Zukünftige Energie- und Industriesysteme
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Die Bereitstellung industrieller Prozesswärme ist eine zentrale Herausforderung für ein zukünftiges, treibhausgasneutrales Energiesystem. Durch einen Vergleich der Prozesswärmebereitstellung in zwei Energiesystemszenarien werden Gemeinsamkeiten, die auf Richtungssicherheit hindeuten, dargestellt, sowie methodische und inhaltliche Gründe für Abweichungen herausgearbeitet.
Die Bereitstellung industrieller Prozesswärme ist eine zentrale Herausforderung für ein zukünftiges klimaneutrales Energiesystem. In diesem Artikel wird die Vielfalt an etablierten und neuen Energieträgern und Technologien zur treibhausgasarmen bzw. -neutralen Bereitstellung von Prozesswärme vorgestellt. Zudem werden ihre wichtigsten Stärken und Schwächen skizziert, um daraus geeignete Anwendungsfelder und eine Priorisierung ihres Einsatzes zu identifizieren.
Combined heat and power (CHP) production in buildings is one of the mitigation options available for achieving a considerable decrease in GHG emissions. Micro-CHP (mCHP) fuel cells are capable of cogenerating electricity and heat very efficiently on a decentralised basis. Although they offer clear environmental benefits and have the potential to create a systemic change in energy provision, the diffusion of mCHP fuel cells is rather slow. There are numerous potential drivers for the successful diffusion of fuel cell cogeneration units, but key economic actors are often unaware of them. This paper presents the results of a comprehensive analysis of barriers, drivers and business opportunities surrounding micro-CHP fuel-cell units (up to 5 kWel) in the German building market. Business opportunities have been identified based not only on quantitative data for drivers and barriers, but also on discussions with relevant stakeholders such as housing associations, which are key institutional demand-side actors. These business opportunities include fuel cell contracting as well as the development of a large lighthouse project to demonstrate the climate-neutral, efficient use of fuel cells in the residential building sector. The next step could involve the examination and development of more detailed options and business models. The approach and methods used in the survey may be applied on a larger scale and in other sectors.
Eine besondere Herausforderung für die Wärmewende stellen leitungsgebundene Wärmeversorgungsstrukturen dar. Aufgrund ihrer hohen Kapitalbindung bei gleichzeitig hoher Lebensdauer müssen hier frühzeitig die richtigen Weichen in Richtung Energiewende gestellt werden. Eine Vielzahl von Akteuren, Stadtwerken und Energieversorgern, über Planer und Handwerker bis hin zur Immobilienwirtschaft stehen vor der Schwierigkeit, einen langfristig kompatiblen Pfad in Richtung Klimaschutz und Energiewende einzuleiten. Vor diesem Hintergrund sollen in diesem Artikel aus technologischer Sicht Optionen aus dem Themenfeld "LowEx und gekoppelte Wärmeversorgungsstrukturen" näher betrachtet werden.
Auf dem Weg vom Energierohstoff zum Endnutzer entstehen Energieverluste durch Transport, Aufbereitung und Umwandlung, die dazu führen, dass der Primärenergieträger, also der Energierohstoff, nur mit einem bestimmten Nutzungsgrad in einen Endenergieträger (vom Endkunden eingekauften Energieträger für die Nutzung im Gebäude) umgewandelt wird. Der Kehrwert dieses Nutzungsgrades heißt "Primärenergiefaktor". Je größer der Primärenergiefaktor, desto größer die Verluste der Bereitstellung.
Distributed cogeneration units are flexible and suited to providing balancing power, thereby contributing to the integration of renewable electricity. Against this background, we analysed the technical potential and ecological impact of CHP (combined heat and power) systems on the German minutes reserve market for 2010, 2020 and 2030. Typical CHP plants (from 1 to 2800 kWel) were evaluated in relation to typical buildings or supply cases in different sectors. The minutes reserve potential was determined by an optimisation model with a temporal resolution of 15 min. The results were scaled up to national level using a scenario analysis for the future development of CHP. Additionally, the extent to which three different flexibility measures (double plant size/fourfold storage volume/emergency cooler) increase the potential provision of balancing power was examined. Key findings demonstrate that distributed CHP could contribute significantly to the provision of minutes reserve in future decades. Flexibility options would further enhance the theoretical potential. The grid-orientated operating mode slightly increases CO2 emissions compared to the heat-orientated mode, but it is still preferable to the separate generation of heat and power. However, the impacts of a flexible mode depend greatly on the application and power-to-heat ratio of the individual CHP system.
Preventing the worst consequences of climate change would require that GHG emissions be reduced to levels near zero by the middle of the century. To respond to such a daunting challenge, we need to rethink and redesign the currently highly energy-dependent infrastructures of industrial societies and particularly the urban infrastructures to become low- or even zero-carbon cities. Sustainable urban infrastructures need technology. In this paper focused on Western European Cities, we discuss a wide set of technologies in the fields of building, energy and transport infrastructures that can significantly contribute to a reduction of energy and/or GHG emissions and are already available or are in the pipeline. Based on the review of a recent study for the city of Munich, we then present how a mix of these technologies could reduce CO2-emissions by up to 90% for the metropolis of 1.3 million inhabitants and that this strategy could be economically attractive despite a high initial investment.
All of the residential buildings of a city like Munich could be entirely redesigned for EUR 200 per inhabitant annually, which is about one third of an average annual natural gas bill.
For the option of “carbon capture and storage”, an integrated assessment in the form of a life cycle analysis and a cost assessment combined with a systematic comparison with renewable energies regarding future conditions in the power plant market for the situation in Germany is done. The calculations along the whole process chain show that CCS technologies emit per kWh more than generally assumed in clean-coal concepts (total CO2 reduction by 72-90% and total greenhouse gas reduction by 65-79%) and considerable more if compared with renewable electricity. Nevertheless, CCS could lead to a significant absolute reduction of GHG-emissions within the electricity supply system. Furthermore, depending on the growth rates and the market development, renewables could develop faster and could be in the long term cheaper than CCS based plants. Especially, in Germany, CCS as a climate protection option is phasing a specific problem as a huge amount of fossil power plant has to be substituted in the next 15 years where CCS technologies might be not yet available. For a considerable contribution of CCS to climate protection, the energy structure in Germany requires the integration of capture ready plants into the current renewal programs. If CCS retrofit technologies could be applied at least from 2020, this would strongly decrease the expected CO2 emissions and would give a chance to reach the climate protection goal of minus 80% including the renewed fossil-fired power plants.