Total rural_heat demand too low in eGon100RE

[CarlosEpia]

pypsa_eur inlcudes a total rural_heat demand for Germany of 3.09e+08 MWh but the last version of eGon100RE only has 1.49e+08 MWh

[ClaraBuettner]

It took quite some time to find the problem since it is in the high aggregation level.
The problem is related to missing mapping of CTS buildings to MV grids; there were no entries for CTS buildings in boundaries.egon_map_zensus_mvgd_bulidings.

I found these lines where eGon2035 is still the hard-coded basis:

powerd-data/src/egon/data/datasets/electricity_demand_timeseries/mapping.py

Lines 31 to 56 in f0db3e5

	db.execute_sql(
	sql_string=f"""
	INSERT INTO {EgonMapZensusMvgdBuildings.__table_args__["schema"]}.
	{EgonMapZensusMvgdBuildings.__tablename__}
	SELECT
	bld.id as building_id,
	peak.sector,
	zensus.id as zensus_population_id,
	mvgd.bus_id::integer
	FROM (
	SELECT "id"::integer, geom_point
	FROM openstreetmap.osm_buildings_synthetic
	UNION
	SELECT "id"::integer, geom_point
	FROM openstreetmap.osm_buildings_filtered
	) AS bld,
	demand.egon_building_electricity_peak_loads AS peak,
	society.destatis_zensus_population_per_ha
	AS zensus,
	boundaries.egon_map_zensus_grid_districts AS mvgd
	WHERE bld.id = peak.building_id
	-- Buildings do not change in the scenarios
	AND peak.scenario = 'eGon2035'
	AND ST_Within(bld.geom_point, zensus.geom)
	AND mvgd.zensus_population_id = zensus.id;

I could imagine that changing this will solve it.
I don't know why everything else was working, it might also effect status2019.
However, I will try it out and push a branch/PR if it worked.