Fall 2016: Flexible Ramping Product Faqs

California Independent System Operator

Fall 2016: Flexible Ramping Product FAQs

1.What are the differences between Flexible Ramping a) Uncertainty Requirements, b) Uncertainty Awards, c) Forecasted Movement, and d) Uncertainty Movement?

Uncertainty Requirement is an hourly value received from a 30-day histogram that accounts for hourly uncertainty due to net forecast errors (both due to demand and VER forecasts). The histogram sends each hour’s up/down requirement to market on a daily basis along with the surplus demand curves (which are used to procure Flex Ramp Up/Down awards in FMM and RTD markets).Uncertainty Requirements are produced for each hour of the day on a daily basis (a value each for FMM and RTD markets, and also in upward and downward directions).

The market may not procure flexible ramping capacity beyond the requirement, but may procure less than the requirement if market prices are very high (i.e. the cost of not procuring extra flex ramp capability becomes less than the cost of procuring). Flexible Ramping Product awards, both upward (FRU) and downward (FRD), procured from the FMM and RTD markets are called uncertainty awards (which are different from uncertainty requirements and uncertainty movement).

Forecasted Movement is defined for the resource energy schedules as the difference between the first advisory and binding interval energy schedules/dispatch of the same market run, and may be either negative (downward) or positive (upward). Forecasted Movement is only determined at the resource level for both the Fifteen-Minute Market (FMM) and Real-Time Dispatch (RTD) markets.

As shown in the figure below, the represented RTD or RTPD market run would determine the forecasted movement as the first advisory minus next binding interval.

Note that the binding RTD interval is first 5-minute interval of the RTD market run, while the binding FMM interval is the second 15-minute interval of the RTPD market run. “First Advisory” pertains to the advisory interval immediately following the binding interval.

Uncertainty movement is defined as the Binding Interval of the next market run minus the first Advisory interval of the current market run. Uncertainty Movement is only determined for the 5-minute market (RTD), and is provided in both resource- and category-specific values.

Note that the binding RTD interval is first 5-minute interval of the RTD market run. “First Advisory” pertains to the interval immediately following the binding interval.

2.What do the resource FRU/FRD award values represent in FMM and RTD Markets?

A resource may receive one of the following outcomes regarding Flex Ramp Product MW awards:

a non-zero FRU/FRD award
a zero FRU/FRD award
a NULL FRU/FRD award

Our explanation references FRP-BRQ-0130 of the external Flexible Ramping Product BRS provided on the CAISO website:

The table below also provides descriptions of the different outcomes.

No. / FRU/FRD Award / Reason for Outcome / BRS Reference
1 / Non-Zero / Generator/Intertie resource was eligible, and received a FRU/FRD award so that it may recover the opportunity cost it incurred when dispatched short of its expected economic output. / See FRP-BRQ-0130, first sentence: Resource eligibility defined as:

5-minute Dispatchable
with RTM economic bids

2 / Zero / Generator/Intertie resource was eligible, and had not received a FRU/FRD award. Either the market achieved its flex ramp requirement prior to awarding the resource or no flex ramp capacity was needed for that interval (i.e. the economic bids met the requirement). / See FRP-BRQ-0130, first sentence: Resource eligibility defined as:

5-minute Dispatchable
with RTM economic bids

3 / NULL / Generator/Intertie resource was not eligible, so no FRU/FRD award was possible (i.e. NULL returned).
Even if ineligible (and having a NULL FRU/FRD award), the resource will still have an associated FRU/FRD price since it may have forecasted movement based on its MW differential between the Binding and Advisory Intervals of a given market run. Recall, forecasted movement is separate from the FRU/FRD uncertainty awards we are discussing. / See FRP-BRQ-0130, first sentence: Resource eligibility defined as:

5-minute Dispatchable
with RTM economic bids

Example provided in FRP-BRQ-0130, 3rd paragraph, explains how a NULL occurs:
“For example, a dispatchable supply or intertie resource (of types defined in FRP-BRQ-0170) which is self-committed/self-scheduled from the Day-Ahead Market and is without RTM economic bids will not receive FRU/FRD awards from the market. If the same resource has an RTM economic bid, it may receive FRP uncertainty awards.”
Reason for having a FRU/FRD price is explained in the 4th paragraph of FRP-BRQ-0130:
“Regardless of eligibility, forecasted movement (which settles separate from the FRU and FRD uncertainty awards) occurs for any resource whose schedule (includes self-schedule) moves from binding to the first advisory of the same market run. Load type resources shall settle for forecasted movement as described in FRP-BRQ-1512).”

Therefore, ineligible resources receiving NULL FRU/FRD awards will still need their associated FRU/FRD prices in order to settle their Forecasted Movement (if any). The CAISO API accounts for this condition.

3.How are Forecasted Movement and Uncertainty Movement Calculated from CMRI’s FMM and RTD Movement Points Report?

As described by the Glossary of Terms for the Flexible Ramp Product BRS, the CMRI FMM/RTD Movement Points report defines movement as follows:

Forecasted Movement (FM) = [MOVEMENT_END, next interval] - [MOVEMENT_START, target interval]

Uncertainty Movement (UM) = [MOVEMENT_START, target interval] - [MOVEMENT_END, target interval]

Example: Scheduling Coordinator (“SC01”) has a resource (“ResA”, at MSG configuration “ResA_X1”) with the following Movement_Start and Movement_End points in the Fifteen-Minute Market (FMM). From these movement points, both ResA’s Forecasted Movement and Uncertainty Movement market values can be determined.

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