• Energy Research
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Optimisation results for the lowest lifetime cost system consisting of solar photovoltaic (PV), hybrid photovoltaic-thermal (PV-T) and solar-thermal collectors alongside battery and hot-water storage systems for meeting the electrical and thermal (hot-water) needs of three multi-effect distillation (MED) plants. The updated results are from optimisations runs carried out in response to peer-review comments.

This study is to our knowledge the first to describe the effect of a Gas-Gas Heater (GGH) of a coal fired power plant's has on (i) the H2SO4 concentration and (ii) the particle/aerosol number concentration and particle size distribution present in the flue gas. In the absence of a GGH, homogenous nucleation takes places inside the Wet Flue Gas Desulphurisation (WFGD) converting the gaseous H2SO4 into aerosol H2SO4. This leads to a high aerosol number concentration behind the WFGD with 80% of the aerosols being smaller than 0.02 μm. This implies that an amine based carbon capture (CC) installation treating this flue gas can suffer from amine mist formation due to the high amount of available nuclei (i.e., H2SO4 aerosols) resulting in high amine emissions. In contrast, in the presence of a GGH not only 70% of the H2SO4 is removed from the flue gas (measured at the Nijmegen powerplant), but also homogenous nucleation in the WFGD is prevented resulting in low particle number concentrations. The flue gas leaving the GGH will not create any mist formation issues in an amine based CC installation due to the low amount of nuclei present in the flue gas. It is not the reduction in H2SO4 concentration by 70% inside the GGH as such that prevents mist formation but absence of H2SO4 in its aerosol form. These results are most likely quite widely transformable to other power plants that burn low sulfur coal i.e., around 0.7 weight%. This information will serve future pilot and demo CC installation around the world; in particular when retrofitted on power plants that have a GGH.

Is it true that a nuclear technology approach to generate electric energy offers a clean, safe, reliable and affordable, i.e., sustainable option? In principle yes, however a technology impact on the environment strongly depends on the actual implementation bearing residual risks due to technical failures, human factors, or natural catastrophes. A full response is thus difficult and can be given first when the wicked multi-disciplinary issues get well formulated and “resolved”. These problems are lying at the interface between: the necessary R&D effort, the industrial deployment and the technology impact in view of the environmental sustainability including the management of produced hazardous waste. As such, this problem is clearly of multi-dimensional nature. This enormous complexity indicates that just a description of the problem might cause a dilemma. The paper proposes a novel holistic approach applying Multi-Criteria Decision Analysis to assess the potential of nuclear energy systems with respect to a sustainable performance. It shows how to establish a multi-level criteria structure tree and examines the trading-off techniques for scoring and ranking of options. The presented framework allows multi-criteria and multi-group treatment. The methodology can be applied to support any pre-decisional process launched in a country to find the best nuclear and/or non-nuclear option according to national preferences and priorities. The approach addresses major aspects of the environmental footprint of nuclear energy systems. As a case study, advanced nuclear fuel cycles are analyzed, which were previously investigated by the Nuclear Energy Agency (NEA/OECD) expert group WASTEMAN. Sustainability facets of waste management, resource utilization and economics are in focus.

The use of liquid metals in solar power systems is not new. The receiver tests with liquid sodium in the 1980s at the Plataforma Solar de Almer a (PSA) already proved the feasibility of liquid metals as heat transfer fluid. Despite the high efficiency achieved with that receiver, further investigation of liquid metals in solar power systems was stopped due to a sodium spray fire. Recently, the topic has become interesting again and the gained experience during the last 30 years of liquid metals handling is applied to the concentrated solar power community. In this paper, recent activities of the Helmholtz Alliance LIMTECH concerning liquid metals for solar power systems are presented. In addition to the components and system simulations also the experimental setup and results are included.

AbstractThermochemical biorefineries for the production of chemicals and materials can play an important role in the bioeconomy. However, their economic viability is often questioned under the premise of the economy of scale. This paper presents a regional, modular biorefinery concept for the production of the platform chemicals hydroxymethylfurfural (HMF), furfural and phenols from the lignocellulosic perennial miscanthus, which can be cultivated on marginal and degraded areas. The paper focuses on the question of the minimum selling price of HMF and the optimal plant size for this purpose, using the region of Baden‐Württemberg, Germany, as an example. Based on small pilot plant results, a scalable process simulation was created via AspenPlus. This allows different scenarios and process combinations of this multi‐output biorefinery concept to be compared with each other. Using this, a minimum sales price for the main product HMF is calculated using methods of dynamic investment cost calculation according to the net present value method. Based on this, the plant capacity was scaled. The scenarios and sensitivity analyses show that, with an accuracy of ±15%, regional biorefineries could already offer platform chemicals at prices of 2.21–2.90 EUR/kg HMF at the current stage of development. This corresponds to three to four times the price of today's comparative fossil base chemicals and is thus a competitive option from the authors’ point of view. The local biomass and the heat prices were identified as the main influencing factors. As a result, the selection of the location will have a decisive influence on the economic viability of such concepts in the case of further development and optimization of the process in first demonstration plants.

Abstract In this study, voltage relaxation and impedance spectroscopy are introduced as in-operando methods for detecting lithium plating in commercial lithium-ion cells with graphitic anodes. Voltage relaxation is monitored subsequent to defined charge steps of variable amplitudes, charge throughputs, termination criteria and at different ambient temperatures yielding dependencies over a wide experimental parameter range. An adapted differential voltage analysis is presented to resolve the characteristic mixed potential evolving in case of plating. Impedance spectroscopy is applied in parallel to the relaxation phase to trace a possible alteration of the cell's impedance due to the concurrent depletion of reversibly deposited lithium. The introduced voltage differentials are shown to resolve the mixed potential with restrictions only for little charge throughputs. The comparison of voltage relaxation and already established stripping discharge reveals similarities of the underlying physicochemical processes and allows an estimate of the amount of deposited lithium in case of relaxation. In the evolution of the cell's impedance, a reversible shrinkage of the high frequency intersection resistance and the arc representing the anodic charge transfer process are identified as indicators towards plating. The presented methods solely rely on non-destructive measurement quantities and thus are fully suitable for the application in battery management systems.

This paper aims to fill a research gap in the area of consumer-citizen attitudes to business models for decentralized energy storage, at the level of households and buildings. The study focuses on the interaction of such attitudes and their underlying motivation factors with socio-cultural, contextual factors. Self-determination theory (SDT) is used as a theoretical framework, to connect interpersonal and contextual factors, addressing the question of how contexts influence the motivation to support energy storage. Drawing on SDT, this study examines the role of autarky (independence from the energy system), autonomy (control over energy management) and relatedness (degree of sharing required) in this regard, embedded and interpreted in the socio-cultural local context of two demonstration sites in Sweden and Portugal. A mixed method approach is used. Quantitative survey data provides information on local social and cultural dimensions, followed by stakeholder consultation workshops that elicit participants’ views on different models of decentralized energy storage. The findings raise questions of how to improve autarky and autonomy for prosumers, while keeping the need for time investment low and provide flexibility regarding the required degree of interaction between prosumers. Implications for business models and policy support for citizen-centered sustainable urban energy systems are derived.