In May, China's hydropower output has increased significantly compared with April amid heavy rainfall in key production areas in the south.
May's hydropower generation totaled 85.8 TWh, a 13.3% rise from April, data from the National Bureau of Statistics showed.
However, it still fell short of expectation. Despite in a huge amount as a whole, the precipitation is quite uneven.
Taking Yunnan province – one of key hydropower production regions in southwestern China – as an example, the drought situation continued until the first half of May. The Ministry of Emergency Management even launched a national Level-IV emergency response on May 18 to the severe drought in Pu'er and Yuxi cities. It was not until mid-June that most of regions in Yunnan witnessed rainfalls, but mostly rainstorms, which were hardly used to generate electricity.
Therefore, China's May hydropower generation was still 16.5% lower than the same month last year, and the decline accelerated by 7.3 percentage points from the previous month.
From January to May, the year-to-date output totaled 355.8 TWh, an 11.3% fall year on year, which was an increase of 1.9 percentage points from January-April.
Among all major hydropower provinces – Sichuan, Yunnan, Hubei, Guizhou, and Guangxi – only Sichuan and Yunnan saw a month-on-month increase in May, while the remaining provinces showed a downward trend, with the largest decline in Guangxi reaching 26.64%.
The top provinces for hydropower generation in May were: Sichuan, Yunnan, Hubei, Qinghai, Hunan, Guizhou, Guangxi, and Gansu, generating a total of 70.68 TWh, accounting for 82.38% of the country's total.
In June, as China's southern regions entered the monsoon season earlier than previous years, precipitation will likely further improve. This can also be seen from the water level of the Three Gorges Hydropower Station. Since June, the storage volume has increased significantly, even more than the same period last year in mid-June.
However, too much rainfall will result in floods above the alarm level, and it will, on the contrary, curb hydropower output, as hydropower stations will take flood prevention as a top priority by lowering storage volume to prepare for possible flood peaks.
Since the beginning of June, 52 rivers in eight provinces saw the flood rise above the alarm levels. In Hubei, the northwest, southwest, and southeast regions were hit by heavy rainstorms. The river water level rose rapidly and hydropower reservoir exceeded alarm levels, forcing all 285 hydro stations in the province to take an all-out effort to discharge.
In this case, upstream cascade hydropower stations will store water and reduce outflow, so that power generation will be curbed.
As the flood prevention is the first priority this month for most stations, sufficient precipitation will be difficult to convert into power. Hydropower generation will be less likely increase significantly in June.
(Writing by Alex Guo Editing by Tammy Yang)
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