Zero-Emission Harbor Tug Initiative
Frequently Asked Questions
Everything you need to know about the world’s largest zero-emission harbor tug program — eight battery-electric tugs, two ports, one historic commitment to clean air.
Engineering A Cleaner Tomorrow
8
Battery-Electric Tugs
Ports of LA & Long Beach
$200M
Total Investment
Vessels + charging infrastructure
6 MWh
Battery Capacity
Per vessel
100%
Emission Reduction
Zero exhaust at point of operation
Section 01
About the Program
It is the largest marine zero-emission tug program in the world — eight battery-electric harbor tugs for the Ports of Los Angeles and Long Beach, backed by $200 million in combined vessel and charging infrastructure investment. Curtin Maritime leads the program alongside Arc Boats (powertrain and battery systems), Motive Energy (charging), and Snow & Co. Shipyard in Seattle, where the boats are being built.
We are a California-based harbor services company with over 550 employees. We run the largest Tier 4 emissions-compliant tug fleet in the country and own 50% of Snow & Co. Shipyard in Seattle, where all eight ZE tugs are being built. The ZE program operates publicly under the Curtin Harbor Services brand.
Harbor tugs run around the clock in the middle of port communities — assisting large cargo ships in and out of berth on every shift. Tugboats are significant contributors to port-area diesel emissions, and they operate right where people live and work in San Pedro and Wilmington. POLA and POLB together handle about 40% of U.S. container imports, so decarbonizing harbor tugs here has national reach, not just local impact.
Our first vessel, the Tuuli C, launched May 5, 2026 and is in the water undergoing outfitting. Sea trials start in October 2026. The second vessel launched August 18, 2026. This is active commercial deployment — not a pilot or a proposal.
Hull #1 (55-ton, Tuuli C): California arrival December 2026
Hull #2 (55-ton): Sea trials February 2027
Hull #3 (70-ton): Launch March 2027
Hull #4 (70-ton): Launch June 2027
Hulls 5–8: Construction starts mid-to-late 2027
Target: Four tugs in service by Q1 2028; all eight by Q4 2029.
Hull #2 (55-ton): Sea trials February 2027
Hull #3 (70-ton): Launch March 2027
Hull #4 (70-ton): Launch June 2027
Hulls 5–8: Construction starts mid-to-late 2027
Target: Four tugs in service by Q1 2028; all eight by Q4 2029.
Yes, and that is the plan. The charging facility deploys anywhere without fixed infrastructure at the destination. We are working with MARAD on a federal framework to fund this model at major U.S. ports. As larger ports upgrade to electric, cleaner diesel tugs cascade to smaller ports across the nation. We intend to share and license the technology rather than keep it proprietary.
Section 02
Vessels & Technology
Yes — performance parity with diesel was the non-negotiable design requirement. Three classes cover the full range of ship-assist work: 55-ton bollard pull for standard container and cargo vessels, 70-ton for larger ships, and 100-ton class for the heaviest jobs.
Each vessel carries a 6 MWh battery pack. A full charge from 0 to 100% takes approximately 2.5–3 hours on megawatt-class MCS fast chargers. Vessels have both AC and DC charge inlets for operational flexibility.
The tugs were designed to handle a full working day of escorting and docking ships in the Ports of LA and Long Beach. Sea trial data currently being collected will provide comprehensive endurance figures under real operating conditions.
Arc Boats telemeters all vessel data wirelessly in real time — power draw, charge cycles, geolocation by charging station, and operating loads. Every boat in the fleet is a live data source, supporting grant reporting, R&D, and customer emissions accounting.
Yes. The vessels were designed with open, configurable space above deck for alternate fuel configurations. They can be retrofitted with hydrogen fuel cells as that technology matures and becomes cost-effective. What we are building now will not be obsolete in five years.
Section 03
Charging Infrastructure
No. Existing 480V/400A shore power at both POLA and POLB supports overnight charging from day one — no new infrastructure required to get started. Permanent fast-charging facilities follow as the program scales. The charging infrastructure is being designed with self-generation micro grids, powered by natural gas or hydrogen, to ensure the project adds no strain to the current grid.
Curtin is building one charging facility per port. At POLA, our Berth 56/AltaSea site is in plan check with LADWP and LA DBS. The centerpiece is a barge carrying a 10 MWh battery storage system and four MCS fast chargers — the 10 MWh buffer ensures available energy during micro grid maintenance. Fast charging at POLA targets Q1–Q2 2027. The Long Beach site is in active planning.
Section 04
Environmental Impact
Zero exhaust at the point of operation — no diesel combustion, no particulate matter, no NOx. Harbor tugs currently run all day in San Pedro and Wilmington, communities that have carried a disproportionate air quality burden from port operations for decades. Eight fewer diesel tugs operating in that neighborhood is a direct, measurable improvement for the people who live there.
Compared to a conventional Tier 3 harbor tug, the annual reductions per vessel are dramatic: over 1,400 tons of CO₂ and 11 tons of NOx + HC displaced every year. That’s the equivalent of removing more than 180 semi-trucks — or roughly 300 passenger cars — from the road.
Section 05
Regulatory & Policy
California ports submitted decarbonization plans in February 2024, with implementation starting in 2030. Curtin’s program is something ports can contract right now. We are working with CARB, AQMD, POLB, and POLA to ensure ZE harbor craft are recognized as a critical component for ports to meet those targets.
BACT — Best Available Control Technology — is CARB’s designation for the cleanest viable option in a given equipment category. If CARB designates battery electric as BACT for harbor tugs, it becomes the standard every new tug in California must meet. That changes the market permanently and reduces long-term dependence on grants. Securing this designation is one of our primary regulatory goals.
Yes. Every ZE Tug job invoice arrives with an audit-grade certificate stating the emissions of that specific tug job: zero tank-to-wake, with metered energy data behind it. The customer receives two things on one invoice: the tug job itself, and a clean, defensible line item for emissions disclosure their sustainability office is already required to produce.
Section 06
Our Partners
Arc is a company operating on the leading edge of battery propulsion technology. Founded by Mitch Lee and Ryan Cook, Arc designs their battery packs, powertrain, thermal control systems, and software in-house — and installs and commissions all components directly. This full-lifecycle model separates Arc from the field and delivers unmatched functionality and quality. Their powertrain is the heart of every ZE tug.
For years, Motive has been at the forefront of the EV energy sector, crafting innovative, customized solutions. They bring broad experience in EV program development, project design, LADWP and SCE collaboration, permitting, and facility installation. Their ability to shepherd a charging infrastructure project from concept to installed facilities makes them the ideal partner.
Snow is a premier boatbuilder and ship repair company in Seattle’s Ballard shipbuilding hub — a powerhouse creating high-performance commercial vessels for the fishing industry, government agencies, tug operators, and aquaculture companies. Curtin holds a 50% ownership stake in Snow, which eliminates the traditional disconnect between builder and operator, giving us direct control over timely delivery and program viability.
Section 07
Working With Us
Yes. Curtin will operate the first boats ourselves while we prove them in commercial service. As the program grows, we are open to direct charters, leases, partnerships, and vessel sales. We are already in charter discussions with other operators and have offered four contracting structures. Reach out to discuss which arrangement fits your operation.
We are actively working with PACAC (Port Community Action Committee), the Coalition for Clean Air, and the Harbor Community Benefit Foundation. Community voices carry real weight in SCAQMD proceedings and with CARB. We want organizations in San Pedro, Long Beach, and Wilmington at the table as partners. Email us at ZETI@curtinmaritime.com to connect.