How Swapping Stations Solve India's Solar Surplus Problem

India has too much electricity at noon and not enough at 7 PM.

In 2025, India added 38 GW of new solar capacity, a national record [1]. Between May and December of that same year, the grid operator switched off 2.3 TWh of solar generation, enough to power half of India's entire 50,000-bus electrification ambition for a full year [2], because the grid had no place to send it. Solar developers received an estimated ₹575–690 crore ($6.05–7.26M) in compensation for energy they generated and were paid to discard [2]. That same evening, coal plants ramped up to fill the gap.

This is the duck curve. It deepens every year as solar capacity grows faster than the grid's ability to absorb it.

The Standard Solution: Raising Electricity Costs for Everyone

The textbook response to the duck curve is on-site battery storage at solar farms: absorb the midday surplus, release it in the evening.

The problem is what it costs, and who ultimately pays.

A utility-scale solar farm in India generates electricity at a levelised cost of approximately ₹2.3–3.6/kWh ($0.024–0.038/kWh), among the lowest in the world [3]. DISCOMs pay a Power Purchase Agreement (PPA) tariff of approximately ₹2.5–3.0/kWh ($0.026–0.032/kWh) [4]. The margin is thin by design. Solar projects in India are financed on long-term PPA certainty, not per-unit spread.

Adding on-site battery storage to manage curtailment costs an additional ₹0.6–1.5/kWh ($0.006–0.016/kWh) on top of that [5]. On many projects, this pushes the all-in cost above the PPA tariff entirely, making storage economically non-viable without government Viability Gap Funding. The developer is not choosing between a fat margin and a thin one. He is choosing between a viable project and an unviable one.

But there is a consequence that goes beyond the individual developer. When battery capex is amortised over units of electricity sold, the PPA tariff must rise to cover it. Higher PPA tariffs mean higher electricity costs across the grid, borne by DISCOMs and ultimately passed to consumers. Every rupee of farm battery capex that India's solar sector is forced to add is a rupee that makes electricity more expensive for the country.

Swapping stations, connected via the same distribution grid, absorb part of that same midday surplus, paid for entirely by fleet operators. To the extent that our energy inventory reduces the solar surplus a farm would otherwise need to store on-site, it proportionally reduces the farm battery capex that must be amortised into the PPA tariff. We are not eliminating farm batteries. We are reducing the need for them, and in doing so, contributing to keeping electricity costs lower for India. The swapping stations sit where the vehicles are: logistics hubs, depot endpoints, route turnarounds. Not where the sun is. But connected via the grid, they perform the same absorption function, without a rupee of the developer's capital.

Why EVs Should Charge During the Day, Not at Night

The received wisdom is that EVs charge at night, off-peak, when electricity is cheap.

For a coal-dominated grid, this was correct. Coal runs continuously; nighttime charging absorbed its surplus cheaply. For a solar grid, it is precisely wrong.

The surplus is at noon. By evening, solar has gone, coal is ramping to serve peak demand, and the grid is under maximum stress. The gap between midday and evening electricity prices in India widened fivefold between 2019 and 2025, from ₹0.14/kWh to ₹0.71/kWh [6]. Nighttime EV charging adds demand at the worst possible moment. Daytime charging absorbs energy that is otherwise being switched off.

Our swapping network charges its energy inventory during solar surplus hours. The energy stored powers vehicles at any hour, day or night. The inversion is structural, not a scheduling choice.

The Coal Constraint That Makes This Permanent

India's coal fleet cannot step aside for solar. The CEA's Indian Electricity Grid Code 2023 sets a Minimum Technical Load of 55% for thermal plants, meaning a 500 MW plant cannot safely run below 250 MW [7]. The ramp rate is approximately 1% of rated capacity per minute, so that same plant can only change output by 5 MW per minute [7].

Coal is already running near this floor during peak solar hours. When solar drops in the evening, coal cannot ramp fast enough. GRID-India has documented an evening ramp requirement of approximately 60 GW that must be absorbed in hours [8]. India's Power Ministry has confirmed coal capacity will be held at approximately 307 GW through 2035 [9].

The duck curve deepens before it narrows. This is the grid India's commercial fleets will operate within for the next decade.

What the Energy Inventory Does

Every swapping station maintains an energy inventory, a pool of fully charged batteries staged for immediate deployment. We control when the station charges and at what rate. This is charge tokenisation: the decoupling of when energy is absorbed from when a vehicle arrives. The station draws a constant, flat load, scheduled during solar surplus hours.

