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 $2.50 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.
Constraints called by WPS after 2014:
| Dates |
# of days |
Customers affected |
Reason |
| Mar 1-3, 2014 |
3 |
Transportation and Interruptible |
Daily gas supply and pipeline capacity |
| Feb 19, 2015 |
1 |
Transportation |
High Flow Constraint |
| Nov 6, 2016 |
1 |
Transportation |
Low Flow Constraint |
| Jan 1-7, 2018 |
7 |
Transportation |
High Flow Constraint |
| Jan 29-31, 2019 |
3 |
Transportation |
High Flow Constraint |
| Feb 25, 2019 |
1 |
Transportation |
High Flow Constraint |
| Mar 4, 2019 |
1 |
Transportation and Interruptible |
High Flow Constraint |
| Feb 6-22, 2021 |
17 |
Transportation and Interruptible |
High Flow Constraint |
| Dec 23 – 26, 2022 |
4 |
Transportation and Interruptible |
High Flow Constraint |
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 $2.50 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.
