Abstract
Coal generation ramps up after sunset to meet evening demand.
India’s solar growth has cut midday fossil generation, but output has risen after sunset, according to Ember.
A report published on 12 August said that fossil generation in India averaged 125 gigawatts (GW) at 1 p.m. in the first half (H1) of 2026, down from 135 GW at the same hour in H1 2023.
Fossil generation during non-sunny hours, however, averaged 168 GW in H1 2026, up 22GW from H1 2023. Generation peaked at 174 GW at 7 p.m., leaving a gap of almost 50 GW between the midday low and evening peak.
The report added that solar supplied 10% of global electricity in H1 2026, up from 8.9% in H1 2025 and 5.6% in H1 2023. Global solar generation also doubled from 769 terawatt-hours (TWh) in H1 2023 to 1,564 TWh in H1 2026.
Join Asian Power community
“Cheap daytime solar has become the most powerful transformative force reshaping power grids globally, growing faster than any other source of electricity,” said Kostantsa Rangelova, Global Electricity Analyst at Ember.
Solar met more than 25% of global electricity demand between 11 a.m. and 2 p.m. on the average day in H1 2026, but fell to near zero between 8 p.m. and 5 a.m.
Ember said India and the EU face a common challenge: insufficient storage to carry solar generation past sunset, leaving non-sunny hours dominated by fossil power.
India's solar growth has also increased pressure on the power system during periods of high solar output. On sunny days, coal generation can reach its technical minimum, forcing wind and solar curtailment to keep coal plants online at midday.
Ember said batteries could shift 34% of new daily solar generation into non-sunny hours in 2026, based on expected battery additions of 459 gigawatt-hours and solar growth in H1 2026.
The report said the figure represents a theoretical ceiling because not all batteries shift solar generation and some remain underused.
“Better market design and optimisation are needed to ensure batteries are used to their full potential,” Ember said.