Function	Grid effect
Charges during solar surplus hours	Absorbs generation that would otherwise be curtailed
Constant, flat load at all times	Predictable, DISCOMs and grid operators can plan around it
No draw during evening peak	Reduces coal ramp burden at the moment of highest grid stress
Energy stored in mobile form	Serves vehicles day or night, regardless of solar hours
Paid for by fleet BaaS subscriptions	No grid subsidy or viability gap funding required

NITI Aayog has proposed that all future renewable installations be paired with balancing capacity [10]. Our swapping network delivers that balancing function at the demand end, without a rupee of grid-specific capital, and without being physically co-located with any generation asset.

Less Lithium. Better Utilisation.

A swappable bus carries 64% less total system lithium than a fixed-battery equivalent, even after accounting for station energy inventory. The energy inventory is not idle capital. It is absorbing solar surplus, staging energy for deployment, and turning over continuously as vehicles swap in and out. The oversized battery problem and why swapping eliminates it is examined in full.

What India Is Already Paying for Storage

The grid needs two things to manage rising solar generation: storage at the supply end, and flexibility at the demand end. They are not substitutes. They are complements. India is investing heavily in the supply end.

The Government of India has committed approximately ₹91,000 crore ($9.58B) of Viability Gap Funding for 43.2 GWh of stationary Battery Energy Storage System (BESS) capacity [11]. An additional 30 GWh tranche, mobilising ₹33,000 crore ($3.47B) of investment, was approved in June 2025 [12]. Yet between 2022 and May 2025, only about 219 MWh of the 12.8 GWh auctioned reached operation, less than 2% of the committed capacity [11].

The economic strain is real. The lowest discovered tariff for 2-hour BESS in 2025 was around ₹1.48 lakh per megawatt per month, against a benchmark cost of roughly ₹2.3 lakh per megawatt per month that analysts say reflects actual project costs [13]. Three quarters of the awarded 2-hour BESS capacity in 2025 sits in what analysts classify as the "risky" tariff category, where developers committed to tariffs below what is likely to be economically viable to deliver [13]. The auctions are happening. The operational megawatt-hours are not following.

This makes the demand-side answer more valuable, not less. Swapp Stations provide flexibility on a different cost basis. They are financed by fleet operators, deployable in months, and do not depend on subsidy to be viable. As stationary BESS struggles to scale at the pace the grid needs, distributed demand-side flexibility delivered through swapping networks becomes part of how India closes the gap.

The Close

India will keep adding solar panels. The duck curve will keep getting fatter. Pressure on solar developers to add batteries will keep rising. That pulls PPA tariffs upward. Electricity costs more for everyone. Left unchecked, clean energy risks the same cost spiral that made crude oil a geopolitical weapon. Swapp Stations interrupt this chain. Every station absorbing midday surplus reduces the farm battery demand that would otherwise be amortised into the national tariff. The architecture that makes this possible is charge tokenisation. In doing so, Swapp Stations sit at the intersection of mobility, energy storage, and solar generation, three industries that have never shared infrastructure.

The fleet is the entry point. The intersection is the endgame. Every solar panel India adds makes our network more valuable. That is not coincidence. This is what it looks like to engineer for India's reality, not against it. The discipline of Swadesi is where that philosophy is examined.

Sources & Citations

[1] Ministry of New and Renewable Energy (MNRE), Government of India. Press Information Bureau, March 2026. https://www.pib.gov.in/PressReleasePage.aspx?PRID=2250039

[2] Ember — Beyond Capacity: Why India's Power System Must Get Flexible, January 2026. Curtailment volume from GRID-India TRAS operational records. Compensation estimated at TRAS tariff range of ₹2.5–3.0/kWh applied to 2.3 TWh curtailed; paid from Deviation and Ancillary Service Pool Account maintained by GRID-India; cost socialised through consumer tariffs. Bus energy calculation: 50,000 buses × 200 km/day × 1.3 kWh/km × 365 days = 4.75 TWh/year; 2.3 TWh ≈ half of that. https://ember-energy.org/latest-insights/beyond-capacity-why-indias-power-system-must-get-flexible-to-harness-its-solar-potential/ Corroborated by: Observer Research Foundation (ORF) — India's Solar Expansion: From Capacity Addition to Integration Challenges, May 2026. https://www.orfonline.org/expert-speak/india-s-solar-expansion-from-capacity-addition-to-integration-challenges

