Fakultät 09 / Cologne Institute for Renewable Energy
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After 50 years, there is still an ongoing debate about the Limits to Growth (LtG) study. This paper recalibrates the 2005 World3‐03 model. The input parameters are changed to better match empirical data on world development. An iterative method is used to compute and optimize different parameter sets. This improved parameter set results in a World3 simulation that shows the same overshoot and collapse mode in the coming decade as the original business as usual scenario of the LtG standard run. The main effect of the recalibration update is to raise the peaks of most variables and move them a few years into the future. The parameters with the largest relative changes are those related to industrial capital lifetime, pollution transmission delay, and urban‐industrial land development time.
To achieve sustainable development, the energy transition from lignite burning to renewable energy resources for electric power generation is essential for Greece. Wind and solar energy have emerged as significant sources in this transition. Surprisingly, numerous studies have examined the potential for onshore wind based on land eligibility, while few studies on open-field photovoltaic (PV) installations have been conducted. Therefore, based on the Specific Framework for Spatial Planning and Sustainable Development for Renewable Energy Sources (SFSPSD-RES), along with insights from previous relevant studies, this work conducts a land eligibility analysis of onshore wind and open-field PV installations in Greece using the software Geospatial Land Availability for Energy Systems (GLAES 1.2.1) and ArcGIS 10.2. Additionally, through an in-depth exploration of wind and solar PV energy potential in decommissioned lignite mines integrated with wind power density (WPD) and global horizontal irradiation (GHI) maps, this study compares the suitability of wind versus solar as energy sources for the decarbonization of Greece. Overall, despite the greater spatial eligibility for onshore wind turbines compared to open-field PV power plants, the relatively lower wind energy potential and operational limitations of wind turbines lead to the study’s conclusion that solar energy (PV) is more suitable for the decarbonization of Greece.
The decarbonization and the substitution of fossil fuels with hydrogen have emerged as critical objectives in the ongoing energy transition. However, the lack of understanding and awareness surrounding industrial-scale hydrogen projects and their potential hinder progress in addressing these challenges. To expedite the transition process, it is imperative to cultivate a sense of awareness and sensitivity among industrial-scale hydrogen projects, dimensions of generation plants, and potential use cases for hydrogen and its co-products from electrolysis.
This research endeavors to answer the fundamental question: "How can a general sense of awareness and sensitivity for hydrogen projects be established in a manner that is easily comprehensible?" To accomplish this goal, a systematic approach is proposed. The research leverages renewable generation profiles in hourly resolution data from photovoltaic plants and onshore/offshore wind turbines, to ascertain the available electricity that can be utilized for electrolysis. By employing scientifically grounded assumptions about the parameters of electrolysis plants, the design and resource requirements will be determined and visually represented. Additionally, predefined use cases for the produced hydrogen and its by-products will be considered, and diverse supply capacities will be visualized across sectors such as mobility, industry, and housing, considering in non-cumulative manner. In addition, the potential of hydrogen as a long-term storage media for renewable electricity can be assessed.
The outcome of this research manifests as an accessible web tool called the "Electrolysis Calculator". This user-friendly tool necessitates four user-input values and performs calculations for primary electrolysis design parameters, encompassing full-load hours, resource consumption, generated energy, and substance quantities. Furthermore, the web tool provides intuitive visualizations of typical use case capacities, aimed at fostering awareness and understanding of hydrogen projects among its users.
The web tool enables decision-making and promoting widespread adoption of hydrogen as an alternative energy carrier and long term storage media.
Reducing the carbon emissions from hotels on non-interconnected islands (NII) is essential in the context of a low carbon future for the Mediterranean region. Maritime tourism is the major source of income for Greece and many other countries in the region, as well as hot-temperate and tropical regions worldwide. Like many NIIs, Rhodes attracts a high influx of tourists every summer, doubling the island’s energy demand and, given the high proportion of fossil fuels in the Rhodian energy supply, increasing carbon emissions. Using the theoretical framework ‘FINE’, this paper presents the optimisation of a medium-sized hotel’s energy system with the aim of reducing both cost and carbon emissions. By introducing a Photovoltaic (PV) net metering system, it was found that the carbon emissions associated with an NII hotel’s energy system could be reduced by 31% at an optimised cost. It is suggested that large-scale deployment of PV or alternative renewable energy sources (RES) in NII hotels could significantly reduce carbon emissions associated with the accommodation sector in Greece and help mitigate climate change.
