Building a Non-Annual Context --------------- ### Introduction Artelys Crystal Super Grid can run non-annual simulations. While traditional simulations generally span one year, this guide will equip you with the knowledge to conduct simulations with **duration different of one year**, such as 2-year or 6-month long simulations. By following this documentation, you will learn how to set up and execute energy simulations with custom durations tailored to your specific needs. It is important to note, however, that non-annual simulations come with certain **limitations**, which will be explained at the end of this page (e.g. assets modeling, performance considerations, etc.). ### How to Create a Non-Annual Context from the Interface To create a non-annual context directly from the interface, click on the Create context button in the Home View.
![Create context operation](../../_static/create_context_operation.png)
This operation enables the creation of a new empty energy system on your server. The following parameters need to be filled out by the user to perform the operation: - **Study**: Select the name of the study in which you want to create your energy system. - **Context type**: Select the context type of your new context. The context type depends on the study you select. - For energy system simulation, choose _SIMULATION_ or _PATHWAY_SIMULATION_. - For capacity expansion planning, choose _OPTIM_CAPA_ or _PATHWAY_OPTIM_. - **Context name**: Choose the name of your energy system. This name should be _unique_ within the selected study. - **Timestep count**: Enter the number of timesteps you want to represent for your energy system. - **Timestep duration**: Specify the duration in minutes of each timestep. - **Start date**: Set the start date of the energy system you want to model. To create a non-annual context, change the default **Timestep count** value from 8760 hours (1 year) to 17520 for a 2-year simulation or 4380 for a 6-month simulation. ### How to Create a Non-Annual Context from a Zip Import The structure of import files is the same as that of a context with an annual duration. For more details , refer to the [Energy System Modelling documentation](../basics/energy_system_modelling.md). Specificities concern: - The CONTEXT.csv file - The timeseries CSV files #### CONTEXT.csv File for a Non-Annual Context To create a non-annual context, the CONTEXT.csv needs to be updated as follows. The difference with a classic yearly context is in the **TIMESTEP_COUNT** column (cf above).
![CONTEXT.csv](../../_static/context_csv_non_annual_duration.png)
#### Timeseries CSV for a Non-Annual Context All timeseries CSV files inside the _Context_data > timeseries_ folder need to be updated as follows. While the header remains the same as for an annual context, the number of rows must match the TIMESTEP_COUNT.
timeseries.csv
In this example, a 2-year context is created. The timeseries file contains 17520 rows. This example uses a single test case, but multiple test can also be included for a non-annual context, as explained in [Energy System Modelling](../basics/energy_system_modelling.md). ### Limitations of the Non-Annual Resolution in ACSG #### Temporal KPI Visualization When conducting energy simulations with varying context durations, a key challenge is the visualization of temporal Key Performance Indicators (KPIs). Temporal KPIs (for a list of temporal KPIs, see [Temporal KPIs](../../kpis/temporal_kpis/index.rst)) can be visualized for a non-annual context. However, issues may arise when attempting to visualize results from two contexts with different durations within the same study.

Recommendations

To maintain consistency and clarity in your temporal KPIs, it is advised to compare contexts on the same graph to ensure a uniform X-axis. To display an indicator for multiple contexts on the same graph, move the **Context** filter in **Data** from **Split charts** to **Display and filter** (see [Indicators view documentation](../views/indicators.md) for more details on manipulating the Indicator view). For example, if you are comparing two contexts starting both in January 2030 - one lasting one year and the other two years - this approach allows for easier comparison of what happens during the first year of the simulation for both contexts.This method ensures consistent KPI visualization across all your energy systems, facilitating easier interpretation of results.
#### Performance Extending the duration of a context, such as a running a 5-year simulation, generates significantly more data, which can strain computational resources. This increase in data volume can lead to decreased performance, affecting processing speed and memory usage. Long context durations require more computational power and storage, potentially slowing down the simulation process and extending the time needed for data analysis and visualization.

Recommendations

To mitigate the impact on computational resources when using a longer context duration, consider the following strategies: - Decrease the number of modeled assets to reduce data complexity; - Increase the timestep duration of your context (see [Energy Simulation in Non-Hourly Resolution](non_hourly_resolution.md) for guidelines on building a context with a non-hourly resolution). These adjustments can help maintain efficient performance and ensure smoother simulations and analyses.
#### Assets Modeling Modeling of assets requires meticulous attention to detail, especially regarding the units used for asset attributes. Misunderstandings or misconfigurations in units can lead to inaccurate simulations, infeasible optimizations, and misleading results.

Assets with VOLUME_TARGET behavior

For assets with the active **VOLUME_TARGET** behavior (such as *BIOGAS_IMPORTS*, *BIOMASS_IMPORTS*, *VOLUNTARY_LOAD_CURTAILMENT*), the **STORAGE_CAPACITY** and **MINIMUM_VOLUME** attributes are in **MWh** and apply for the entire context duration, not just one year. To ensure that a maximum of half of the total potential is used during the first year, set your storage availability timeseries so that the first year has a value of 50% and the second year 100%.

CO2 Emissions limit

When applying a CO2 emissions limit across multiple nodes, the CO2 budget provided is in tCO2e and applies **to the entire simulation duration**.
.. warning:: Hydro timeseries, especially *min storage level* timeseries, are typically given for a full year. These timeseries must be carefully adapted if you plan to simulate a context with a non-annual duration, particularly when this duration is not a multiple of one year (e.g. 6 or 18 months). Failure to do so can lead to infeasibilities.