PyPSA-Eur-MGA: Analysing the Near-Optimal of a Renewable Power System Model

Paper

Models for long-term investment planning of the power system typically return a single optimal solution per set of cost assumptions. However, typically there are many near-optimal alternatives that stand out due to other attractive properties like social acceptance. Understanding features that persist across many cost-efficient alternatives enhances policy advice and acknowledges structural model uncertainties. We apply the modeling-to-generate-alternatives (MGA) methodology to systematically explore the near-optimal feasible space of a completely renewable European electricity system model. While accounting for complex spatio-temporal patterns, we allow simultaneous capacity expansion of generation, storage and transmission infrastructure subject to linearized multi-period optimal power flow. Many similarly costly, but technologically diverse solutions exist. Already a cost deviation of 0.5% offers a large range of possible investments. However, either offshore or onshore wind energy along with some hydrogen storage and transmission network reinforcement are essential to keep costs within 10% of the optimum.

• F. Neumann, T. Brown, The Near-Optimal of a Renewable Power System Model, 2019, Preprint submitted to PSCC2020, arXiv:1910.01891

Installation and Usage

Clone the main repository and the PyPSA-Eur submodule

../ % git clone --recurse-submodules https://git.scc.kit.edu/FN/pypsa-eur-mga.git

Install and activate the conda environment with

conda env create -f environment.yaml
conda activate pypsa-eur-mga

Workflow

TODO: workflow chart

• solve_base: Solves the network to optimality using the regular cost-minimisation objective, which serves as reference value for the MGA iterations.
• generate_list_of_alternatives: Generates a list of alternative objectives defining the power system component, its carrier filter, and the optimisation sense as <COMPONENT>+<CARRIER>+<SENSE>. Each experiment corresponds to one MGA iteration. This is a snakemake checkpoint.
• generate_alternative: Solves the network to optimality with the original cost-minimisation objective as constraint with the cost minimum plus some slack {epsilon} as upper bound. The new objective is built from the {objective} wildcard (from generate_list_of_alternatives).
• extract_results: Collects and exports results of all near-optimal solutions into several .csv files.
• extract_curtailment: Extracts curtailment data into a separate .csv file.
• extract_gini: Calculates and exports the Gini coefficient of different near-optimal solutions.

Plotting

There is some plotting functionality provided in scripts/plotting which can be used for example in scripts/plotting.ipynb.

Results

TODO: Data on zenodo.