Positive Impact of Red Soil on Albedo and the Annual Yield of Bifacial Photovoltaic Systems in Ghana
(2023)
The annual yield of bifacial photovoltaic systems is highly dependent on the albedo of the underlying soil. There are currently no published data about the albedo of red soil in western Africa. In this study, the impact of the albedo of red soil in Ghana on the energy yield of bifacial photovoltaic systems is analysed. A bifacial photovoltaic simulation model is created by combining the optical view factor matrix with an electrical output simulation. For an exact simulation, the albedo of red soil at three different locations in Ghana is measured for the first time. The average albedo of every red soil is clearly determined, as well as the measurement span including instrumentation uncertainty; values between 0.175 and 0.335 were measured. Considering these data, a state-of-the-art bifacial photovoltaic system with an average of 19.8% efficient modules in northern Ghana can achieve an annual energy yield of 508.8 kWh/m2 and a bifacial gain of up to 18.3% in comparison with monofacial photovoltaic panels. To summarise, red soil in two out of three locations in Ghana shows higher albedo values than most natural ground surfaces and therefore positively impacts the annual yield of bifacial photovoltaic systems.
The annual yield of bifacial photovoltaic systems is highly dependent on the albedo of the underlying soil. There are currently no published data about the albedo of red soil in western Africa. In this study, the impact of the albedo of red soil in Ghana on the energy yield of bifacial photovoltaic systems is analysed. A bifacial photovoltaic simulation model is created by combining the optical view factor matrix with an electrical output simulation. For an exact simulation, the albedo of red soil at three different locations in Ghana is measured for the first time. The average albedo of every red soil is clearly determined, as well as the measurement span including instrumentation uncertainty; values between 0.175 and 0.335 were measured. Considering these data, a state-of-the-art bifacial photovoltaic system with an average of 19.8% efficient modules in northern Ghana can achieve an annual energy yield of 508.8 kWh/m2 and a bifacial gain of up to 18.3% in comparison with monofacial photovoltaic panels. To summarise, red soil in two out of three locations in Ghana shows higher albedo values than most natural ground surfaces and therefore positively impacts the annual yield of bifacial photovoltaic systems.
This study aimed to simulate the sector-coupled energy system of Germany in 2030 with the restriction on CO2 emission levels and to observe how the system evolves with decreasing emissions. Moreover, the study presented an analysis of the interconnection between electricity, heat and hydrogen and how technologies providing flexibility will react when restricting CO2 emissions levels. This investigation has not yet been carried out with the technologies under consideration in this study. It shows how the energy system behaves under different set boundaries of CO2 emissions and how the costs and technologies change with different emission levels. The study results show that the installed capacities of renewable technologies constantly increase with higher limitations on emissions. However, their usage rates decreases with low CO2 emission levels in response to higher curtailed energy. The sector-coupled technologies behave differently in this regard. Heat pumps show similar behaviour, while the electrolysers usage rate increases with more renewable energy penetration. The system flexibility is not primarily driven by the hydrogen sector, but in low CO2 emission level scenarios, the flexibility shifts towards the heating sector and electrical batteries.
Potential analyses identify possible locations for renewable energy installations, such as wind turbines and photovoltaic arrays. The results of previous potential studies for Germany, however, are not consistent due to different assumptions, methods, and datasets being used. For example, different land-use datasets are applied in the literature to identify suitable areas for technologies requiring open land. For the first time, commonly used datasets are compared regarding the area and position of identified features to analyze their impact on potential analyses. It is shown that the use of Corine Land Cover is not recommended as it leads to potential area overestimation in a typical wind potential analyses by a factor of 4.7 and 5.2 in comparison to Basis-DLM and Open Street Map, respectively. Furthermore, we develop scenarios for onshore wind, offshore wind, and open-field photovoltaic potential estimations based on land-eligibility analyses using the land-use datasets that were proven to be best by our pre-analysis. Moreover, we calculate the rooftop photovoltaic potential using 3D building data nationwide for the first time. The potentials have a high sensitivity towards exclusion conditions, which are also currently discussed in public. For example, if restrictive exclusions are chosen for the onshore wind analysis the necessary potential for climate neutrality cannot be met. The potential capacities and possible locations are published for all administrative levels in Germany in the freely accessible database (Tool for Renewable Energy Potentials—Database), for example, to be incorporated into energy system models.
