# Release Notes¶

## Synchronisation Release - Ukraine and Moldova (17th March 2022)¶

On March 16, 2022, the transmission networks of Ukraine and Moldova have successfully been synchronised with the continental European grid. We have taken this as an opportunity to add the power systems of Ukraine and Moldova to PyPSA-Eur. This includes:

• the transmission network topology from the ENTSO-E interactive map.
• existing power plants (incl. nuclear, coal, gas and hydro) from the powerplantmatching tool
• country-level load time series from ENTSO-E through the OPSD platform, which are then distributed heuristically to substations by GDP and population density.
• wind and solar profiles based on ERA5 and SARAH-2 weather data
• hydro profiles based on historical EIA generation data
• a simplified calculation of wind and solar potentials based on the Copernicus Land Cover dataset.
• electrical characteristics of 750 kV transmission lines

The Crimean power system is currently disconnected from the main Ukrainian grid and, hence, not included.

This release is not on the master branch. It can be used with

git clone https://github.com/pypsa/pypsa-eur
git checkout synchronisation-release


## Upcoming Release¶

• Add an efficiency factor of 88.55% to offshore wind capacity factors as a proxy for wake losses. More rigorous modelling is planned [#277].
• The default deployment density of AC- and DC-connected offshore wind capacity is reduced from 3 MW/sqkm to a more conservative estimate of 2 MW/sqkm [#280].
• Following discussion in #285 we have disabled the correction factor for solar PV capacity factors by default while satellite data is used. A correction factor of 0.854337 is recommended if reanalysis data like ERA5 is used.
• Resource definitions for memory usage now follow [Snakemake standard resource definition](https://snakemake.readthedocs.io/en/stable/snakefiles/rules.html#standard-resources) mem_mb rather than mem.
• Network building is made deterministic by supplying a fixed random state to network clustering routines.
• New network topology extracted from the ENTSO-E interactive map.
• The unused argument simple_hvdc_costs in add_electricity was removed.
• Iterative solving with impedance updates is skipped if there are no expandable lines.
• Switch from Germany to Belgium for continuous integration and tutorial to save resources.
• Use updated SARAH-2 and ERA5 cutouts with slightly wider scope to east and additional variables.

## PyPSA-Eur 0.4.0 (22th September 2021)¶

New Features and Changes

• With this release, we change the license from copyleft GPLv3 to the more liberal MIT license with the consent of all contributors [#276].
• Switch to the new major atlite release v0.2. The version upgrade comes along with significant speed up for the rule build_renewable_profiles.py (~factor 2). A lot of the code which calculated the land-use availability is now outsourced and does not rely on glaes, geokit anymore. This facilitates the environment building and version compatibility of gdal, libgdal with other packages [#224].
• Implemented changes to n.snapshot_weightings in new PyPSA version v0.18 (cf. PyPSA/PyPSA/#227) [#259].
• Add option to pre-aggregate nodes without power injections (positive or negative, i.e. generation or demand) to electrically closest nodes or neighbors in simplify_network. Defaults to False. This affects nodes that are no substations or have no offshore connection.
• In simplify_network, bus columns with no longer correct entries are removed (symbol, tags, under_construction, substation_lv, substation_off) [#219]
• Add option to include marginal costs of links representing fuel cells, electrolysis, and battery inverters [#232].
• The rule and script build_country_flh are removed as they are no longer used or maintained.
• The connection cost of generators in simplify_network are now reported in resources/connection_costs_s{simpl}.csv [#261].
• The tutorial cutout was renamed from cutouts/europe-2013-era5.nc to cutouts/be-03-2013-era5.nc to accomodate tutorial and productive cutouts side-by-side.
• The flag keep_all_available_areas in the configuration for renewable potentials was deprecated and now defaults to True.
• Update dependencies in envs/environment.yaml [#257]
• Continuous integration testing switches to Github Actions from Travis CI [#252].
• Documentation on readthedocs.io is now built with pip only and no longer requires conda [#267].
• Use Citation.cff [#273].

