In late December 2009, Siemens Energy and the utility China Southern Power Grid put into operation the first pole of a HVDC system of enormous scale and magnitude. With a transmission capacity of 5000 MW and covering a distance of more than 1400 km, the Yunnan-Guangdong high-voltage direct-current transmission system (HVDC) recently is the world’s most powerful of its kind implemented. At the same time it is the first HVDC link operating at a transmission voltage of 800 kV. Commissioning of the second pole and thus startup of the entire system is scheduled for mid-2010.

China has raised the DC voltage of its new long-distance HVDC links to 800 kV in order to further reduce transmission losses and to be able to bridge even greater distances. For example, the ecofriendly, CO2-free power generated by several hydro power plants will be transported with low-loss transmission via the new 800-kV HVDC link to the rapidly growing industrial region in the Pearl River delta in Guangdong Province with its megacities Guangzhou and Shenzhen. This high-efficiency HVDC system can reduce annual CO2 emissions by over 30 megatons, which would otherwise have been produced by additional fossil-fueled power plants linked to the interconnected grid in Guangdong Province.

“Successful commissioning of the first pole of currently the world’s most powerful HVDC system shows that our efforts to get 800-kV HVDC technology ready for concrete projects have paid off. As technology leader in this field we have thus set new benchmarks,“ said Udo Niehage, CEO of the Power Transmission Division of Siemens Energy.

Together with its Chinese partners Siemens designed the entire HVDC system for the Yunnan-Guangdong project and supplied the core components, which included 800-kV and 600-kV converter transformers, DC filters and 800-kV direct-current components.

Energy-efficient, high-voltage direct-current (HVDC) transmission systems for low-loss transmission of large quantities of power over long distances are part of Siemens’ Environmental Portfolio. In fiscal 2009, revenue from the Portfolio totaled about EUR23 billion, making Siemens the world’s largest supplier of ecofriendly technologies. In the same period, our products and solutions enabled customers to reduce their CO2 emissions by 210 million tons.