As part of South Korea's effort boosting the share of renewable power to 20% by 2030, up from 7% now, state-run Korea Electric Power Corp. (KEPCO) has joined hands with GE of the U.S. in building a 4 GW high-voltage direct-current grid.

The prospective grid, at estimated cost of US$320 million, will cover the eastern region of South Korea extending to Seoul, aiming to boost the stability and reliability of the nation's power supply.

Compared with alternating-current grid, high-voltage direct-current grid boasts huge-volume power transmission and less loss in long-distance transmission, lowering total cost. Such a direct-current grid is indispensable for boosting the share of renewable energy, which is generated in the form of direct current.

To be carried out by KAPES, a joint venture between KEPCO and GE, the project will be a 500 kV two-pole system, consisting of two inverter stations. Scheduled for completion by the end of 2021, it will minimize impact on the environment.

KAPES was set up by KEPCO and Alstom of France jointly in 2013 for dedication to developing South Korea's high-voltage direct-current power transmission systems but the latter's stake was taken over by GE later on after GE acquired Alstom's grid division.

Jean-Pierre Faure, regional leader of East Asia Pacific of GE Grid Solutions, pointed to the long-standing cooperative relationship between GE and KEPCO, as the duo started to jointly build grids in South Korea back in early 1980s, with the latest cooperative project being a 1.5 GW high-voltage direct-current grid, which broke ground in 2014 and is scheduled for completion by the end of 2019. The system will transmit power generated by the power plant in Dangjin to populous Pyeongtaek and Seoul.

GE pointed out that in response to the rapid growth of Korea's energy need, expanding by near 35% over the past 10 years, the Korean government put forth a 47.7 GW renewable-energy plan last Dec., consisting of 30 GW, or 63%, of PV power and 16 GW, or 34%, of wind power. The facilities, to be built by the public and private sectors jointly, are meant to substitute coal-fired thermal power and nuclear power. The aforementioned direct-current grid is part of the plan.

At present, coal-fired thermal power and nuclear power meet 70% of Korea's power need, leaving only 7% to renewable energy, including mere 1% for wind power and PV power. Korea hopes to raise the installation capacity of renewable energy to 58.5 GW, up from 11.3 GW now, by 2030, cutting the share of coal-fired thermal power to 36.1% and that of nuclear power to 23.9%. The direct-current grid plays a critical role in achieving the goal.

(First figure is a conceptual diagram, source: Ian Muttoo via Flickr CC BY-SA 2.0 TW)