With shrinking water levels in the Yangtze river basin in the wake of the worst drought to hit the country in five decades straining water and energy resources across ten provinces in southern and central China, hydropower groups are lobbying the government to give the green light for suspended plans to build dams in the untapped upper reaches of the Brahmaputra, or Yarlung Tsangpo as it is known in Tibet.

“The power shortage means we have to build more hydroelectric dams,” Zhang Boting, deputy secretary-general of the Chinese Society of Hydropower Engineers, told The Hindu in an interview.

Mr. Zhang said China's hydropower development had, so far, focused on the Yangtze river — across which the Three Gorges Dam was built — and the Yellow river, in part due to concern voiced by countries downstream of China's western rivers.

But with rising power shortages, coupled with increasing international pressure on China to reduce its carbon emissions, the country could no longer afford to leave the Tsangpo's potential untapped, he said.

“Now, because we are facing pressure to save energy, we have to consider how we can build these dams, and find a way to cooperate with countries in the lower reaches,” he said.

In November 2010, China began damming the Yarlung Tsangpo for the first major hydropower project in Tibet, at Zangmu. The first set of generators at the 510-MW project will come into operation in 2014.

Zangmu is the only one of at least 28 proposed dams on the Yarlung Tsangpo that has been approved. “We put in place a dam in Zangmu because Tibet is in dire need of energy,” said Mr. Zhang. “But this project is an exception. We do not yet have in place a comprehensive plan for the development of other dams on the river.”

Mr. Zhang expressed confidence that in spite of opposition from some non-governmental organisations, it was only a matter of time before more hydropower projects were approved in light of the growing power crisis.

Power shortages have been particularly evident this year as a result of the drought across the Yangtze river delta. The State Grid, China's national electricity distribution company, has estimated this summer's electricity deficit at 40 Gigawatts, the highest since 2004.

China's hydropower companies say one single dam on the Brahmaputra — at its “Great Bend”, where it begins its journey towards India — could bridge that gap. Sinohydro, a state-owned hydropower company, has detailed on its website a proposal for a 38-gigawatt plant at Motuo.

Mr. Zhang said the dam on the great bend could save up to 100 million tonnes of coal. But considering the difficult terrain, and the more than 1,000-metre fall of the river, he said the project would pose technological barriers.

However, other dams on the Yarlung Tsangpo's upper reaches were feasible. “The technology is sufficient, except in the U-turn of the Yarlung Tsangpo where it is difficult to put in equipment,” he said.

Mr. Zhang ruled out any diversion of the water, stressing that India would not be affected by the run-of-the-river power generation projects.

“Countries in the lower reaches will feel anxieties, but there will be no negative impact downstream,” he said. “I believe that India can benefit from our development of the Yarlung Tsangpo. The key thing is how we can cooperate on using the water.”

But regardless of India's concerns, he said, it was a question of when — and not if — the projects could go ahead. “China has come to consider this issue a little late,” he said. “But to save energy, we have to tap these rivers.”