A proposed energy U-turn by South Korea’s new government would put the environment at the centre of energy policy, shifting one of the world’s staunchest supporters of coal and nuclear power toward natural gas and renewable energy.

If implemented, the ambitious plans by the world’s fourth biggest coal importer and second biggest liquefied natural gas (LNG) buyer will have a big impact on producers.

Reuters Newsagency reports South Korea’s LNG imports could jump by more than 50 per cent by 2030, while coal shipments could peak as early as next year.

However, experts warn that any move to halt construction of a raft of new coal and nuclear plants, many of which are already being built, could threaten energy security, spark claims for massive compensation and push up electricity prices.

The plan by the new administration of left-leaning President Moon Jae-in which took power in early May would move a notable laggard in renewable energy toward green energy, responding to public concerns over air pollution and nuclear safety.

“The government can’t neglect people’s demands and in the long term it’s right to pursue clean and safe energy.

“But there will be many challenges,” said Professor Sonn Yang-Hoon, economics professor at Incheon National University.

South Korea, Asia’s fourth-largest economy, gets 70 per cent of its electricity from thermal coal and nuclear reactors, and offers tax benefits to both sectors to ensure abundant electricity at affordable prices.

While President Moon’s energy roadmap is still being hashed out, his staff said that care for the environment would play a central role in forming policy.

“Currently taxes are imposed on gas for power generation, and we plan to correct the skewed tax system by seeking to levy environmental taxes on coal and nuclear,” said Professor Paik Ungyu, an energy engineering professor at Hanyang University who advises President Moon on energy policy.

The government hopes to boost gas-fired generation from about 18 per cent now to 27 per cent by 2030 and boost the use of renewable energy, now mainly hydro, from roughly five per cent to 20 per cent, said Professor Paik.

At the same time, coal’s contribution would fall from about 40 per cent to 21.8 per cent and nuclear from 30 per cent to 21.6 per cent, based on power demand growth of 2.2 per cent.

Reuters reports a key short-term option is to boost the operating rates of gas-fired power stations from 40 per cent to 60 per cent through the reduction or removal of tariffs on gas imports.

Coal and nuclear power are exempt from import tariffs.

The price of gas-fired electricity in March was US$0.116 a kilowatt-hour (kWh), 40 per cent more than coal and nearly double the cost of nuclear power, according to data from Korea Electric Power Corp (KEPCO).

Long-term energy economics favour policy change, with renewable costs falling sharply due to improved technology and LNG prices sliding more than 70 per cent from their 2014 peak on a huge supply increase, especially from Australia and the United States.

“If there are no new nuclear and coal plants, the potential LNG imports could be 46-49 million tonnes a year depending on the success of the renewable targets,” said Chong Zhi Xin, principal Asia LNG analyst at energy consultancy Wood Mackenzie.

President Moon this month ordered a temporary halt on 10 old coal-fired power plants and outlined plans to bring forward their permanent closure.

More controversially, he pledged during his campaign to review existing plans to build nine coal power plants and eight nuclear reactors, including the part-completed Shin Kori No 5 and No 6, citing safety concerns.

Experts estimate up to US$2.7 billion has already been committed on Shin Kori No5 and No6 by state-run Korea Hydro and Nuclear Power.

Work has also started on the coal plant projects, although all are less than 10 per cent complete.

If forecasts suggest that not building the new plants means South Korea will be unable to meet projected electricity demand, then the government’s pledges will not be feasible, said Kim Nam-il, senior research fellow at the Korea Energy Economic Institute

The Independent Power Producer Association, which represents the coal and gas industries, estimates that nearly US$2 billion has also been spent on the nine coal-fired plants under threat, raising the issue of compensation.

“The government can’t unilaterally push cancellations as private companies have already invested in the projects.

“If the government scraps a plan, it would have to compensate properly,” said Professor Yoo Seung-Hoon, energy policy professor at Seoul National University of Science and Technology.