Local browser workbook for vessel fuel records, MRV scope checks, CO2 totals, transport work, and EEOI.
| Vessel | Year | Voyage | Op. | Type | MRV scope | Departure | Arrival | Distance | Cargo | Fuel | CO2 | EEOI | Fuel types | Actions |
|---|
Save records to generate a report.
The NauticalSolver MRV CO2 Recorder is a private, browser-based workbook for recording ship fuel consumption and operational emissions data. It allows vessel operators, technical departments and marine engineers to keep separate records for sea passages, port stays, anchorage, manoeuvring, canal transits and other activities. Each record can include voyage identification, ports, operating time, distance travelled, cargo carried, fuel types, fuel quantities and user-selected MRV scope.
From these entries, the recorder calculates total fuel, vessel CO2 emissions, transport work, EEOI, fuel per nautical mile, CO2 per nautical mile, total recorded time and an overall distance-to-time ratio. Records can be filtered, grouped by vessel or voyage and exported as CSV, Excel, PDF reports or JSON backups. The tool is intended for internal recordkeeping, preliminary calculations and technical cross-checking before data enters a company’s controlled reporting and verification process.
Local-data notice: Records remain in the browser storage of the device being used unless they are exported. NauticalSolver does not receive or store the vessel, voyage or fuel information entered in this workbook. Clearing browser data, changing browsers or using another device may make the local records unavailable.
The workbook separates vessel details from individual operational records. This makes it possible to maintain data for more than one vessel while keeping each voyage or activity attached to the correct ship. The vessel profile can include the vessel name, IMO number, type, gross tonnage, deadweight, main-engine power, auxiliary-engine information, boiler notes and a default fuel type.
Each operation record can contain:
Keeping activities as separate records helps users review whether fuel has been assigned to the correct voyage, port stay or operational period. It also prevents port consumption, anchorage consumption and voyage consumption from being merged into one unexplained annual total.
The recorder performs direct arithmetic from the values entered by the user. It does not estimate fuel from engine power, speed or SFOC. Fuel quantities must therefore come from the operator’s chosen measurement or reconciliation method, such as tank soundings, flow meters, bunker records or another method defined in the company’s procedures.
Each fuel entry has a consumed mass and an emission factor. The recorder multiplies these values to obtain the CO2 emitted by that fuel row.
CO2 emitted (t) = Fuel consumed (t) × Emission factor (t CO2/t fuel)
When several fuels are used during the same operation, the recorder calculates each fuel separately and then adds the results. This is useful for voyages or port periods that include a fuel change, pilot fuel, blended fuel or separate consumption by different machinery groups.
Total fuel (t) = Sum of all fuel quantities in the record
Total CO2 (t) = Sum of all calculated fuel-row CO2 values
The fuel factors provided by the recorder are editable at record level, and users can create custom fuel factors. A default value is therefore a starting point rather than proof that the factor is appropriate for a particular fuel batch, regulatory system or reporting year.
For cargo entered in tonnes, the recorder calculates transport work as cargo mass multiplied by distance travelled.
Transport work (t·nm) = Cargo carried (t) × Distance travelled (nm)
This implementation uses tonnes and nautical miles only. It does not calculate transport work from TEU, passengers, lane metres, deadweight, cubic metres or other cargo-capacity units. When cargo quantity changes during a voyage, the operation should be divided into suitable records or the cargo value should be prepared according to the company’s approved method before entry.
EEOI expresses the CO2 emitted in relation to the transport work performed. The recorder converts total CO2 from tonnes to grams and divides it by tonne-nautical-mile transport work.
EEOI (g CO2/t·nm) = Total CO2 (t) × 1,000,000 ÷ Transport work (t·nm)
A result is available only when both distance and cargo are greater than zero. Port stays, ballast records and other operations with no tonne-based transport work may still contain valid fuel and CO2 information, but they cannot produce a tonne-based EEOI from this formula.
EEOI is a voyage or operational efficiency indicator. It should not be confused with an attained annual Carbon Intensity Indicator, which uses a separate regulatory calculation and ship-capacity basis. This recorder does not calculate required CII, attained annual CII or a CII rating.
Fuel per nautical mile = Total fuel ÷ Distance travelled
CO2 per nautical mile = Total CO2 ÷ Distance travelled
Total recorded time = Navigation hours + Ice hours + Anchorage hours + Port hours
Overall distance-to-time ratio = Distance travelled ÷ Total recorded time
The speed value shown by the recorder uses the complete recorded time, including anchorage and port time when those fields contain values. It is therefore an overall distance-to-total-time ratio. It should not be interpreted as the vessel’s average navigational speed unless the record contains only navigation time.
