High-Flow Constraint Days
Whenever there are problems with daily gas supply, daily pipeline capacity or annual gas supply that could result in insufficient gas to meet the needs of all customers, WPS may declare a High-Flow Constraint Day. This is usually associated with the coldest days of the winter, but may occur on other days. For example, gas supplies can be cut if there is a production problem at the wellhead.
The probability of a High-Flow Constraint Day during the summer period is highest during the first two weeks in April. The pipeline capacity available to WPS decreases more than 40% on April 1 because of lower customer demand during the summer period. However, cold temperatures in early April could result in higher-than-normal gas use, which could exceed contracted pipeline capacity.
WPS may declare a High-Flow Constraint Day when any one or more of the following types of conditions exist:
- Daily Gas Supply: When total demand on our system is expected to exceed the total gas supply being delivered to our system for that day.
- Daily Pipeline Capacity: When very high demand or an unusual circumstance on the pipeline limits the capacity available for delivering gas to our system.
- Annual Gas Supply: When our gas in storage is drawn down to certain levels and we can't continue to routinely use that gas supply to meet the balancing needs of transportation customers. WPS must maintain adequate gas in storage to meet the needs of firm system customers.
WPS usually has capacity and supply to meet the needs of interruptible system and transportation customers. A High-Flow Constraint Day is declared only as a last resort to protect firm system customers and avoid pipeline penalties. High-Flow Constraint Days are declared for transportation customers first, then interruptible system customers (as needed) to avoid pipeline penalties.
If a transportation customer can buy more gas and deliver it to the WPS city gate station on a High-Flow Constraint Day, WPS normally can deliver that gas to the customer.
Impacts for Transportation Customers
- Notification: Customers are notified at least 2 hours before the gas day begins so they can take actions to control their gas use within their approved nominations.
- Duration: A constraint day lasts for an entire gas day (24 hours). Conditions may require WPS to declare consecutive constraint days.
- Restrictions: A customer may use only its approved nomination — the amount of gas ANR Pipeline or Guardian Pipeline deliver to the WPS system for that specific customer's use. A customer in a gas pool should not exceed the volume allocated for that customer by the pool administrator.
- Penalty for using too much gas: The surcharge for an Unauthorized Use of Gas is applied to each therm of gas burned that exceeds a customer's Nominated Firm Service (if any). The surcharge is $2 per therm if ANR Pipeline or Guardian Pipeline do not declare a Cease and Desist Order. When ANR Pipeline or Guardian Pipeline declare a Cease and Desist Order, the charge is $10 per therm plus any incremental costs.
- Charge for using too little gas: Normal daily balancing charges still apply if a customer uses less gas than it delivers to the WPS system.
- Optional service: Customers may contract with WPS for Peak Day Backup/Annual Supply Backup Service. This contracted service, which is nominated in advance, may be used in addition to the approved nomination.
High-Flow Constraint Days Declared by WPS January 1994 - Present
| Dates | # of Days | Customers Affected | Reason |
|---|---|---|---|
| Jan. 17-18, 1994 | 2 | Transportation & Interruptible | Daily gas supply & pipeline capacity |
| Feb. 1-5, 1996 | 5 | Transportation | Daily gas supply & pipeline capacity |
| Feb. 15-18, 1996 | 4 | Transportation | Annual gas supply |
| Mar. 6-8, 1996 | 3 | Transportation | Annual gas supply |
| Jan. 23, 2003 | 1 | Local Interruptible | Localized pipeline capacity |
| Jan. 24, 2003 | 1 | Transportation & Interruptible | Pipeline capacity |
| Jan. 22, 2004 | 1 | Transportation | Pipeline capacity |
Impacts for Interruptible System Customers
- Notification: Customers are usually notified at least 1 hour before the interruption period begins so they have time to switch over to an alternate fuel or take other actions to curtail gas use.
- Duration: A constraint day may require an interruption during any part of a day. Conditions may require WPS to declare consecutive constraint days.
- Restrictions: Customers must switch to an alternate fuel or shut down the process being served by the interruptible gas supply.
- Penalty for using too much gas: The surcharge for an Unauthorized Use of Gas is applied to each therm of gas burned that exceeds a customer's Nominated Firm Service (if any). The surcharge is $2 per therm if ANR Pipeline or Guardian Pipeline does not declare a Cease and Desist Order. When ANR Pipeline or Guardian Pipeline declares a Cease and Desist Order, the charge is $10 per therm plus any incremental costs.
- Optional service: Customers may contract with WPS for Nominated Firm Service for a portion of their gas load. This contracted service, which is purchased in advance, may be used during a High-Flow Constraint Day.