1 Distributed Generation Task Force November 5, 2007

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Distributed GenerationTask Force

November 5, 2007

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• ERCOT requires a fifteen (15) minute settlement interval

• Vast majority of Customers do not have this level of granularity

• Profiles are created using adjusted static models• Models estimate customer level interval load based on

• calendar-type data (season, day of week, time of day)

• weather data (temperature, wind-speed, cloud-cover, dew-point)

• Backcasted Profiles are generated the day following a trade day and used for all settlements (initial, final and true-up)

• Load Profiling• Converts monthly kWh reads to fifteen (15) minute

intervals• Enables the accounting of energy usage in settlements

ERCOT Load Profiling

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• ERCOT Load Profile Models are documented in Appendix E of the Load Profiling Guide on the ERCOT website

http://www.ercot.com/mktrules/guides/loadprofiling/current.html


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• ESI IDs are linked to Load Profile Models by their Load Profile ID

• Rules for assigning ESI IDs to Load Profile ID are also documented in Appendix D of the Load Profiling

http://www.ercot.com/mktrules/guides/loadprofiling/2007/11/AD001/Appendix_D_-_Profile_Decision_Tree_110107.xls


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3 Load Profile Groups3 Load Profile Groups 10 Segments 10 Segments

Residential (2)Residential (2)

Low-Winter RatioLow-Winter Ratio (Non-electric Heat)(Non-electric Heat)High-Winter RatioHigh-Winter Ratio (Electric Heat)(Electric Heat)

Business (5)Business (5)

Low Load FactorLow Load FactorMedium Load FactorMedium Load FactorHigh Load FactorHigh Load FactorNon-DemandNon-DemandIDR DefaultIDR DefaultOGFLTOGFLT

Non-Metered (2)Non-Metered (2)

Lighting (Street Lights)Lighting (Street Lights)Flat (Traffic Signals)Flat (Traffic Signals)

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8 ERCOT Weather Zones8 ERCOT Weather Zones

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8 8 Weather Weather

ZonesZones

10 Profile10 ProfileSegmentsSegments

80 Load Profiles80 Load Profiles

Total ProfilesTotal Profiles

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Profiling Example

Application of Backcasted Load Profiles to an ESI ID*Application of Backcasted Load Profiles to an ESI ID*

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(15-

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ute)

Published RESLOWR_SCENT backcasted load profiles for 11/15/03 thru 12/14/03: 729.53 Total kWh

RESLOWR_SCENT ESI ID Meter Read: 1,460 kWh from 11/15/03 thru 12/14/03.Each published backcasted load profile value is multiplied by a scalar of approx. 2.0

** Actually applied to groups of ESI IDs with similar characteristiActually applied to groups of ESI IDs with similar characteristics.cs.

Application of Backcasted Load Profiles to an ESI ID*Application of Backcasted Load Profiles to an ESI ID*

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(15-

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ute)

Published RESLOWR_SCENT backcasted load profiles for 11/15/03 thru 12/14/03: 729.53 Total kWh

RESLOWR_SCENT ESI ID Meter Read: 1,460 kWh from 11/15/03 thru 12/14/03.Each published backcasted load profile value is multiplied by a scalar of approx. 2.0

** Actually applied to groups of ESI IDs with similar characteristiActually applied to groups of ESI IDs with similar characteristics.cs.

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Profiling ExampleOne Day

ESIID - 1/15/2007

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Actual Load Profile Load

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ESIID - 1/15/2007

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ESIID - 1/15/2007

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Interval

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Sunrise Sunset

LoadGeneration

Net Load Load as Profiled

• 105 kWh of load is offset with 24 kWh of photovoltaic generation behind the meter

• Standard RESHIWR profile allocates the 81 kWh of net load for the day without considering the presence of generation behind the meter

Standard Profiles with Distributed Generation

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ESIID - 8/10/2007

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ESIID - 8/10/2007

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Interval

kWh Load

Generation

Net LoadLoad as Profiled

Sunrise Sunset


• 58 kWh of load is offset with 34 kWh of generation behind the meter


• Net load of 24 kWh reflects 5 kWh of reverse registration on the meter

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ESIID - 8/10/2007

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ESIID - 8/10/2007

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Interval

kWh

Generation

Load Net Load Load as Profiled

Sunrise Sunset


• 58 kWh of load is offset with 34 kWh of generation behind the meter


• Meter Detent prevents 5 kWh of reverse registration on the meter

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Excerpts from the Load Profiling Guide:

16.1.3 Chunking Profiling Methodology Description

The chunking method of Load Profiling for TOU customers means that a standard profile is applied to the customer’s consumption data for a meter reading period. However, the energy for each TOU period in the Load Profile is scaled so that it is equal to the metered energy (kWh) for the TOU period. For each TOU period within a meter read cycle, the metered consumption during the Time-of-Use (TOU) period is allocated to time intervals within the TOU period in proportion to the Load Profile level at each interval in that period.