A bifacial Photovoltaic (PV) simulation model is created by combining the optical View Factor matrix with electrical output simulation in python to analyse the energy density of bifacial systems. A discretization of the rear side of the bifacial modules allows a further investigation of mismatching and losses due to inhomogeneous radiation distribution. The model is validated, showing a deviation of -1.25 % to previous simulation models and giving hourly resolvedoutput data with a higher accuracy than existing software for bifacial PV systems.
In this study the link between renewable energies and employment in Senegal is analyzed.
The Sustainable Livelihood Approach is used to understand the investigated situation in a holistic view. To successfully implement renewable energies in Senegal and to have a significant impact on the employment market, the governmental framework and the technical education has to improve, to match the needs of the labor market.
Rural communities do not have all the assets to lift themselves out of poverty and disadvantages by the usage of renewable energy. Solar irrigation, off-grid systems and solar devices impact the level of education and the labor force in rural areas in Senegal.
Moreover, access to a reliable energy source improves people’s livelihood in terms
of health, education, income and employment.
The resulting employment effect of adding 20 MW with the solar power plant Senergy 2 can be estimated with 28.686 created jobs (0,54 % of total employment).
Upcoming power projects offer employment opportunities for graduates of the master study renewable energies. Furthermore, the demand of specialized engineers and
technicians in the distribution and project planning sector will rise.
Im Rahmen des Technologiescreenings sind zunächst relevante Technologien, die Einfluss auf das Energienachfrageverhalten für Haushalte besitzen, identifiziert worden. Dabei ist ausschließlich eine technologische Betrachtung erfolgt, das individuelle Nutzerverhalten von Haushaltsbewohnern wurde dabei nicht betrachtet. Die Einordnung der Technologien sind in Standard Energietechnologien: Erzeuger, Umwandler, Verbraucher und Speicher kategorisiert. Zudem zeigt die in die Kategorien Messsysteme, Gebäudeautomation und Energiemanagementsysteme. Dabei handelt es sich um, digitale Technologien mit Aspekten und Anwendungen von Energietransparenz und -management. Zeitraum des kontinuierlichen Technologie-Screenings war von 2017-2020.
Das interdisziplinäre Forschungsprojekt “Smarte Technologien für Unternehmen” untersuchte im Zeitraum von Juli 2017 bis Dezember 2020 Anwendungs- und Akzeptanzprobleme zum Einsatz smarter Technologien in KMU und entwickelte darauf aufbauend Lösungsansätze zur Steigerung der Energieeffizienz sowie zum Energie- und Lastmanagement. Dazu wurden smarte Technologien zunächst im Zuge eines Screenings identifiziert, kategorisiert und bewertet. In den qualitativen und quantitativen Nutzeranalysen wurden Unternehmer*innen in den Fokus der Analyse gestellt, um den Wissensstand sowie Chancen und Barrieren zum Einsatz smarter Technologien in KMU darzulegen. Mit der Durchführung transdisziplinärer Anwendungstests wurde ein zentraler Lösungsansatz entwickelt: Die Effizienzanalyse von KMU mittels mobiler Messtechnik und Visualisierungstools als potenzielle Strategie zur Reduktion von Energieverbräuchen.
Die Ergebnisse dieses anwendungsorientierten Forschungsprojektes zeigen die Anwendungs- und Akzeptanzprobleme zum Einsatz smarter Technologien in KMU auf und geben Handlungsoptionen zur Steigerung der Energieeffizienz mit Hilfe ausgewählter smarter Produkte und Tools.