Bugs and Compatibility

• Support for PyPSA v0.18 [#268].
• Minimum Python version set to 3.8.
• Removed six dependency [#245].
• Update plot_network and make_summary rules to latest PyPSA versions [#270].
• Keep converter links to store components when using the ATK wildcard and only remove DC links [#214].
• Value for co2base in config.yaml adjusted to 1.487e9 t CO2-eq (from 3.1e9 t CO2-eq). The new value represents emissions related to the electricity sector for EU+UK+Balkan. The old value was too high and used when the emissions wildcard in {opts} was used [#233].
• Add escape in base_network if all TYNDP links are already contained in the network [#246].
• In solve_operations_network the optimised capacities are now fixed for all extendable links, not only HVDC links [#244].
• The focus_weights are now also considered when pre-clustering in the simplify_network rule [#241].
• in build_renewable_profile where offshore wind profiles could no longer be created [#249].
• Lower expansion limit of extendable carriers is now set to the existing capacity, i.e. p_nom_min = p_nom (0 before). Simultaneously, the upper limit (p_nom_max) is now the maximum of the installed capacity (p_nom) and the previous estimate based on land availability (p_nom_max) [#260].
• Solving an operations network now includes optimized store capacities as well. Before only lines, links, generators and storage units were considered [#269].
• With load_shedding: true in the solving options of config.yaml load shedding generators are only added at the AC buses, excluding buses for H2 and battery stores [#269].
• Delete duplicated capital costs at battery discharge link [#240].
• Propagate the solver log file name to the solver. Previously, the PyPSA network solving functions were not told about the solver logfile specified in the Snakemake file [#247]

## PyPSA-Eur 0.3.0 (7th December 2020)¶

New Features

Using the {opts} wildcard for scenarios:

• An option is introduced which adds constraints such that each country or node produces on average a minimal share of its total consumption itself. For example EQ0.5c set in the {opts} wildcard requires each country to produce on average at least 50% of its consumption. Additionally, the option ATK requires autarky at each node and removes all means of power transmission through lines and links. ATKc only removes cross-border transfer capacities. [#166].
• Added an option to alter the capital cost (c) or installable potentials (p) of carriers by a factor via carrier+{c,p}factor in the {opts} wildcard. This can be useful for exploring uncertain cost parameters. Example: solar+c0.5 reduces the capital cost of solar to 50% of original values [#167, #207].
• Added an option to the {opts} wildcard that applies a time series segmentation algorithm based on renewables, hydro inflow and load time series to produce a given total number of adjacent snapshots of varying lengths. This feature is an alternative to downsampling the temporal resolution by simply averaging and uses the tsam package [#186].

More OPSD integration:

• Add renewable power plants from OPSD to the network for specified technologies. This will overwrite the capacities calculated from the heuristic approach in estimate_renewable_capacities() [#212].
• Electricity consumption data is now retrieved directly from the OPSD website using the rule build_load_data. The user can decide whether to take the ENTSO-E power statistics data (default) or the ENTSO-E transparency data [#211].

Other:

• Added an option to use custom busmaps in rule cluster_network. To use this feature set enable: custom_busmap: true. Then, the rule looks for custom busmaps at data/custom_busmap_elec_s{simpl}_{clusters}.csv, which should have the same format as resources/busmap_elec_s{simpl}_{clusters}.csv. i.e. the index should contain the buses of networks/elec_s{simpl}.nc [#193].
• Line and link capacities can be capped in the config.yaml at lines: s_nom_max: and links: p_nom_max: [#166].

Changes

• Don’t remove capital costs from lines and links, when imposing a line volume limit (lv) or a line cost limit (lc). Previously, these were removed to move the expansion in direction of the limit [#183].
• The mappings for clustered lines and buses produced by the simplify_network and cluster_network rules changed from Hierarchical Data Format (.h5) to Comma-Separated Values format (.csv) for ease of use. [#198]
• The N-1 security margin for transmission lines is now fixed to a provided value in config.yaml, removing an undocumented linear interpolation between 0.5 and 0.7 in the range between 37 and 200 nodes. [#199].
• Modelling hydrogen and battery storage with Store and Link components is now the default, rather than using StorageUnit components with fixed power-to-energy ratio [#205].
• Use mamba (https://github.com/mamba-org/mamba) for faster Travis CI builds [#196].
• Multiple smaller changes: Removed unused {network} wildcard, moved environment files to dedicated envs folder, removed sector-coupling components from configuration files, updated documentation colors, minor refactoring and code cleaning [#190].

Bugs and Compatibility

• Add compatibility for pyomo 5.7.0 in cluster_network and simplify_network [#172].
• Fixed a bug for storage units such that individual store and dispatch efficiencies are correctly taken account of rather than only their round-trip efficiencies. In the cost database (data/costs.csv) the efficiency of battery inverters should be stated as per discharge/charge rather than per roundtrip [#202].
• Corrected exogenous emission price setting (in config: cost: emission price:), which now correctly accounts for the efficiency and effective emission of the generators [#171].
• Corrected HVDC link connections (a) between Norway and Denmark and (b) mainland Italy, Corsica (FR) and Sardinia (IT) as well as for East-Western and Anglo-Scottish interconnectors [#181, #206].
• Fix bug of clustering offwind-{ac,dc} generators in the option of high-resolution generators for renewables. Now, there are more sites for offwind-{ac,dc} available than network nodes. Before, they were clustered to the resolution of the network (elec_s1024_37m.nc: 37 network nodes, 1024 generators) [#191].
• Raise a warning if tech_colors in the config are not defined for all carriers [#178].

