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The aim of this study was to assess if dairy intensification is associated with increased efficiency in food production, nutrient, and energy use. In-depth data from 12 high-input confinement-based and 12 low-input grass-based dairy farms in southwest Germany were analyzed. The study found that relative to high-input dairy systems, low-input grass-based dairy systems were 334% better in human-edible crude protein conversion efficiency and 328% better in human-edible gross energy conversion efficiency. Low-input dairy systems showed 28% higher nitrogen and 98% higher phosphorus use efficiencies. Results revealed no difference in energy conversion efficiency between the contrasting dairy systems. As a result, the ongoing intensification of dairy systems utilizing substantial amounts of human-edible crops, puts global food security at risk, has undesirable side effects on the environment and fails to utilize the evolutionary advantage of ruminants. [ABSTRACT FROM AUTHOR]

A methodology for identifying suitable locations for the CO2‐based production of olefins in Germany is presented. Based on electricity and CO2 requirements, locations are identified that can provide sufficient CO2 and renewable energy for the conversion of CO2 to olefins. In addition, the use of existing infrastructures is taken into account. The regional, technical renewable energy potential in Germany is sufficient to produce ∼ 800 kt of olefins from CO2‐based methanol per year in one plant. But the currently available CO2 point sources with high CO2 concentrations of around 100 % are not sufficient to meet the CO2 requirement of an 800 kt a−1 methanol‐to‐olefins plant. If existing refineries are preferred due to existing infrastructure services, locations in the north of Cologne, in Lower Saxony, and in Brandenburg are particularly suitable. A full substitution of fossil olefins by CO2‐based olefins is possible in Germany. The challenge is to provide sufficient renewable electricity for the production of H2 with a low CO2 intensity. [ABSTRACT FROM AUTHOR]

Highlights • A new approach for the calculation of quarter-hourly CO 2eq intensity is presented. • Effects of charging strategies on the environmental impact of BEVs are derived. • Large amounts of CO 2eq emissions are saved by optimizing the charging time. • The temporal variation of CO 2eq intensity in winter is small compared to summer. • The CO 2eq savings potential is significantly greater during the day than at night. Abstract In many countries, the replacement of internal combustion engine vehicles (ICEVs) with battery electric vehicles (BEVs) offers an opportunity to reduce CO 2 equivalent (CO 2eq) emissions in traffic. BEVs have significantly greater energy conversion efficiency from energy storage to wheel (tank-to-wheel [TTW]) and zero tailpipe emissions; these features are in stark contrast to the environmental burdens posed by vehicle production and electricity generation (well-to-tank [WTT]). Since CO 2eq emissions from vehicle use of BEVs account for the majority of the entire life cycle emissions, it is important to closely examine the CO 2eq intensity of electricity generation, which varies based on the sources of energy in the electricity mix of each country and time of day. This paper compares the environmental impact of diesel and electric buses in the city of Aachen throughout their life cycles and analyzes the effects of electricity generation with reference to variation in charging time. Based on recorded driving profiles, the vehicle dynamics of the longitudinal motion are simulated, and the energy demand as a function of the altitude profile and ambient temperature is calculated. The calculation of the quarter-hourly CO 2eq intensity is combined with the vehicle life cycle model in order to examine the effects of electricity generation on BEV life cycle emissions. To analyze the correlation between charging time and BEV environmental impact, different charging scenarios are defined, and CO 2eq savings from replacing ICEVs with BEVs are estimated. Scenario analyses are conducted over both short- and long-term time scales to predict the future environmental and economic benefits and costs of BEVs compared to ICEVs. The results demonstrate a significant dependency of BEV environmental impact on charging time, which varies by time of day and season. At night, the contribution of renewable energies to the electricity mix is low, and the variation in CO 2eq intensity is limited; therefore, the environmental impact of charging time is lower compared to charging at noon. The larger CO 2eq emissions of BEV production are compensated for all scenarios within the first year of operation. However, if BEVs are charged with electricity generated exclusively by lignite-fired power plants, more CO 2eq emissions are released over their lifetimes compared to ICEVs; this scenario also holds when ICEVs are fueled with biodiesel. Overall, the positive environmental balance of BEVs is not based on a low CO 2eq intensity, but on the greater energy conversion efficiency and the possibility of recuperating braking energy. These properties are particularly advantageous in urban traffic. [ABSTRACT FROM AUTHOR]

