The transition to a net-zero economy with increased electrification of transport and heating poses electricity supply challenges during the winter months, particularly in PV-dominated systems. This ...study explores comprehensively various strategies and their combinations to address potential winter electricity deficits in Switzerland. Our innovative modelling integrates three sectors (electricity, heat, and transport), neighbouring countries, and environmental life cycle considerations. Among potential strategies to mitigate Swiss winter electricity deficit, electricity imports from neighbouring countries are taken as the benchmark policy strategy. Our analysis reveals that only gas-fired power plants and alpine PV, if applied in isolation, are technology options that alleviate the Swiss winter deficit and reduce cost at the same time. Increasing other single power technologies individually, or importing hydrogen, alleviate the deficit, too, but they inflate energy system costs by 18%–34% compared to relying on electricity imports. Despite the strategies for mitigating the winter deficit assessed being substantially different, our study found no significant environmental concerns regarding local land requirements or critical raw material needs. However, each strategy might imply the need for certain fuel imports and can have a profound impact on determining cost-optimal heating strategies for buildings. With an additional 1.4 GW of gas-fired power plant fuelled by domestic bio-methane, 4 GW of alpine PV, 2.2 GW of wind turbines, and no cost increase compared to its current roadmap, Switzerland could have a fully renewable energy system with a reduced winter deficit and no fuel imports.
•Comparison of technology options to reduce Switzerland’s winter electricity deficit.•Gas turbines, alpine PV and their combination with wind turbines are cost-efficient.•Materials demand and land use for each option are not a concern for feasibility.•Trade-offs arise: fuel imports, social acceptance, use of unproven technologies.
During recent years, quantum computers have received increasing attention, primarily due to their ability to significantly increase computational performance for specific problems. Computational ...performance could be improved for mathematical optimization by quantum annealers. This special type of quantum computer can solve quadratic unconstrained binary optimization problems. However, multi-energy systems optimization commonly involves integer and continuous decision variables. Due to their mixed-integer problem structure, quantum annealers cannot be directly used for multi-energy system optimization.
To solve multi-energy system optimization problems, we present a hybrid Benders decomposition approach combining optimization on quantum and classical computers. In our approach, the quantum computer solves the master problem, which involves only the integer variables from the original energy system optimization problem. The subproblem includes the continuous variables and is solved by a classical computer. For better performance, we apply improvement techniques to the Benders decomposition. We test the approach on a case study to design a cost-optimal multi-energy system. While we provide a proof of concept that our Benders decomposition approach is applicable for the design of multi-energy systems, the computational time is still higher than for approaches using classical computers only. We therefore estimate the potential improvement of our approach to be expected for larger and fault-tolerant quantum computers.
•Quantum computing for multi-energy system optimization.•Benders decomposition using quantum computers.•Hybrid optimization combining quantum and classical computer.•Master problem solved on quantum computer.•Quantum approach feasible but outperformed by classical computers.
Electricity-based fuels are one promising option to achieve the transition of the energy system, and especially the transport sector, in order to minimize the role of fossil energy carriers. One ...major problem is the lacking compatibility between different techno-economic assessments, such that recommendations regarding the most promising Power-to-Fuel technology are difficult to make. This work provides a technically sound comparison of various Power-to-Fuel options regarding technological maturity and efficiency, as well as cost. The investigated options include methanol, ethanol, butanol, octanol, DME, OME3-5 and hydrocarbons. To guarantee the comparability, all necessary chemical plants were designed in Aspen Plus® to determine material and energy consumption, as well as investment costs within the same boundary conditions and assumptions in all simulations and calculations. Individual technical aspects of the various synthesis routes, as well as their advantages and disadvantages, are highlighted.
With an assumed electrolysis efficiency of 70% and considering the energy demand for the CO2 supply and the energy and operating material demand of the chemical plants, depending on the selected electrofuel, 30–60% of the primary energy in renewable electricity can be stored in the lower heating value of the electrofuel. In the presented results, the costs of H2 supply are responsible for 58–83% of the total manufacturing costs and thus have the greatest potential to reduce the latter. For the base case (4.6 €/kgH2), various electrofuels will have costs of manufacturing of between 1.85 and 3.96 €/lDE, with DME being the cheapest.
•Techno-economic analysis of Power-to-Fuel processes from a comparative perspective.•Chemical plant design in Aspen Plus® for Power-to-Fuel pathways.•All simulations with the same assumptions and under the same boundary conditions.•Flowsheet–based, component-specific cost calculation.•Production-specific advantages and disadvantages of various e-fuels.