[3] IRENA — Renewable Power Generation Costs in 2024, July 2025. India utility-scale solar LCOE at $0.038/kWh (~₹3.61/kWh). Most optimistic current estimate at ₹2.3–2.5/kWh from: India Energy & Climate Center (IECC), UC Berkeley — Plummeting Solar+Storage Auction Prices in India, September 2025. https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2025/Jul/IRENA_TEC_RPGC_in_2024_Summary_2025.pdf https://live-iecc-gspp.pantheon.berkeley.edu/resources/reports/plummeting-solarstorage-auction-prices-in-india

[4] Recent solar auction tariffs discovered as low as ₹2.48/kWh. Range of ₹2.5–3.0/kWh from MNRE/SECI tender records. Reported in: Mercom India, 2025–2026. https://www.mercomindia.com

[5] India Energy & Climate Center (IECC), UC Berkeley — Implications of India's Solar+Storage Auctions for 24/7 Clean Power, May 2025. Storage adder of ₹0.6–1.5/kWh implied from reverse-engineering of recent SECI and NHPC auction results. https://iecc.gspp.berkeley.edu/wp-content/uploads/2025/05/IECC-Implications-of-Indias-SolarStorageauctions-for-24-7-clean-power.pdf

[6] Outlook Business — Why India's Solar Grid Has a Flexibility Problem, May 2026. Midday-to-evening price gap from Indian Energy Exchange (IEX) market records. https://www.outlookbusiness.com/industry/india-solar-boom-grid-storage-duck-curve-explained

[7] Central Electricity Authority (CEA), Government of India — Indian Electricity Grid Code 2023. MTL 55% and 1% per minute ramp rate formalised under this code. https://cea.nic.in Reported in: Mercom India — CEA Calls for Lowering Thermal Load, February 2026. https://www.mercomindia.com/cea-calls-for-lowering-thermal-load-to-restrict-renewables-induced-duck-curve

[8] GRID-India (Grid Controller of India Limited) — Evening ramp requirement and frequency band violation data, FY2024-25. Reported in: Mercom India, February 2026. https://www.mercomindia.com/cea-calls-for-lowering-thermal-load-to-restrict-renewables-induced-duck-curve

[9] Reuters — India Has No Immediate Plans to Add Coal Power Capacity Beyond 2035, December 2024. Statement by Pankaj Agarwal, Secretary, Ministry of Power, Government of India. https://hk.marketscreener.com/news/india-has-no-immediate-plans-to-add-coal-power-capacity-beyond-2035-official-says-ce7d51ddda88ff26

[10] NITI Aayog, Government of India — Making India Atmanirbhar in Advance Battery Storage; NITI Aayog + RMI India — Need for Advanced Chemistry Cell Energy Storage in India, September 2022. https://www.niti.gov.in/making-india-aatmanirbhar-advance-battery-storage https://www.niti.gov.in/sites/default/files/2022-09/RMI-India-battery-report-v6-14092022.pdf

[11] IEEFA — India's Battery Storage Boom: Getting the Execution Right, 2025. ₹91,000 crore (~$9.58B) VGF for 43.2 GWh BESS; 12.8 GWh auctioned 2022–May 2025; 219 MWh operational by mid-2025. https://ieefa.org/resources/indias-battery-storage-boom-getting-execution-right

[12] JMK Research & Analytics — VGF Scheme Expands to Support 30 GWh of New Standalone BESS Development in India, June 2025. Ministry of Power approved expanded VGF for 30 GWh of BESS on 10 June 2025; ₹5,400 crore scheme expected to mobilise ₹33,000 crore of investment. https://jmkresearch.com/vgf-scheme-expands-to-support-30-gwh-of-new-standalone-bess-development-in-india/

[13] IEEFA — India's Energy Storage Push Gathers Momentum, but Tariff Viability and Financing Hurdles Loom Large, October 2025. 75% of allocated 2-hour BESS capacity classified as "risky" tariff category; lowest 2-hour BESS tariff in 2025 was ₹1.48 lakh per MW per month against ₹2.3 lakh per MW per month benchmark cost. https://ieefa.org/articles/indias-energy-storage-push-gathers-momentum-tariff-viability-and-financing-hurdles-loom