Biodiesel is an important bridging biofuel for reducing greenhouse gases (GHG). In 2015, Germany introduced a new GHG based quota scheme for biofuels. However, the use of default GHG values for rapeseed cultivation could provide inaccurate for specific regions and locations. Therefore, the aim of this paper was to use RELCA (a REgional Life Cycle inventory Approach) to assess the regional and spatial variation of GHG emissions associated with biodiesel production in Central Germany and to compare these results with the default values of the Renewable Energy Directive (RED), as well as to identify potential mitigation options for biodiesel production. The RELCA simulations indicated GHG emissions of 31.9–39.83 CO 2 eq./MJ, with emission magnitude changing between biodiesel configurations due to their locations within the CG region. In comparison with typical RED values for biodiesel, the CG simulations showed 13–31% greater mitigation potential. The results also indicated that the configuration of biomass and conversion plant needs to be assessed to develop the most appropriate mitigation strategies. Current GHG mitigation strategies are limited to the energy sector, allowing leakages within the agricultural sector. Therefore, for more spatially targeting GHG accounting to be implemented, sustainability certification should be expanded to other biomass markets. [ABSTRACT FROM AUTHOR]

Bioenergy conversion technologies have been frequently described and analysed in the literature, but a comprehensive and detailed comparison between the complex individual characteristics of each technology is still lacking. Therefore, the paper contains a description of the technical, economic and environmental properties of each technology with a special focus on the German bioenergy sector. The study presents an analysis of different bioenergy applications with regard to their specifications, power/heat output range and their areas of application. Due to the fact, that biomass combustion applications are the most widespread and market proven renewable conversion technologies, a detailed analysis of decentralised, biomass-fired CHP plants is presented in the paper. The overview of the individual characteristics of different biomass conversion routes shows that biogas plants achieve high electrical efficiencies, are available with a broad range of capacities and belong to the established technologies. Although the investment costs of biogas plants are relatively high, biomass conversion with anaerobic digestion can be seen as one of the most promising option for a sustainable energy supply in Europe. [ABSTRACT FROM AUTHOR]

Many digesters in Germany are not operated at full capacity; this offers the opportunity for codigestion. Within this research the potentials and limits of a flexible and adapted sludge treatment are examined with a focus on the digestion process with added food waste as co-substrate. In parallel, energy data from a municipal wastewater treatment plant (WWTP) are analysed and labscale semi-continuous and batch digestion tests are conducted. Within the digestion tests, the ratio of sewage sludge to co-substrate was varied. The final methane yields show the high potential of food waste: the higher the amount of food waste the higher the final yield. However, the conversion rates directly after charging demonstrate better results by charging 10% food waste instead of 20%. Finally, these results are merged with the energy data from the WWTP. As an illustration, the load required to cover base loads as well as peak loads for typical daily variations of the plant's energy demand are calculated. It was found that 735 m³ raw sludge and 73 m³ of a mixture of raw sludge and food waste is required to cover 100% of the base load and 95% of the peak load. [ABSTRACT FROM AUTHOR]

Energy and exergy efficiencies of the wheat and rye bread and hamburger bun making processes are assessed based on data from Turkey and Germany. Amount of the land required to produce the same amount of wheat in Turkey is 3.34 times of that required in Germany; this ratio is 2.30 for the rye grain. These results show that the efficiency of the conversion of the solar energy into the grain mass is low in Turkey. CDP (Cumulative degree of perfection) for the wheat and the rye grain production is 3.73 and 4.96 in Turkey, and 11.26 and 10.46 in Germany. Specific energy utilization for rye bread production is almost the same in Turkey and Germany; but it is 12% higher in Turkey for wheat bread and hamburger bun making. Hamburger bun production requires the maximum energy utilization due to the higher weight loss in baking. The rye bread production process requires the minimum energy utilization due to the lower energy input in the agriculture and higher efficiency in the flour production. The maximum exergy destructions occur during the milling and the baking steps. [ABSTRACT FROM AUTHOR]