Decarbonizing fossil fuel-dependent district heating systems is essential for achieving carbon neutrality, particularly in cold climates. In Finland, district heating operators are concentrating on ...electrifying these systems. However, the 2022 energy crisis in Europe has highlighted concerns about heat production costs and the security of heat supply with this approach. This study examines the economic feasibility and risks associated with electrified district heating systems and the early decommissioning of thermal power plants in the interconnected district heating systems of Helsinki, Espoo, and Vantaa. The case study is simulated and optimized to find the least-cost solution while meeting heat demand for various 2025 scenarios, assuming high energy market prices as in 2022 and more normal circumstances. Simulation results indicate that shutting down fossil fuel-based combined heat and power plants in Helsinki and Espoo would create a shortfall in base-load heat production, increasing dependency on heat imported from Vantaa. Both cities are expected to employ more cost-competitive biomass boilers to mitigate the reduction in coal-based heat production, which would decrease operational costs but also reduce revenue from electricity sales due to reduced combined heat and power capacity. Consequently, Vantaa is likely to benefit from its substantial storage and waste and biomass combined heat and power capacity, enabling efficient heat production at reduced costs. Across both scenarios, the analysis demonstrates a significant decrease in emissions and less reliance on imported fuels, highlighting the potential benefits of electrified district heating systems even amidst high electricity market prices.
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•Fluctuating electricity prices raise concerns about electrified district heating.•The feasibility of interconnected electrified district heating in the Helsinki area.•2025 scenarios with the planned decommissioning of thermal plants.•Helsinki and Espoo cities become importers of heat and reliant on biomass.•Electrified DH is competitive even with extreme energy prices.
Hydrogen is a promising solution for the decarbonisation of several hard-to-abate end uses, which are mainly in the industrial and transport sectors. The development of an extensive hydrogen delivery ...infrastructure is essential to effectively activate and deploy a hydrogen economy, connecting production, storage, and demand. This work adopts a mixed-integer linear programming model to study the cost-optimal design of a future hydrogen infrastructure in presence of cross-sectoral hydrogen uses, taking into account spatial and temporal variations, multiple production technologies, and optimised multi-mode transport and storage. The model is applied to a case study in the region of Sicily in Italy, aiming to assess the infrastructural needs to supply the regional demand from transport and industrial sectors and to transfer hydrogen imported from North Africa towards Europe, thus accounting for the region's role as transit point. The analysis integrates multiple production technologies (electrolysis supplied by wind and solar energy, steam reforming with carbon capture) and transport options (compressed hydrogen trucks, liquid hydrogen trucks, pipelines). Results show that the average cost of hydrogen delivered to demand points decreases from 3.75 €/kgH2 to 3.49 €/kgH2 when shifting from mobility-only to cross-sectoral end uses, indicating that the integrated supply chain exploits more efficiently the infrastructural investments. Although pipeline transport emerges as the dominant modality, delivery via compressed hydrogen trucks and liquid hydrogen trucks remains relevant even in scenarios characterised by large hydrogen flows as resulting from cross-sectoral demand, demonstrating that the system competitiveness is maximised through multi-mode integration.
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•A hydrogen supply chain model is extended to study delivery to multi-sector demand.•Industrial uses impose flat profiles with large quantities, while mobility demand is more variable.•The cost-optimal hydrogen infrastructure relies on combined transport modes.•Cross-sectoral deployment of hydrogen has positive impact on the cost of infrastructure.
•Sector coupling leads to lower cost of energy supply in a RE-based system.•Power sector becomes the backbone of the entire energy system.•Integration impact depends on demand profiles, flexibility ...and storage cost.•Electrolysers are an important source of flexibility in an integrated system.•All sector defossilisation is achieved even for severe conditions as of Kazakhstan.
Transition towards long-term sustainable energy systems is one of the biggest challenges faced by the global society. By 2050, not only greenhouse gas emissions have to be eliminated in all energy sectors: power, heat, transport and industry but also these sectors should be closely coupled allowing maximum synergy effects and efficiency. A tool allowing modelling of complex energy system transition for power, heat, transport and industry sectors, responsible for over 75% of the CO2eq emissions, in full hourly resolution, is presented in this research and tested for the case of Kazakhstan. The results show that transition towards a 100% sustainable and renewable energy based system by 2050 is possible even for the case of severe climate conditions and an energy intensive industry, observed in Kazakhstan. The power sector becomes backbone of the entire energy system, due to more intense electrification induced sector coupling. The results show that electrification and integration of sectors enables additional flexibility, leading to more efficient systems and lower energy supply cost, even though integration effect varies from sector to sector. The levelised cost of electricity can be reduced from 62 €/MWh in 2015 to 46 €/MWh in 2050 in a fully integrated system, while the cost of heat stays on a comparable level within the range of 30–35 €/MWh, leading to an energy system cost on a level of 40–45 €/MWh. Transition towards 100% renewable energy supply shrinks CO2eq emissions from these sectors to zero in 2050 with 90% of the reduction achieved by 2040.
This paper analyses the role of sector coupling towards 2050 in the energy system of Northern-central Europe when pursuing the green transition. Impacts of restricted onshore wind potential and ...transmission expansion are considered. Optimisation of the capacity development and operation of the energy system towards 2050 is performed with the energy system model Balmorel. Generation, storage, transmission expansion, district heating, carbon capture and storage, and synthetic gas units compete with each other. The results show how sector coupling leads to a change of paradigm: The electricity system moves from a system where generation adapts to inflexible demand, to a system where flexible demand adapts to variable generation. Sector coupling increases electricity demand, variable renewable energy, heat storage capacity, and electricity and district heating transmission expansion towards 2050. Non-restricted investments in onshore wind and electricity transmission reduce emissions and costs considerably (especially with high sector coupling) with savings of 78.7€2016/person/year. Investments in electric power-to-heat units are key to reduce costs and emissions in the heat sector. The scenarios with the highest sector coupling achieve the highest emission reduction by 2045: 76% greenhouse gases reduction with respect to 1990 levels, which highlights the value of sector coupling to achieve the green transition.