Im Rahmen des Technologie-Screenings wurden smarte Technologien für den Einsatz in mittelständischen Unternehmen (vorzugsweise KMU) im Zeitraum von 2017-2020 in einem kontinuierlichen Monitoringprozess betrachtet. Dadurch konnte mit dem Screening ein umfassender Überblick über die Angebotsseite und den Markt smarter Technologien geschaffen werden. Ebenso wurden potenzielle Technologien für den Einsatz im Anwendungstest des Forschungsprojekts VISE-U identifiziert. Insgesamt umfasst das Technologie-Screening sechs spezifische Technologie-Kategorien, denen wiederum einzelne Systeme auf Herstellerebene zugeordnet wurden. So konnten in Summe 20 Systeme unterschiedlicher Hersteller hinsichtlich des Aufbaus sowie der Funktionsweise samt Technologie-Steckbrief beschrieben werden. Die Steckbriefe zeigen dazu die technische Beschreibung, Komponenten sowie Schnittstellen der Systeme auf und referenzieren auf weiterführende Informationen auf den Webseiten der Hersteller.
The rising worldwide energy demand leads to the depletion of fossil fuels reserves and at the same time, it increases the environmental impact caused by emissions of greenhouse gases (GHG).
Utilization of fossil fuels causes not only climate change impacts such as global warming, but also many other environmental problems such as water and soil contamination that pose potential risks to human and animal health.
Furthermore, increasing population growth leads to increased food demand and consumption. This upward trend creates competition between food and bioenergy markets. Hence, the so‐called “food or fuel” discussion is back.
Challenges to counteract deciding between food and fuel that focus on the need to produce sustainable energy, while protecting environment, are the keys to replacing fossil fuels and lowering their greenhouse gas emissions. For this purpose, a completely new strategy with a proper sustainable system to supplying world’s energy demand must be found.
The goal of the ComProSol project is the mobilization of currently unused biogenic contingents such as residual and waste material for bioenergy feedstocks. Another budding option is the reactivation of fallow land to grow energy crops and short rotation coppice for energy recovery.
In the course of Germany’s bioeconomy program, which will switch the economy from a petro-based to a bio-based society, the prioritized utilization of bio-based resources should always be the hierarchically most valuable. Food and forage production are given preference over material recycling and extracting raw materials. Another driver is the growing consciousness of environmental issues and nature conservation which limits the available cultivatable area by law. As a result, there is a supply bottleneck of economically competitive feedstock for bioenergy. In this context, the interdisciplinary project is based on the systematic interconnection of applications to create utilization cascades.
Methodical corrective measures of ComProSol focus on influencing fuel properties by preconditioning through substrate and additive compound blending, sieving and compacting, and integrating process optimization. Collaboration with other subprojects that deal with bio- or thermal-chemical conversion will provide additional impetus for developing utilization applications.
The initial work package of ComProSol, which recently started, defines the scope by dint of a regional potential feedstock cadaster in order to specify the further roadmap.
Intelligent use of energy is one of the keys to success for an energy revolution. To meet this challenge, smart meters are suitable tools because INTELLIGENT use of energy means not only to use efficiency technology, but also to determine load shifting potentials and use them accordingly. Especially farms with high power consumption are becoming increasingly concerned about reducing energy costs due to rising energy prices and need a systematic analysis of their operational energy flow. To find solutions for farms, the NaRoTec e.V., the TH Köln, and the Machinery Ring Höxter-Warburg have joined forces with partners and launched the project "Intelligent Energy in Agriculture", which is funded by the state of NRW. The aim of the project is to be able to give individual advice recommendations for energy optimization of agricultural holdings. This will be achieved inter alia through an operational energy audit and current measurements in different operating ranges. To achieve this, smart meters were installed in selected energy-intensive dairy and pig farms. As part of the project, the installed smart meter information about the consumption of various plants and their components were analyzed, regularities and adaptability in loading history identified, and the energy efficiency of the equipment and systems used verified (especially pumps, ventilators, feeding systems). Then recommendations were formulated to shift electricity-intensive processes to times with low electricity costs and high intrinsic power production. The resulting findings will be used as the basis for intelligent energy management in the further course of the project. Overall, efficiency streamlining measures in the field of ventilation and lighting systems, flexible dry feeding systems by decoupling power purchase and consumption, as well as energy savings and related CO2 savings were determined.
