Environmental Load of Business Activities

The depletion of energy resources, global warming, threats to biodiversity and other environmental problems are having an increasingly serious impact on the global environment. Given these situations, the SUMCO Group (Japan) identifies forms of energy such as electric power, chemical substances, waste products, and wastewater as significant environmental aspects in its production activities. And we pursue initiatives to consider the environment and reduce environmental load across all of our business activities.

Business Activities and Environmental Load in 2025 (SUMCO Group [Japan])

Flowchart of SUMCO Group’s domestic business activities and environmental impact for 2025. The diagram shows a flow from Input (Energy, Water, PRTR substances) on the left, to Business Activities (Product Development, Procurement, Manufacturing, Transport) in the center, and Output (GHG emissions, transport CO2 emissions, wastewater, waste, PRTR substances) on the right.

(remark)

Underlined items are subject to third-party verification.

Figures are rounded to the nearest whole number, so the total of the breakdown and the total value shown may differ.

Additionally, data of High-Purity Silicon Corporation has been incorporated since 2024.

List of Boundaries

Site Energy
usage		 GHG
emissions		 Water withdrawal/
waste-water		 Industrial waste
generated		 VOC
emissions		 PRTR
emissions		 Atmospheric pollutant
emissions		 Abbreviation
Includes SUMCO Group
companies in Japan		 Kyushu Factory (Nagahama, Imari) ○ ○ ○ ○ ○ ○ ○ SUMCO
Kyushu Factory (Kubara, Imari) ○ ○ ○ ○ ○ ○ ○
Kyushu Factory (Saga) ○ ○ ○ ○ － － ○
Yonezawa Plant ○ ○ ○ ○ ○ ○ －
Chitose Plant ○ ○ ○ ○ － － －
JSQ Division ○ ○ ○ ○ － ○ ○
Sales Office (Tokyo) － ○ － － － － －
Sales Office (Osaka) － ○ － － － － －
Sales Office (Fukuoka) － ○ － － － － －
SUMCO TECHXIV Corp. Nagasaki Plant ○ ○ ○ ○ ○ ○ ○ STC
SUMCO TECHXIV Corp. Miyazaki Plant ○ ○ ○ ○ － ○ ○
SUMCO Technology Corp. Noda Plant ○ ○ ○ ○ － ○ ○ STEC
High-Purity Silicon Corporation ○ ○ ○ ○ ○ ○ ○ HSJ
SUMCO Group
Companies Overseas		 SUMCO Phoenix Corporation ○ ○ ○ ○ － － ○ SPX
PT. SUMCO Indonesia ○ ○ ○ ○ － － ○ SPTI
FORMOSA SUMCO TECHNOLOGY CORPORATION ○ ○ ○ ○ － － ○ FST
High-Purity Silicon America Corporation ○ ○ ○ ○ － － ○ HSA
SUMCO Europe Sales Plc ○ ○ － － － － － SES
SUMCO Singapore Pte.Ltd. ○ ○ － － － － － SSGP
SUMCO Taiwan Technology Corporation ○ ○ － － － － － STWN
  • Including all Japan and overseas sites.
  • Since 2024, High-Purity Silicon Corporation and High-Purity Silicon America Corporation have been included in the boundaries.

Environmental Load (SUMCO Group / domestic)

GHG emissions (domestic) (thousand tons-CO2e per year)

  • Bar graph showing the trend of SUMCO’s GHG emissions (Scope 1+2).
  • Bar graph showing the trend of STC’s GHG emissions (Scope 1+2).
  • Bar graph showing HSJ’s GHG emissions (Scope 1+2).
  • Bar graph showing the trend of Scope 3 GHG emissions (Domestic).

Water withdrawal (domestic) (Mm3 per year)

  • Bar graph showing the trend of SUMCO's water consumption.
  • S Bar graph showing the trend of STC’s water consumption.
  • Bar graph showing HSJ’s water consumption.

Environmental Load (SUMCO Group / overseas)

Map showing the overseas locations of the SUMCO Group.

GHG emissions (overseas) (thousand tons-CO2e per year)

  • Bar graph showing the trend of SPTI’s GHG emissions (Scope 1+2).
  • Bar graph showing the trend of FST’s GHG emissions (Scope 1+2).
  • Bar graph showing the trend of SPX’s GHG emissions (Scope 1+2).
  • Bar graph showing the trend of HSA’s GHG emissions(Scope 1+2).

