Harnessing Natural Power, Inalum Rewrites the Future of Industry
PT Indonesia Asahan Aluminium (Inalum) has received the Gold PROPER 2025 ranking from the Ministry of Environment and Forestry, demonstrating its commitment to environmental management, emission reduction, and community empowerment.
As Indonesia’s largest aluminium producer, Inalum relies on approximately 95% renewable energy from Hydroelectric Power Plants (PLTA) for its production, while also preserving the sustainability of the Lake Toba environment.
Throughout 2025, Inalum recorded aluminium production of 280,082 metric tonnes (MT) and sales of 280,141 MT, marking the highest record in over 50 years of operation.
The company is also actively implementing Environmental, Social, and Governance (ESG) programmes through conservation, reforestation, and social initiatives such as scholarships, empowerment of MSMEs, and village development.
Inalum was established in January 1976 and has made numerous breakthroughs for Indonesia’s economic development and society.
One major breakthrough by the company is building the aluminium industry on the foundation of the Hydroelectric Power Plant (PLTA) in Paritohan, Toba Samosir Regency, North Sumatra Province.
The company utilises the power of the Asahan River, which flows from Lake Toba in North Sumatra, as an energy source that is not only cheap but also sustainable.
The PLTA has been operational since 1981, or more than 43 years ago. Notably, 14,000-14,300 kWh is required to produce one tonne of aluminium. With a cheaper electricity source, production costs can also be reduced.
Inalum now has three dam units: the Regulating Dam, Siguragura Dam, and Tangga Dam, as well as two PLTAs: Siguragura PLTA and Tangga PLTA. Both PLTAs have a capacity of 603 Megawatts (MW).
The electricity generated by the PLTA is transmitted through 271 transmission line towers spanning 120 km from Paritohan in Toba Samosir Regency to the aluminium smelting plant in Kuala Tanjung Regency.
As the manager of three dams, Inalum continuously monitors the Lake Toba water level throughout the year, both in the dry and rainy seasons. This step ensures that the PLTA and surrounding communities do not face water shortages during the dry season or flooding during the rainy season.
Inalum’s responsibility in managing the dams is also manifested in preserving the Lake Toba ecosystem through reforestation of critical lands to support water reserve recovery.
Three Main Inalum Programmes
Inalum achieved the PROPER Gold 2025 due to several sustainable innovations that directly impact energy efficiency, water, and emission reductions.
There are at least three flagship programmes that are key to this achievement. First, the SIMULTAN (Simultaneous Multi-Line Tank Operation) Programme, which increases energy efficiency by up to 289.2 gigajoules (GJ). This innovation is a strategic step in reducing energy consumption in operational processes.
In addition, Inalum implements the OPTIMIST (Optimal Mist System) Programme, which focuses on water usage efficiency. Through the application of high-pressure mist technology in the tank temperature control system, this programme has saved up to 702 cubic metres (m3) of water.
Meanwhile, from an environmental perspective, the CARGO (Carbon Reduction through Gas Optimization) Programme has made a significant contribution. Optimising pipelines at the IT Surabaya facility has reduced greenhouse gas (GHG) emissions by 86.13 tonnes of CO2 equivalent.
These various innovations strengthen Inalum’s position as a company that is not only oriented towards business performance but also committed to sustainable industrial practices.
Inalum’s Environmental and Social Responsibility
As part of the MIND ID group, Inalum is committed to adding value for society and the environment through positive contributions via the Sustainability Pathway. The Sustainability Pathway is a strategic ESG framework to ensure the implementation of responsible and sustainable operational practices across the group.
In terms of environmental preservation, Inalum has carried out many programmes. One of them is biodiversity conservation and preservation. This preservation includes planting endemic trees and mangroves, as well as animal breeding.
In implementing the Environmental and Social Responsibility (TJSL) programme, Inalum refers to applicable regulations and best standards in corporate social responsibility implementation.
This programme focuses on sustainable community empowerment through two main schemes: the Micro and Small Business Funding Programme (PUMK) and the Non-PUMK TJSL Programme.
The flagship TJSL programmes implemented include higher education scholarships, development of INATA Early Childhood Education, economic empowerment through PUMK, and village empowerment.
Inalum’s commitment to sustainability values has earned the company the Gold ranking in PROPER 2025.