Smart Energy最新文献

4th-generation district heating networks confront numerous challenges such as integrating decentralized renewable energy sources, bidirectional heat transfer, new storage concepts, low-temperature operation, custom heat supply, data management, and advanced control strategies. Laboratory and hardware-in-the-loop testing offer a safe, cost-effective environment for testing and validating these innovations. This paper presents a framework for joint experiments in multiple remote laboratories, enhancing the testing of district heating system components. This distributed testbed enhances the efficiency of testing by utilizing existing equipment and expertise from various laboratories, thereby reducing costs and time and allowing for more scenarios to test. It targets manufacturers, grid operators, and research institutions, facilitating collaborative lab work for technology testing before field deployment. This approach allows for diverse test scenarios, considering component interactions across different locations without identical hardware or software. The framework's efficacy is shown in a proof-of-concept with a low-temperature district heating network integrated across four Fraunhofer Institutes. An initial experiment connects a test building and a ground-source heat pump physically existing in different labs with emulated models of a district heating network and a geothermal source. Results from a three-week operation validate the framework's performance.

This paper presents three scenarios (policy, renewables and electrification and efficiency) for transitioning to a 100 % renewable electricity sector in Austria, based predominantly on wind and photovoltaics, alongside sector-specific electrification. Considering renewable expansion targets and three distinctive weather years from an overall system perspective, the core objective is to minimize variable costs of electricity storage and dispatchable power plants. The model developed determines their optimal dispatch for meeting the underlying electricity demand each hour. Within the scenarios for renewable expansion, a special focus lies on integrating short-duration (batteries), medium-duration (pumped storage hydro) and long-duration (hydrogen) energy storage. Our analysis reveals the significant impact of weather patterns on renewable electricity generation, particularly the differences between winter and summer generation quantities. This necessitates seasonal balancing and the mitigation of extremes like low wind power events, which require corresponding backup capacities. This contrast is particularly evident when comparing the years 2030–2050, wherein in the latter, certain dispatchable generators are only utilized in one of the three underlying weather years during extreme weather conditions. In our paper, we demonstrate how, especially for hydrogen production and storage, weather conditions influence production levels and the re-electrification demand. The results indicate the feasibility of achieving a fully decarbonized energy system in Austria through suitable policy measures and expanded renewable generation, with long-duration storage playing a crucial role in seasonal balance and compensating for the absence of fossil fuel generation. Strategic planning is essential to aligning the expansion of renewable energy generation with the necessary flexibility.

Positive Energy Districts are seen as a stepstone towards climate-neutrality for European cities. The concept aims to make districts an active contributor to urban energy systems. However, the definition of PEDs is relatively loose and there is currently a lack of a common European assessment methodology, which makes it difficult to evaluate PED in practice. This research evaluates the energetic assessment methodologies developed in three PED-relevant projects in Europe – namely MAKING CITY, Zukunftsquartier Wien, and Zero Emission Neighbourhood – in order to derive recommendations for a common PED assessment framework. For this purpose, the three methodologies have been applied to case study districts in Germany. Subsequently, the application of the methodologies has been analysed based on their general practicality as well as their fulfilment of the PED objectives. The findings suggest that a positive energy balance might not be considered as a prerequisite of PEDs as this strict requirement sets a high entry barrier for districts that lack the intrinsic factors for surplus renewable energy production. For PED as an inclusive framework, the focus should be on delivering positive impacts for the districts and the wider energy systems; whilst the positive energy balance can be seen as a complementary rather than a mandatory condition.

The transition to smart energy systems is a crucial component for ensuring sustainability and reducing carbon emissions. Electrification is a key factor in achieving these goals, with the transport sector being an integral part of the equation. The integration of the transport sector with the electricity sector will facilitate a reduction in carbon emissions. This paper assesses the potential of electric bus depots to function as smart energy infrastructures. Analyzing the energetic system flexibility of the electrified public transport system is at the core. Previous studies emphasize the importance of identifying and managing the optimal operation strategies of electrified transport to achieve system flexibility. This work concentrates on Germany as a reference market for balancing and electricity markets at the center of the EU. The flexibility potential of a bus fleet with 80 electric buses is analyzed under optimal participation in the short-term electricity and balancing market. The bus fleet operator acts as a storage systems aggregator, which combines mobile and stationary storages to enhance energy flexibility. The study measures the potential contribution for the stability of the electricity grid in Germany. The additional battery degradation that arises with the provision of balancing services is part of the economic equation. The analysis is based on historical data from 2020, 2021, and 2022 and investigates hypothetically lower and higher demand for balancing energy in the load-frequency control area of Germany and Denmark. The paper concludes by demonstrating the feasibility of the electrified bus depot as an integral component of smart energy systems. These findings contribute to a better understanding of the electrification of transport, sector integration, and the role of infrastructures in achieving smart energy systems and showcases the attractiveness of this business model.