Abstract: A clear consensus exists in German society that renewable energy resources have to play a dominant role in the future German energy supply system. However, many questions are still under discussion; for instance the relevance of the different technologies such as photovoltaic systems and wind energy converters installed offshore in the North Sea and the Baltic Sea. Concerns also exist about the cost of a future energy system mainly based on renewable energy. In the work presented here we tried to answer some of those questions. Guiding questions for this study were: (1) is it possible to meet the German energy demand with 100% renewable energy, considering the available technical potential of the main renewable energy resources? (2) what is the overall annual cost of such an energy system once it has been implemented? (3) what is the best combination of renewable energy converters, storage units, energy converters and energy-saving measures? In order to answer these questions, we carried out many simulation calculations using REMod-D, a model we developed for this purpose. This model is described in Part I of this publication. To date this model covers only part of the energy system, namely the electricity and heat sectors, which correspond to about 62% of Germany's current energy demand. The main findings of our work indicate that it is possible to meet the total electricity and heat demand (space heating, hot water) of the entire building sector with 100% renewable energy within the given technical limits. This is based on the assumption that the heat demand of the building sector is significantly reduced by at least 60% or more compared to today's demand. Another major result of our analysis shows that – once the transformation of the energy system has been completed – supplying electricity and heat only from renewables is no more expensive than the existing energy supply. [Copyright &y& Elsevier]

Abstract: A clear consensus exists in the German society that renewable energies have to play a dominant role in the future German energy supply system. However, many questions are still under discussion; for instance the relevance of the different technologies such as photovoltaic systems and wind energy converters installed offshore in the North Sea and the Baltic Sea. Also concerns exist about the cost of a future energy system mainly based on renewable energies. In order to be able to address the raised issues on a scientifically sound basis we have set up a new simulation model REMod-D (Renewable Energy Model-Deutschland) that models the energy balance of the electricity and heat sector including all renewable energy converters, storage components and loads for a future German energy system for a whole year based on an hourly energy balance. The target energy systems modeled use a high fraction up to 100% of renewable energies to cover the electricity and heat demand (heating and hot water). The model includes also energy retrofit of buildings as a measure to reduce future heat loads of the building sector. A mathematical–numerical optimizer is applied in order to identify system configurations with minimal overall annual cost. In this first part of a two-paper series we describe the methodology of the REMod-D model and discuss cost and performance values of all included components and in the second part we will discuss the results. [Copyright &y& Elsevier]

Abstract: Germany has set a target of a minimum of 80% renewable energy in the power sector for the year 2050. Among renewables, a very high share of fluctuating sources is foreseen, which may substantially decrease the security of the energy supply and grid stability. Biomass-based conversion systems offer technical alternatives for flexible power generation to compensate for such fluctuations and the resulting residual load. Demand-oriented electricity can be provided by storing untreated biomass or solid, liquid, or gaseous biofuels in the existing infrastructure or by developing biological and technical alternatives. Making existing plants more flexible will increase costs due to larger storage capacities and conversion units and reduced full-load hours, but higher income can be obtained by selling electricity at peak times and by taking advantage of legislative incentives. This paper summarizes the current legislative and market conditions in Germany for demand-oriented power generation, describes possible technical solutions based on solid, liquid and gaseous biofuels, and provides an economic assessment of selected technical concepts. The results show the potential for bioenergy, especially biogas and combined heat and power (CHP) systems to play a significant role in ensuring the security of the energy supply system that is in transition in Germany. [Copyright &y& Elsevier]

Abstract: This study analyses the use of liquid, solid and gaseous biomass for power generation in Germany with respect to the Renewable Energy Sources Act (EEG), a significant policy instrument for promoting electricity generation based on renewable energy sources. The aim is the identification of bioenergy conversion pathways that have a low environmental impact and are cost-effective. To achieve this objective several research steps were undertaken, including a life-cycle analysis (LCA), economic analysis and the determination of the CO2 abatement costs. Besides, the authors show and discuss how a simplification of the environmental assessment by considering only the impact category greenhouse gases or the application of different calculation methodologies (i.e. allocation rules between electricity and heat produced) can affect the results. Overall the results show that the use of solid (wood) and gaseous biomass pathways causes both the lowest environmental impacts and electricity production costs when used for electricity generation. The choice of the modelling and calculation methodology may significantly influence the outcome (i.e. application of an exergetic allocation increases the environmental burden related to electricity generation). The lowest CO2-abatement costs were determined for the biodegradable waste pathway. [Copyright &y& Elsevier]

