CAISO DER Wholesale Market Participation Hinges on Metering

A trade group told Utility Dive this month that a CAISO accounting change could bring more than 2 GW of behind-the-meter resources into the wholesale market. The coverage put the horizon somewhere in 2027 and 2028, which reads like something to check on next year. For most of the question that is right. For the one piece of it that decides what a utility has to buy, it is wrong by about fourteen months, because CAISO DER wholesale market participation is being settled through a metering reform that is already in draft final and on a board calendar for October.

The initiative is called Demand and Distributed Energy Market Integration, DDEMI in the filings. It has been running as a stakeholder process since a working group kicked off in February 2025. A straw proposal and issue paper came out on March 13, 2026, a revised straw proposal on June 11, and a Track 1 draft final proposal on July 8 with a web meeting the following day. CAISO’s own schedule for the initiative posts another paper on August 19, holds a meeting on August 21, closes comments on September 4, and places a board decision in the October 26 to 28 window.

That is a sixteen-day reading window between the paper and the comment deadline, and it is open right now.

What the accounting change actually does

The mechanism is narrow and worth stating precisely, because the shorthand in trade coverage loses the part that matters.

DDEMI would treat a distributed energy resource aggregation as a discrete resource inside CAISO’s revised demand response framework. That resource may export within a load zone, but only until the site’s net load reaches zero. Below zero, meaning true net export back onto the distribution system, the aggregation has to enter the appropriate generation interconnection queue like any other generator.

Nothing gets built to make this work. The batteries, the water heaters and the thermostats are already installed behind meters across California. What changes is how their output is counted and paid for, which is why the word “accounting” is doing real work in the description rather than serving as a euphemism.

The 2 GW is an estimate from an advocate

The figure belongs to Brian Turner, Senior Director at Advanced Energy United. Advanced Energy United is a trade association for advanced energy companies, which does not make the number wrong but does make it interested. No calculation method or data source has been published alongside it. CAISO has issued no 2 GW projection of its own.

So the honest form of the sentence is that a trade association estimates upwards of 2 GW, and the dishonest form is that CAISO’s accounting change adds 2 GW. Anyone building a demand case on the second version is building on a press quote.

This is the same discipline we applied to utility large-load numbers last week. When the party publishing a figure benefits from the figure being large, the useful question is not whether to believe it but what instrument sits behind it. Our read on how to discount a pipeline number against a contracted one sets out the general version of that test, and it travels to advocacy estimates without much modification.

CAISO DER tariff metering is Track 1, not a later phase

Here is the part the headline buries. The July 8 draft final proposal is specifically a metering document. In the description carried by counsel tracking the docket, it “introduces targeted metering reforms to better capture behind-the-meter demand response by recognizing customer-level exports within a resource-level load curtailment network.”

Read that clause slowly, because it names the whole problem. A demand response resource has historically been settled at the resource level as a block of curtailed load. A customer inside that block who has a battery is not just curtailing, they are exporting at the meter. Under the old counting method that export either disappears into the aggregate or breaks the baseline. Track 1 is the work of recognizing it as what it is.

Counting reform is metering reform. You cannot recognize a customer-level export inside a resource-level curtailment without deciding what meter reads it, at what interval, and over what path the reading travels. That decision is the one with a bill of materials attached, and it is the first track rather than a downstream detail.

The net-load-zero cap means less equipment than the headline suggests

The export boundary is the most interesting engineering choice in the proposal, and it cuts against the natural reading of a 2 GW story.

Stopping paid export at net load zero means an aggregation can be paid to take a site to neutral and no further. Real backfeed onto the feeder requires the generation interconnection queue. For a distribution engineer that is the correct line: backfeed is the condition that breaks protection coordination and pushes voltage regulation outside its band, and a market rule that quietly created thousands of new injection points would have handed distribution planners a problem the market did not price.

The procurement consequence is that DDEMI as drafted does not set off a distribution-side interconnection wave. No fleet of new reclosers with reverse-power elements, no wholesale re-coordination of feeder protection, no rush of service upgrades. The utility does not inherit a backfeed problem under this design. That is a smaller and duller story than 2 GW of new resources, and it is the one a municipal or cooperative planner should actually act on.

It also puts a boundary around what the market rule can pull. Anything that wants to sell real export is back in the same generation queue it was always in, subject to the same study and the same upgrades.

DER aggregation telemetry requirements are the open question

What the proposal has not published is a specification.

No telemetry cadence, no communications protocol, no metering configuration and no submetering standard appears in the public coverage of the initiative. Anyone writing a hardware bill of materials for DDEMI today is inventing it. That is worth saying plainly, because the temptation for a supplier or a distributor is to translate a market-design headline into a product list six months before the design says anything about products.

