Coal’s diminishing role in India’s electricity transition

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Analysis - Coal’s diminishing role in India’s electricity transition (PDF)

Methodology

Methodology to simulate power system operation

Model & scope: Ember’s PyPSA-India model, chronological least-cost dispatch model; one node per state; FY 2031–32, hourly (8,760).
Capacity: Exogenous & fixed (existing + pipeline with commissioning timelines+ policy targets aligned with NEP (if plausible)). No endogenous build.
Demand: Historical hourly shapes scaled to 20th EPS peaks and annual energy by state.
Costs & constraints: Marginal costs (actual where available, assumed for pipeline and new capacity) and unit limits (ramp, auxiliary, technical minimums; storage efficiency/SOC/charge-discharge).
VRE profiles: State-level hourly solar/wind from historical weather and observed production, consistent with spatial siting.
Interstate transfers: Fixed limits from Grid-India/NLDC, NEP 2031-32, and OpenStreetMap (AC from voltage/circuits; HVDC from published ratings).
Dispatch rationale: All-India least-cost dispatch, solved day-by-day with 2-hour look-ahead at an hourly resolution. Outputs reflect economic dispatch; real operations may diverge due to PPAs/market rules.

Full documentation can be found here

Annexure 1: Coal minimum generation calculation (2025)

The calculations below apply only to the three illustrative days shown in the dispatch figure (actual and modelled), and do not represent annual values.

Metric	Value
Net maximum generation from coal	170 GW
Auxiliary consumption	8%
Minimum Technical Load (MTL)	55%
Gross maximum generation	185 GW (= 170 / (1 – 8%) ≈ 184.78)
Gross MTL @ 55% of 185 GW	102 GW (= 185 × 0.55 = 101.75)
Net MTL @ 55% of 185 GW	94 GW (= 102 × 0.92 ≈ 93.84)

Annexure 2: Coal minimum generation calculation (Modelled 2031)

The calculations below apply only to the three illustrative days shown in the dispatch figure (actual and modelled), and do not represent annual values.

Metric	Value
Net maximum generation from coal	190 GW
Auxiliary consumption	8%
Minimum Technical Load (MTL)	55%
Gross online at peak	206.5 GW (= 190 / (1 – 8%) ≈ 206.52)
Gross MTL @ 55% of 206.5 GW	113.6 GW (= 206.5 × 0.55 ≈ 113.58)
Net MTL @ 55% of 206.5 GW	104.5 GW (= 113.6 × 0.92 ≈ 104.51)
Midday coal generation (observed)	112 GW
Midday gap above MTL	7.5 GW (= 112 − 104.5 = 7.5)

Acknowledgements

Contributors

Ember: Tito Das, Dave Jones, Ardhi Arsala Rahmani, Reynaldo Dizon, and Chelsea Bruce-Lockhart.

Cover image

Aerial view of the Hambach open-pit coal mine operated by RWE in Niederzier and Elsdorf, North Rhine-Westphalia, featuring solar panels installed within the mining area.

Credit: hansenn / Getty Images Plus