Indonesia's state railway cuts energy intensity 22 percent while carrying more passengers than ever

What happened

PT Kereta Api Indonesia (KAI), the state railway operator, reported that its energy intensity per customer fell 22.05 percent in 2025, from 0.0263 gigajoules (GJ) per customer in 2024 to 0.0205 GJ per customer in 2025. The improvement came in a year when the company carried more people and more freight than ever before, not less. KAI's Vice President of Corporate Communication, Anne Purba, disclosed the figures on July 25, 2026, describing energy as one of the central inputs to running a reliable rail service and framing the intensity metric as the clearest signal of whether that input is being used well.

The headline number sits inside a broader set of results. KAI's total energy consumption across the group fell 15.39 percent, from 11,945,467 GJ in 2024 to 10,107,302 GJ in 2025, even as the company served 492,657,571 customers, an increase of 8.67 percent over the 453,343,189 served the year before. Energy intensity per ton of freight carried also fell, by 15.82 percent, from 0.1726 GJ per ton in 2024 to 0.1453 GJ per ton in 2025. Intensity measured against revenue dropped 14.57 percent, from 0.3308 GJ per billion rupiah to 0.2826 GJ per billion rupiah. Freight volumes themselves grew modestly, from 69,201,670 tons in 2024 to 69,571,601 tons in 2025, meaning the efficiency gain was not the byproduct of doing less business.

"The lower the intensity, the more efficient the energy use," Anne Purba said, describing intensity, rather than raw consumption, as the metric that best captures whether growth and sustainability are moving together.

The mechanics behind the numbers

Three separate levers appear to be driving the result, according to KAI's own disclosures across the year. The first is fuel substitution. KAI's locomotives and gensets have run entirely on B40 biosolar, a blend of 40 percent palm-based biodiesel and 60 percent petroleum diesel, since February 2025, following technical trials that began in 2024. In 2025 alone, Biosolar B40/B35 consumption reached 255,047.87 kiloliters, equivalent to 9,666,314.31 GJ, the dominant share of the company's total energy use. KAI President Director Bobby Rasyidin has described the shift as a gradual roadmap rather than a single switch: pure diesel through 2017, B20 from 2018 to 2019, B30 from 2020 to 2022, B35 through 2023 and 2024, B40 in 2025 and 2026, and now trials toward B50, which the government mandated nationwide from July 1, 2026. KAI built dedicated B40 mixing and refueling infrastructure at five locations, in Cipinang, Arjawinangun, Lempuyangan, Cepu and Pasar Turi, to support the transition.

The second lever is management, not machinery. Alongside the fuel switch, KAI has strengthened energy governance: consumption measurement, periodic monitoring, and evaluation across every regional operating division, backed by energy management training intended to build conservation awareness among frontline workers. Anne Purba has been explicit that this administrative layer, not just the biofuel blend, is treated as a distinct source of the efficiency gain.

The third lever is electrification and renewables at the margins. KAI has installed rooftop and depot solar capacity, with figures reported by the company ranging from 3,435.5 kilowatt-peak (kWp) across 66 locations in a June 2026 disclosure to 4,430.65 kWp across 92 locations in an April 2026 disclosure. Sirkularium notes this discrepancy rather than resolving it silently. Either figure remains a small share of total energy supply, but both point in the same direction: distributed solar generation at depots and stations is expanding steadily. KAI has also committed to 1,038.7 kilometers of electrified rail routes, including the Rangkasbitung-Merak, Cikarang-Cikampek and Bogor-Cigombong corridors, and is piloting Battery Electric Multiple Unit (BEMU) technology.

Why it matters for industrial decarbonization

Railways already carry a disproportionately small share of transport-sector emissions relative to the mobility they provide. Analysis cited by KAI's sustainability team places rail at roughly 1 percent of transport emissions in Indonesia, against approximately 89 percent for road transport, while emissions intensity for KAI's own services runs at 15 grams of CO2 equivalent per passenger-kilometer for the Jabodebek LRT and 16.43 grams per passenger-kilometer for intercity trains. That baseline efficiency is precisely why the 2025 intensity improvement is significant beyond KAI's own balance sheet: it demonstrates that a large, growing, state-owned operator can compress its energy footprint per unit of service using the same three levers, fuel substitution, management discipline, and incremental electrification, that apply across Indonesia's energy-intensive industrial sectors.

KAI's own net zero pathway, developed with support from the UK's Partnering for Accelerated Climate Transition (UK PACT) programme, Palladium and Kynergy Consulting, targets a 25.76 percent emissions cut by 2030 against a 647,785 ton CO2 equivalent baseline, rising to reductions cited as 33.55 percent by one company disclosure and 35.55 percent by another for 2035, a discrepancy Sirkularium flags rather than adjudicates, then 78.17 percent by 2050, before reaching net zero in 2060. KAI's Vice President of Sustainability, Tria Mutiari Meilan, and Kynergy Consulting's project director, Rekyan Eckersley, have both framed the roadmap around four pillars: electrification, operational efficiency, cleaner fuel, and carbon absorption through reforestation, KAI has planted more than 107,000 trees since 2021.

"Electrification allows us to reduce carbon emissions directly through system design while creating a more eco-friendly transport ecosystem," Tria Mutiari Meilan said of the company's roadmap.

The numbers behind the wider policy context

KAI's fuel transition sits inside a national biodiesel program with substantial macroeconomic weight. The government's B50 mandate, effective nationwide from July 2026, is projected by the Ministry of Energy and Mineral Resources to generate national foreign exchange savings in the range of Rp157.28 trillion to Rp177 trillion this year, alongside an estimated Rp24.68 trillion in added value for the crude palm oil supply chain and roughly 2.21 million jobs supported across that chain. KAI's own adoption of B40 and preparation for B50 places one of the country's largest state-owned transport operators inside that same policy architecture, converting a national energy security objective into measurable operational efficiency at the level of an individual enterprise.

Sirkularium's view

For government and public institution stakeholders, KAI's 2025 results offer a template rather than a one-off statistic. The company achieved its efficiency gain while growing ridership and freight volumes, which answers directly the concern that energy efficiency and service expansion are in tension. It reached that outcome through three levers that are all replicable elsewhere in Indonesia's state-owned enterprise portfolio and its broader industrial base: substituting toward higher domestic biofuel blends on an announced and predictable timeline, embedding energy measurement and accountability into routine operations rather than treating it as a one-time audit, and layering in distributed renewable generation and electrification where capital allows.

What is worth watching next is whether KAI's intensity gains persist as B50 rolls out nationally and as electrification projects on the Rangkasbitung-Merak and Cikarang-Cikampek corridors come online, since each represents a step change rather than a marginal improvement. Sirkularium also sees value in Indonesia's other state-owned enterprises and energy-intensive industrial subsectors, cement, steel, textiles and pulp and paper among them, publishing intensity metrics with the same transparency KAI has now demonstrated twice in a single year. Standardized, comparable intensity reporting across state-owned enterprises would give policymakers a much clearer picture of where efficiency investment is working and where it still needs support, financing or regulatory encouragement to scale.