## PyPSA-Eur 0.2.0 (8th June 2020)¶

• The optimization is now performed using the pyomo=False setting in the pypsa.lopf.network_lopf(). This speeds up the solving process significantly and consumes much less memory. The inclusion of additional constraints were adjusted to the new implementation. They are all passed to the network_lopf() function via the extra_functionality argument. The rule trace_solve_network was integrated into the rule solve_network and can be activated via configuration with solving: options: track_iterations: true. The charging and discharging capacities of batteries modelled as store-link combination are now coupled [#116].
• An updated extract of the ENTSO-E Transmission System Map (including Malta) was added to the repository using the GridKit tool. This tool has been updated to retrieve up-to-date map extracts using a single script. The update extract features 5322 buses, 6574 lines, 46 links. [#118].
• Added a 30 minute video introduction and a 20 minute video tutorial
• Networks now store a color and a nicely formatted name for each carrier, accessible via n.carrier['color'] and n.carrier['nice_name'] (networks after elec.nc).
• Added an option to skip iterative solving usually performed to update the line impedances of expanded lines at solving: options: skip_iterations:.
• snakemake rules for retrieving cutouts and the natura raster can now be disabled independently from their respective rules to build them; via config.*yaml [#136].
• Removed the id column for custom power plants in data/custom_powerplants.csv to avoid custom power plants with conflicting ids getting attached to the wrong bus [#131].
• Add option renewables: {carrier}: keep_all_available_areas: to use all availabe weather cells for renewable profile and potential generation. The default ignores weather cells where only less than 1 MW can be installed [#150].
• Added a function _helpers.load_network() which loads a network with overridden components specified in snakemake.config['override_components'] [#128].
• Bugfix in base_network which now finds all closest links, not only the first entry [#143].
• Bugfix in cluster_network which now skips recalculation of link parameters if there are no links [#149].
• Added information on pull requests to contribution guidelines [#151].
• Improved documentation on open-source solver setup and added usage warnings.
• Updated conda environment regarding pypsa, pyproj, gurobi, lxml. This release requires PyPSA v0.17.0.

## PyPSA-Eur 0.1.0 (9th January 2020)¶

This is the first release of PyPSA-Eur, a model of the European power system at the transmission network level. Recent changes include:

• Documentation on installation, workflows and configuration settings is now available online at pypsa-eur.readthedocs.io [#65].
• The conda environment files were updated and extended [#81].
• The power plant database was updated with extensive filtering options via pandas.query functionality [#84 and #94].
• Continuous integration testing with Travis CI is now included for Linux, Mac and Windows [#82].
• Data dependencies were moved to zenodo and are now versioned [#60].
• Data dependencies are now retrieved directly from within the snakemake workflow [#86].
• Emission prices can be added to marginal costs of generators through the keyworks Ep in the {opts} wildcard [#100].
• An option is introduced to add extendable nuclear power plants to the network [#98].
• Focus weights can now be specified for particular countries for the network clustering, which allows to set a proportion of the total number of clusters for particular countries [#87].
• A new rule add_extra_components allows to add additional components to the network only after clustering. It is thereby possible to model storage units (e.g. battery and hydrogen) in more detail via a combination of Store, Link and Bus elements [#97].
• Hydrogen pipelines (including cost assumptions) can now be added alongside clustered network connections in the rule add_extra_components . Set electricity: extendable_carriers: Link: [H2 pipeline] and ensure hydrogen storage is modelled as a Store. This is a first simplified stage [#108].
• Logfiles for all rules of the snakemake workflow are now written in the folder log/ [#102].
• The new function _helpers.mock_snakemake creates a snakemake object which mimics the actual snakemake object produced by workflow by parsing the Snakefile and setting all paths for inputs, outputs, and logs. This allows running all scripts within a (I)python terminal (or just by calling python <script-name>) and thereby facilitates developing and debugging scripts significantly [#107].

## Release Process¶

• Checkout a new release branch git checkout -b release-v0.x.x.
• Finalise release notes at doc/release_notes.rst.
• Update envs/environment.fixed.yaml via conda env export -n pypsa-eur -f envs/environment.fixed.yaml --no-builds from an up-to-date pypsa-eur environment.
• Update version number in doc/conf.py and *config.*.yaml.
• Open, review and merge pull request for branch release-v0.x.x. Make sure to close issues and PRs or the release milestone with it (e.g. closes #X).
• Tag a release on Github via git tag v0.x.x, git push, git push --tags. Include release notes in the tag message.
• Create pre-built networks for config.default.yaml by running snakemake -j 1 extra_components_all_networks`.