Get transfer capacity (NTC / MaxBex)

Get cross-border transfer capacity (NTC / MaxBex) for a zone pair.

Returns the TSO-allocated commercial transfer capacity — the maximum MW market participants can schedule. This is forward-looking and reflects reliability margins (TRM), N-1 security, and flow-based allocation; it is typically a fraction of the physical line nameplate rating. Not the same as PyPSA s_nom line capacity (also surfaced in the map UI), which is the engineering thermal nameplate.

Capacity is asymmetric: the MW available from A→B is not the same as B→A. This endpoint returns both directions for the requested pair in a single response under series:

• direction = "forward" — capacity in the requested A→B direction.
• direction = "reverse" — capacity in the opposite B→A direction.

Values are always non-negative MW (direction is encoded in direction, not in the sign of the number).

Sources:

• entsoe (A61 NTC forecasts; default) — Net Transfer Capacity, covers most non-flow-based borders.
• jao (MaxBex) — Maximum Bilateral Exchange for flow-based regions (CORE, Nordic, SWE, Italy-North, Cross-CCR) where A61 returns nothing.

Requests with from_zone and to_zone swapped relative to the canonical edge in exchanges.yaml are accepted — the response flips the forward/reverse mapping accordingly. canonical_edge in the response always echoes the underlying catalog key so callers can re-key against their own state if needed.