Renewables Get a Tougher Grid Test Under FERC Order

New US grid standards push solar, wind, and batteries to stay online during disruptions, reshaping investment and technology decisions

18 Dec 2025

US power regulators have approved new reliability standards that require clean energy projects to play a more active role in keeping the electricity system stable, reflecting the growing importance of renewables in the power mix.

Order No. 909, approved by federal regulators, tightens expectations for so-called inverter-based resources, including solar, wind and battery storage. Grid operators will now be required to ensure these assets remain connected and support the system during most voltage or frequency disturbances, rather than shutting down automatically.

For much of the past decade, many inverter-based projects were designed to disconnect when conditions moved outside normal ranges. That approach was widely accepted when renewables accounted for a smaller share of supply. As their contribution has grown, regulators have become increasingly concerned that sudden, simultaneous disconnections could worsen grid stress during disruptions.

The new order seeks to address that risk by aligning the behaviour of clean energy assets more closely with that of conventional power plants. Regulators say inverter-based resources should now be treated as core infrastructure, with clear obligations to ride through faults and help stabilise the system.

Industry participants say the decision is less a surprise than a formal recognition of how the grid is changing. Utilities are expected to revisit planning assumptions and operating practices. Developers may need to incorporate compliance and control systems earlier in project design, while equipment manufacturers are assessing how clearer requirements could influence future inverter and storage technologies.

The move also carries implications for investors. More defined rules could reduce long-term regulatory uncertainty and support continued investment in clean energy. However, the potential need to upgrade or retrofit existing projects could increase costs, depending on how the standards are applied across different regions and grid operators.

Order No. 909 forms part of a broader shift in regulatory thinking as renewable generation continues to expand. Federal officials have signalled that a cleaner power system must also be a more resilient one, with reliability standards evolving alongside the energy transition.