What is Bunkering?• Bunkering

– Filling ships and barges with fuel used to power ships

• Bunker– Gets its name from the containers on ships and in ports

that it is stored in– In the days of steam they were coal bunkers but now

they are bunker-fuel tanks

• Bunker fuel– Technically any type of fuel oil used aboard ships

Fuel Bunkering Market• Bunker Fuel Brokers

– Work as independent agents brokering fuel between two parties

• Shore Supplier (terminal)– Might sell fuel to the barge company or directly to ship

• Barge/Bunkering Company– Transfers fuel to the ship owners– May or may not own oil

• Ship Owners– Purchases fuel from barge owner or shore supplier

Tank Strapping / Gauging

Bunker Sources of Error

Bunker Tank

1 cm tape error = 0.25% error for a 4m level

Potential savings on 9000 tonne stem $7,500

°C°C

Bunker Sources of Error – Temperature

°C °C °C °C °C

Placement of temperature probe is critical for optimum volume to mass conversion

Is the temperature measurement representative of total bunker?

Average calculation vs single pointSavings can be significant 2°C error on temp (avg) = 0.1%

error for a 991g/l product at 50°CSavings $$$

Tank A Tank B

D

Sources of Error - Density & Stratification Sources of Error - Density & Stratification Sources of Error - Density & Stratification Sources of Error - Density & Stratification

Tank Stratification

Errors of 0.25% to 1.5% possible

Consider a Bunker with 5% Entrained Air

Mass for MassA direct mass measurement will give a negligible error

Mass for MassA direct mass measurement will give a negligible error

Volume for UncertaintyA volume measurementwill give a + 5% error

Volume for UncertaintyA volume measurementwill give a + 5% error

– $654/MTn x 3000tns = $1.96M/Bunker• (A 1% volume error due to air = ~$20,000)

– Drive Gain can be used to indicate presence of entrained gas

Bunker Sources of Error – Volume to Mass Conversion

Manual

Conversion formula:Actual volume > net volume > weight(vac) > weight(air) =(?)% calc error

Volume-based Measurement

Automated

BDN

Direct Mass Measurement

Custody Transfer Processes• Custody transfer is simply an agreement between two Parties:

Buyer and Seller

However, the Bunkering process is not so simple

Bunker Fuel Custody Transfer

• Make sure “I’m getting what I’m paying for”

• Eliminate idle/downtime due to refueling operation

• Reduce the number of billing discrepancies and arbitration claims

• Repeatable, accurate measurement – globally accepted

• Reasonable capital costs to support operations

• Lifecycle cost considered for operational efficiency

Operating VesselBargeFuel Storage Terminal

Bunkering custody transfer needs are the same as other industries

Bunker Fuel Custody Transfer Challenges

• During Validation– Volume to mass conversions– Temperature compensations– Stacked uncertainties of reference

system– Product quality concerns

• Actual Operational Challenges– Inherent differences between tank

measurements – Entrained gas (Air bubbles) – Product holdup in barge pipelines– Placement of meter for buyer’s confidence– Potential for backflow through meter

Operating VesselBargeFuel Storage Terminal

Fuel Bunkering Custody Transfer

Main Line

Storage

Barge

Refinery

PumpStation

Container Vessel

Fuel Bunkering Custody Transfer

Fuel Tank To Engines

Barge

On Barge Deck

Below the Deck of Vessel

Shipping Vessel

Hose