Reduction of Environmental Impact in Plants: Gunma Complex

Gunma Complex uses electricity and natural gas with low emissions of greenhouse gases as energy sources.

Although energy consumption in this Complex rises as the production of silicone products increases, it approaches the promotion of energy savings (reduction of average annual rate of 1% in original units) and the reduction of greenhouse gas emissions (reduction of 45% in comparison with 1990 by 2025 in original units) by introducing a cogeneration system and renewable energy and by implementing measures to save energy in the manufacturing processes.

Both electric power and steam are generated from the cogeneration system using natural gas as fuel to supply the plants. The electric power is used for motors and lighting, and the steam is used as the heating sources for manufacturing facilities. In addition, power is generated by steam turbines using the pressure difference of steam. The energy utilization efficiency of the system is higher than that of commercial power supply and steam supply from boilers and thus greatly contributes to energy savings and the reduction of greenhouse gas emissions.

The reactive heat generated in the production processes are collected and effectively used as steam generation and product heating. In addition, part of the steam generated in the cogeneration system produces cold water using absorption type refrigerators, and the cold water is used as the cooling source for the manufacturing facility and the air conditioners in the clean rooms.

Operation aimed at saving energy is promoted in each manufacturing process.

In the manufacturing process of the intermediate material of silicones, we are making improvements aimed at the effective use of thermal energy. Our new manufacturing method introduced in 2023 effectively utilizes the thermal energy generated by chemical reactions as the thermal energy required for the manufacturing process, resulting in a 48% reduction in energy consumption and a 47% reduction in greenhouse gas emissions compared to before the method was introduced.

Solar panels with a power generation capacity of approx.148 kW were installed at the Goubara plant, and operation started in March 2021. They cover part of the power used at the plant, and the reduction of CO₂ emissions of approx.72.3 tons per year is expected from annual power generation of approx.160 MWh.^*

In addition, at the Gunma Complex, new solar power generation facilities were installed in the west area of the Isobe Plant and began operation in July 2023. This facility will generate 155 MWh of electricity per year, covering part of the power used at the plant, and is expected to reduce CO₂ emissions by approximately 67 tons per year^*.

Because the production line uses a clean room, air conditioning runs 24 hours a day. Introducing one high-efficiency modular chiller was enough to reduce the energy consumption by 39% (9% of the total power of the target plant).

Gunma Complex is surrounded by an environment rich in nature and takes in almost all amounts of the water necessary for the production of silicones from peripheral rivers.

Since the manufacturing of chemical products requires a large amount of water, this Complex recirculates the water taken in and reutilizes it for production facilities and cooling water as much as possible in order to minimize the amount of water taken in from rivers. In addition, we perform the purification treatment before discharging water to rivers to control the water quality thoroughly.

Furthermore, in addition to recycling used wastewater and reusing it for other purposes, we are reducing the amount of wastewater discharged from our plants in the first place through measures such as installing an exhaust gas absorption tower to reduce the amount of water used in the scrubber (exhaust gas treatment equipment) and switching to a manufacturing method that does not use cleaning water.

The Gunma Complex is equipped with various facilities to effectively utilize limited water resources and prevent the discharge of pollutants outside the complex.

Efforts are underway at the Gunma Complex to achieve the Shin-Etsu Group's goal of zero waste emissions (a 1% or less ratio of final landfill disposal volume to waste generation volume). These efforts also include promoting waste generation reduction in terms of emission intensity. Besides, emissions reduction targets have been set to prevent air pollution. Measures to reduce emissions have been implemented, such as switching to fuels with a lower environmental load.

Industrial waste materials from each plant are collected for incineration and disposal at the incineration facility at the Isobe plant. To reduce dioxin emissions from this incineration facility, the Isobe plant is working on operation management optimization through around-the-clock operation and stable incineration at high temperatures. Its efforts also extend to utilizing the heat generated at the incineration facility to produce steam for each plant.

The Gunma Complex positively uses natural gas as an environment-friendly energy source along with electricity. Natural gas is an ideal energy source: it does not produce much nitrogen oxide (NOx) emissions, which are deemed responsible for acid rain and air pollution, and produces no sulfur oxide (SOx) emissions (see the figure above). Accordingly, the Gunma Complex stays well below the emission standard for NOx, and its SOx emissions remain below the measurable lower limit.