Korean companies have rarely traded their carbon emission rights on the South Korean main bourse this year due to a weak supply, data showed Sunday.

According to the Korea Exchange, the total volume of traded emission rights stood at 1.08 million tons as of Thursday, a combined figure of 113,000 Korean allowance units and 968,000 Korean credit units.

Korean allowance units refer to the rights allocated directly by the government. Korean credit units are offset emission permits, converted from the greenhouse gas reductions through individual companies’ external projects.

The total trading volume is a meager 0.2 percent of the 500 million ton of emission rights allocated by the government this year.

The KRX launched the carbon trading system in 2015 to provide 525 local companies with opportunities to reduce carbon emissions through selling leftover or buying shortages of emissions rights.

However, companies are reluctant to sell their leftover emissions rights, which can be rolled over to the next year, observers said.

For the first emissions trading scheme during 2015-2017, compliance companies have reported their 2015 greenhouse gas emissions to the government by the end of March.

They face the first compliance deadline at the end of June. By then, companies should either buy emissions rights from the market to fill up the government-allocated amount or use additional emissions rights in advance from future allocations. Those failing to do so are subject to penalty, three times the amount of the market price of KAU.

A shortage in the supply side has pushed up the price of emissions rights. The price of KAU rose 21,000 won ($17.60) as of Thursday from 12,000 won as of the end of 2015. The price of KCU rose 18,500 won from 13,700 won during the same period.

By Kim Yoon-mi (yoonmi@heraldcorp.com)