20160204press release.pdf

Rocky Mountain Power submits updated curtailment plan
to be used during times of energy supply shortages

Case No. PAC-E-15-10, Order No. 33428
Contact: Gene Fadness [phone]
www.puc.idaho.gov

BOISE (Feb. 4, 2016) – The Idaho Public Utilities Commission is taking comment through Feb. 25
on an update to a Rocky Mountain Power plan outlining the steps the utility would take to
curtail energy use during energy supply emergencies.

Rocky Mountain Power serves about 75,000 customers in eastern Idaho.
The current curtailment plan, last updated in 1993, is outdated by advances in technology,
changes in industry practice and the utility’s generation capacity. Further, the 1993 plan
addresses only long-term shortages and not the more typical short-term events.
The shortages addressed in the 1993 plan included steps the company could take to mitigate
long-term energy shortages, such as those caused by prolonged drought or operational
constraints on the transmission grid. The proposed updated plan adds the more common
shorter-term emergencies such as a temporary loss of generation, failed equipment, extreme
weather and temperatures, or a system disturbance within the Western Interconnection.
Rocky Mountain Power already has demand-side management (DSM) programs under which
customers can reduce load during peak consumption periods, and it has large-use customers
that contractually agree to be interrupted to achieve reductions in load.
The plan anticipates five stages that are used as the energy deficit increases.
The first stage is to implement load shedding from customers that can be contractually
interrupted or are part of the company’s existing demand side management program.
The second stage is a public appeal to voluntary load reduction by all customers.
The third stage is a mandatory curtailment of no more than two hours during peak-use times by
customers who have been grouped into blocks of about 100 megawatts near selected
distribution feeders. However, distribution feeders serving facilities essential to the public
welfare are avoided. These include hospitals, 911 centers, airports, large water and sewer
treatment plants, prisons, police and fire stations and other facilities critical to electric system
operation.
The fourth step is a mandatory curtailment in two-hour block rotations during peak or non-
peak hours. The fifth step is mandatory emergency load reduction.
Under the former plan, only the State of Idaho could declare an energy emergency that would
trigger curtailment. The updated proposed plan recognizes the role of the Western Electricity
Coordinating Council (WECC) and its Regional Reliability Coordinator to implement and enforce
regional reliability standards in the Western U.S. for a coordinated effort to effectively manage
energy shortage situations.
Emergencies that threaten the integrity of the electric system can develop at any time due to a
shortage of generation or disturbances on the system, either locally or within the Western
Interconnection. To prevent total collapse of the system, the proposed plan states that WECC
or the Idaho PUC may order energy curtailments. However, nothing precludes Rocky Mountain
Power from requesting voluntary load reduction at any time.
The proposed plan also eliminates financial penalties that could be assessed parties for
noncompliance with curtailment orders.
Comments can be submitted electronically through Feb. 25 by going to www.puc.idaho.gov.
Click on “Case Comment Form” under the “Consumers” heading and enter the case number,
PAC-E-15-10, with your comment. Comments can also be mailed to P.O. Box 83720, Boise, ID,
83720-0074.
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