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Preparing Networks
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The preparation process of the PyPSA-Eur energy system model consists of a group of ``snakemake`` rules which are briefly outlined and explained in detail in the sections below:

- ``build_shapes`` to generate GeoJSON files with shapes of the countries, exclusive economic zones and `NUTS3 <https://en.wikipedia.org/wiki/Nomenclature_of_Territorial_Units_for_Statistics>`_ areas.
- ``build_cutout`` to prepare smaller weather data portions from `ERA5 <https://www.ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era5>`_ for cutout ``europe-2013-era5`` and SARAH for cutout ``europe-2013-sarah``.

With these and the externally extracted ENTSO-E online map topology (``data/entsoegridkit``), it can build a base ``PyPSA`` network with the following rules:

- ``base_network`` builds and stores the base network with all buses, HVAC lines and HVDC links, while
- ``build_bus_regions`` determines `Voronoi cells <https://en.wikipedia.org/wiki/Voronoi_diagram>`_ for all substations.

Then the process continues by calculating conventional power plant capacities, potentials, and per-unit availability time series for variable renewable energy carriers and hydro power plants with the following rules:

- ``build_powerplants`` for today's thermal power plant capacities using `powerplantmatching <https://github.com/FRESNA/powerplantmatching>`_ allocating these to the closest substation for each powerplant,
- ``build_renewable_potentials`` for the installation potentials for solar panels, onshore and offshore wind turbines constrained by landuse restrictions and natural protection areas,
- ``build_renewable_profiles`` for the hourly capacity factors in each substation's Voronoi cell for PV, onshore and offshore wind, and
- ``build_hydro_profile`` for the hourly per-unit hydro power availability time series.

The central rule ``add_electricity`` then ties all the different data inputs together into a detailed `PyPSA` network stored in ``networks/elec.nc`` containing

.. todo:: probably move parts into ``add_electricity`` docstring

- today's transmission topology and transfer capacities (optionally including lines which are under construction according to the config settings ``lines: under_construction`` and ``links: under_construction``),
- today's thermal and hydro power generation capacities (for the technologies listed in the config setting ``electricity: conventional_carriers``), and
- today's load time-series (upsampled in a top-down approach according to population and gross domestic product)

It further adds extendable ``generators`` and ``storage_units`` with **zero** capacity for

- photovoltaic, onshore and offshore wind installations with today's locational, hourly wind and solar pv capacity factors (but **no** current capacities)
- long-term hydrogen and short-term battery storage units (if listed in the config setting ``electricity: extendable_carriers``)
- additional open- and combined-cycle gas turbines (if ``OCGT`` and/or ``CCGT`` is listed in the config setting ``electricity: extendable_carriers``)

.. each rule description should have a list of parameters
.. from the config.yaml that affect this rule.

Build Shapes
=============================

.. automodule:: build_shapes

Build Cutout
=============================

.. automodule:: build_cutout

Prepare HVDC Links
=============================

.. automodule:: prepare_links_p_nom

Base Network
=============================

.. automodule:: base_network

Build Bus Regions
=============================

.. automodule:: build_bus_regions

Build Country Full Load Hours
=============================

.. automodule:: build_country_flh

Build Hydro Profile
=============================

.. automodule:: build_hydro_profile

Build Natura Raster
=============================

.. automodule:: build_natura_raster

Build Renewable Profiles
========================

.. automodule:: build_renewable_profiles

Build Power Plants
=============================

.. automodule:: build_powerplants

Add Electricity
=============================

.. automodule:: add_electricity