Image credit Arc

Introduction

As ports, marinas, and harbor operations aim to reduce their environmental impact, they’ve had to set a new goal: establishing a new infrastructure that will support the necessary changes in vehicles and equipment.

Ports across the country are under increasing pressure to reduce emissions while maintaining the throughput necessary for global trade. But electrifying harbor operations is far more complex than replacing diesel engines with batteries. It requires new vessels and new charging equipment capable of delivering industrial-scale power in environments that were never designed for it.

Marine services provider Curtin Maritime has teamed up with Arc Boats, Snow & Company, AltaSea at the Port of Los Angeles, and Motive to address this challenge. Together, these industry leaders are creating, powering, and deploying one of the first electric tugboat fleets in the nation, alongside the megawatt charging platform to keep it operating.

Background

In 2006, the Port of Los Angeles introduced its Clean Air Action Plan (CAAP), an initiative to reduce emissions from port activity while maintaining the operational capacity that supports a major portion of the U.S. economy. The plan emerged as concerns were growing about air quality in the Los Angeles basin. Diesel particulate matter (DPM) had been classified as a toxic air contaminant, and the EPA identified diesel emissions as likely carcinogenic to humans.

With cargo traffic expanding rapidly, port authorities faced increasing pressure from regulators and surrounding communities to reduce emissions. CAAP became the framework guiding environmental progress at the port for decades. Early phases of the plan delivered major improvements. Cleaner trucks replaced aging diesel fleets, ships began plugging into shore power while docked, and cargo-handling equipment was modernized.

But by the late 2010s, many of the more easily achievable gains had been captured. The next phase of emissions reductions required focusing on equipment and systems that had historically been considered too complex, too distributed, or too operationally sensitive to change.

Challenge

Today, tugboats are one of the most significant remaining producers of emissions at the Port of Los Angeles. While they represent a relatively small share of the port’s harbor craft, their environmental footprint is disproportionately large.

Eliminating or slowing tugboat operations is not an option. Harbor assist vessels are essential to port logistics. They guide massive cargo ships safely through harbor channels, position vessels at berth, and assist during departures. Without them, vessel movements slow, schedules unravel, and congestion compounds throughout the port.

These harbor tugboats are strong candidates for electrification. They follow a predictable operating pattern, typically starting and finishing their day at the same base of operations. But while this can simplify charging logistics, it does not solve the problem of finding adequate power to charge these boats in time to maintain the rhythm of port operations.

Harbor assist vessels routinely push and pull cargo ships weighing more than 100,000 metric tons. Their propulsion systems must deliver tremendous bursts of force, known as bollard pull, within seconds. These duty cycles place extraordinary demand on their power systems. Electrifying tugboats therefore becomes an engineering challenge defined by power density, energy storage, reliability under extreme load, and recharge time under commercial duty cycles.

Approximately 17% of all US containerized trade passes through the Port of Los Angeles, and stops and delays will slow a significant portion of the American economy. There are two critical challenges to address when bringing electrification to harbor operations:

1. Creating electric harbor tugs
2. Ensuring the ports can power them reliably during short operational windows

Solution

Establishing a Fleet of Electric Harbor Tugs

Through a $160 million contract with Curtin Maritime, Arc Boats and Snow & Company are building a fleet of electric ship-assist tugboats for the Port of Los Angeles, located at AltaSea’s facility. Among the first of its kind, this is a fleet electric vessels that don’t produce fumes, require little maintenance, and use zero fuel.

• 8 electric ship-assist tugboats
• Over 4,000 horsepower per tug
• 6-8 megawatt-hour (MWh) battery system per tug
• 2 independent lithium battery systems inside the hull
• 55 tons of bollard pull

This electric tug design incorporates battery systems that are over 100 times larger than the battery packs found in most passenger EVs. Because of this, the power requirements for harbor operations using these electric tugs resembles industrial electrical demand, similar to what cranes, factories, or buildings require.

Using a charging system designed for a standard electric vehicle would result in a tugboat spending hours connected to a charger. This would ripple across the entire port operation: congestion would increase, vessel arrival windows would begin to overlap, and operational delays would stack throughout the harbor.

As the second part of our solution, we ensured charging would be fast, predictable, and reliable.

Powering the Fleet

To deliver the power and turnaround required at the port, Curtin Maritime partnered with Motive’s Sustainable Solutions division to design and deploy megawatt-scale charging infrastructure on the water. The resulting system is a barge-based charging platform built to withstand the conditions of harbor operations.

At the platform’s core are four 1-megawatt megawatt charging systems (MCS) capable of delivering high-voltage DC power while accommodating the demanding duty cycles and fast turnaround requirements of harbor assist operations.

Supporting those chargers is a 10-megawatt-hour battery energy storage system (BESS) that acts as an energy buffer for the entire operation.

Rather than pulling massive bursts of electricity directly from the grid during short charging windows, the battery system stores energy and dispatches it when needed. This approach helps:

• Stabilize power delivery during peak charging events
• Reduce sudden demand spikes on the local grid
• Ensure consistent charging performance during busy harbor operations

Pending port approval, planned solar resources are also intended to complement the battery system and further reduce lifecycle emissions.

The result will be a resilient energy system capable of delivering industrial-scale electricity directly where harbor operations require it.

Conclusion

Reducing emissions in ports and marinas is a technological challenge, but more critically it requires a change to the infrastructure supporting these operations. To truly affect change requires coordination between vessel operators, energy infrastructure providers, and port authorities, as well as engineering solutions that understand and respect the operational realities of maritime logistics.

At the Port of Los Angeles, Curtin Maritime, Arc Boats, Snow & Company, and Motive are demonstrating how those pieces can come together.

Electric harbor assist vessels provide the propulsion. A barge-based power platform with megawatt-scale charging bridges the gap between port operations and the electrical grid. And together, they set the stage for the next phase of port electrification.