The grid wants to see inside: EMT models, inverter control and large-load tracking

Victoria Shinder09 October 2026, 07:472 min read

Three documents from 7 and 8 October come from different countries and different institutions. They make the same demand: the people responsible for the grid want to see inside things they do not own — and they are arguing over who pays for that visibility.

1. Inside the converter — Great Britain. NESO's final report on Grid Code change GC0168 asks Ofgem to let the system operator demand electromagnetic transient models from generators completed before September 2022. The reason is physics: as wind, solar, batteries and HVDC replace synchronous machines, oscillations, inverter instability and transient overvoltage happen on time scales that slower models miss. The dispute is money. The Panel recommended an alternative that waits for a cost-recovery mechanism in the charging code, because for older plant a validated model may mean reverse-engineering controls the manufacturer no longer supports.

2. Inside the control channel — the EU. An expert group advising the Commission recommends restricting high-risk suppliers of inverter components and software, third-party certification of inverters under the Cyber Resilience Act, and keeping remote control and firmware signing inside the EU. Its risk yardstick is explicitly a grid one: how much generation an attacker could control compared with the continental grid's 3,000 MW frequency reserve. The cost question appears here too, in the report's own caveat — restrictions could hurt the market without alternative supply, and the experts say they did not do the full risk assessment.

3. Inside the load forecast — the United States. DOE's filing at FERC asks PJM to allocate the cost of its 6.8 GW backstop procurement on updated forecasts and to track every large-load project — in service, delayed, shrunk or cancelled — so costs follow the data centres that caused them. Here visibility is the cost mechanism: without project-level data, DOE says, PJM cannot avoid double counting or cut the target when forecast load never arrives.

What connects them. In each case the operator's model of the system has fallen behind the system itself — converters it cannot simulate, control paths it cannot see, loads it cannot verify. And in each case the fight is over who carries the cost of closing that gap: legacy generators or all users through charges (GB), manufacturers and buyers through restricted supply (EU), or the new loads themselves (PJM).

What to watch. Ofgem's GC0168 decision and the CUSC cost-recovery changes CMP456/466; whether the Commission picks up the expert group's call to classify inverters as Class II under the CRA; and PJM's revised filing due by 29 October. Asset owners in all three markets should assume that "provide the data" is becoming a condition of connection, and price it in.

This analysis draws on: NESO, "GC0168 Final Modification Report" (8 October 2026) — https://www.neso.energy/gc0168-final-modification-report ; pv magazine, "EU expert group urges curbs on high-risk solar suppliers" (8 October 2026) — https://www.pv-magazine.com/2026/10/08/eu-expert-group-urges-curbs-on-high-risk-solar-suppliers/ ; Utility Dive, "DOE presses PJM on ratepayer protections from large load costs" (8 October 2026) — https://www.utilitydive.com/news/doe-pjm-ferc-ratepayer-protection-large-load-data-center/832479/