• Energy Research

Environmental protection and energy efficiency are important topics for sea port management, which is characterized by long-term investments. To assess the environmental impact of port equipment, we investigate different equipment types with fossil, hybrid and electric drive technologies, in cooperation with our project partner Hamburg Port Consulting (HPC). An ecological assessment of port equipment will support terminal operators who aim to make sustainable investment decisions. We conduct a comparative life cycle assessment (LCA) of different port equipment types including the three above-mentioned drive technologies. Various LCA impact categories, such as climate change, terrestrial acidification and particulate matter formation, were calculated and compared. Thus, we aim to foster a more comprehensive understanding of the environmental performance of port equipment. The results show the contribution of each life cycle phase to the environmental performance of an equipment type within each impact category and thus allow for a comparison of different port equipment types. So far, little comprehensive research exists regarding sustainable port operations. Especially, port operators often lack knowledge about the environmental impact of port processes, whereof it is necessary to provide a good basis to fill in this gap.

Abstract In regions with high livestock density, manure supply often exceeds demand and complete local deployment would lead to severe environmental damage due to over-nutrification. One solution is to use the surplus in other regions, which have lower nutrient-levels. To decrease costs associated with transport the manure can first be used in biogas plants of those regions. To date, however, the economic and ecological consequences of this solution are unclear. Here, we develop a model of the consequences from the perspective of a biogas plant owner and apply it to a case study in Lower-Saxony, Germany. The model determines the maximal profitable manure transport distance from a financial point of view. Furthermore, it examines selected environmental impacts for various scenarios with an assumed transport range of 150 km, a typical distance. For dry poultry manure transport distances up to 700 km and more can be financially advantageous. Emission reductions occurred in all scenarios in the impact categories Greenhouse Gas and Acidification. The model can support decision-makers in the livestock and biogas industries in determining whether to transport manure and, if so, how far.

Abstract The transition from the current electricity system to a renewable electricity supply poses immense economic, technological, and policy challenges. Energy system models represent the complexity of interactions in combined processes from extraction of primary energy to the use of the final energy to supply services and goods. While these models were originally focused on energy security and costs, climate change, as the most pressing environmental concern as well as sustainability in general require the consideration of a broader range of decision-relevant aspects. In this context, scenario planning and multi-criteria decision-making can complement energy system analysis in the development and evaluation of energy scenarios. Therefore, we propose a combination of these three methods and illustrate it in a case study that investigates the transition of the electricity sector in Lower Saxony, Germany, to energy from renewable sources. The results of our case study show that the integration of multi-criteria analysis allows for better Problem structuring by focusing on relevant alternatives, external uncertainties, and evaluation criteria. The integration of scenario planning allows for a systematic investigation of external uncertainties. Thereby, the fallacy of investigating particular assumptions for uncertain parameters, which are however not consistent with the assumptions in the scenario, can be avoided. Finally, combining the methods allows for a more balanced and objective evaluation of alternative energy systems in terms of multiple criteria, which can be used to inform discussions among stakeholders and may thus increase acceptance.

Many arid and semi-arid regions of the world face growing freshwater scarcity, requiring increased utilization of seawater desalination to augment the existing freshwater resources. Seawater reverse osmosis (RO) is currently one of the most deployed technologies, due to its electrical energy efficiency and comparatively low costs. However, the required energy for desalination processes is often still converted from fossil sources. Given the growing demand for seawater desalination and the energy sector's parallel decarbonization, the substitution by renewable energy sources (RES) is a critical issue. The volatility, lower availability of renewable energy, and cost for required electrical energy storage (EES) are all obstacles to the decarbonization of large-scale desalination plants and may affect production volume and water production costs negatively. This paper presents a mathematical model to determine a cost-optimal energy conversion and EES mix for the design and operation of large-scale seawater RO desalination plants. The linear program ensures satisfaction of the plant's energetic demands. Furthermore, the model allows to investigate the general feasibility of integrating RES into large-scale desalination processes, which are examined by means of a case study while employing location-specific weather data. Different types of energy conversion technologies and the effect of EES on operating behavior, greenhouse gas emissions, and water unit costs are investigated. Specifically, the indirect storage of electrical energy via the smart management of a desalination plant's oversized RO membranes is examined and compared to battery energy storage (BES). Results indicate that RES cannot meet an RO desalination plant's full and constant electrical load demand without a high BES capacity, which is probably not feasible from a technical and economic point of view. The economic penalty from energy storage costs on one unit of desalinated water ranges from 3.10 $/m3 up to 5.38 $/m3. However, operating an oversized RO desalination plant intermittently could reduce the energy-related costs substantially and potentially provide a more appropriate way of adapting to a volatile supply of energy from renewable sources in order to decarbonize the desalination processes. Specific emissions of desalinated water can be reduced from 1.5 kg CO2 eq./m3 when relying mostly on combined cycle gas turbines down to 0.124 kg CO2 eq./m3 by intermittent operation and fully relying on renewable energy sources.