Intelligent use of energy is one of the keys to success for an energy revolution. To meet this challenge, smart meters are suitable tools because INTELLIGENT use of energy means not only to use efficiency technology, but also to determine load shifting potentials and use them accordingly. Especially farms with high power consumption are becoming increasingly concerned about reducing energy costs due to rising energy prices and need a systematic analysis of their operational energy flow. To find solutions for farms, the NaRoTec e.V., the TH Köln, and the Machinery Ring Höxter-Warburg have joined forces with partners and launched the project "Intelligent Energy in Agriculture", which is funded by the state of NRW in Germany. The aim of the project is to be able to give individual advice recommendations for energy optimization of agricultural holdings. This will be achieved inter alia through an operational energy audit and current measurements in different operating ranges. To achieve this, smart meters were installed in selected energy-intensive dairy and pig farms.
As part of the project, the installed smart meter information of one of the dairy Farms is used to optimize the energy consumption of the farm and increase the degree of self-sufficiency. A good way to achieve this is by taking a closer look at the cooling process of the produced milk since it is one of the most energy consuming processes on a dairy farm. In addition an installation of an ice cooling system instead of a direct cooling system enables the possibility to store self-produced energy in the form of ice and use it later on when it is needed to cool the milk. This flattens the usual energy peaks throughout the day and increases the degree of self-sufficiency. To ensure a sufficient amount of self-produced energy with solar power plants of various sizes were designed. The different sizes of the power plants are defined by the use of the gathered smart meter data is used to cover different electric loads in addition to the ice water cooling system. Afterwards the different simulated models are compared to find the best balance between energy production, investment cost and a high degree of self-sufficiency. First results show that using an ice cooling system in combination with a solar power plant improvement the degree of self-sufficiency by up to 7.8 %.
The utilization of roadside-green-cuttings (grass) for anaerobic digestion increases provides an additional possible source of organic waste for use as a renewable energy source. Grass can be used as a substrate to increase biogas yield. Nevertheless, the anaerobic digestion of this kind of waste can be limited due to the fact that it could be contaminated with heavy metals, in particular from traffic emissions and industrial activity. For this reason the biogas production of grass from a busy road was assessed. Samples of roadside-grass were washed with an organosulphide, which is used for the removal of heavy metals from wastewater.
A comparison of the anaerobic digestion of washed and unwashed roadside grass was performed. Results showed that the anaerobic digestion of the unwashed grass was much more effective than the washed grass. A second experiment was carried out and co-fermentation of manure and farm-grass was prepared for anaerobic digestion. Lead was added in the concentrations 500, 1000 and 2000 mg Pb2+/kg. The results showed that the higher the lead concentration, the lower the inhibition of the biogas yield. The grass could be acting as phytoremediator for high lead concentrations. The grass could contain organic compounds, which can as-similate heavy metals.
Anaerobic Digestion of spent grains: Potential use in small-scale Biogas Digesters in Jos, Nigeria
(2014)
In order to ascertain biogas yield potential and applicability of spent grains (SG)1 in small-scale biogas production, laboratory batch fermentation was performed with various masses of dry and wet SG using sewage sludge (SS)2 and digested maize silage (DMs) 3 as inoculums. Different volumes of biogas and CH4 were measured with higher volumes observed for batch fermentation with DMs in com-parison to those produced by SS. Results from the study reveals minimum biogas yield of 118.10 L/kg
VS and maximum yields of 769.46 L/kg VS, which are indicative of the possible use of SG for domestic biogas production in Jos, Nigeria. The study established the fact that the use of both dry and wet SG results in the yield of a useful amount of biogas having 40 - 60 % CH4 content depending on the inoculum and amount of volatile solids present. Using the parameters of dry matter and volatile solids contents analysed for SG and DMs, it was estimated that a reactor volume of 6.47 m3 would be capable of meeting the daily cooking needs of rural households in Jos, Nigeria.