Why would an oil company want to know how much fuel your supply vessel burned last month? For years, few charterers asked. Today, many of the companies that charter OSVs report their own emissions against shared frameworks, with independent checks. The Oil and Gas Decarbonization Charter (OGDC), signed by 55 producers, is one example. As their reporting becomes more structured, OSV emissions data faces the same scrutiny. As a result, for OSV owners, the question is shifting from how much a vessel emitted to whether anyone can trace, compare and trust that figure.
Understand How the Oil and Gas Decarbonization Charter Reaches OSVs
The COP28 presidency launched the OGDC in Dubai in 2023 to get national, private and independent oil and gas companies to speed up climate action. Its 55 signatories, from TotalEnergies and ADNOC to dozens of national oil companies, produce around 40% of the world’s oil.
Each backs the same goals: near-zero methane and an end to routine flaring by 2030, then net-zero emissions from operations by 2050. Signing is voluntary.
The reporting is what matters for vessel owners. In 2025, signatories shared emissions data for the first time using a common framework, and most of it underwent independent third-party assurance.
The Charter was launched at COP28 to get national, private and independent oil and gas companies to speed up climate action. In practice, it asks them to clean up how they produce, while the wider debate about how much they produce goes on.
The contract matters too. In many OSV time charters, the charterer pays for the fuel and directs the vessel’s daily work. So, the same vessel usually sits in the owner’s Scope 1, and can appear in either Scope 1 or Scope 3 for the charterer, depending on its approach.
Either way, a company that has its own figures checked will expect the same rigor from the vessel data it receives.
Read more: OGDC, 2025 (2025 Status Report: Implementing Action)
Read more: GHG Protocol, 2004 (Corporate Accounting and Reporting Standard)
Separate Voluntary Pledges from OSV Reporting Obligations
Two kinds of pressure are building, and they work differently.
The first is voluntary. The OGDC binds only its signatories. It can reach vessel owners indirectly, through tender questions, contract clauses, and the data charterers request.
The second is regulatory, and for vessels working in European waters it already applies:
- EU MRV: since January 2025, offshore vessels of 400 GT (gross tonnage) and above monitor and report their emissions on voyages linked to EU ports.
- EU ETS: from 2027, offshore vessels of 5,000 GT and above pay for those emissions, with allowances due in 2028.
- Proposed extension: in July 2026, the European Commission proposed bringing certain ships between 400 and 5,000 GT into the ETS from 2031, with offshore worksites in EU waters treated as ports of call.
- UK ETS: large offshore vessels enter the UK scheme from 2027.
At global level, the IMO will try again to adopt its Net-Zero Framework at its December 2026 meeting.
Both pressures lead back to the same place: the vessel’s daily report. The figure an MRV verifier checks is the figure a charterer will ask about.
Read more: Engine, 2026 (Proposed EU ETS review brings smaller vessels into scope)
Read more: Carbon Brief, 2026 (Q&A: How countries got the global net-zero shipping deal back on track)
Apply Three Tests to Your OSV Emissions Data
Most OSVs already report a lot. Daily reports carry fuel remaining on board, engine hours, position and activity. Collecting the data is largely solved. Turning it into a figure that holds up is the harder part.
Three tests tell a raw number apart from decision-ready emissions data.
Test 1: Can each tonne be attributed to an activity?
A daily total says how much fuel a vessel used. Attribution says what the vessel was doing when it burned it: transit, DP, standby or port.
That split changes the conversation. Across the fleets Opsealog monitors, PSVs and AHTS spend around 45% of the year on standby. In 73% of that time, the vessel has no work order or the worksite isn’t ready. Weather explains only 10%.
Attribution shows how much of a vessel’s footprint comes from waiting, and that the causes often sit in planning and worksite readiness, outside the vessel.
Test 2: Can it be compared consistently across vessels?
A fuel figure gains meaning next to similar vessels doing the same type of work. That comparison holds only when every vessel and every contract uses the same definitions. A standby hour on one PSV should mean the same thing on the next.
Opsealog’s 2026 Global OSV Market Report applies this across a full year of data from 239 vessels and 122 designs. Consistent definitions also expose energy losses between sister vessels that look identical on paper.
Read more: Opsealog, 2026 (2026 Global OSV Market Report)
Test 3: Can it be trusted and validated?
The crew, the owner’s office and the charterer can each hold a different version of the same day. An auditor will ask for the data.
A figure earns trust when it is checked against what the engines and sensors recorded, and every correction is logged. Opsealog’s activity scoring model reconciles reported data with sensor inputs for this reason. In one fleet, a slow steaming engine configuration long assumed to be efficient turned out to load the generators poorly and add emissions. Only high-frequency data showed it.
Put Decision-Ready Data to Work on Board and in Contracts
Data that passes all three tests does more than satisfy an auditor.
On board, it changes habits. Recommendations stick when crews understand why a vessel runs the way it does. In a six-month pilot on 25 BOURBON vessels, real-time monitoring combined with recommended best practices saved 45 to 50 tonnes of CO₂ per vessel each month.
It also measures change. In Angola, more than 1,700 daily reports gave a baseline solid enough to test a fuel additive on five vessels: 3.3% less fuel and about 3,600 tonnes of CO₂ avoided. The same method applies to a new engine or a new operating profile.
In contracts, it gives both sides one version. The owner can show where the fuel went. The charterer can see how much of it better planning would save.
Every vessel generates data. The value comes from what a team does with it.
Read more: Opsealog, 2024 (BOURBON and Opsealog partner to reduce fleet emissions)
Read more: Opsealog, 2026 (Marine Fuel Optimization Starts with Data)
Have the Answer Ready Before the Question Arrives
Back to the opening question. Oil companies want to know what your vessel burned because their own reporting is becoming more structured and more closely checked. Regulation is moving the same way for the vessels themselves.
Both will ask the same three questions. Can the figure be attributed to an activity, compared across vessels, and trusted?
The owners who can answer yes to all three will have the easier conversation.