Water withdrawal (overseas) (Mm3 per year)

  • Bar graph showing the trend of SPTI’s water consumption.
  • Bar graph showing the trend of FST’s water consumption.
  • Bar graph showing the trend of SPX’s water consumption.
  • Bar graph showing HSA’s water consumption.
  • In 2024, the GHG emission factors of the overseas affiliates were based on either local emission factors or the International Energy Agency (IEA) Emission Factors. In 2025, only local emission factors were used.

Environmental Data (SUMCO Group / domestic and overseas)

GHG Emissions Data

(thousand tons-CO2e per year)

Calculation Method 5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
Scope 1
(direct)		 Conventional 27 28 33 － －
SBT-compliant*1 － － 83 83 79
Scope 2
(indirect)		 Conventional 812 765 942 － －
SBT-compliant*1 － － 1,194 1,097 1,047
Scope 3
(other indirect)		 Conventional 758 882 1,133 － －
SBT-compliant*1 － － 1,842 1,702 1,814
Scope 1&2 Conventional 839 793 975 － －
SBT-compliant*1 － － 1,277 1,181 1,126
Scope 1, 2&3 Conventional 1,597 1,675 2,109 － －
SBT-compliant*1 － － 3,119 2,883 2,940
  • For the 2023 calculation, we have added the SBT-compliant calculation methods.
    Under this methodology, High-Purity Silicon Corporation and High-Purity Silicon America Corporation have also been included in the boundary.
    From 2024 onwards, we disclose the results using SBT-compliant calculation methods.

(remark)

Figures are rounded to the nearest whole number, so the total of each Scope and the total value shown may differ.

Greenhouse Gas Emissions Scope3 Data (SUMCO Group / domestic and overseas)

(thousand tons-CO2e per year)

Category 2025
Domestic Overseas
1 Purchased goods and services 467 147
2 Capital goods 491 164
3 Fuel- and energy-related activities (not in Scope 1 or 2) 150 62
4 Upstream transportation and distribution 97 21
5 Waste generated in operations 20 3
6 Business travel 6 1
7 Employee commuting 19 5
8 Upstream leased assets Not applicable Not applicable
9*1 Downstream transportation and distribution 3 4
10*1 Processing of sold products 82 30
11 Use of sold products Not applicable Not applicable
12*1 End-of-life treatment of sold products 23 16
13 Downstream leased assets Not applicable Not applicable
14 Franchises Not applicable Not applicable
15*1 Investments 5 0

(remark)

Figures are rounded to the nearest whole number, so the total of the breakdown and the total value shown may differ.

GHG Emissions Data (by Company)

(thousand tons-CO2e per year)

Calculation Method 5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
SUMCO*1 Conventional 1,228 1,316 1,691 － －
SBT-compliant*2 － － 2,065 1,795 1,650
STC Conventional 131 120 184 － －
SBT-compliant*2 － － 185 164 186
HSJ SBT-compliant － － 153 155 142
FST Conventional 165 167 171 － －
SBT-compliant*2 － － 360 401 582
SPX Conventional 60 60 52 － －
SBT-compliant*2 － － 95 87 76
SPTI Conventional 12 12 11 － －
SBT-compliant*2 － － 34 25 21
HSA SBT-compliant － － 226 257 283
Others*3 SBT-compliant － － 0.3 0.2 0.2
Total Conventional 1,587 1,675 2,109 － －
SBT-compliant*2 － － 3,119 2,883 2,940
  • Domestic Greenhouse Gas Emissions Scope3 is aggregated as "SUMCO".
  • For the 2023 calculation, we have added the SBT-compliant calculation methods.
    Under this methodology, High-Purity Silicon Corporation and High-Purity Silicon America Corporation have also been included in the boundary.
    From 2024 onwards, we disclose the results using SBT-compliant calculation methods.
  • Overseas non-manufacturing sites

(remark)

Figures are rounded to the nearest whole number, so the total of the breakdown and the total value shown may differ.

GHG Data (Scope 1) (SUMCO Group / domestic)

(tons)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
CO2 27,000 28,000 67,670 62,831 69,442
CH4 － － 6 3 3
N2O － － 14 18 16
HFC 0.014 0.014 5.63 5.30 3.20
PFC － － 0.048 0.048 0.034
SF6 － － 0.0009 0.0022 0.0012
NF3 － － － － －
  • Figures are rounded to the nearest whole number, so the total of the breakdown and the total value shown may differ.
  • From 2023 onwards, we have disclosed the results using SBT-compliant calculation methods. Under this methodology, High-Purity Silicon Corporation and High-Purity Silicon America Corporation have also been included in the boundary.

