India's Proposed Grid-Forming and Mandatory Storage Rules: What the CEA Draft Could Mean for Rajasthan's Solar and Wind Industry

India's renewable-energy transition is moving into a new technical phase. The Central Electricity Authority's September 2026 draft proposes requirements that could make grid-forming capability and co-located energy storage part of the design conversation for future solar and wind projects.

For Rajasthan—one of India's largest renewable-energy states—the significance goes beyond equipment specifications. The draft raises questions about project cost, inverter architecture, storage sizing, grid stability, procurement, skills, safety and the way developers plan projects after 1 July 2027.

What the CEA Draft Proposes

The draft proposes that renewable generating stations covered by the future framework and commissioned after 1 July 2027 should have at least 15% of inverter capacity with grid-forming capability. It also proposes grid-forming capability for the power conversion systems of BESS.

For applicable ground-mounted solar and onshore wind projects, the draft also proposes co-located energy storage sized at not less than 10% of the plant's installed capacity, with a minimum two-hour duration initially. The proposed duration requirement increases in later periods, including a four-hour window from July 2029 to June 2031 under the draft trajectory.

These Are Proposed Rules, Not Final Requirements Yet

The most important qualification is that this is a draft regulatory proposal. Stakeholders should not describe the provisions as already-final operating law. The consultation deadline is 4 October 2026, and the final framework may retain, modify or clarify individual provisions.

What Is a Grid-Forming Inverter?

Most conventional renewable inverters have historically operated as grid-following devices: they synchronise to an existing grid voltage and frequency reference. Grid-forming controls are designed to establish or support voltage and frequency references and can contribute to system stability as inverter-based resources become a larger share of the power system.

Why India Is Considering Grid-Forming Capability

As conventional synchronous generation forms a smaller proportion of the generation mix at certain times, the grid can have lower physical inertia and different fault-level and stability characteristics. High penetration of inverter-based resources therefore requires new approaches to frequency, voltage, fault response and system strength.

Why the 15% Requirement Matters

A minimum grid-forming share would make advanced inverter-control capability a project-design requirement rather than an optional demonstration technology for affected projects. Developers would need to consider equipment selection, plant controls, interoperability, commissioning tests and compliance earlier in project development.

Why Mandatory Storage Changes Project Economics

A storage requirement changes the renewable project from a generation-only asset into a combined generation-and-flexibility system. Developers must evaluate battery power, energy duration, degradation, augmentation, thermal management, fire safety, warranties, controls, auxiliary consumption and replacement assumptions—not only module or turbine economics.

MW and MWh Must Not Be Confused

A requirement expressed as a percentage of plant MW describes battery power. Duration determines energy capacity in MWh. For example, a 10 MW battery operated for two hours represents 20 MWh before considering usable-energy and operating constraints. Project economics therefore depend on both power and duration.

Potential Impact on Rajasthan

Rajasthan's large solar and wind pipeline means any final national requirement could have disproportionate relevance to the state's developers, EPC contractors, OEMs, transmission planners and workforce. Projects with high renewable concentration may also benefit from technologies that improve system strength and time-shift energy, although costs and optimal locations will vary.

Opportunity for the Rajasthan BESS Ecosystem

If the final rules drive large-scale co-located storage, the opportunity extends beyond battery-cell supply. It includes PCS and inverter systems, EMS and controls, containers and thermal management, fire detection and suppression, transformers and switchgear, integration engineering, testing, commissioning, O&M, diagnostics, insurance and risk engineering.

Skills and Testing Will Become Critical

Grid-forming systems cannot be treated as a simple equipment substitution. Developers and utilities will need expertise in control interactions, plant modelling, grid studies, commissioning and performance verification. Training institutions and engineering teams in Rajasthan should begin building capability before requirements take effect.

Safety Must Scale With Storage

Rapid BESS deployment must be accompanied by rigorous engineering around cell chemistry, thermal runaway, ventilation, detection, suppression, isolation, emergency response, spacing, enclosure design, BMS operation and site-specific risk assessment. Mandatory storage without equally strong safety and O&M capability would create avoidable risk.

Questions the Final Framework Should Clarify

Industry will need clarity on applicability to projects already under development, treatment of hybrids, storage technology neutrality, testing protocols for grid-forming performance, operating obligations, augmentation and replacement, connectivity studies, treatment of captive/open-access projects, and how compliance interacts with state and central grid codes.

What Developers Should Do Now

Developers should map projects against proposed commissioning dates, engage inverter and BESS suppliers on grid-forming roadmaps, model storage cost and duration scenarios, review land and interconnection implications, strengthen fire and electrical safety specifications, and follow the final CEA notification rather than relying on summaries of the draft.

What Rajasthan's Industry Should Watch

The final text after consultation; detailed technical standards and testing requirements; OEM product availability; storage procurement and financing; RERC and transmission-utility implementation; project-specific connectivity requirements; and whether future tenders begin embedding grid-forming and storage obligations ahead of broader deadlines.

Key Takeaways

The CEA draft marks a shift from renewable capacity addition toward renewable integration. It proposes at least 15% grid-forming inverter capability for affected future renewable plants, grid-forming PCS for BESS and co-located storage for applicable ground-mounted solar and onshore wind projects. For Rajasthan, the implications span project economics, technology, skills, safety and grid planning.

Frequently Asked Questions

Are the CEA grid-forming and storage requirements final?

No. The September 2026 provisions discussed here are draft proposals subject to consultation and finalisation.

What percentage of renewable inverter capacity is proposed to be grid-forming?

The draft proposes at least 15% grid-forming inverter capacity for affected renewable generating stations commissioned after 1 July 2027.

Does the draft propose mandatory storage?

For applicable ground-mounted solar and onshore wind projects, the draft proposes co-located ESS capacity linked to plant size and specified duration requirements.

Why does grid-forming capability matter?

It can help inverter-based resources support voltage, frequency and broader system stability as the share of conventional synchronous generation declines at certain times.

Why is Rajasthan especially relevant?

Because Rajasthan has a very large and growing concentration of solar and wind capacity, making renewable-integration requirements particularly important for developers, grid planners and the local supply chain.

REAR Perspective

The proposed framework should be viewed as part of India's transition from simply adding renewable megawatts to operating a power system with very high inverter-based generation. Rajasthan should prepare not only with more projects, but with stronger engineering capability, storage safety, testing infrastructure, workforce skills and coordination between developers, OEMs, utilities and regulators.