China puts first 2-tonne tethered balloon into operation

China's first two-tonne-class tethered balloon entered trial operation in a major power transmission project on Monday, providing a brand-new solution for transportation in power grid construction projects in high-altitude and ecologically sensitive areas, according to the State Grid.

The project is a massive ultra-high voltage (UHV) power transmission line that will carry clean energy from Xizang Autonomous Region in southwest China across thousands of kilometers to the Guangdong-Hong Kong-Macao Greater Bay Area in south China.

At the construction site, a large balloon with a diameter of 25 meters and a volume of 8,000 cubic meters slowly rose into the air.

As multiple mooring lines were simultaneously extended and retracted, the heavy construction materials suspended beneath the balloon were lifted off the ground and moved smoothly along a predetermined route toward the mountainous work site.

"This is our newly developed load-bearing tethered balloon. We have just completed a maximum load test of two tonnes at an altitude of 4,000 meters. Next, we will conduct a hoisting operation for power supply materials over a straight-line distance of 500 meters and a vertical drop of 120 meters," said Qin Jian, researcher at the Transmission and Transformation Engineering Technology Research Institute of the State Grid Electric Power Engineering Research Institute.

A heavy-lift tethered balloon involves launching a helium-filled balloon into the air and connecting it to the ground with one or several cables.

By adjusting the cable, the balloon's altitude and horizontal position are controlled to facilitate the transport of materials at high altitudes.

The balloon can travel up to 800 meters and carry a maximum load of two tonnes, with a positional accuracy of within 0.5 meters.

As the construction of new power grids is extending more rapidly into high-altitude, remote mountainous and ecologically sensitive areas, the transportation of materials for transmission projects has become a major challenge constraining construction progress.

Traditional road construction for transportation have long cycles and significant ecological disruption, while drones, though agile and flexible, face limitations in scenarios requiring heavy loads or prolonged continuous transport.

Tethered balloon transport technology effectively overcomes these difficulties.

"The construction section where this technology is applied is located in an uninhabited mountainous area at an altitude of over 4,000 meters. Many tower sites are situated on steep ridges inaccessible by road, making this the section with the highest altitude, most treacherous terrain and most challenging operations in the entire project. The two-tonne tethered balloon is better suited to high-altitude conditions characterized by thin air and strong winds, and its load capacity and stability can better meet transportation requirements," said Feng Tao, project manager of the State Grid Henan Power Transmission and Transformation Company.

China puts first 2-tonne tethered balloon into operation

In a special series on the Long March, a landmark event in the history of the Communist Party of China (CPC), the Huajiang Gorge Bridge in southwest China's Guizhou Province, the world's highest bridge, has demonstrated how the Long March spirit lives on.

This year marks the 90th anniversary of the Long March, a crucial turning point in Chinese history which contributed to the founding of the People's Republic of China.

In the special series Marching On, China Global Television (CGTN) correspondents retrace the original route of the Long March across several provinces to find out that the Long March's enduring spirit—marked by determination and resilience—continues to inspire generations of Chinese people as they pursue better lives through innovation and hard work.

In the first episode of the series, a CGTN correspondent kicks off the journey across rugged hills and river‑carved valleys in Guizhou Province, a key region along the Long March route. He stands in awe atop the Huajiang Gorge Bridge, completed in 2025 by local engineers and workers. With a deck soaring 625 meters above the river, the bridge is a testament to the enduring spirit of overcoming adversity.

The remarkable transformation of mountainous Guizhou—with a nearly twelvefold increase in per capita GDP over the past two decades—reflects the enduring legacy of the Long March spirit, which remains evident in all aspects of contemporary Chinese life.

The Red Army soldiers, forerunners of today's People's Liberation Army, began their strategic retreat in 1934. They endured raging rivers, snow-capped mountains, and vast grasslands—some marching as far as 12,500 kilometers—before finally reaching Yan'an in Shaanxi Province in 1936, where they established the CPC headquarters before the People's Republic of China was founded in 1949.

From barriers to bridges: unpacking Long March legacy in Guizhou