A highly-resolved power system model of Germany for REMix

# PowGER
A highly-resolved power system model of Germany for REMix

## Data sources:
- Renewable energies excl. Hydro: Open Power System Data (https://data.open-power-system-data.org/renewable_power_plants/2020-08-25)
- Conventional power plants incl. Hydro: powerplantmatching matched data set by FRESNA (https://github.com/FRESNA/powerplantmatching/blob/master/matched_data_red.csv)
- demand distribution: by population data set GEOSTAT-grid-POP-1K-2011-V2-0-1.zip from https://ec.europa.eu/eurostat/de/web/gisco/geodata/reference-data/population-distribution-demography/geostat
- demand time series: Entso-E Transparency Platform Load for Germany
- time series for power import/export: physical cross border flows from ENTSO-E Transparency Platform (https://transparency.entsoe.eu)
- time series and capacity potentials for renewables from EnDat
- nodes and links between nodes: pypsa-eur gridkit extract from ENTSO-E https://github.com/PyPSA/pypsa-eur/tree/10fbc9225c9d46f90b5f1d54460fc00fadf4c404/data/entsoegridkit
- two missing links (L99998, L99999) has been filled manually with data from ENTSO-E Grid Map (https://www.entsoe.eu/data/map/) google maps for distances/lengths
- nodes and links for offshore wind Alpha Ventus has been removed, because and substation Hagermarsch isn't connected to the german transmission grid.
- node and link for offshore wind farm Nordergründe has been removed for modelling reasons

### data-2030
- No nuclear power plants
- Removed all lignite and coal power plants commissioned before 1990
- export and import time series from 2021
- time series for PV and Wind from 2018
- time series for hydro run of river from 2011