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• I have confirmed this bug exists on the lastest release of PyPSA.

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Issue Description

Hi everyone, I have found an issue with the rolling horizon functionality if linearized_unit_commitment is set to True and if ramp rates are exceeding 1. Potentially, this is not even a bug, as one might ask why ramp rates larger than 1 would be needed. This is because we use the data as well to model reserves, where you need to assess what level can be provided within, for example, 15 min. There, it can make a difference whether the hourly pu ramp rate is 1 or 2. Maybe it is possible to simply cap the ramp rate at 1 for the calculations, but allow to include higher ones in the n.generator table?

Reproducible Example

import pypsa 

n = pypsa.examples.scigrid_de()
disp = ['Gas', 'Hard Coal',  'Waste', 'Brown Coal', 'Oil', 'Nuclear']
n.generators.loc[n.generators.carrier.isin(disp), "committable"] = True
n.generators.loc[:, "ramp_limit_up"] = 1
n.generators.loc[n.generators.carrier.isin(disp), "ramp_limit_up"] = 1.5
n.optimize.optimize_with_rolling_horizon(solver_name=solver_name, linearized_unit_commitment=True, horizon=12)

Expected Behavior

Rolling horizon solves all horizons after another without crashing

Installed Versions