•Sector coupling increases demand flexibility and renewable energy integration.•Electricity-to-heat is a cost-effective way to decarbonise most of the heat sector.•Decarbonisation targets might not be reached without sector coupling.•Restricting onshore wind and/or grid expansion reduces the value of sector coupling.•Detailed variable renewable energy modelling is important in future energy systems.
Climate change threats and the necessity to achieve global Sustainable Development Goals demand unprecedented economic and social shifts around the world, including a fundamental transformation of ...the global energy system. An energy transition is underway in most regions, predominantly in the power sector. This research highlights the technical feasibility and economic viability of 100% renewable energy systems including the power, heat, transport and desalination sectors. It presents a technology-rich, multi-sectoral, multi-regional and cost-optimal global energy transition pathway for 145 regional energy systems sectionalised into nine major regions of the world. This 1.5 °C target compatible scenario with rapid direct and indirect electrification via Power-to-X processes and massive defossilisation indicates substantial benefits: 50% energy savings, universal access to fresh water and low-cost energy supply. It also provides an energy transition pathway that could lead from the current fossil-based system to an affordable, efficient, sustainable and secure energy future for the world.
•Energy transition in power, heat and transport sectors is feasible across the world.•Power sector emerges as the backbone of the entire energy system.•Defossilisation and electrification result in the rise of overall system efficiency.•The described energy transition scenario is compatible with the 1.5 °C target.•Final energy demand grows in a cost-optimal pathway without carbon dioxide removal.
This paper analyses optimal electricity investments (PV and battery storage) to decarbonise heat supply in residential buildings under different heat pump and energy retrofitting scenarios in a ...detailed representation of the Swiss power and heating system. The sensitivity of PV and storage deployment, including lithium-ion (LiB) and vanadium redox flow batteries (VRFB), with respect to distribution network capacity is also investigated. We propose an open-source dispatch sector coupling model (GRIMSEL-AH) to minimise energy system costs (social planner perspective) for heating and electricity supply in Switzerland with hourly and daily time resolution for electricity and heating respectively. Moreover, our representation of the Swiss energy system includes various types of consumers and urban settings which are represented with monitored electricity demand data for each sector and simulated heat demand data at the building level for the residential sector. We find that under a “business as usual” heat pump deployment and retrofitting rate, the optimal electricity investments correspond to 27.8 GWp of PV combined with 16.9 GW (33.8 GWh) for LiB and 1.9 GW (7.6 GWh) for VRFB. For this case, 57% (13.3 TWth/year) of the residential heat demand is covered by heat pumps with a total installed capacity of 19.7 GWth by 2050 (capacity exogenously set with its operation optimised). With increasing heat pump deployment, retrofitting rates are found to have a large impact on the investment in storage and a 100% heat pump scenario for the residential sector appears to be feasible. Our results show that heat pumps do not only decarbonise heat but also provide extra flexibility to the power system, since they increase local PV self-consumption, resulting in higher PV deployment. The model and the methodology presented in this study can be applied to other countries.
•Open-source sector coupling modelling framework with flexible heat pump operation.•Impact of heat pump and energy retrofitting scenarios on electricity investments.•Retrofitting rates have a significant impact on the storage investment.•Heat pumps provide extra flexibility by increasing local PV self-consumption.•Trade-offs between storage and distribution grid upgrade are discussed.
This review gives a worldwide overview on Power-to-Gas projects producing hydrogen or renewable substitute natural gas focusing projects in central Europe. It deepens and completes the content of ...previous reviews by including hitherto unreviewed projects and by combining project names with details such as plant location. It is based on data from 153 completed, recent and planned projects since 1988 which were evaluated with regards to plant allocation, installed power development, plant size, shares and amounts of hydrogen or substitute natural gas producing examinations and product utilization phases. Cost development for electrolysis and carbon dioxide methanation was analyzed and a projection until 2030 is given with an outlook to 2050.
The results show substantial cost reductions for electrolysis as well as for methanation during the recent years and a further price decline to less than 500 euro per kilowatt electric power input for both technologies until 2050 is estimated if cost projection follows the current trend. Most of the projects examined are located in Germany, Denmark, the United States of America and Canada. Following an exponential global trend to increase installed power, today's Power-to-Gas applications are operated at about 39 megawatt. Hydrogen and substitute natural gas were investigated on equal terms concerning the number of projects.
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•Electrolysis and methanation costs are estimated to fall by up to 75% under 500 €/kWel until 2050.•Most projects are located in Germany, Denmark, the United States and Canada.•95 Power-to-Gas projects with a combined load of 38.6 MWel are active in early 2019.•Exponential global increase in installed PtG-capacity is expected between 1993 and 2050.•The years 2012–2015 mark a breakthrough in average plant size and installed capacity.
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