Abstract Products derived from crude oil form the basis for large segments of energy and production systems. However, the availability of crude oil is limited and the combustion of fossil fuels contributes to global warming. Biorefineries can produce a product portfolio similar to that of crude-oil refineries from renewable resources and thus promote transformation towards a more sustainable bioeconomy. The actual product portfolio of a given biorefinery, however, depends on the choice and capacity of the production units used to upgrade raw materials to marketable products. Thus, to improve biorefinery product competitiveness, we apply an algorithm that combines an exact optimization algorithm nested in an Evolutionary Strategy with Geographic Information Systems to determine a wood-based biorefinery's optimal configuration, capacity, and location within the Cariboo District in Canada. The results indicate that there are numerous locations with similarly attractive economic potentials for biorefineries with 450,000 to 550,000 tons of biomass input capacity in the investigated area.

Many manufactured items receive surface coatings for decoration and/or protection against damage. In a number of places along the production line emissions of (VOC) Volatile Organic Compounds can occur. Because VOC are a major contributor to photochemical smog, control of VOC emissions is a major concern for the industries' commitment to the environment. Approaches for process optimisation have a long tradition within chemical and process engineering for the systematic identification of cost- and resource-efficient production options. The challenge in the context of supply chain management is the optimal recovery and reuse of materials not only for single substances or energy flows in large chemical installations, but also for smaller production processes and various mass and energy flows within and between enterprises. Based on a case study from the industrial coating of bicycle frames, an approach for Multi Objective Pinch Analysis (MOPA) for the evaluation of overall recovery potentials for energy, water and VOC is presented. Moreover, a metric for resource efficiency is introduced as a measure for the possible savings potential and for the savings ultimately realised. This integrated approach requires a tight coupling of mass, energy, economic and environmental assessment methods and demands a highly interdisciplinary approach.

Cogeneration of heat and electricity is an important pillar of energy and climate policy. To plan the production and distribution system of combined heat and power (CHP) systems for residential heating, suitable methods for decision support are needed. For a comprehensive feasibility analysis, the integration of the location and capacity planning of the power plants, the choice of customers, and the network planning of the heating network into one optimization model are necessary. Thus, we develop an optimization model for electricity generation and heat supply. This mixed integer linear program (MILP) is based on graph theory for network flow problems. We apply the network location model for the optimization of district heating systems in the City of Osorno in Chile, which exhibits the “checkerboard layout” typically found in many South American cities. The network location model can support the strategic planning of investments in renewable energy projects because it permits the analysis of changing energy prices, calculation of break-even prices for heat and electricity, and estimation of greenhouse gas emission savings.

Purpose In Italy, composting olive mill waste has become a common practice, since it mitigates the environmental problems associated with spreading the waste on land. Compost can be used to prepare growth media for plant nursery cultivation as a substitute for peat, a non-renewable resource whose extraction has long raised environmental concerns. Here, we investigate two common composting procedures--open windrow and static-pile in gas-permeable bags--and compare them to evaluate their environmental impact. Methods We perform a cradle-to-grave life cycle assessment (LCA) in accordance with ISO 14040 and 14044. The LCA considers carbon storage in the soil after 100 years, fugitive greenhouse gas (GHG) emissions, and the impacts avoided by substituting for peat. We use cumulative energy demand, global warming potential (GWP), acidification potential, and eutrophication potential indicators in a contribution analysis and explore how the re-use of olive pits for energy production and reduction of commercial fertilizers improves the environmental balance. We also present a scenario analysis that indicates how parameter fluctuations affect the results. Results and discussion Our study shows that peat's impacts can be significantly reduced from 1162.3 to 96.3 kg CO2-eq/Mg for open windrow compost or 43.1 kg CO2-eq/Mg for static-pile compost in gas-permeable bags. For static-pile composting, the lack of volatile organic compound and ammonia emissions and the detection of oxygen concentrations above 12% vol. suggest fully aerobic conditions. Fugitive greenhouse gas emissions were the most important contributions to the GWP. In the contribution analysis for static-pile composting, the avoidance of compost spreading and the carbon storage effect (due to compost usage) contributed 54% of the overall impacts to GWP and between 21 and 45% to the other indicators. Conclusions This LCA study illustrates how horticulturists can improve their resource management practices by recycling olive mill waste materials. Proper management of composting unit aeration can reduce fugitive GHG emissions.