New Delhi, July 17 -- For the first time, combined wind and ground-mounted solar generation briefly crossed 100 gigawatts (GW) on India's power grid this week. The milestone comes as India races to add clean energy while grappling with the transmission and flexibility challenges of absorbing intermittent power.

At 12:05pm IST on 13 July, the two sources generated a record 103.7GW, according to data from Grid Controller of India Ltd. Renewable power also reached a record 42.79% of all-India demand at 12:29pm that day.

The 100GW mark held for the next two days. Wind and solar generation peaked at 102.42GW on 14 July and 100.9GW on 15 July.

The surge comes as India races to add renewable capacity while confronting a more immediate problem...