855-200-01-0 Propulsion System Cost Comparison.pdf

Owner: State of Michigan Department of Natural Resources Charlevoix Fisheries Research Station

96 Grant St.

Charlevoix, MI 49720

855-200-01 Hybrid vs. Standard Propulsion System Cost Comparison

Rev 0 – March 24, 2023

Written by: Boksa Marine Design, Inc 16627 Fishhawk Blvd., Suite 101

Lithia, FL 33547

(813) 654-9800

Rev: 0

Date: 3/24/2023

REVISIONS

REV. DESCRIPTION BY DATE

0 Release for discussion JHP 3/24/2023

GROUP 1 - SUMMARY

SECTION 101 – INTRODUCTION

A research vessel is being designed to replace the M/V Steelhead, which had twin diesel engines, reduction gears, shafts, and propellers. As part of the design process, BMD is investigating the cost of a similar conventional diesel propulsion system, vs. any hybrid or more environmentally conscious. This document summarized the cost differences, as well as the operational differences between conventional propulsion and a hybrid propulsion arrangement.

The options investigated include:

1. Conventional diesel propulsion

2. Hybrid-diesel propulsion (158 kWh battery bank)

3. Conventional diesel propulsion build, with a hybrid retrofit taking place ~10 years later

Based on the mission and use of this vessel, BMD recommends Option 1 as the most cost-effective.

If Michigan DNR requires a hybrid system, Option 2 would be the recommended route, at an up-front cost of approximately 1.67 x Option 1.

When considering operational costs, a conventional diesel propulsion system should be considered as a similar operational cost, except for the replacement of batteries during major overhaul periods or in event of failure. This can be annualized to approximately $8-10,000 per year. The annual fuel and electrical costs are also summarized below, as an illustration of cost benefits.

SECTION 102 – VESSEL PARTICULARS

Length, Molded 77’-11”

Length, Waterline 73’-4”

Beam, Molded 26’-0”

Draft, Scantling 6’-0”

Displacement (prelim.) 145.5 LT

GROUP 2 – CONSTRUCTION COST ANALYSIS

INTRODUCTION

This section provides approximate prices to compare each option.

Only the items listed/described below are included in this cost analysis. Items in the propulsion and electrical system that will NOT change between options are not discussed. These items generally include:

- Propeller, shafts, bearings, & seals

- Engine auxiliary systems, engine room equipment, etc.

- Standard electrical distribution system

All costs are estimated in 2023 dollars. This estimate also generally includes a 10% shipyard markup on materials and subcontractors.

OPTION 1 – CONVENTIONAL DIESEL PROPULSION

Total Cost for items investigated: $505,000

The estimated costs for Option 1 are to be used as a baseline for comparison with other options.

Specific engine and gear model numbers are not described here, but these costs are meant to represent standard EPA Tier 3 Cummins, CAT, or John Deere engines with corresponding gearboxes. A summary of all equipment included in this cost includes:

- 440 hp diesel engine (425-450 hp range, depending on usage rating)

- Reduction gear, 2.5:1 ratio, 7 deg. down angle (or similar)

- 30 kW 120/240V diesel generator

OPTION 1

SWBS Section Notes Cost

100 Structure $0 200 Propulsion Systems Diesel engines & gears $450,000 300 Electrical Systems $0 400 Command & Control $0 500 Auxiliary Machinery Generator $55,000 800 Shipyard Support $0

$505,000

OPTION 2 – HYBRID-DIESEL PROPULSION

Total Cost for items investigated: $847,000

To estimate the cost for Option 2, the cost estimate from Option 1 was adjusted by adding the following:

- 158 kWh battery bank and rack

- Additional 30% to estimated gearbox cost to replace with a parallel-hybrid type

- Reduction of 5% to engine cost to account for lower top-end power requirement (425hp instead of 440 hp, for example)

- 25 kW electric propulsion motor

- Battery charging system and shore connection

- Battery & motor management system, including cabinets, wiring, panels, & controls

