IDEAS: Issue #2: DR vs DER Definition
 Issue Identified:
Does/should DER in ERCOT include Demand Response? If so, should either DER rule
promulgation subsume existing DR rule improvement efforts (Loads in SCED v2.0), or
should DER rules be made flexibly enough to include DR with the set of viable market
operations of a DER, or potentially neither? Answer: Neither. The definition of DR
should continue to be a resource that is not capable of injecting into the system and is
a withdrawal from the system.
 Issue Development:
The definition of Demand Response; whether Controllable, aggregated, or passive
should remain as it is today, with DER being defined as a Generation Resource, which
may be an energy storage device, or an aggregation of Generation Resources (which
may include an energy storage device), or an aggregation of Generation Resources
(which may include an energy storage device) and Load Resource(s), but never a Load
Resource by itself, which is interconnected at or below 60 kV, dispersed in the same
Load Zone, and is capable of injecting electrical energy onto the distribution system.
This issue is framed by the existing regulatory framework, which includes the following:
Substantive Rule §25.501(h) says that,
“ERCOT shall use zonal energy prices for loads […]”.i
ERCOT Nodal Protocols Section 2.1 defines Load Resource as,
“A Load capable of providing Ancillary Service to the ERCOT System
and/or energy in the form of Demand response and registered with
ERCOT as a Load Resource.”ii
One of the sub-sets of Load Resources, Aggregate Load Resource, is
defined within the ERCOT Nodal Protocols Section 2.1 as,
“A Load Resource that is an aggregation of individual metered
sites, each of which has less than ten MW of Demand response
capability and all of which are located within a single Load
Zone.”iii
Given the above, while a Distributed Energy Resource may consist of an aggregation
that may include Load Resources, and thus have (lower case) demand response /
flexible load operations behind the DER meter as a component of that DER, the DER as
a whole is made distinct from the similar Aggregate Load Resource by the fact that it is
“capable of injecting electrical energy onto the distribution system.”
 Detailed Explanation:
This distinction stands on the basic concept that DR is a load or aggregation of various
generation/storage and load resources that is a net withdrawal from the system.
 Analysis:
What are the implications for PUC rule? Based on the definition of DR not being
changes there should not be an effect on the PUCT rule.
Could we create a second category of DER Heavy that includes DR, settled at LZ SPP?
The question is not could we but why would we. DR can already be settled at LZ SPP.
 Solve/Solution:
Make certain that the definition for DER maintains the distinction between DER and DR
which are two fundamentally different resources and capable of providing distinct
benefits to the system.
i
CHAPTER 25. SUBSTANTIVE RULES APPLICABLE TO ELECTRIC
SERVICE
PROVIDERS.
Subchapter S. WHOLESALE MARKETS.
§25.501. Wholesale Market Design for the Electric Reliability Council of Texas.
(h) Zonal energy prices for loads. ERCOT shall use zonal energy prices for loads that
consist of an aggregation of either the individual load node energy prices within each
zone or the individual resource node energy prices within each zone. Individual load
node or resource node energy prices shall be the locational marginal prices, consistent
with subsection (e) of this section, resulting from security-constrained, economic
dispatch. ERCOT shall maintain stable zones and shall notify market participants in
advance of zonal boundary changes in order that the market participants will have
an appropriate amount of time to adjust to the changes.
ii
iii
ERCOT Nodal Protocols 2.1
ERCOT Nodal Protocols 2.1