Grid-based multi-energy systems—modelling, assessment, open source modelling frameworks and challenges

Abstract

Background: The transition to a sustainable future challenges the current energy grids with the integration of variable, distributed renewable energy sources. On a technical level, multi-energy systems may provide the necessary flexibility to minimise the gap between demand and supply. Suitable methods and tools are necessary to derive relevant results and to support a transition to renewable energy sources. While several, dedicated tools to model grids and infrastructure of single-energy carriers exist, there are no tools capable of modelling multi-energy systems in detail. Thus, this paper presents the necessary aspects to consider when modelling grid-based multi-energy systems, presents three open source frameworks for modelling grid-based energy systems and points out the major challenges. Methodology: The current main aspects and challenges for modelling grid-based energy systems are derived from a literature review. Three open source multi-energy modelling frameworks (Calliope, oemof, urbs) are presented, and the extent to which they consider these aspects and how they tackle challenges is analysed. Grid-based MES modelling: We identified five general energy system modelling aspects (modelling scope, model formulation, spatial coverage, time horizon, data) and three aspects specific to modelling energy grids (level of detail, spatial resolution, temporal resolution). While the specific aspects mainly influence the representation of the technical parts of the energy system and the computational effort, the general aspects primarily relate to the system boundaries and scope of the model. For the evaluation of the modelling results, we identified several assessment criteria, including economic, energetic, exergetic and reliability. Each of the studied open source modelling frameworks provides generic capabilities to model energy converters, and the electricity, gas and district heat networks. However, the general and specific aspects present respective challenges. Relating to the general aspects, complexity of model formulation increases when including additional boundary conditions. The accuracy of the results is also dependent on data quality. Temporal and spatial resolutions are the major specific challenges for modelling the energy infrastructure. Conclusions: There is still a broad field of opportunities for researchers to contribute to grid-based energy system modelling. This encompasses especially the consideration of short-and long-term dynamics of renewable energy sources in planning models.

Optimal Municipal Energy System Design and Operation Using Cumulative Exergy Consumption Minimisation

“…Energy-based means that only the energy consumption over a certain period of time (usually one year) is considered for analysis. A power-based perspective also takes into account the variation in energy consumption over time [11].…”

“…enables the utilisation of synergies, and provides the necessary flexibility for integrating variable RES. MES can also relieve the strain on the energy transmission and distribution infrastructure [11,12].…”

HyFlow—A Hybrid Load Flow-Modelling Framework to Evaluate the Effects of Energy Storage and Sector Coupling on the Electrical Load Flows

“…In conclusion, there are separate load flow calculation tools, but according to [34] it is not possible to interconnect the energy carriers. Additionally Lund et al and Pillai et al [11,12] claim that studies with a higher spatial coverage and resolution usually do not account for system operation and infrastructure details.…”

“…Additionally Lund et al and Pillai et al [11,12] claim that studies with a higher spatial coverage and resolution usually do not account for system operation and infrastructure details. Kriechbaum et al [34] conclude, that MES modelling approaches should incorporate the interactions between different energy carriers and models need to further include physical load flows in the implemented network connections. Tools that are capable of modelling physical load flows of the three grid-bound energy carriers and offer interconnections between them with hybrid elements do not exist.…”

Energy Indicators in the Context of Globalization

“…One of the current challenges is to use as high share of clean and sustainable energy [1]. However, fossil fuels are used in a high percentage [2]. It is estimated that, in 2060, the share of renewable energy will be around 75% of total world electricity production [3].…”