The power plants will generate a combined 8000 megawatts of power.
Approval granted for the projects reportedly represents the first time in three decades that private contractors have been cleared to build coal stations in the energy-hungry country.
Bloomberg said the four companies engaged to build the plants were Samsung C&T, Tongyang Power, SK Engineering & Construction and a unit of Dongbu Group.
The move to diversify South Korea’s energy sector to include more coal, nuclear and renewables follows a number of blackouts due to government miscalculation of power demands.
A notable power outage in September 2011 cut electricity to 1.6 million South Koreans, including 400,000 in Seoul.
Cellphones and ATMs became disconnected as well, prompting local media to dub the incident a “man-made disaster”.
All of the country’s private coal companies were integrated into state-controlled giant Korea Electric Power Corporation which supplies more than 90% of South Korea’s electricity.
South Korea is the world’s third-largest importer of coal and a top-10 steelmaker, having produced almost 70 million tonnes last year.