…ibility

When brownfield carries forward s_nom_opt from a previous horizon as
s_nom_min, solver floating-point tolerance can make s_nom_min exceed
s_nom_max by a tiny amount (e.g., 0.00013 MW on a 33,585 MW line).
This creates an infeasible constraint that crashes the solver.

Extends the fix from PRs PyPSA#840 and PyPSA#952 (which handle global transmission
constraints) to also cover per-line s_nom_max and DC link p_nom_max.

…ibility (#2115)

* fix: clamp s/p_nom_max in brownfield to prevent floating-point infeasibility

When brownfield carries forward s_nom_opt from a previous horizon as
s_nom_min, solver floating-point tolerance can make s_nom_min exceed
s_nom_max by a tiny amount (e.g., 0.00013 MW on a 33,585 MW line).
This creates an infeasible constraint that crashes the solver.

Extends the fix from PRs #840 and #952 (which handle global transmission
constraints) to also cover per-line s_nom_max and DC link p_nom_max.

* fix: clip H2/gas retrofit remaining capacity to non-negative

When barrier solutions without crossover produce slightly imprecise
p_nom_opt values, the already-retrofitted H2 pipeline capacity can
marginally exceed the original pipe capacity. This makes
remaining_capacity negative, setting p_nom_max < p_nom_min = 0,
which causes infeasibility at the next planning horizon.

Observed on 115-cluster myopic runs with BarConvTol=1e-4:
  H2 pipeline retrofitted ES2 7 -> FR2 1: p_nom_max = -0.000649 MW
  H2 pipeline retrofitted GB1 3 -> GB1 7: p_nom_max = -0.000169 MW

Apply the same clip(lower=0) pattern used for AC lines and DC links.

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Co-authored-by: Fabian Neumann <[email protected]>
Co-authored-by: Lukas Trippe <[email protected]>