Capacity optimization#

Introduction#

In addition to the simulation of operations at hourly resolution, Artelys Crystal Super Grid offers the ability to jointly perform the optimization of investments.

The costs considered include annualized investment costs and fixed operating costs. The model minimizes total system costs, combining investment and operational expenses, to determine the optimal set of investments and the operation of each component within the energy system.

OPTIM_CAPA context type#

To perform a capacity optimization, the context type in the CONTEXT.csv must be set to OPTIM_CAPA (instead of SIMULATION, for instance).

OPTIM_CAPA context type in CONTEXT.csv

OPTIM_PMAX behavior#

To optimize the capacity of a given asset, use the behavior OPTIM_PMAX. Instead of specifying a fixed capacity with the \(PMAX\) attribute, define the minimum (\(PMAXMIN\) attribute) and maximum (\(PMAXMAX\) attribute) capacities to be installed. The capacity \(PMAX\) of the asset will be optimized such that \(PMAXMIN \leq PMAX \leq PMAXMAX\), taking into account investment costs (annualized \(CAPEX\), in €/MW/year) and Fixed Operational Costs (\(FOC\), in €/MW/year). Thus, the cost of installing new capacities for this asset is given by \(installedCapacities * (CAPEX + FOC)\).

OPTIM_PMAX example

For more details on the OPTIM_PMAX behavior, please refer to the Behaviors documentation.

OPTIM_CAPA - SIMULATION sequence#

An option allows for directly restarting a simulation at fixed \(PMAX\), following the capacity optimization. The optimal values obtained during the first optimization are retrieved and injected into the context as attributes of the optimized assets. This enables setting two different Loss of Load values: one for capacity optimization and another for simulation. This option is highly recommended as it ensures that the marginal costs reflect the short-term marginal costs at the end of the simulation stage, and not the long-term marginal costs (slightly higher, taking into account system investments) used during capacity optimization.

Setting the option#

This sequence is available for contexts of type OPTIM_CAPA and PATHWAY_OPTIM. For these contexts, the Boolean parameter SIMU_AFTER_OPTIM_CAPA is used to activate or deactivate the option. This parameter can be edited in the CONTEXT.csv file or via the Map view, by clicking on the context name:

Simulation after capacity optimization - CONTEXT.csv file Resimulate after capacity optimization - Map view

For Loss of Load assets, the PRICE_SIMU_AFTER_OPTIM_CAPA attribute allows for a second LoL price value per asset, which will be used specifically for the fixed capacity simulation. This attribute is only activated for contexts of type OPTIM_CAPA or PATHWAY_OPTIM when the SIMU_AFTER_OPTIM_CAPA parameter is set to True. If PRICE_SIMU_AFTER_OPTIM_CAPA is not specified in LOSS_OF_LOAD.csv, a default value of 3000 €/MWh is applied.

Example LOSS_OF_LOAD.csv with PRICE_SIMU_AFTER_OPTIM_CAPA

Consequences on results#

Running a fixed-capacity simulation after the initial optimization is invisible for the user, with results remaining almost identical. The main difference appears in the Marginal Costs indicator: with the SIMU_AFTER_OPTIM_CAPA option, energy prices become consistent and directly interpretable in both trajectory and classic capacity optimization, similar to a simple simulation. Additionally, the Loss of Load cost indicator is impacted, as it now incorporates the value of PRICE_SIMU_AFTER_OPTIM_CAPA in its calculation.