Energy industry sees surge in recycling waste energy

[Image source: DALL·E]

Recycling waste energy is gaining traction in South Korea’s energy industry, which is currently experiencing a downturn. The idea is to minimize the amount of energy that is thrown away or wasted to save costs and reduce carbon emissions.

According to industry sources on Wednesday, several companies that are focused on the energy business, including SK Group subsidiaries, are dedicated to developing waste energy recycling methods. SK innovation Co. subsidiary SK energy Co. began operating a power boiler with a cogeneration system in Ulsan, South Gyeongsang Province, in June 2014.

The core of the cogeneration system is capturing the heat from the exhaust gases generated by gas engine generators and using it as fuel to operate the boiler, with the company minimizing waste and saving raw materials by reusing the previously discarded thermal energy. It expects that recycling 50 tons of high-temperature exhaust gas per hour will reduce carbon dioxide emissions by 48,000 tons annually, as well as reducing the use of liquefied natural gas (LNG) as boiler fuel, resulting in an annual cost saving of around 19.1 billion won ($13.8 million).

Power boilers are facilities that produce steam required for various processes. SK energy, which is seeking ways to reactivate the aging, inefficient existing power boilers, devised a cogeneration system that recycles exhaust gas heat, which has been applying since 2024.

SK incheon petrochem Co. is also using waste heat to supply heating water. The company invested 20 billion won in a “heat recovery process” that captures the heat generated during the adsorption process of paraxylene, a petrochemical product, and uses it to heat water. The hot water heated by waste heat is supplied to 40,000 households in Incheon and Cheongna, Gyeonggi Province.

The company’s innovative use of its geographical proximity to a large residential complex sets it apart from other petrochemical companies. The amount of heat recycled by SK incheon petrochem through the heat recovery process totals 28 gigacalories annually, which is equivalent to the amount of energy that would be produced by operating a 37-megawatt (MW) thermal power plant for a year. This recycling reduces annual carbon dioxide emissions by 50,000 tons.

The use of LNG cold energy is also being explored in various ways. Traditionally, cold energy was perceived as energy discarded into the sea or air, but recent advancements in cold energy recovery technology and growing interest in eco-friendly processes have increased attention on cold energy.

LNG, stored in liquid form at an ultra-low temperature of -162 degrees Celsius, is supplied to consumers as vaporized city gas. When the liquid vaporizes, it releases the cold energy it contains, which can be used in air liquefaction, cold energy generation, and refrigerated warehouses.

The Korean government has designated “energy recycling” as a national agenda item and included LNG cold energy in the third Energy Basic Plan. In response, Korea Gas Corp. is engaged in research and development on using ultra-low temperature cold energy, such as operating cold storage and logistics centers that use LNG cold energy.