| Result | Implemented calculation | Displayed unit |
|---|---|---|
| Fuel-row CO2 | Fuel consumed × emission factor | t CO2 |
| Total fuel | Sum of fuel quantities | t |
| Total CO2 | Sum of fuel-row CO2 | t CO2 |
| Transport work | Distance × cargo carried | t·nm |
| EEOI | Total CO2 × 1,000,000 ÷ transport work | g CO2/t·nm |
| Fuel per distance | Total fuel ÷ distance | t/nm |
| CO2 per distance | Total CO2 ÷ distance | t CO2/nm |
| Total time | Sum of all four time categories | h |
| Overall speed value | Distance ÷ total recorded time | kn |
Consider a cargo-vessel operation with the following entries:
MGO CO2 = 20.000 × 3.206 = 64.120 t CO2
HFO CO2 = 5.000 × 3.114 = 15.570 t CO2
Total fuel = 20.000 + 5.000 = 25.000 t
Total CO2 = 64.120 + 15.570 = 79.690 t CO2
Transport work = 18,000 × 1,250 = 22,500,000 t·nm
EEOI = 79.690 × 1,000,000 ÷ 22,500,000
EEOI = 3.54 g CO2/t·nm
Fuel per nm = 25.000 ÷ 1,250 = 0.020 t/nm
CO2 per nm = 79.690 ÷ 1,250 = 0.063752 t CO2/nm
Total recorded time = 100 + 6 + 14 = 120 h
Overall distance-to-time ratio = 1,250 ÷ 120 = 10.42 kn
The factors in this example match values currently available in the recorder, but an actual report must use the factor and accounting treatment applicable to the fuel, documentation, monitoring method and reporting framework concerned.
A voyage record often needs more detail than one departure-to-arrival line. Fuel may be consumed while the vessel is at sea, waiting at anchorage, manoeuvring, operating cargo equipment, remaining in port or transiting a canal. Recording these periods separately can make fuel reconciliation easier and can provide a clearer explanation of why two voyages with similar distance and cargo produced different emissions.
Separate records are also useful when:
The selected MRV scope is stored as a manual category. Port names, countries and operation type may help the user review that choice, but the recorder does not make a legal determination of whether a voyage, ship, port call or activity falls within a current reporting or emissions trading system.
The recorder includes several commonly used marine fuel names and default CO2 factors. It also permits the factor in an individual fuel row to be edited and allows a custom fuel to be saved locally. This is important because the correct treatment of a fuel may depend on its specification, fossil or biogenic component, blend composition, sustainability evidence, reporting framework and the period being reported.
A physical combustion factor should not automatically be treated as a final regulatory factor. Methane slip, nitrous oxide, upstream well-to-wake emissions, eligible-fuel claims, zero-rating rules and lifecycle greenhouse-gas intensity are outside the calculator’s direct CO2 multiplication method. Where any of these matters apply, the result should be reviewed and adjusted within the appropriate controlled reporting system rather than assumed from the recorder alone.
Monitoring, reporting and verification frameworks require more than a numerical CO2 result. Depending on the applicable rules, a company may also need an approved or assessed monitoring plan, defined measurement methods, documented data sources, quality controls, evidence retention, uncertainty management, independent verification and submission through an official reporting platform.
The NauticalSolver recorder can support the preparation and checking of operational data, but it does not replace those processes. It does not determine ship eligibility, legal responsibility, port-of-call status, geographical scope, reportable greenhouse gases, allowance obligations, verification status or submission deadlines.
Compliance limitation: Treat every result as an internal calculation until it has been reconciled with the vessel’s source records, company procedures, applicable monitoring plan and the latest official requirements. The words “MRV” and “scope” in this workbook do not mean that a record has been legally classified or verified.
Port suggestions are provided to make data entry faster. The recorder combines a short list of commonly used ports, locally saved custom ports and a larger optional port dataset. Users can still type a port manually when it does not appear in the suggestions.
Suggested names, codes, countries, coordinates and regional descriptions must be checked before they are used in a controlled report. Port databases can contain historical, incomplete or differently formatted entries, and a suggested code should not be treated as official UN/LOCODE validation.
The workbook stores vessels, records, custom ports, custom fuel factors and settings in local browser storage. This supports private day-to-day use without sending operational records to a NauticalSolver server. However, local browser storage is not a managed company database and is not a substitute for an approved document-retention system.
The available export options serve different purposes:
Exporting a JSON backup regularly is recommended, especially before clearing browser data, replacing a device, changing browser profile or carrying out a large import. A backup should also be stored in accordance with the company’s own access-control and data-retention procedures.
Does the MRV CO2 Recorder upload vessel data?
No. The attached implementation stores records in the user’s browser.
Data leaves the browser only through an export or another action initiated
by the user.
Why is the EEOI result unavailable?
A tonne-based EEOI requires both distance and cargo to be greater than
zero. A port stay, ballast condition or incomplete record may therefore
have fuel and CO2 totals without an EEOI value.
Can several fuels be entered in one operation?
Yes. Each fuel row is calculated separately using its entered emission
factor, after which the recorder totals the fuel and CO2.
Does the tool decide whether a voyage is within EU or UK scope?
No. Scope is selected manually. The user must apply the latest official
rules and the company’s controlled procedures.
Is the generated PDF an official emissions report?
No. It is a locally generated technical summary. Formal reports may
require prescribed formats, independent verification and submission
through an official platform.
Is EEOI the same as CII?
No. This recorder calculates a tonne-based EEOI from entered fuel, cargo
and distance. It does not calculate attained annual CII, required CII or a
ship rating.
The following tools can be used for separate calculations and technical cross-checks:
The following primary sources provide further information. Always consult the latest version and any company-specific guidance applicable to the vessel:
NauticalSolver provides this recorder for educational, preliminary and internal technical use. Final emissions data must be checked against source documents, approved procedures and the requirements applicable at the time of reporting.