India to mandate battery storage on new solar and wind farms from July 2027

From 1 July 2027 developers of new solar and on‑shore wind projects will be required to install co‑located battery storage equal to at least 10 % of the plant’s installed capacity, with a minimum discharge duration of two hours. The draft rules, prepared by the Central Electricity Authority (CEA), tighten further for projects commissioned between July 2029 and 2031, keeping the 10 % share but extending the minimum duration to four hours.

The storage mandate arrives amid a wave of renewable‑energy construction that has outstripped the pace of grid expansion. In the first quarter of the year, grid and transmission constraints accounted for nearly two‑thirds of renewable curtailments, totalling 300 GWh, according to the clean‑energy think‑tank Ember. Ember’s June analysis added that India needs around 10 GWh of battery storage “immediately” to stop curtailments when coal plants cannot drop below technical minimums.

Media additions

“Developers are adding battery storage to photovoltaic projects to attract buyers and reduce curtailments,” Santosh Sarangi, Secretary of the Ministry of New and Renewable Energy said last month. He noted that without storage, solar farms see curtailments during the hottest months and peak daytime hours.

India’s renewable‑energy surge is not limited to utility‑scale farms. The power sector added approximately 45 GW of installed solar capacity in the last financial year – an increase of over 40 % in a single year – while rooftop solar grew 47 % from roughly 17 GW to 25 GW in the same period. The country now ranks third globally in renewable‑installed capacity and has pledged to reach 500 GW of non‑fossil‑fuel capacity by 2030 and net‑zero emissions by 2070.

Why storage matters now

Rapid capacity additions have exposed the grid’s limited ability to absorb intermittent generation. Between April and June, India “curbed nearly 14 % of its solar power output” because surplus daytime generation clashed with a constrained transmission network. The draft rules therefore pair the 10 % storage requirement with a mandate that new projects include grid‑forming inverter technology – devices that can sustain voltage and frequency stability as renewable share climbs.

Both Oilprice and The Bridge Chronicle stress that the rule applies to “all new solar and on‑shore wind projects commissioned after July 1 2027”.

Digital backbone for compliance

Meeting the storage target will intersect with India’s parallel push for a digital public infrastructure – the India Energy Stack (IES). Announced for rollout in 2025, IES aims to create a federated architecture that assigns globally unique identifiers to every battery, meter, transformer and distributed‑generation asset. The platform will deliver “verifiable energy credentials” that prove a plant meets the 10 % storage rule without manual audits.

The pv‑tech analysis notes that India’s power sector currently operates on “multiple legacy systems … largely in isolation”, limiting traceability and transaction capability across distribution utilities, regulators and market operators. By standardising data exchange, open APIs and digital identities, IES is designed to lower entry barriers for startups, enable AI‑driven forecasting and support new market mechanisms such as peer‑to‑peer trading and virtual power plants.

A 12‑month proof‑of‑concept for IES is under way across Delhi, Gujarat, Andhra Pradesh, Uttar Pradesh and Mumbai, slated for FY 2026‑27. The pilot will test interoperability, data‑governance and stakeholder engagement, laying the groundwork for a national rollout.

Key elements of the storage mandate

• Applicable to all solar and on‑shore wind projects commissioned after 1 July 2027.
• Minimum battery capacity = 10 % of the renewable plant’s installed rating.
• Minimum storage duration = two hours for projects up to 30 June 2029; four hours for projects between July 2029 and 2031.
• Mandatory inclusion of grid‑forming inverter technology.
• Regulation drafted by the CEA and released as public draft rules.

What to watch next

• July 2027 – Commencement of the mandatory storage rule for projects coming online.
• July 2029 – Rule becomes stricter, extending the required discharge duration to four hours.