By Ye Ruolin and Yuan Ye *
SHANGHAI (IDN | China Dialogue) — With few coal reserves to call its own and winter rains too erratic to rely on hydropower, central China’s Hunan province had long faced frequent electricity blackouts, an annoyance to residents and a hindrance to economic growth. So, when an ultra-high voltage power line was approved in 2015, hopes were high.
The new Ultra-High Voltage (UHV) connection would run all the way from the energy-rich Jiuquan region in northwestern Gansu province, and bring in enough coal, wind, and solar power to answer a quarter of Hunan’s energy needs.
At the time, a confident employee of Hunan’s provincial grid operator told state-owned news outlet Economic Information Daily that “after the line is built, we expect Hunan will not have any power shortages for the next 10 years.” At a cost of 26 billion yuan (US$3.9 billion), the 2,383km Jiuquan–Hunan line went into operation in 2017, becoming part of China’s growing UHV network.
In December, when a cold front hit parts of China, that confidence was put to the test. While factories were already running at full tilt to compensate for Covid-19-related shutdowns elsewhere in the world, people turned up their heating – which in the southern half of China often runs on electricity – as temperatures plunged. Hunan authorities predicted an electricity shortage of 3 to 4 gigawatts, or about 10%, for the winter peak season. Apparently unable to increase supply, they reined in demand instead, turning down thermostats in government offices, switching off street lamps, and forcing companies to halt production under rolling outages.
In a report analysing how such power rationing could have been avoided, China Energy News, an outlet overseen by party newspaper People’s Daily, pointed to the persistently underperforming Jiuquan–Hunan UHV line. An anonymous Hunan-based electricity expert told the outlet that it had always been operating at just slightly more than half its planned capacity, leading them to conclude Hunan couldn’t depend on other provinces.
“A relative afar is less use than a close neighbour,” the expert said. “When solving energy shortages, you can only rely on local power sources.”
It was a chilling repudiation of the country’s ambitions for UHV, a technology full of country-spanning potential that has so far been hampered by a Balkanised power system, technological incompatibilities with green energy, and questions of financial feasibility in a future liberalised market.
Expensive and difficult to build, UHV lines transmit energy at 800,000 volts and above, double the voltage of conventional high-voltage lines, allowing them to transmit up to five times more electricity at minimal energy loss along the way. They are seen as the answer to China’s energy imbalance: whereas energy sources, including wind and sunshine, are mostly found inland, much of the country’s population lives toward the coast.
UHV lines should also enable China to rely more on renewable energy, necessary if the country is to make good on President Xi Jinping’s pledge to be carbon neutral by 2060. Piping in power from far away can mitigate the unpredictability of wind and solar energy, making UHV key to combating climate change.
China has been at the forefront of UHV technology for over a decade, with its first such line going into operation in 2009 and a current network of 31 lines. Its building spree shows no signs of slowing down. In a plan published on 1 March, the country’s largest grid operator State Grid said it wants to build another seven lines in the next five years.
But that enthusiasm belies continued disappointment. According to China Energy News, many UHV lines are running at just a bit more than 60% of their design capacity due to technological limits and conflicts of interests between power generators, grid companies and local governments. This figure is an eyesore for the central government. In report after report, the National Energy Administration has implored grid companies to do better.
Shanghai’s distant relative
On the outskirts of Shanghai, amid farm fields and wetlands and within earshot of the sea, stands the city’s sole long-distance UHV converter station, a colorless collection of buildings surrounded by a constantly buzzing forest of metal poles and coils. Zhang Dezhen, an engineer at the station, waves his finger in the direction of the wires that sweep up to soaring towers and disappear into the foggy distance. He explains they connect Shanghai with the Xiangjiaba hydropower dam, 1,900km away in southwestern China’s Sichuan province.
The line, with a maximum capacity of 6.4 gigawatts, can supply up to 40% of the city’s electricity. “This is the most important line in Shanghai’s power system,” Zhang tells Sixth Tone. According to State Grid, the hydropower from Sichuan allows Shanghai to burn 1.3 million fewer tons of coal per year, saving about 2.7 million tons of carbon dioxide emissions annually.
But this, too, could be increased. Zhang says the Xiangjiaba–Shanghai line only operates at full capacity from April to November, warm months when air conditioners drive up energy demand. During Shanghai’s usually mild winters, the State Grid limits the amount of power the UHV line carries. “(We) have to consider the stability of Shanghai’s grid system,” Zhang says. If the UHV line is responsible for too much of Shanghai’s total power supply, any glitch – such as weather damage anywhere along the wire’s trajectory – could crash the city’s grid. “It’s about not putting all the eggs in one basket,” he says.
In early January, the same historic cold spell that earlier overwhelmed Hunan threatened the stability of Shanghai’s power system. Zheng Qingrong, director of the demand response management center at State Grid subsidiary Shanghai Electric Power Company, tells Sixth Tone the company at the time predicted it would face tight supplies and had bought additional power from other provinces. Such purchases sometimes carry a markup, he says.
The city’s UHV line also brought relief. “This winter’s allocation was higher than last year’s,” says Zhang, the UHV engineer. “At the time local Shanghai power stations were already doing everything they could to produce at full capacity.” Though soaring demand in the city of over 24 million people caused some local loss of electricity from overloaded equipment, there was never a shortage.
A month later, the US state of Texas became an example of what can happen without such connectivity. The state famously runs its own grid, which isn’t linked up with the rest of the country. When a winter storm hit – potentially caused by the same climate change-linked phenomenon that caused the frigid temperatures in eastern China – the inability to import electricity was among the factors in the ensuing disaster, Zheng says. Over 4 million people lost power, and hundreds suffered carbon monoxide poisoning when they tried to stay warm by running their cars in their garages.
Further interconnectivity between provinces is the answer to help China’s grid weather the growing challenges posed by surging power demand and unpredictable climate, Zheng says. Currently, provinces are connected in six regional grids and trade some of their power, but mostly according to medium- and long-term contracts. The government aims to increase electricity trading and create a national market. At the same time, State Grid is striving to link more province-level regions to a UHV line – presently six are left unconnected – thus creating a nationwide “super grid.”
* This article was originally published on China Dialogue under a Creative Commons licence. But was first published on Sixth Tone. Ye Ruolin is a science and technology reporter at Sixth Tone. Yuan Ye is a features reporter at Sixth Tone writing about health, education, and the environment. [IDN-InDepthNews – 02 April 2021]
Photo: Power lines at Shanghai Fengxian Converter Station in January 2021 Credit: Wu Huiyuan/Sixth Tone.
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