Dive Brief:
- The California Independent System Operator wants input on thorny issues associated with a spike in large loads, such as cost allocation for transmission, speed to power and the risks posed to short-term demand forecasting.
- CAISO laid out these issues in a paper released Jan. 20, and is asking for written comments to be submitted by Feb. 25. Data center load in the CAISO grid is expected to increase by 1.8 GW by 2030 and 4.9 GW by 2040, according to a January forecast from the California Energy Commission.
- “We wanted to take an opportunity to put an informational document out to stakeholders, because we're getting a lot of questions about how the ISO manages large loads and plans for large loads on the ISO system,” said Danielle Mills, CAISO’s infrastructure policy development principal, during a Feb. 5 webinar about the paper.
Dive Insight:
Mills noted that large load growth is an “issue with a lot of attention and some urgency behind it across the country, but also an issue that has a lot of nuance from region to region about how it's treated and dealt with.”
CAISO’s paper is careful to acknowledge that nuance and defer to regulators like the Federal Energy Regulatory Commission and North American Electric Reliability Corp. on many of the questions it raises. In October, the Department of Energy directed FERC to issue an Advanced Notice of Proposed Rulemaking on large load interconnections, and CAISO said it “anticipates additional clarity from FERC before issuing specific proposals.”
NERC is also working on a final version of its Reliability Guideline: Risk Mitigation for Emerging Large Loads document, aiming to release it in the second quarter of this year after issuing a draft version for comments in November.
“We've been watching FERC’s order on PJM and their co-located issue docket, and taking all of that in and thinking through any potential changes that the ISO may consider, as well as potential tariff changes,” Mills said. “At this point, we're just having an information session, and put out the issue paper to better understand the scope of the issue more broadly. But we will continue to monitor these ongoing regulatory dockets.”
CAISO’s paper often focuses on the logistical issues posed by a rapid increase in large loads, and the current barriers to addressing those issues. On the issue of cost allocation, CAISO writes, “It will not be possible in many instances to distinguish between which networked facilities were triggered by the load or by the generation. Likewise, it will not always be clear to the extent other ratepayers benefit from networked facilities triggered by the new large load.”
As a result, enhancing large load cost allocation rules and responsibilities will “require significant coordination across tariffs, including the ISO’s.”
CAISO also notes that “as large loads combined with [distributed energy resource] technologies proliferate, their increasing flexibility creates more uncertainty and makes them more difficult to predict.”
Some key looming challenges to short-term demand forecasting include: limited visibility into DER operations, rapid growth in co-located large land DER adoption, evolving retail rate structures, and expansion of load flexibility programs, CAISO said.
“Without visibility into large load and DER-driven demand changes, the ISO may need to rely more heavily on near-term reliability products like flexible ramping and regulation reserves adding cost and complexity,” CAISO said.
While offering customized service to large load customers can allow for faster interconnection — addressing the “speed to power” issue — new service offerings need to be carefully incorporated into system operations and aligned with existing planning activities, CAISO said.
“New service offerings will require a clear understanding of existing NERC requirements and may need adjustments to the ISO planning standards to more accurately account for system conditions, withdrawals, and transmission service provision,” the paper said.
