Non-firm connection
How it works
The connecting party and the operator agree the conditions under which power may be curtailed (e.g. when a line or transformer is overloaded). The operator — often via an Active Network Management system — monitors the network in real time and, when needed, issues a command to reduce import or export to an agreed level (down to zero, or to a guaranteed baseline). Outside curtailment periods the party uses its full capacity. Charging often separates a reservation charge (typical of firm capacity) from a charge for energy actually delivered; under a non-firm contract the charge is usually volumetric. Some agreements guarantee a low baseline of firm capacity so the customer need not shut down entirely.
Problem solved
It addresses the long wait times and high costs of a firm connection, which requires network reinforcement sized for rarely occurring peak loads. This is especially relevant for fast-growing loads (AI data centres) and renewable generation that get stuck in the connection queue.
Components
Intentional, temporary reduction of power import or export ("dispatch down") to maintain grid stability and security.
Contractual terms defining when and to what extent the operator may curtail power, and what baseline (if any) firm capacity is guaranteed.
The process of identifying and relieving network congestion (lines, transformers) that triggers curtailment signals.
An operator control system that monitors network flows in real time and automatically issues curtailment commands to non-firm connected parties.