Abstract: For a conceivable fossil-fuelled electricity production strategy with CO2 capture, the location of available storage options could play a key role for plant siting, as additional CO2 transport infrastructure might be required in some configurations. The possible spatial separation of electricity generation and centralised fossil hydrogen production with Carbon Capture and Storage (CCS) allows an additional degree of freedom in the system in enabling the transport of hydrogen instead of electricity. This paper analyses energy conversion and transport tasks associated with the plant locations offered by this enhanced scheme. By considering various scenarios for Germany, we describe different gasification/reforming options with CO2 capture and estimate their cost, including required new infrastructures. The results point out that moderate additional costs could allow the implementation of a first level hydrogen transport infrastructure instead of building a CO2 transportation network. This could be a smooth way to finance and facilitate the transition to a future larger hydrogen-based energy system. On the long term, this infrastructure would be in place for the transport of non-fossil hydrogen. [Copyright &y& Elsevier]

Abstract: Since the 80s power production with solar thermal power plants has been a way to substitute fossil fuels. By concentrating direct solar radiation from heliostats very high temperatures of a thermal fluid can be reached. The resulting heat is converted to mechanical energy in a steam cycle which generates electricity. High efficiencies and fast start-up are reached by using air as a heat medium, as well as using porous ceramic materials as solar receiver of the concentrated sunlight. In Germany the construction of a 1.5MWe solar tower power plant began in 2008. It is operational since December 2008 and started production of electricity in the spring of 2009. In Greece and Cyprus, countries with high solar potential, the development of this competitive solar thermal technology is imperative, since it has already been implemented in other Mediterranean countries. [Copyright &y& Elsevier]

The use of semi-natural grasslands for the production of renewable energy through conventional conversion techniques faces major limitations because of chemical and physical properties of the biomass. A new conversion procedure was developed which separates the biomass, as silage, into a liquid phase for biogas production and into a solid fraction to be used as fuel. Separation (mechanical dehydration) is carried out with a screw press after mashing with water (hydrothermal conditioning). The effect of hydrothermal conditioning at different temperatures (5, 60 and 80°C) and mechanical dehydration on mass flows of plant compounds into the press fluid was investigated for five grassland pastures typical of mountain areas of Germany. Results show that 0·18 of the crude fibre was transferred into the fluid, whereas more digestible organic compounds, such as crude protein and nitrogen-free extract, showed mass flows of 0·40 and 0·31 respectively. While 0·52–0·89 of potassium (K), magnesium (Mg) and chloride (Cl), which are detrimental for the combustion of the press cake, were transferred into the press fluid, more than 0·50 of calcium, which has positive combustion properties, remained in the press cake. Significantly ( P < 0·05) higher mass flows were detected at conditioning temperatures of 60°C (K and Mg) and 80°C (crude fibre and nitrogen-free extract) compared with the 5°C treatment. Because of the separation of solids and liquids, high proportions of P (0·61–0·74) and K (0·64–0·85) but only 0·32–0·45 of nitrogen exported from the grassland would be recycled with an application of the digestates from the anaerobic digestion of the press liquid. [ABSTRACT FROM AUTHOR]

Biofuels are liquid or gaseous fuels made from plant matter and residues, such as agricultural crops, municipal wastes and agricultural and forestry by-products. The term biofuels can refer to fuels for direct combustion for electricity production, but is generally used for liquid fuels for transportation. Biofuels are made from biomass through biochemical or thermochemical processes. Currently much attention is fo cused on utilization of ethanol, methanol, biodiesel, biocrude, and methane as biofuels. The European Union is on the third rank of biofuel production world wide, behind Brazil and the United States. In Europe, Germany is the largest, and France the second largest producer of biofuels. Most biofuels in commercial production in Europe today are based on sugar beet, wheat and rapeseed, which are converted to bioethanol/ETBE and biodiesel. The European Commission has set as a goal that by the end of 2005, 2% of the energy used in transportation shall be biofuels. The use of biofuels is then to grow by 0.75% annually. The ambition is to have 5.75% biofuels in transportation by 2010. [ABSTRACT FROM AUTHOR]

In Germany, Proton Motor is supplying the innovative hybrid drive for what is believed to be the world''s first fuel cell-powered passenger vessel, in the Zemships (Zero Emission Ships) project. In the summer the vessel will start operating in Hamburg, on the Alster river and in the harbor area, carrying up to 100 passengers at a time. [Copyright &y& Elsevier]