aerobic stabilization/composting processes. Anaerobic bacteria selectively degrade organics and with the discontinuous concept the non-degradable part is simply brought out of the process as solid digestate in batches. Post-treatment of the solid residues as well is much simpler as for digestate sludge making solid waste treatment concepts using DDD comparably cost efficient. Amongst the industrialized DDD processes the GICON-Process is the only two stage process on the market. The discontinuous solid waste treatment using the principle of percolation is designated to derive a COD-enriched percolate by hydrolysis which is transferred to a high performance fixed bed reactor for biological methanation. Advantages to the so far wider spread single stage processes are higher efficiency of the installed reactor volume, more stable processing, less disposition for silting of digestate, very high methane concentration in biogas from the methane reactor, controllability of biogas production and less incrustation of pipes and aggregates.

The offshore wind resources globally present a great opportunity for green power generation. Both types, fixed and floating foundations, will play a major role in utilizing these resources. The preliminary design of the floating system called GICON (R)-Tension Leg Platform (UP) is meant to provide a solution for harnessing the power of offshore wind at water depths between 20 m and 350 m. In addition a design for water depth up to 700 m is currently under development. The research project is a joint development of private industry and academic institutions. The main partners are ESG GmbH and Technische Universitat Freiberg. Currently ongoing research includes the comparison of calculated data with experimental data obtained by wave tank experiments with a scale model at the Maritime Research Institute Netherlands (MARIN) in June 2013. These tests have provided insights regarding the dynamic characteristics of the GICON (R)-TLP by analyzing the system's response to different load cases. Furthermore, the results of the scale model tests at MARIN have confirmed that a superposition of the internal forces for wind and wave loads can be assumed for the structural design. This can be traced back to the stiffness of the mooring line system and the innovative mooring line configuration. (C) 2014 Elsevier Ltd. All rights

The ambition to apply carbon capture and storage (CCS) requires the provision of effective monitoring approaches that can be applied to detect and to characterize a potential migration or leakage of CO2 and saline formation water into geological compartments between the storage formation and the protected groundwater resource. The sensitivity of monitoring techniques to detect such leakages into near-surface groundwater is therefore discussed in this study. The most significant geochemical processes following a CO2 leakage are the lowering of the pH due to the formation of carbonic acid and a rising of the electric conductivity (EC) due to mineral (especially carbonate) dissolution in the groundwater. It is shown that the variation in the EC is in principle detectable by geoelectric measurements. The detectability is reduced in non-calcareous aquifers, because the variation in the EC as a consequence of carbonate dissolution is at a lower level. Since the carbonate contents in such aquifers are barely known, a regionalization of carbonate contents in North German aquifers was only possible based on groundwater analyses. Although the geoelectric measurements can be in principle capable of detecting the effects of a CO2 leakage, their results can only cover a comparatively small area. The area-wide survey method of airborne-electromagnetics was tested for a base- line monitoring and may be suitable to detect CO2 leakages, but evaluating the sensitivity of this method with respect to variations in the geological parameters and boundary conditions of the CO2 leakage needs to be part of future works.

Abstract The Offshore Wind Resources in deep water, but also the currently experienced issues with conventional foundations, are driving the solution requirements for new offshore wind power platforms. The latest monitoring results of German offshore wind farms show the challenges the industry is facing. Ecological impacts as well as foundation technology issues are forcing the sector to look for alternatives. The paper will introduce a technology of a floating TLP-structure in open relief design with a specific configuration of mooring line system used for wind turbines, suited for water depths greater than 30 meters. The unique aspect of the GICON TLP is its modular framework structure which allows buoyancy and load transfer functions to be decoupled from each other and instead be applied to the specific structural elements. The overall structural behavior is characterized by lattice structures in the connection node of column and boom and the entire rigger area. The load and stress forces on the structure are clearly defined and unwanted or double loads as well as overloads can be prevented. The structure is designed to handle both the tension forces from the mooring system as well as the buoyant force. The total buoyant force can optionally be adjusted via additional buoyancy elements of variable shapes and dimensions, preferably in the form of spherical or circular cylindrical hollow bodies. These can be set at various locations across the truss structure to adapt to different deployment site requirements. In numerical simulations the dynamic behavior of the TLP under linked hydrodynamic and aerodynamic loading is taken into account also regarding different geometric configurations of the mooring line system and various types of anchorage systems at the sea floor. Using characteristic Campbell-diagrams structural stiffness of each component is optimized aiming at a soft-stiff design of the TLP-structure. Eigenfrequencies are calculated for various water depths and different geometric conditions of the mooring system. Numerical modeling validation is confirmed by tank tests. Data and video from the tank tests will be shared a part of the presentation. GICON researchers plan to install a full-scale pilot plant in the Baltic Sea in 2013.

A small scale and temporally limited CO2 injection test was performed in a shallow aquifer to investigate the geochemical impact of CO2 upon such aquifers and to apply and verify different monitoring methods. Detailed site investigation coupled with multiphase simulations were necessary to design the injection experiment and to set up the monitoring network, before CO2 was injected over a ten-day period at three injection wells, at a depth of 18 m below surface level into a quaternary sand aquifer located close to the town of Wittstock in Northeast Germany. Monitoring methods comprised groundwater sampling and standard analyses, as well as trace element analyses and isotope analyses; geoelectrical borehole monitoring; passive samplers to analyse temporally integrated for cations and multi-parameter probes that can measure continuously for dissolved CO2, pH and electrical conductivity. Due to CO2 injection, total inorganic carbon concentrations increased and pH decreased down to a level of 5.1. Associated reactions comprised the release of major cations and trace elements. Geoelectrical monitoring, as well as isotope analyses and multi-parameter probes proved to be suitable methods for monitoring injected CO2 and/or the alteration of groundwater.

According to the German Federal Soil Protection Act, the soil, contaminated sites, and any water pollution caused by harmful soil changes shall be remediated in such a manner that no hazards, considerable disadvantages or considerable nuisances for individuals or the general public occur long term. Prior to implementation of any measure, a remediation investigation regulated by Annex 3 to the Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV) is prescribed in the form of a comparative review of suitable measures (e.g. remediation methods and strategies). The stipulated measure and its consequences for the polluter must be in reasonable proportion to the hazard which has to be prevented. This means that preference must be given to that measure/combination of measures which, while being equally effective, represents the “milder means” (i.e. is necessary) and which exhibits an adequate cost-benefit ratio. Due to the complex circumstances involved in each individual case of contamination (such as geological and hydrogeological site characteristics, specific nature of the impact, and relevance of the protected assets affected by specific uses), no thresholds have been legally prescribed under German law for determining the need for remediation, nor have remediation target values been defined. Instead, the competent authorities were accorded a considerable degree of discretion, which has proved its worth in enforcement.