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China’s Hydro Potential And UHV Transmission: John Kemp

John Kemp, Reuters – Wednesday November 12 2008

–John Kemp is a Reuters columnist. The opinions expressed are his own–

LONDON (Reuters) – China has two related (but somewhat distinct) power problems:

(1) The country is struggling to generate enough power overall as price controls encourage wasteful use of cheap electricity. China is unable to mine enough coal or transport it in sufficient quantities to meet demand, while the enormous volume of coal burning generates massive pollution.

(2) China suffers regional power shortages when generation drops in one province or region and the lack of long-distance power transmission capacity means that power cannot be routed in from other regions where there is surplus capacity.

The country has six distinct regional electricity grids – five managed by the massive State Grid Corporation of China (SGCC), and a sixth managed independently by China Southern Grid Corporation covering the provinces of Guangdong, Guangxi and Guizhou. Even within these grids, power transmission capacity is limited, and the links between them are weak.

The central government has made creation of a unified national grid system a top economic priority to improve the efficiency of the whole power system and reduce the risk of localised shortages. It will also enable the country to tap the enormous hydro potential from western China to meet booming demand from the eastern coastal provinces.


The main problem is voltage drop when power is sent over very long distances from one region of the country to another. But SGCC believes long distance inter-regional transmission will be possible by using ultra-high voltages (UHV) of 800kV, based on an extension of technology already in use in other parts of the world.

Following research and testing, SGCC has announced construction of the first long-distance UHV line from Sichuan, which is rich in hydro-electric potential, to the eastern load centre of Shanghai.

Shanghai already receives hydro-electric power from the massive Three Gorges Dam on the Changjiang (Yangtze) at Sandouping in Hubei province. But the new DC 800kV UHV line would enable it to receive power from twice as far west from the Xiangjiaba dam on the Jinsha river (a tributary of the Changjiang much further upstream).$file/Xiangjiaba-Shanghai_176x268.jpg

(For more details see

Xiangjiaba will have total generating capacity of 6,400 MW. When completed, the nearby Xilodu Dam will add a further 12,600 MW (about 55 percent of the size of the planned Three Gorges output), making it the world’s third-largest hydro-electric dam, ranking after the Three Gorges and Brazil’s Itaipu.

Xilodu and Xiangjiaba are two of a series of massive new hydro projects that the government plans in south-western and western China to take advantage of the massive run off from the Himalayas and the Tibet plateau.

SGCC plans to bring a single pole of the Xiangjiaba-Shanghai line into commercial operation within two years (2010) and the second pole a year later (2011). SGCC plans to complete a total of 10 UHV projects by 2015 and 15 by 2020 (see

In most cases, these will bring power from massive new hydro facilities in south-western China to the industrial and residential centres of the east.


China has massive untapped potential for generating hydro-electric power. The government’s official survey data show the country could theoretically generate 694 GW from hydro sources, of which about 541 GW is technically feasible and 401 GW is economically feasible (see table

By end-2005, the country had installed 130 GW of hydro capacity. But there was still another 270 GW of capacity which would be both technically and economically feasible to develop. Untapped economically feasible hydro potential is equivalent to 4.5 times the peak summer power demand of Guangdong province – the site of China’a massive export-oriented and often foreign-invested manufacturing hub.

Two-thirds of the untapped hydro potential is located in the two neighbouring provinces of Yunnan and Sichuan in the south-west, which could each generate an additional 87 GW of power from hydro sources. The key point is both provinces could be linked by UHV transmission lines to the major load centres at Guangdong on the south coast and Shanghai-Zhejiang on the east coast.

Dams and power lines are already under construction. Provided both technologies can be mastered, south China’s power problems could be solved within the next 4-7 years.


There are much smaller amounts of untapped feasible potential in the far west in Xinjiang (13 GW) and Qinghai (10 GW), though both provinces are largely empty and a long way from either industry or population centres.

The biggest hydro potential of all is in Tibet which could theoretically generate 201 GW alone but where conditions are so challenging that only 110 GW is technically feasible and only 8 GW would make any economic sense.

The untapped potential in the rest of China is much more limited – amounting to no more than 66 GW in total. Some 22 GW is located in other southern and central provinces – leaving about 40 GW of untapped but feasible potential across the rest of northern and north-eastern China.

Northern and north-eastern China relies heavily on thermal generation from the local coalfields. But the skewed distribution of untapped hydro resources suggests the country has substantial capacity to bring on new clean and cheap power in the south, while northern China will remain reliant on increasingly expensive and polluting thermal generation.


South China from the Changjiang valley down to the South China Sea was the first part of the economy to liberalise in the 1980s and 1990s and is home to much of the country’s most modern and often foreign-invested manufacturing industries. Northern and north-eastern China’s older industrial base has fallen behind, remains focused on the domestic economy and has suffered relative decline.

Top officials have repeatedly urged northern provinces to make greater efforts to modernise. But the distribution of hydro reserves suggests this divide could be reinforced in future. It is the northern provinces, not the south, that have been plagued by coal shortages and power rationing this summer.

It seems likely the cost of power will need to rise substantially over the medium term (2-5 years) to curb wasteful consumption and slow the rate of growth in electricity demand. In theory, the government could raise power costs by a similar amount across the whole of China in the interests of inter-regional equity.

But given that the power shortages are already in the north, while much of the new hydro potential is in the south, it is possible that energy charges will rise further and faster in the north, accentuating the existing regional imbalances further.

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