Japan mulls thermal efficiency target rules

Japan is considering revising regulations for a minimum heat efficiency for the country's thermal power generation plants, to accelerate the phasing out of ageing and inefficient coal-fired capacity.

The working group to mull regulatory measures to phase out inefficient coal-fed plants by 2030, created in August under the trade and industry ministry (Meti), has proposed to set a new thermal efficiency target exclusive to coal-fired power plants although details of efficiency levels and collateral measures remained unclear.

Several commission members have voiced support for the proposal. But there are also concerns that this could result in over-regulation.

Meti has defined the minimum heat efficiency levels for coal, LNG and oil-fired power plants. The level should be at 41pc for existing coal-fired power plants and 42pc for new plants. Efficiency for LNG-fed plants should exceed 48pc for existing plants and 50.5pc for new facilities, while oil burning is encouraged to have at least 39pc efficiency for both existing and new plants.

But the current energy saving law lumps all thermal power units, only requiring electricity producers to achieve an average 44.3pc of heat efficiency. This means a power firm could achieve the target by using advanced, highly efficient gas-fired unit even if it continues using an inefficient coal-fed unit.

The working group has pointed out the current law does not necessarily guarantee the effectiveness of improving coal-fired power generation efficiency. Only 24 of 46 firms that operate coal-fired power plants have so far achieved 41pc efficiency, according to the Meti survey.

Meti in July proposed starting discussions to scrap inefficient coal-fired power plants, to help the country meet a 2030 goal to cut greenhouse gas emissions by 26pc from 2013-14 levels. The phase-out is targeted at units that are not equipped with the latest clean coal technology such as coal gasification combined-cycle and ultra-super critical infrastructure. This implies Japan may scrap or mothball 25.3GW of inefficient coal-fired units, or about half of the existing coal-fired capacity.

Japan's power sector aims to reduce carbon dioxide emissions by 35pc from 2013-14 levels to 0.37 kg/kWh by 2030, by complying with an energy saving law. Meti also requires power firms that sell more than 500 GWh/yr of electricity to observe a "sophisticated method of energy supply structures" law, to have a minimum 44pc of their fuel from non-fossil sources by 2030, to achieve the carbon dioxide reduction goal.

Carbon dioxide emissions by the country's power firms totalled 345mn t in 2019-20, equivalent to 0.444 kg/kWh, according to preliminary data released by the electric power council for a low carbon society, a group of 62 Japanese power producers. The 2019-20 emissions were lower by 7.3pc from 372mn t, or 0.463 kg/kWh, in 2018-19.

By Motoko Hasegawa