The global shift towards decentralised energy systems has assigned municipalities a key role in achieving national climate neutrality objectives. As the main stakeholders in the local energy transition, municipalities are responsible for the decarbonization of the local energy system through the extensive integration of renewable energy sources into existing systems. However, this integration requires new approaches and system adjustments, such as energy storage deployment, to satisfy the variable nature of renewable energy sources. The integration of novel solutions, such as energy storage, is difficult because of the diverse range of stakeholders involved, each with their own perceptions and expertise. This study uses the Fuzzy Cognitive Mapping (FCM) methodology to analyse the mental models of different stakeholders regarding their perceived importance of different factors influencing the implementation of energy storage in municipalities. The approach of this study enables a better understanding of municipal energy systems and its dynamics. The results reveal that support schemes such as subsidies and awareness campaigns are key to all stakeholders. Municipalities tend to focus on local needs and technological solutions, while energy experts prioritize technical aspects and national policies. Municipalities address challenges linearly, missing interconnections, whereas energy experts consider feedback loops and system requirements. The study highlights the need for common ground to drive effective policy and infrastructure development. The results could be used to facilitate discussions with policy makers on why energy storage is important and what policy measures should be considered to accelerate its deployment.

Given the strong seasonal nature of heating demands, peak heat is important during colder seasons. Instead of peak heat plants, seasonal large-scale thermal energy storage (TES) could be utilized. These can be charged during warmer seasons and discharged when required, decreasing the need for peak heat plants. Systems modelling studies on seasonal TES are lacking. Thus, a long-term local energy system model is applied under different scenarios to investigate the potential roles of seasonal TES in an evolving heating system. The results show that seasonal TES is economically viable for: all future electricity price cases for low TES construction costs, corresponding to repurposing of underground oil storages, and for most electricity price cases for mid- and high construction costs, corresponding to new underground excavations. Seasonal TES mainly decrease the investments in and usage of electric boilers or biogas boilers, while increase the utilization of heat pumps. Other technologies may be affected depending on the future trajectory of electricity price developments. The size of the TES is between 3 and 7% of the annual district heating heat demand, depending on construction cost and electricity price development. The expansion of district heating into new housing is mostly unaffected by the availability of TES.

This study elucidates the authentic utilization of Vehicle-to-Home (V2H) system, a bi-directional DC charger for residential use and appraises power conversion losses incurred during V2H charging and discharging, utilizing data from commercial Home Energy Management Systems (HEMS). This approach offers the advantage of ascertaining operational efficiency within practical scenarios at a reduced cost relative to empirical data acquisition.

The empirical examination of results revealed that V2H households exhibited more frequent connections to the charger and engaged in more substantial charging activities compared to Charging-only households.

When estimating the power conversion efficiency in the context of V2H charging and discharging, a partial load efficiency curve was constructed for the input power of the V2H charger, thereby confirming that the peak efficiency closely approximated the nominal rated efficiency. These identified characteristics hold value for V2H system simulations. Furthermore, it was confirmed that a substantial standby power, ranging from 92 to 142 kWh per year, was generated when the V2H charger remained inactive in the sampled households. Additionally, the lack of reverse power flow to the external grid from the V2H system led to an observed increase in V2H partial load operation, resulting in a situation characterized by diminished conversion efficiency.

This paper takes a novel modelling approach by considering high spatial resolution heat generation potentials for district heating and integrating them into a European energy system model. Subsequently, a modelling analysis of an integrated energy system including district heating, electricity and hydrogen supply for 25 EU Member States and the year 2050 is carried out. In contrast to existing approaches, the modelling approach captures the heterogeneous resource availability in district heating. The results show multivalent district heating networks based on a wide range of renewable and excess heat sources used directly or in combination with large-scale heat pumps. The high spatial resolution of the heat generation potentials allows a detailed cost comparison of different possible future technology mixes in district heating. The paper finds that the use of heat pumps, geothermal energy and industrial excess heat offer slight cost advantages for the energy system as a whole. Geothermal heat can also provide cost advantages for district heating generation.

A significant increase in grid connection requests from industrial customers has lead to long connection queues. Combined with long lead times on grid construction, the result is significant socioeconomic losses due to lack of grid capacity. Distribution system operators (DSO) have therefore introduced non-firm connections as an alternative, where the new grid customer may connect on the condition that the DSO retains the right to disconnect the grid customer if necessary. An option to potential disconnection is for customers to leverage flexibility to stay below an agreed capacity level. Unfortunately, many existing grid customers possess flexibility potential but lack incentives to utilise it. To address this, we propose a “coordinated non-firm connection”, where the new grid customer forms an energy community with existing grid customers to coordinate flexibility and capacity utilisation. To demonstrate technical feasibility and incentive compatibility, we formulate a complementarity model. Applying this model to a case study involving three industrial grid customers, we showcase both technical potential and incentive compatibility. Results illustrate how energy community members engage in capacity trading within a local market, ensuring adherence to grid limitations. The game theory-based model confirms sufficient economic benefit for all members to participate.