The requirement to watch for has three parts, and each one moves a different line on a quote:

The counting method decides whether a customer-level export can be read from an existing revenue meter or needs a separate device behind it. Interval data at fifteen minutes is a different purchase from real-time telemetry at four seconds, and the gap between those two is where most of the money in this category sits.

The communications path decides whether the aggregator’s own gateway is sufficient or whether the reading has to arrive over the utility’s advanced metering network. That is a question about who owns the data path, and it is answered in tariff language rather than in a datasheet.

The eligibility gate decides which installed base qualifies at all. There is a live example of what that looks like once it is written down. ComEd’s Rider SDVPP, approved by the Illinois Commerce Commission on June 30, 2026, applies two hardware gates to every enrolled asset: an IEEE 1547-2018 smart inverter, with UL 1741 SA accepted only as a temporary fallback, and an advanced meter, since customers without one are excluded outright. Two sentences in a tariff, and a large share of an installed fleet is either in or out.

Until CAISO writes its equivalent of those two sentences, the honest position is that the category is real and the spec is not yet knowable. Our analysis of what public grid data can and cannot tell you about interconnection makes a related point about the difference between a resource being valuable somewhere and a circuit being able to accept it, and the same gap between market signal and engineering fact applies here.

Two clocks, and they do not run at the same speed

The 2027 and 2028 dates in the coverage are real, but they belong to a different proceeding.

Turner’s own optimistic case for participation at scale is the first half of 2027. The CPUC has allowed itself until February 2028 to resolve the open questions in its parallel demand response rulemaking. Those are the dates for the state commission’s side of the design, and they are why the story reads as slow.

CAISO’s market-design clock is the fast one, and it closes this year. A board decision in late October is a decision about the market rule, the counting method and the tariff language, which is precisely the layer that determines a metering specification. Waiting for the CPUC to finish before reading the CAISO paper gets the sequence backwards.

One more thing belongs in any assessment of how likely this is to land as drafted. CPUC staff have opposed a related CAISO demand response revision proposal on the grounds that it could leave ratepayers worse off. A story sourced to a single advocate reads as momentum. The same story with the state commission’s own staff on the record against a neighboring piece of it reads as a contested proceeding with a real chance of a narrowed outcome, which is the more accurate picture.

What to do before September 4

For a municipal utility or a cooperative with behind-the-meter storage already sitting in its territory, there are four things worth doing in the next three weeks.

Read the paper CAISO posts on August 19 for the counting method, and specifically for whether a customer-level export is read from the revenue meter or from a device behind it. That single answer sets the equipment question for the next several years.

Check whether your advanced metering deployment can produce interval data at whatever cadence the paper names, because if it cannot, the gap is yours and not the aggregator’s.

Decide your position on who owns the data path before an aggregator arrives asking to enroll your customers, since the utility inherits the interconnection, protection and data consequences either way.

File a comment by September 4 if the counting method would strand your installed metering base. A comment window that nobody from the municipal and cooperative side uses produces a rule written for the parties who did.

The broader pattern here is one we keep running into. A market rule that changes nothing physical can still rewrite an equipment specification, and it does so on a regulatory calendar rather than a construction one. The same thing happened on the large-load side when curtailment stopped being a contract term and became an equipment spec enforced with utility-owned breakers and relays. It happened again as state mandates and battery economics pushed virtual power plants from pilot to procurement. Each time, the buyers who read the tariff before the datasheet were a year ahead of the ones who waited for a product announcement.

Related Reading

• What Public Grid Data Can’t Tell You About Interconnection
• The VPP Procurement Wave Is Here
• Data Center Load Flexibility Is Now an Equipment Spec

Market-design changes like this one move faster than the trade coverage that follows them, and the dates that matter are usually buried in a stakeholder calendar rather than in a headline. The Feeder is our free monthly rundown of the regulatory and supply signals that change what utility buyers have to spec. One email a month, no charge.

Frequently Asked Questions

What is the CAISO accounting change that could add 2 GW of DER?

It is the Demand and Distributed Energy Market Integration initiative, or DDEMI. The design treats a distributed energy resource aggregation as a discrete resource that may export within a load zone until the site's net load reaches zero. A straw proposal and issue paper came out March 13, 2026, a revised straw proposal June 11, and a Track 1 draft final proposal July 8.

Is the 2 GW figure a CAISO forecast?

No. It is an estimate given to Utility Dive by Brian Turner, Senior Director at Advanced Energy United, which is a trade association for advanced energy companies. CAISO has published no 2 GW figure and no methodology for this one is public. Treat it as an advocate's estimate, and cite it that way if you use it.

When does this actually decide anything?

Two separate clocks run here. CAISO's own schedule posts a paper August 19, holds a meeting August 21, closes comments September 4, and puts a board decision in the October 26 to 28 window. The CPUC's parallel demand response rulemaking runs much longer, with the commission having allowed itself until February 2028.