1. Thoughts on DER Aggregations ERCOT Staff DREAM TF Sept. 28, 2015 1DER Aggregations

2. ERCOT developed a methodology for QSEs to maintain the population of their Aggregate Load Resources (ALRs) to support Load Participation in SCED See Other Binding Document and data formatting guidelines here: http://www.ercot.com/services/programs/load/laar/index This could serve as a model for QSEs to maintain Aggregate Distributed Energy Resources (ADERs) with non-static populations –For example, a DER Light consisting of multiple rooftop solar installations ALR Precedent DER Aggregations 2Sept. 28, 2015

3. Changing ALR parameters will be managed by the Resource Entity and the QSE using a market interface dedicated to ALR population maintenance. ALR parameters will be established in the Network Model by the ALR’s Resource Entity using the Resource Asset Registration Form (RARF). ALRs that are subject to dynamically changing populations should set their RARF parameters at levels that will accommodate several months of potential growth so as to reduce the need for frequent RARF submissions. The QSE may add or subtract Premises from an ALR at any time. The QSE shall update appropriate telemetry values when a change is made to the population. QSEs shall report to ERCOT its ALR population changes on a monthly basis via the market interface. –The updates shall include start and stop dates for new Premises in the ALR and/or Premises that have left the ALR. If a Premise is vacated, the Stop Date should reflect that date; and if a new customer later moves into that Premise and joins the ALR, a new start date should be used. –In the competitive choice areas, QSEs will manage the ALR population by ESI ID, which ERCOT will then cross-reference to its internal systems. In the NOIE territories, QSEs shall provide unique meter identifiers consistent with the requirements detailed elsewhere in this document. ALR OBD Language DER Aggregations 3Sept. 28, 2015

4. In the market interface developed to support ALRs, encrypted data is transferred via internet to the ERCOT ‘NAESB server’ –Server is consistent with North American Energy Standards Board (NAESB) standards Transport mechanism and server could be leveraged for ADER maintenance –Data fields will be different since current system is specific to demand response REPs are already qualified and compliant with the transport mechanism and the server interface 3 rd Party QSEs and NOIEs would need to become compliant Maintaining Aggregations DER Aggregations 4Sept. 28, 2015

5. Population maintenance could be similar for ALRs and ADERs, but other issues will be different –ADERs will likely need to be constrained within DSP footprints as well as Load Zones ALRs are constrained only by Load Zone –Load Zone Shift Factors which apply to ALRs will not be appropriate for an Aggregated DER Light or Heavy Shift Factor will need to be unique to each ADER Light/Heavy –Metering requirements different –Telemetry values different –M&V different Population maintenance for DERs Light and Heavy will directly impact formation of appropriate LMPs Other ADER issues DER Aggregations 5Sept. 28, 2015

6. Questions? DER Aggregations Sept. 28, 2015 ON OFF 6