Section 1600 Report - Data Request Comments and Responses (May 23, 2011)

Generating Availability Data System (GADS): Mandatory Reporting of Conventional Generation Availability Data

The following is excerpted from the "GADS Data Request Comments and Responses" document:


On March 21, 2011, NERC posted a request for public response regarding mandatory Generating Availability Data System (GADS) reporting for all conventional generating units 20 MVA or larger in North America. The completion data for public response was May 5, 2011. At the close of the 45-day public comment period, NERC received 19 comments as follows:

  • 11 responses from Investor-owned Utilities
  • 5 responses from Independent Power Producers
  • 1 response from a public utility commission
  • 1 response from a consultant
  • 1 response from an Independent System Operator

Executive Summary of the Responses.

We appreciated the responses by the 19 entities that provided comments. Each comment was evaluated and discussed by the GADS Task Force (GADSTF) leadership. One of the repeated comments from the responses was the concern about the large amount of design data requested. In the GADS Task Force Report, there were 18 pages, summarizing the many design fields currently collected by GADS. In the GADS webinar, it was estimated that about 50 percent of the fields were required when in a more thorough review, about 35 percent of the design fields are identified as needed information. After reviewing the comments regarding design data, the GADSTF leadership recommended that the design data requirement be reduced to nine (9) elements per unit, regardless of unit type.

The nine design data fields were chosen for two specific reasons:

  • Allowing GADS data to be matched with information collected in the Transmission Availability Data System (TADS). One goal of NERC is to allow the GADS and TADS databases to interact with each other. Certain data fields are needed to allow generating units to be located in areas where transmission lines are located. Specific fields allow that interaction.
  • Editing the event and performance data to insure the continued quality of information collected by GADS.

The nine design data fields are:

  • GADS utility code (assigned by GADS Services)
  • GADS unit code (assigned by the reporting company following the guidelines in Appendix C of the GADS Data Reporting Instructions.)
  • NERC Regional entity where the unit is located
  • Name of the unit
  • Commercial operating date
  • Type of generating unit (fossil, combined cycle, etc.)
  • MW size (nameplate)
  • State or province location of the unit.
  • Energy Information Administration (EIA) Plant number

The GADSTF will review the other design data fields and will make recommendations to expand it if needed.

Another reoccurring comment was the MVA size of the units collected starting January 1, 2012. There are a number of small hydro, gas turbine and other unit types that currently do not report to GADS. Some units are very old and in remote locations. Expense and time to report these units are not budgeted to report them to GADS starting next year.

Therefore, the GADSTF leadership reviewed this issue and considered requiring generating units report to GADS in two annual “phase-in” steps. Specific new units in commercial operation from 2000-2010 the GADSTF showed the following:

MW Size Range Percent of New Reported Units Number of units
< 20 MW 0.3 4
20 to < 50 MW 17.42 229
50 to < 75 MW 8.14 107
75 to < 100 MW 12.16 160

The increased amount of data by each region is as follows:

NERC Regions 20 MW+ 50 MW+ 75 MW+ 100 MW+
FRCC 98.55% 93.25% 86.03% 83.06%
MRO 93.80% 85.20% 77.30% 71.07%
NPCC 97.24% 92.40% 89.68% 87.06%
RFC 98.59% 93.95% 90.70% 86.42%
SERC 98.03% 93.47% 89.43% 83.66%
SPP 96.75% 89.03% 80.24% 74.28%
TRE 99.46% 97.34% 94.21% 92.05%
WECC 98.26% 90.57% 84.89% 77.36%
Percent of total 97.93% 92.49% 87.95% 82.98%

Based on additional analyses, it is proposed that generator on the NERC Compliance Registry report generating units according to the following schedule:

  • Starting January 1, 2012, all generating units 50 MW and larger nameplate are required to report to NERC. The revised list (9 items) design data will be completed by December 31, 2011. Event and performance data for the first quarter of 2012 will be to NERC by April 30, 2012.
  • Starting January 1, 2013, all generating units 20 MW and larger nameplate are required to report to NERC. The revised list (9 items) design data will be completed by December 31, 2012. Event and performance data for the first quarter of 2013 will be to NERC by April 30, 2013.
  • All generating units under 20 MW nameplates will be invited to be part of NERC GADS on a voluntary basis. All smaller than 20 MW units who currently report to GADS on a voluntary basis are encouraged to continue reporting to GADS.

“MW Nameplate” will be calculated by the MVA recorded on the unit’s generator times the power factor. For example, a 100 MVA unit with a .90 power factor would be a 90 MW unit.

No comments were received regarding the event and performance data collection fields recommended by the GADSTF.

No comments were received on any other of the GADSTF recommendations that are not related to design or timing for reporting smaller (between 20-50 MW) units.

In summary, the GADSTF proposes that GADSTF recommendation be changed to limit the design data to the nine mentioned fields and the generating units be phased in with 50 MW and larger starting January 1, 2012 and 20 MW and larger starting January 1, 2013.

Responses to the Comments

The Section 1600 request included the four specific questions in the Section A of the Data Request. All comments have been considered and responses are provided below (in the document link).

Additional information is available from the report published by the NERC’s Generating Availability Data System Task Force (GADSTF), which can be viewed at .

  NERC GADS Task Force issues (05/27/2011) Revised Final Draft GADSTF Recommendations Report.

To view the GADSTF report and the Section 1600 request for comments, please go to

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