- Battery room gas detection system

- Battery cooling system

- Battery room fire suppression

- Battery room A60 fire insulation

- Removal of diesel generator

- Additional $20,000 to electrical system to account for added complexity

- Additional $70,000 contingency to shipyard support cost to account for added complexity

OPTION 2

SWBS Section Notes Cost

100 Structure Add fire insulation $8,000 200 Propulsion Systems Hybrid gearbox, smaller engine, electric motor $528,000 300 Electrical Systems Battery bank & rack; added complexity $233,000 400 Command & Control Add battery management & hybrid controls $25,000 500 Auxiliary Machinery Add gas detect, fire suppr, & cooling -$17,000 800 Shipyard Support Contingency to account for shipyard complexity $70,000

$847,000

OPTION 3 – HYBRID RETROFIT IN 2033

Total Cost for Option 1, copied form above: $505,000

Total Cost for Retrofit in 2033 (for items investigated): $651,000

Option 3 total cost: $1,156,000

This section includes two costs – Option 1 is used as the 2023 cost, and the items added below are meant to indicate the estimated 2033 cost IN 2023 DOLLARS. Please note this is a rough estimate and does not attempt to predict or adjust for changes in equipment cost, inflation, labor costs, etc.

The following items are included in the estimate 2033 cost:

- Removal of conventional gearbox

- Installation of parallel-hybrid gearbox, keeping engine on same foundation

- 25 kW electric propulsion motor

- 158 kWh battery bank and rack

- Structural changes to install and provide foundations to battery bank

- Battery charging system and shore connection

- Battery & motor management system, including cabinets, wiring, panels, & controls

- Battery room gas detection system

- Battery cooling system

- Battery room fire suppression

- Battery room A60 fire insulation

- (Note this scenario assumes the existing generator remains, and battery bank is not replacing the generator for AC electrical consumers)

- Shipyard support and labor to install equipment

- Additional $30,000 contingency to account for engineering, design, layout, or tankage changes

OPTION 3 (IN ADDITION TO OPTION 1)

SWBS Section Notes Cost

0 Engineering Engineering design contingency $30,000 100 Structure Structure mods for batteries, additional insulation $26,000 200 Propulsion Systems Switch gearbox with hybrid gearbox, add motor $224,000 300 Electrical Systems Add battery bank & rack $213,000 400 Command & Control Add battery management & hybrid controls $25,000 500 Auxiliary Machinery Add gas detect, fire suppr, & cooling; remove gen $38,000 800 Shipyard Support Labor & additional shipyard complexity $95,000

$651,000

GROUP 3 – OPERATIONAL DISCUSSION

SECTION 301 – FUEL & ELECTRICITY USAGE

The following chart provides an estimate of seasonal fuel and electricity usage in different scenarios.

Please note this is meant to be used as a tool for comparison, NOT as accurate numbers to predict the vessel’s performance. Fuel and electrical usage are highly dependent on operating missions. This table also assumes that you are charged for electrical consumption.

OPTION 1 - CONVENTIONAL DIESEL PROPULSION

Usage Fuel Consump.

(gal/yr)

Fuel Cost ($/yr)

Electricity From Shore (kWh/yr)

Electricity Cost ($/yr)

Total Fuel & Elect Cost ($/yr)

Average 7600 $34,200.00 9500 $1,805.00 $36,005.00

More Low Speed, Less High Speed

4560 $20,520.00 17800 $3,382.00 $23,902.00

More High Speed, Less Low Speed

10640 $47,880.00 7100 $1,349.00 $49,229.00

Fuel Cost $4.50 Electricity Cost $0.19

SECTION 302 – BATTERY REPLACEMENT

The current operators are familiar with maintenance and operation of a conventional diesel propulsion system. The costs summarized in Group 2 include information and basic training from battery and hybrid propulsion vendors on proper equipment use and maintenance.

A battery-hybrid system will require replacement of batteries over time. This battery replacement cost can be annualized to an estimation of 5-7% of up-front (battery-only) cost per year. On this vessel, that can be annualized to between $8,000-$10,000 per year.