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In March 2026, the Central Electricity Authority released the National Generation Adequacy Plan (NGAP) for 2026-27 to 2035-36. It is 1 of the astir broad powerfulness readying exercises, combining least-cost optimization, dispatch modelling and probabilistic reliability investigation to make a procreation premix for 2035-36. It projects a full capableness of implicit 1,100 GW, with astir 70% non-fossil capableness and astir 174 GW/888 GWh of storage.
An important output is the summation of 87.2 GW of ember capableness betwixt 2025-26 and 2035-36. Given the standard and its semipermanent implications, an important question arises: tin this planned ember capableness beryllium replaced with further renewable vigor (RE) and retention portion maintaining the aforesaid adequacy and reliability standards?
The authors undertook a deterministic stress-test modelling workout to measure whether the incremental vigor and adequacy publication expected from the planned 87.2 GW ember summation could beryllium approximated done further renewable vigor and retention nether simplified accent conditions.
Indicative modelling suggests that an further 191 GW of solar, 51 GW of wind, 29 GW of artillery vigor retention systems, and 9 GW of pumped retention whitethorn beryllium required to approximate this publication nether the deterministic assumptions used. This would summation wide RE installations to astir 1,006 GW, compared with astir 764 GW successful the NGAP pathway.
However, dissimilar NGAP, the workout does not measure full-system interactions crossed the full procreation fleet and should truthful beryllium interpreted arsenic a targeted stress-test workout alternatively than a full-system optimization outcome.
Indicative aboriginal results suggest that specified an RE pathway could trim strategy costs by implicit ₹1.4 lakh crore per year, adjacent nether blimpish assumptions connected overbuild and retention requirements needed to negociate accent periods specified arsenic anemic upwind conditions. These estimates stay delicate to assumptions regarding substance prices, retention costs, financing conditions and strategy integration requirements. If ember substance terms escalation is considered, the divergence becomes larger implicit the plus lifecycle.
Further, arsenic India imports 25-30% of its coal, substance terms hazard implicit a 20-25 twelvemonth plus beingness cannot beryllium ignored. In contrast, RE procreation reduces vulnerability to recurring substance proviso risks and shifts the outgo operation toward upfront concern and strategy integration.
An important facet of NGAP is its accent connected adequacy and reliability. Therefore, if RE is deployed arsenic an alternate to coal, the strategy indispensable reliably conscionable request crossed each clip blocks. Therefore, 3 strategy constraints go pivotal.
First, retention continuity is essential. Storage indispensable stay disposable crossed consecutive request cycles. If renewable output is anemic for respective days, retention levels tin fall. Once depleted, the strategy becomes exposed and tin pb to request proviso gaps.
Second, charging sufficiency indispensable beryllium ensured. Storage tin lone discharge what has been charged. With round-trip efficiencies of 80-88%, renewable procreation indispensable transcend request successful bid to some service load and recharge. This creates a request for surplus capableness and/or overbuild, on with periodic curtailment. Testing strategy behaviour crossed consecutive days shows that adequacy depends not lone connected installed capableness (MW), but besides connected disposable stored vigor (MWh).
Third, adjacent erstwhile yearly vigor is sufficient, shortfalls tin look successful circumstantial clip windows, for example, during the modulation from star to non-solar hours oregon extended low-wind periods resulting successful artifact level deficits.
NGAP already captures galore of these dynamics done blase probabilistic modelling and chronological dispatch analysis. However, the published results bash not marque it casual to measure however the strategy behaves nether explicit coal-replacement accent scenarios, peculiarly crossed consecutive periods of debased renewable output oregon retention depletion.
Deterministic accent tests tin complement the NGAP model by making these strategy behaviours much transparent and interpretable. This would not regenerate NGAP’s methodology, but could amended transparency astir cardinal readying choices. It would besides assistance found whether the identified ember capableness reflects binding strategy constraints specified arsenic retention duration, transmission readiness oregon deployment timelines, oregon whether outcomes are delicate to assumptions that could germinate implicit time.
Given that thermal plants typically necessitate 6-8 years to beryllium commissioned, portion retention systems tin often beryllium deployed faster, evaluating alternatives transparently becomes progressively important. Episodes of El Nino and La Nina interaction powerfulness request and hence reserve capacityplanning to mitigate deficits, wherever thermal, retention and hydro tin play a profound role, indispensable relationship forsuch clime impacts.
For excessively long, India’s RE targets person been framed arsenic portion of an vigor modulation story. Instead, RE, retention and thermal targets should beryllium acceptable based connected what minimizes costs to consumers portion inactive maintaining adequacy and strategy reliability nether uncertainty.
NGAP’s rigorous methodology has already provided a beardown foundation. The adjacent measurement is to trial alternate pathways nether accent conditions to place the way which tin champion maximize affordability, reliability and vigor security.
(Alexander Hogeveen Rutter is an autarkic vigor adept with acquisition successful assets adequacy planning, and an Emergent Ventures grantee focused connected vigor policy. Martand Shardul is erstwhile Policy Director (India) astatine GWEC and a erstwhile Fellow astatine TERI. All views are personal)
