Asia's hydropower output fell 17.9% during the seven months through July, data from energy think tank Ember showed, while fossil fuel-fired power rose 4.5%.
In India, hydropower generation fell 6.2% during the eight months ended August in the sharpest decline since 2016.
In some cases, the hydropower output plunge was a result of efforts to conserve water and alter supply patterns.
"This trend of rapidly increasing wind or solar power generation in China could push for hydropower playing this critical regulating function, instead of operating whenever there is water," he added.
However, unlike hydro, wind power is harder to forecast and control, as it varies by local weather conditions.
Persons:
Carlos Torres Diaz, Rystad, Lauri Myllyvirta, Myllyvirta, Ember, Victor Vanya, Sudarshan Varadhan, Jamie Freed
Organizations:
REUTERS, Rights, National Bureau, International Energy Agency, Centre for Research, Clean Energy, Air, Thomson
Locations:
Qiaojia, Yunnan province, Ningnan, Sichuan province, China, Rights SINGAPORE, Asia, India, Vietnam, India's, Philippines, Malaysia, Ember