The increasing complexity of models makes it more difficult to interpret and evaluate the extensive results. The scientific community is therefore faced with the challenge of analyzing complex results and presenting them to a broad audience in a comprehensible way. This can be done particularly easily using graphics, web applications and interactive tools.

ISAaR Charts is an interactive web application for visualizing results of the energy system model ISAaR. Model results of different scenarios can be viewed side by side and filtered with respect to selected criteria. This simplifies an efficient validation and analysis of model results especially for large data sets. It is possible to navigate through different diagram categories, for example energy balances and emissions, and to select which years and regions should be displayed. Changing the selection automatically leads to an immediate update of the diagram. With a single click, it is possible to instantly show and hide data or access more detailed breakdowns without having to recreate the graph manually.

Figure 1: Installed renewable energy capacities in Europe by 2050, broken down by technology. The graph shows results from two different scenarios, solidEU and quEU, of the project eXtremOS .

The data generated by ISAaR is retrieved from the FREM database and prepared for ISAaR Charts. There one can choose from different chart categories. Available for selection in the current version are:

  • Energy balances of various energy carriers (electricity, gas, hydrogen, district heating, biomass and liquid hydrocarbons). These can be displayed with different temporal resolution, from hourly up to the entire year
  • Installed capacities for renewable energies, thermal power plants and further technologies
  • Emissions broken down by sector
  • Cross-border energy flows for the energy carriers electricity and hydrogen
  • Price curves for energy carriers
  • Market reference values and production costs for renewable energies
Figure 2: Offsite PV capacities in the solidEU scenario for the year 2050, broken down per country.

A menu can be used to filter by scenarios (model results), optimization years as well as regions. This selection can be changed at any time in the dashboard, which allows for a quick comparison of the different result. Figure 1 shows an example of an expansion path for renewable energies throughout Europe up to the year 2050, in this case with data from the solidEU scenario of the eXtremOS project. In many diagrams, context-dependent actions are implemented, which are triggered by a click, e.g. on segments of the bar chart, and display more detailed information. Figure 2 shows this as an example for the ground-mounted PV capacities from the solidEU scenario, here broken down by European countries. This view can be accessed by clicking on the corresponding bar segment in Figure 1.


ISAaR Charts is a web application based on the Python Dash open source framework that enables the interactive display of data. The application runs in a Docker container to enable simplified deployment and compatibility independent of the system environment. It can also be used to run multiple containers in parallel and independently, each containing different data sets and configured differently. The advantage of ISAaR Charts is thus the ease of portability to new projects, as data from new projects can be visualized and deployed in a new application with little effort.  This allows us to create such a visualization also as part of service projects for our project partners and to directly provide them with the project result, optionally also with authentication to restrict access to the data. Once the data has been loaded into the dashboard, all graphics are directly available and the selection of the displayed data can be modified as desired.

A visualization of the results for the eXtremOS project (results website: can be found at