A 25-Metre Helium Balloon Is Hauling Two Tons of Power-Line Steel Up Tibet's Peaks
State Grid says China's first 2-ton-class tethered balloon has completed trial runs on the Tibet section of its Tibet–Guangdong ultra-high-voltage line, lifting tower parts onto 4,000-metre ridges without roads or cableways — a 'green air corridor' with uses well beyond power lines.
The machine State Grid showed off on Monday sits somewhere between a weather balloon and a whale: 25 metres across, 8,000 cubic metres of helium, tall as an eight-storey building. Its job is blunt — to float two tons of transmission-tower steel onto a ridgeline 4,000 metres above sea level. On September 21, the company announced that China's first tethered balloon rated for two-ton payloads had completed trial runs on the Tibet section of its Tibet–Guangdong ultra-high-voltage direct-current line, as CCTV Finance reported, with Huanqiu and other state outlets picking it up the same day.
The engineering logic is terrain logic. Ultra-high-voltage lines, which carry power thousands of kilometres from western generation hubs to coastal demand, keep running into passes where no crane can reach and no access road pays for itself. The traditional answers — blasting a construction road, or rigging a cableway up the slope — cost money and scar fragile high-altitude ground. A tethered balloon splits the difference: helium does the lifting, and ground crews spool cable in and out to control the load's altitude and drift, holding it steady while workers bolt towers together. State media's framing — "black tech for deep-mountain construction" — and the official slogan of a "green air corridor" capture the pitch: no road cut, no slope stripped.
Being tethered is the point. Unlike a free balloon, a moored one can be reeled down, repositioned and parked, which is what tower erection actually requires; the trade-off is wind, which sets operating windows rather than ending the concept. For the grid, the trial matters because the Tibet–Guangdong corridor is one of the largest single construction projects in China's power system, and its hardest kilometres are precisely the ones this machine is built to serve. China has built more ultra-high-voltage capacity than the rest of the world combined as it moves Tibet-plateau and desert renewable power eastward, and every new line pushes further into roadless terrain.
The crossover appeal is the part outsiders might miss. Any job that means putting two tons onto a roadless mountainside — mine resupply, firefighting cargo, disaster relief — is the same physics with a different sling, and the low-altitude economy, the policy banner Beijing has spent the year subsidizing through drones and eVTOLs, now has its heavy-lift end demonstrated by a state grid operator rather than a startup. Whether the balloon graduates from trial to routine hauling will show up the honest way: in the construction schedule of the line itself. If towers keep rising through the Tibetan passes this winter without a single new access road cut, the giant helium "porter" will have earned its place in the grid's toolkit.