Low-Flow Constraint Days
Wisconsin Public Service can declare a Low-Flow Constraint Day if it anticipates that too much gas will be nominated and delivered to its system compared to expected use. The greatest probability for a Low-Flow Constraint Day is during summer holidays, especially around July 4, when many industries shut down completely for several days. If transportation customers shut down their operations and don't adjust their nominations, excess gas will be delivered to our system, potentially resulting in penalties that we would need to charge to customers.
WPS must balance total nominations with actual use each day. Any excess gas on our system is transported to storage fields in Michigan. However, there are contractual limits on te amounts that can be transported to storage each day. If a contracted capacity is exceeded, WPS will incur overrun penalty charges. A Low-Flow Constraint Day helps us avoid penalties from the pipeline, which would need to be charged to customers.
Impacts for Transportation Customers
- Notification
- Customers are usually notified at least 2 hours before the constraint day begins so they may adjust their nominations, if needed, to balance with their expected actual use.
- Restrictions
- Customers must use at least as much gas as they nominated.
- Penalties
- Normal daily balancing charges apply to customers who use more gas than they delivered to the WPS system. If WPS receives any pipeline penalty charges, the transportation customers who used less gas than they nominated will be assessed the pipeline penalty charge in place of the normal daily balancing charge.
Impacts for Interruptible Customers
- Notification
- Interruptible customers are not affected and not notified because WPS manages gas supply for them.