Time-Of-Use Methodology

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• Assumed detented meter programmed for 3 time of use periods:-TOU 1 = (Midnight – 7:45 am) & (5:15 pm – Midnight)

-TOU 2 = (7:45 am – 9:45 am) & (3:45 pm – 5:15 pm)

-TOU 3 = (9:45 am – 3:45 pm)

• Careful specification of the TOU periods can allow chunking the standard profile to reasonably approximate the net load of the ESI ID

TOU Profiles with Distributed Generation

ESIID - 1/15/2007

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Interval

kWh

Series3 Series1 TOU 1 TOU 2 TOU 3

Net LoadLoad as Profiled

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ESIID - 8/10/2007

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Series3 Series1 TOU 1 TOU 2 TOU 3

ESIID - 8/10/2007

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Interval

kW

h

Series3 Series1 TOU 2 TOU 3

• In- and Out-Meters programmed for 3 time of use periods:-TOU 1 = (Midnight – 7:00 am) & (7:45 pm – Midnight)

-TOU 2 = (7:00 am – 8:15 am) & (6:00 pm – 7:45 pm)

-TOU 3 = (8:15 am – 6:00 pm)

• TOU periods based on anticipated shape of net load during August

• Both meters detented to measure load flow in one direction

• Flow into ERCOT profiled with a flat profile (for this example)

TOU Profiles with Distributed Generation

Net Load

Load as Profiled

Net to ERCOT

Net as Profiled

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TOU Profiling Considerations

Approval of a new TOU schedule requires Submission of an LPGRR, and Stakeholder Approval Process Up through TAC

Minor ERCOT system changes (table update) provided no more than 4 TOU periods per day type

Flexible TOU periods and day types Periods not necessarily contiguous Up to 7 day types

Flexible definition and number of Seasons TOU periods can be different across seasons

If energy flow into ERCOT is NIDR metered, development of a profiling methodology would be needed to create settlement interval data

Accuracy would be problematic Flat profile would be easiest to create Obtaining higher level of accuracy may not be cost effective

System changes required to accommodate profiling for energy flow into ERCOT (resource data)

TDSP meter limitations may be different than ERCOT limitations

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Output of a Dallas-area Photovoltaic Array

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August 9, 2007 August 10, 2007

sunrise sunset

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Wzone Sunrise Sunset Sunrise Sunset

Coast 7:16 17:46 6:23 20:23East 7:19 17:39 6:15 20:27

Fwest 7:50 18:10 6:45 20:57Ncent 7:29 17:47 6:22 20:37North 7:32 17:43 6:18 20:40Scent 7:28 17:56 6:32 20:34South 7:21 18:00 6:38 20:27West 7:39 18:00 6:35 21:03

Jan-08 Jun-08

Sunrise and Sunset Times

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Excerpts from the Load Profiling Guide:

12.5 Groups of ESI IDs Eligible to Become Profile Segments

For a group of ESI IDs to be a distinct profile segment, the group shall satisfy the following requirements:

• The group is based on readily identifiable parameters, which are not subject to frequent change.

• The group is reasonably homogeneous as defined in Section 12.6.4, “Homogeneity.”

• The group is sufficiently different from other existing profiles as defined in Section 12.6.2, “Difference from Current Profiles.”

• The group is of sufficient size to justify its own profile segment as defined in Section 12.6.3, “Size.”

12.6 Information Required with Request for Change

All requests shall include the following:• Unambiguous Group Identification• Difference from Current Profile Segments• Size• Homogeneity• Quality Assurance Methodology for ESI ID Identification

LPG Requirements for New Profile

Source: InfinitePower.org

Insolation Across Texas

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Average Windspeed by Hour -- North Central WZ

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Average Windspeed by Hour -- North Central WZ

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Average Windspeed by Hour -- Far West WZ

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Average Windspeed by Hour -- Far West WZ

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New Load Profile Considerations

Market Participant submit a request Evaluation Time for request Load Profiling Methodology

Lagged Dynamic Approved for new profiles but system changes needed for

implementation Dynamic sampling required as population increases

Static Models Sample Requirements Collection of Load Research data (18 – 24 months) Sample data analysis and model building Require LPGRR and Stakeholder Approval Process for New Model

150 day Market Notice Required after Stakeholder Approval Process

Documents

1 Distributed Generation Task Force November 5, 2007