By Nick Myers
When institutions are confident, they don’t rush out carefully framed messaging two days before a major regional symposium. They don’t suddenly rediscover the dangers of “fragmentation.” And they don’t rely on allied advocacy groups to circulate modeling that conveniently reinforces their preferred outcome.
Yet that’s exactly what California is doing.
Just days before a scheduled SPP Markets+ Seams Symposium, CAISO released a blog post warning about the dangers of new “seams” and market fragmentation. The timing was conspicuous. It was not accidental. It was strategic.
Because for the first time in years, California’s grip on Western market design is genuinely at risk. (See CAISO Unveils Principles for Western Seams Coordination.)
California Built a System that Depends on the West
California’s grid does not operate in isolation. It relies heavily on imports during evening ramping hours, leans on regional flexibility to manage renewable over-generation and depends on diversity across the West to maintain reliability at a reasonable cost.
The Western Energy Imbalance Market (WEIM) provided measurable benefits, but it also reinforced something California would prefer not to admit: Its system increasingly depends on access to resources outside its borders.
As utilities and states consider anchoring their day-ahead participation in Markets+ rather than California’s Extended Day-Ahead Market (EDAM), that dependency becomes a vulnerability. If enough states choose Markets+, California’s leverage shrinks. Trade patterns shift. Institutional influence weakens. Governance becomes less California-centric.
That is what’s driving the urgency.
Seams exist everywhere. The irony of CAISO’s sudden focus on “seams” is difficult to ignore. Seams are not unique to Markets+. They exist within EDAM as well. Different balancing authorities, governance boundaries and interconnections with other markets create friction points regardless of the market that is chosen.
No market expansion eliminates seams; it simply manages them. Portraying Markets+ participation as inherently “fragmenting” the West ignores the reality that EDAM itself operates across multiple jurisdictions with inherent boundary issues. Market design always involves coordination challenges. The question is not whether seams exist. It is how they are governed and who controls the rules.
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The Aurora Study and Strategic Modeling
At the same time CAISO is amplifying its messaging, the Environmental Defense Fund released a study conducted by Aurora Energy Research comparing regional market outcomes. The modeling emphasizes friction costs and inefficiencies associated with certain participation pathways, while reinforcing the economic case for EDAM alignment. (See APS Would See Greater Savings in EDAM, Analysis Finds.)
Modeling assumptions drive outcomes. Inputs determine results. When an advocacy organization commissions such work during active market competition, the timing is intentional.
Environmental advocacy groups understand that California’s aggressive climate policies benefit from broad regional integration under structures California influences. A smaller footprint makes renewable balancing more difficult. This reality doesn’t invalidate the study, but its ideological perspective should be taken into account.
Governance is the Real Issue
Strip away the rhetoric about seams and fragmentation, and the core issue is governance. EDAM remains rooted in California’s regulatory structure and political environment. Markets+ offers a governance model that many Western states view as more regionally balanced and less tied to one state’s policy priorities.
That distinction matters.
California has not always played well with its neighbors. During WEIM’s rollout, governance control remained tightly anchored in California. Some states participated despite, not because of, the governance structure, largely because the operational benefits outweighed its objectionable governance. Now those same states are being invited to extend deeper into California-centered day-ahead governance. Unsurprisingly, some are reconsidering.
What Happens if California Loses Control?
If California no longer anchors the dominant Western day-ahead market, consequences follow:
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- Reduced ability to shape regional market rules.
- Less influence over transmission prioritization.
- Greater exposure to import price volatility.
- Diminished leverage in balancing renewable intermittency.
California’s grid strategy has quietly assumed continued regional integration under its framework. If those assumptions do not materialize, California faces difficult tradeoffs: higher costs, tighter reserve margins and reduced flexibility. That is the backdrop behind the sudden surge in messaging in support of EDAM.
Markets should compete on their merits. If EDAM offers superior economics, governance and reliability, it should win without resorting to strategically timed blog posts and new studies. If Markets+ offers stronger regional balance and autonomy, states should be free to choose it without being accused of fragmenting the West.
The West is not fracturing. It is deciding. Perhaps the clearest signal of all is this: Institutions panic only when they fear losing something they’ve come to rely on.
California’s anxiety is not really about seams. It’s about control.
Nick Myers is chair of the Arizona Corporation Commission.
