The transmission capacity has now been doubled to 5 GW.

With one pole operating at plus 800 kV and the other at minus 800 kV, the voltage difference between the poles reaches 1600 kV DC.

“This has been an ambitious project including ground-breaking product developments and we have ultimately even managed to complete it ahead of schedule. With DC systems operating at ultra high-voltage levels we now have the transmission technology of the future in our portfolio.

"This technology is ideal for transporting clean, renewable power over thousands of kilometres to consumers – with nearly zero losses,” says Udo Niehage, CEO of the Power Transmission Division of Siemens Energy.

The 5 GW of hydropower is produced in the remote Yunnan Province and is transported 1500 km to the rapidly growing industrial region in the Pearl River delta in Guangdong Province with its megacities Guangzhou and Shenzhen.

Siemens says that at a transmission capacity of 5 GW, losses are as low as around 2% per 1000 km, plus less than 1.5% losses for both converter stations at the sending and receiving end of the transmission line.