20150724press release.pdf

Case No. PAC-E-15-10, Order No. 33345
Contact: Gene Fadness [phone], 890-2712
www.puc.idaho.gov

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

BOISE (July 24, 2015) – Rocky Mountain Power is asking state regulators to approve an updated
plan detailing the steps the utility would take to curtail energy consumption during short-term
energy supply emergencies.

The plan, last updated in 1993, is outdated by advances in technology, changes in industry
practice and the utility’s generation capacity, Rocky Mountain Power claims. Further, the 1993
plan addresses only long-term shortages and not the more typical short-term events.
The long-term shortages addressed in the 1993 plan addressed steps the company could take
to mitigate long-term energy shortages, such as those caused by prolonged drought and
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’s proposed plan recognizes that the company already has demand-side
management (DSM) programs under which customers reduce load during peak consumption
during periods of short supply and it has large customers that already 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. Third is a mandatory up to two-hour curtailment
during peak hours 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 during this rotational curtailment. These include, among others,
hospitals, 911 centers, airports, large water and sewer treatment plants, prisons, police and fire
stations and 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 and final 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 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 Commission 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.
Parties wishing to intervene in the case for the purpose of presenting evidence or cross-
examining witnesses must do so by August 5. Public comments are accepted via e-mail at
www.puc.idaho.gov and clicking on "Case Comment Form,” under the “Consumers” heading.
Fill in the case number (PAC-E-15-10) and enter your comments. Comments can also be mailed
to P.O. Box 83720, Boise, ID 83720-0074 or faxed to [phone].

The company’s proposed plan and other documents related to the case are available on the
commission’s website. Click on “Open Cases” under the “Electric” heading and scroll down to
the above case number.

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