Page 46: of Marine News Magazine (May 2019)

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INLAND PROPULSION

There are some minor differences in the systems. First,

VESSEL: 1800HP the total brake horsepower of each system is slightly dif-

LOCKING RIVER TOWBOAT:

Some basic assumptions for the life cycle cost analysis ferent. The mechanical system has 1800 BHP while the include both a 365 day per year operational tempo with a DE/ES has a maximum of 2000 BHP. Another difference is the mechanical-based design has a total of four engines, 40-year vessel life cycle.

with two of those engines being required to be EPA Tier

IV, while the electrical propulsion design utilizes only three

Tier III generators. The DE/ES system used for these cal- culations is a DC bus system. The system uses AC gen- erators and AC propulsion motors. However, the main propulsion bus is DC. This provides for a smaller, more reliable system and cost-effective solution.

A DE/ES system does increase the initial capital costs of the towboat. This increase is equal to about $400k increase in overall construction cost of a typical 1800HP towboat.

Most of that increase is due to the costs of the batteries and associated battery equipment.

OPERATIONAL COSTS (OPEX)

Operational costs are broken down into two categories:

Fuel Costs and Maintenance Costs. For example:

Capital Cost Comparison

May 2019 46 MN