Include a section on hydro in the build_renewable_profile notebook

[asolavi]

Create a section on hydro in the build_renewable_profile.ipynb notebook, detailing the process made to create the hydro time series. Currently, built_renewable_profile.ipynb focuses on wind and solar.

Hydro modelling is done in three steps:

1. Preparation of hydro-potential data with atlite: ERA5 reanalysis dataset is used, runoff is being integrated across hydrobasins assuming some flow speed and put into cutout. This is done here. More details in the methodology used by atlite can be found here.

2. The output of the time series obtained in step 1 (cutout hydro potential) is normalized in pypsa-earth using the normalization procedure described here. This is done to match country statistics. The result is stored in resources/renewable_profiles/profile_hydro.nc.

3. Attach_hydro in add_electricity, as described here. Specifies how the different hydro types (runoff river (ror), hydro dams (hydro), and pumped storage (PHS) are added to the network in add_electricity.

[AnasAbuzayed]

can be helpful: https://pypsa-eur.readthedocs.io/en/latest/preparation.html#module-build_hydro_profile

[davide-f]

Closed by #61