(Recasts, add details of power plan)
By Meeyoung Cho
SEOUL, June 8 (Reuters) - South Korea has axed plans to build four coal-fired power plants and will boost its nuclear reactor fleet by two more units, as it looks to increase the share of nuclear and gas in power generation and cut reliance on coal.
The planned changes to the country's long-term power supply plan, which will take the number of planned nuclear reactors to 36 by 2029, are parts of efforts to cut carbon emissions, the energy ministry said in a statement on Monday.
Nuclear reactor operator, Korea Hydro and Nuclear Power Co Ltd (KHNP), part of state-run utility Korea Electric Power Corp , currently runs 23 reactors, supplying about a third of electricity for Asia's fourth-largest economy. It is already building or has plans to build another 11 units.
Seoul scrapped a plan to build four coal power plants with a combined 3,740 megawatts (MWs), which were not approved due to fuel and transmission facility issues. Instead, it will add a combined 3,000 MWs through two nuclear power plants, one each in 2028 and 2029, according to the ministry statement.
The ministry will also decide later this month if the country's oldest nuclear power plant Kori No.1 will continue to run past its current expiry date of 2017. The lifespan of the 587-MW reactor in the city of Busan, southeast of Seoul, has already been extended once by 10 years to 40 years.
South Korea, the world's fifth-largest user of nuclear power, decided in January 2014 to cut its reliance on nuclear power to 29 percent of total power supply by 2035. But Seoul remains deeply committed to nuclear energy.
The lastest power plan will be subject to public hearings.
Details of the planned energy mix based upon each facility's contribution in peak demand period is as follows (unit in percent):
Revised (-2029) Previous (-2027) CHG (%p)
Nuclear 28.5 27.4 +1.1
Coal 32.2 34.7 -2.5
Renewable 4.6 4.5 +0.1
Combined heat power 5.8 4.6 +1.2
Oil, pumped storage 4.2 4.5 -0.3
Note: Seoul projects annual electricity demand to grow 2.2 percent annually to a total of 656,883 gigawatt hours of power consumption in 2029 and 111,929 MWs of peak demand in 2029.
Reporting by Meeyoung Cho; Editing by Richard Pullin