Energy Consumption (SUMCO Group / domestic and overseas)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
Electricity usage (GWh) 1,877 1,963 2,327 2,462 2,534
Electricity (converted to heavy oil) (kL) 472,505 494,290 518,737 548,818 564,655
Fuel (converted to heavy oil) (kL) 9,670 10,103 31,212 29,108 31,403
Steam (converted to heavy oil) (kL) － － 16,457 17,653 18,923
  • From 2023 onwards, we have disclosed the results using SBT-compliant calculation methods. Under this methodology, High-Purity Silicon Corporation and High-Purity Silicon America Corporation have also been included in the boundary.

Water withdrawal (SUMCO Group / domestic and overseas)

(Mm3 per year)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
Surface water (rivers, wetland, natural lakes) 15.7 17.3 17.9 20.5 20.3
Water underground (well water) 3.5 3.8 4.1 4.4 4.2
Quarry water － － － － －
Potable water 1.3 1.3 1.2 1.6 1.6
External drainage － － － － －
Rainwater － － － － －
Seawater － － － － －
Total 20.5 22.4 23.2 26.5 26.1

Water withdrawal (by Company)

(Mm3 per year)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
SUMCO 11.1 12.7 13.0 13.4 13.5
STC 4.6 4.8 5.2 5.5 5.3
HSJ － － － 1.3 1.3
FST 3.0 3.0 3.2 4.0 3.5
SPX 1.4 1.5 1.4 1.4 1.4
SPTI 0.4 0.4 0.4 0.3 0.3
HSA － － － 0.7 0.7
Total 20.5 22.4 23.2 26.5 26.1
  • Please refer the page of "Effective Use of Water Resources" for water-stressed area.

Drainage Water (SUMCO Group / domestic and overseas)

(Mm3 per year)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
Total water drained into the ocean 9.1 10.3 10.7 11.9 12.9
Total water drained to surface water sources － － － － －
Total water drained to underground sources / well water sources － － － － －
Total water drained outside of plants (to sewer systems) 4.8 5.1 5.4 5.9 5.8
Other drainage water (to rivers) 3.5 3.5 3.4 3.8 3.6
Total drainage water 17.4 18.9 19.5 21.6 22.3

Drainage Water (by Company)

(Mm3 per year)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
SUMCO 9.6 10.8 10.8 11.1 11.3
STC 4.0 4.2 4.5 4.8 4.7
HSJ － － － 0.8 0.9
FST 2.3 2.3 2.7 3.0 3.5
SPX 1.1 1.2 1.2 1.3 1.2
SPTI 0.4 0.4 0.3 0.3 0.3
HSA － － － 0.3 0.3
Total 17.4 18.9 19.5 21.6 22.3

VOC emissions (SUMCO Group / domestic)

(tons per year)

5 years prior
(2021)		 4 years prior
(2022)		 3 years prior
(2023)		 2 years prior
(2024)		 Last year
(2025)
VOC 11.3 10.3 5.5 4.9 4.1
  • Chemical Substances have been tabulated based on the PRTR system of the Ministry of Economy, Trade and Industry since 2021.

CDP

SUMCO has been recognized by the international NGO “CDP*1” for its efforts in climate change and water security, and in 2025, we were included in the CDP A List*2, for both climate change and water security, recognizing us as one of the highest performing companies in the area of climate change and water resource management.

2025 CDP Scores

Climate Change : A

Water Security : A

In 2025, we responded to two questionnaires on climate change and water security. Please refer to the PDF below for each answer from SUMCO.

CDP Corporate Questionnaire 2025 (PDF)( 1,410KB)
  • An international NGO that works in the environmental field. They send environmental questionnaires to companies and compile the results and analyze and evaluate them on a common scale.
  • The rating system is a 5-rank scale (A, A-, B, B-, C, C-, D, D-, F). The A List is made up of the companies awarded the highest performance rank of "A".

Third Party Verification of GHG Emissions (SUMCO Group / domestic)

We have conducted third-party verification in accordance with ISO14064-3 for Scope 1, 2, and 3 (Categories 1, 2, and 3) to improve the reliability of the calculation results for GHG emissions of the SUMCO Group (Japan), and obtained a verification report.

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Sustainability

Executive Officer Message Materiality (Key Issues) The SUMCO Group's Business Activities and the Sustainable Development Goals (SDGs) Related Policies CSR and Sustainability Promotion Structure Environmental Social Governance SUMCO Vision Disclosure Based on TCFD Recommendations Disclosure Based on TNFD Recommendations Site Data Sustainability Report / CSR Report To ESG-oriented Investors