HVDC cable could trim most grid losses

High voltage dc transmission lines are one way to reduce the amount of power lost in transmission grids from the current average of about 8% to an estimated 1 to 2%, according to Wolfgang Dehen, chief executive of Siemens’ energy unit.

Traditional lines typically lose 8% of power in transmission, leading to higher costs and lower earnings for energy companies. New technology, such as high-voltage direct current, trims the amount of power lost so associated costs also drop, according to Dehen.

He says it is possible to connect cities with distant renewable wind and water farms, and cited the 2,000 km HVDC transmission lines under construction in China. The line will link the Xiangjiaba hydro-electric power plant in the south west to Shanghai on the north-east coast by year’s end. “It’s definitely a higher cost cable, but it’s the only way to bridge the distance and transport large amounts of power from a generation center to users,” he says.

145 kV double-circuit cable connects wind farm to mainland

ABB, Zurich, Switzerland, will supply, install, and commission 116 km of underground cable and 56 km of submarine cable, to strengthen the existing transmission grid and allow using more wind power from the Rødsand II offshore wind park which will be commissioned late 2010. The 145-kV cable is intended to manage overload and has a double-circuit option which helps secure power transmission even if the cable gets damaged. The cable will contribute to Denmark’s goal of 30% renewable energy consumption by 2020.
“This shows how ABB technologies are helping integrate renewable energy, thereby letting more wind power flow into electricity systems”, says Per Haugland, global head of ABB’s Grid Systems business.