A unit trips at 2 a.m. and ACE falls off a cliff. Who has to bring it back, and how fast? That is the heart of BAL-002, and it shows up on the RC exam because Reliability Coordinators have to understand what the Balancing Authority owes the Interconnection after a disturbance. Know the numbers and know who owns the obligation.
Test Tips
- Know the owner. Contingency Reserve obligations sit with the Balancing Authority or Reserve Sharing Group, not the RC. If an answer choice puts the burden on the RC, it is a distractor.
- Memorize 15 and 90. ACE recovery after a Reportable Balancing Contingency Event is a 15-minute clock. Restoring the Contingency Reserve you used is a 90-minute clock that starts when the recovery period ends.
- MSSC drives the size. Most Severe Single Contingency is the largest single contingency the BA could lose (generator, import, or load). Contingency Reserve is sized against it.
- Reportable means 80%. The default reportable threshold is 80 percent of MSSC. Smaller events are not reportable unless a lower threshold has been set.
- Do not mix reserve types. Regulating reserve handles moment-to-moment ACE. Contingency Reserve responds to sudden loss. Questions love to swap them.
- Sharing is allowed. A Reserve Sharing Group can meet the obligation collectively. Watch for questions that assume every BA must carry its own full MSSC.
5 Practice Questions
Question 1
After a Reportable Balancing Contingency Event, within what period must the Balancing Authority recover ACE under BAL-002?
- A. 5 minutes
- B. 10 minutes
- C. 15 minutes
- D. 30 minutes
Question 2
The Contingency Reserve Restoration Period under BAL-002 is, at most, how long?
- A. 30 minutes
- B. 60 minutes
- C. 90 minutes
- D. 120 minutes
Question 3
Which entity carries the primary responsibility for maintaining Contingency Reserve to respond to Balancing Contingency Events?
- A. The Reliability Coordinator
- B. The Balancing Authority or Reserve Sharing Group
- C. The Transmission Owner
- D. The Planning Coordinator
Question 4
What does Most Severe Single Contingency (MSSC) represent?
- A. The largest single generating unit on the Interconnection
- B. The largest single contingency the Balancing Authority could experience, such as loss of a unit, import, or load
- C. The total of all contingencies in the BA area
- D. The peak forecast load for the day
Question 5
A BA loses a resource equal to 90 percent of its MSSC. Using the default threshold, how is this event classified?
- A. Not reportable
- B. A Reportable Balancing Contingency Event
- C. A Frequency Response event only
- D. An Energy Emergency Alert
Answer Key & Explanations
- C. BAL-002 sets a 15-minute Contingency Event Recovery Period for returning ACE to the required level after a reportable event.
- C. The Contingency Reserve Restoration Period is 90 minutes, beginning at the end of the recovery period.
- B. BAL-002 places the obligation on the Balancing Authority or Reserve Sharing Group. The RC coordinates reliability but does not carry the BA's reserve.
- B. MSSC is the most severe single contingency the BA could lose, and it is the basis for sizing Contingency Reserve.
- B. At 90 percent of MSSC the loss exceeds the default 80 percent threshold, so it is a Reportable Balancing Contingency Event. Verify any lower threshold in the current effective BAL-002 at nerc.com.
Always confirm the current effective version of BAL-002 at nerc.com before the exam.
Ready to Pass?
BAL-002 puts the obligation on the BA or Reserve Sharing Group, with 15-minute ACE recovery followed by a 90-minute Contingency Reserve Restoration Period. Keep those responsibilities and intervals clear as you prepare, and take part in the free 30-day RC study sprint: https://epgsolutions.services/pages/free-30-day-rc-study-sprint