A man walks past a coal-fired power plant in Shanghai, China, October 14, 2021.

China's mostly coal-powered thermal generation ticked up 1.5% in 2024, official data showed on Friday, defying expectations that coal generation was peaking, although growth slowed to the lowest in nine years excluding the years of the COVID-19 pandemic.

The data highlighted the challenges in phasing out coal-fired power while meeting China's burgeoning need for power to fuel energy-hungry industries and the electrification of its economy.

Power sector emissions in particular are considered key to China's decarbonisation because of the wide-scale electrification of China's economy, typified by its shift to electric vehicles.

Thermal power generation, which comes mostly from coal while natural gas-fired power plants contribute a small portion, was 6.34 trillion kilowatt-hours (kWh) last year, up 1.5% on the previous year, according to the National Bureau of Statistics.

Peng Chengyao, director for China power and renewables at S&P Global Commodity Insights, said thermal generation came in higher than the consultancy's outlook at the beginning of the year because of higher-than-expected growth in power demand.

For December alone, however, thermal power output fell 2.6% on the year to 827 billion kWh.

Analysts also pinned full-year thermal power growth on weaker-than-expected hydropower output and a scorching summer that pushed up power demand.

Hydropower, China's second-largest power source, recorded its highest output growth in a decade, but that came off a low base as the sector recovered from a punishing drought in 2023.

"Around September, hydropower had a really sharp drop off ... It was just a little better than the severe drought conditions of the year before," said David Fishman, senior manager at consultancy the Lantau Group.

"That, combined with an extended late summer heat wave, meant that renewables were not enough to meet that incremental demand."