The government will expand the recognition of seven types of water resources, including discharged groundwater and wastewater, as renewable energy sources. This plan aims to broaden the scope of thermal energy utilization, which was previously limited to river and seawater, allowing for heating and cooling energy use in urban buildings and industrial complexes.
On November 10, the Ministry of Climate, Energy, and Environment announced that a revised enforcement decree of the "Act on the Promotion of Development, Use, and Distribution of Renewable Energy" was approved during a Cabinet meeting and will take effect on November 17.
The core of this amendment is to provide a legal basis for the Minister of Climate to designate water resources with stable temperature and quantity as thermal energy. The ministry plans to establish a notification on the scope of thermal energy, adding seven types of water resources: discharged groundwater, sewage, treated wastewater, industrial wastewater, treated industrial wastewater, treated sewage and wastewater, and industrial water.
Thermal energy utilizes the properties of water, which is cooler than the air in summer and warmer in winter, for heating and cooling. It can reduce energy consumption by more than 30% compared to existing heating and cooling systems. Thermal energy accounts for 48% of domestic energy consumption and contributes to 29% of greenhouse gas emissions, prompting the government to expand thermal energy as part of its decarbonization efforts.
Previously, domestic thermal energy projects were primarily concentrated around river water and dam areas, limiting their application in urban centers and inland industrial complexes where there is high demand for heating.
The newly added discharged groundwater maintains a stable average temperature of about 15 degrees Celsius year-round, making it suitable for heating and cooling. The average daily discharge from underground spaces, such as subways, tunnels, and large buildings, reaches approximately 581,000 tons. Utilizing this for building heating and cooling is expected to reduce costs associated with installing separate heating sources and minimize energy loss.
The potential for using sewage and wastewater is also significant. Treated sewage maintains temperatures of 12 to 15 degrees Celsius in winter and 20 to 25 degrees Celsius in summer, making it suitable for district heating or hot water supply for industrial processes. The government estimates that if all treated sewage from facilities processing over 500 cubic meters per day, totaling about 20.09 million tons, is utilized, it could secure 3 million Gcal of thermal energy monthly. This theoretical potential assumes recovering about 5 degrees of heat from all discharged water, enough to heat approximately 3 million households for a month.
Industrial water also has the advantage of stable flow and supply. This method recovers heat without consuming the water itself, allowing it to be reused in existing processes as a heating source for industrial complexes.
Since December of last year, the ministry has introduced a thermal energy system with a capacity of 7,000 RT at the Korea Trade Center and is expanding its applications to urban buildings and data centers. At that time, it also set a goal to supply 1 GW of thermal energy by 2030.
In addition to the seven types designated this time, the ministry plans to explore additional thermal energy sources and promote pilot projects for sewage thermal energy distribution. It aims to encourage private investment through pilot projects utilizing new thermal sources.
Song Ho-seok, head of the Ministry's Water Management Policy Office, stated, "Thermal energy, proven effective through pilot projects, will widely spread near demand areas in urban buildings and industrial complexes with this system reform as a stepping stone. We will continuously seek out hidden thermal sources to robustly support carbon neutrality in the thermal energy sector."
* This article has been translated by AI.
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