Bunkering refers to the process of supplying fuel to ships, a critical operation in the maritime industry that ensures vessels have the necessary energy to power their engines and auxiliary systems. This typically involves the transfer of fuel from a storage facility or bunker barge to a vessel and can occur either at sea or in port.

There are several types of bunker fuels used in shipping, each differing in composition, cost, and environmental impact. Conventional liquid marine fuels are generally divided into two categories: distillate fuels and residual fuels.

Distillate fuels, such as Marine Gas Oil (MGO) and Marine Diesel Oil (MDO), are lighter, cleaner-burning fuels commonly used in smaller vessels or in Emission Control Areas (ECAs) due to their lower sulfur content and reduced emissions.

Residual fuels are heavier, less refined, and more cost-effective, making them the preferred choice for large, ocean-going vessels. These include High Sulfur Fuel Oil (HSFO), which contains up to 3.5% sulfur and is typically used by ships equipped with scrubbers, and Very Low Sulfur Fuel Oil (VLSFO), which contains no more than 0.5% sulfur to comply with the IMO 2020 regulations without the need for exhaust gas cleaning systems.

Beyond conventional fuels, Liquefied Natural Gas (LNG) is emerging as a cleaner alternative. Composed primarily of methane and stored at cryogenic temperatures, LNG offers significant emissions benefits—producing virtually no sulfur oxides (SOx), up to 90% less nitrogen oxides (NOx), and significantly lower carbon dioxide (CO₂) compared to traditional fuels—making it an attractive option for compliance with evolving international environmental standards.

While bunkering operations occur globally, a few strategic locations serve as major bunkering hubs, positioned along key trade routes. Singapore is the world's leading bunkering port, recognized for its efficiency, regulatory oversight, and scale. Fujairah in the UAE plays a critical role in the Middle East, particularly for ships transiting the Strait of Hormuz. In Europe, Rotterdam leads in both conventional and LNG bunkering capabilities. Other important hubs include Hong Kong, Shanghai, Panama (especially near the Panama Canal), and Los Angeles/Long Beach on the U.S. West Coast.

Kpler’s Bunker Tracking Reports are designed to provide comprehensive, near real-time insights into global bunkering activity. The product delivers live estimates of bunker fuel sales, along with detailed analysis of bunker supply operations. This includes the activity and distribution of bunker barges, the characteristics of supplying installations, and the profiles of receiving vessels at each major port.

Kpler’s bunker activity tracking is centered around the monitoring of bunker barge movements at each port. This enables the analysis of barge activity, including berthing at storage installations and engaging in ship-to-ship (STS) transfers with receiving vessels.

Kpler employs a proprietary estimation model to calculate the volume of fuel delivered, factoring in vessel characteristics (e.g., size and type), bunker prices, historical port-level sales data, and prevailing market trends. This approach allows for a real-time "nowcast" of monthly bunker sales, enabling the release of complete monthly estimates by the first day of the following month—well ahead of official figures, which are typically released 15–20 days later.

For ports other than Singapore, the estimated volumes are split by fuel grade (e.g., HSFO, VLSFO) based on vessel scrubber status and regression models built using recent official sales data. In Singapore, where each bunker barge typically carries only a single fuel grade, the grade of the fuel delivered is determined at the individual barge level, allowing for greater accuracy.

By analyzing bunker barge berthing patterns at onshore installations and floating storage units (such as VLCCs—particularly prevalent in Singapore), Kpler estimates the share of bunker volumes supplied by each installation. This analysis allows clients to identify key players in the supply chain and benchmark their performance relative to competitors.

Kpler provides bunker delivery estimates broken down by individual barge. This enables stakeholders—such as fuel traders, buyers, and barge operators—to assess operational efficiency and market presence. In Singapore, barges are further categorized by fuel grade (HSFO or VLSFO) for more granular insights.

The platform also tracks all receiving vessels that take bunker from barges each month. These are categorized by vessel type (e.g., Wet Bulk, Dry Bulk, Container) and sub-type (e.g., VLCC, Suezmax, Aframax), helping users understand the demand side of the market.

Kpler consolidates a forward-looking view of vessel traffic with a 7-day lookahead of all vessels expected to call at a given port. This includes the combined average deadweight tonnage (DWT), giving clients a near-term forecast of expected bunker demand.