eTRU Power Requirements Explained: How Much Energy Does an Electric Reefer Use?

Erika Thorson

Electrifying refrigerated trailers is one of the most effective ways facilities can reduce diesel consumption, cut emissions, reduce maintenance, and meet ongoing compliance requirements. Before investing in electrification, facilities need to understand how much power an eTRU uses, what it means for operating costs, and how those requirements impact ROI.

This article breaks down real-world eTRU power needs, what facilities should expect across common operating conditions, and how to plan electrical capacity that supports both today’s fleets and the next generation of refrigerated trailers.

How Much Power Does an eTRU Use?

Electric TRUs draw different amounts of power depending on whether they’re actively cooling down a trailer or maintaining its temperature. These modes directly influence how yards, warehouses, and distribution centers plan electrical capacity.

Pulling Down Temperature (Heavy Load)

This occurs when a trailer first connects to shore power and must pull the temperature of the trailer down to the required temp.

Typical power demand:

  • 15 to 17 kW
  • Duration: 45 to 60 minutes per cycle

This is the peak load a facility should account for when designing electrical capacity.

 Maintaining Temperature (Light Load)

Once a trailer reaches its target temperature, it enters a steady operating mode that represents the majority of TRU runtime.

Typical power demand:

  • 8 to 12 kW
  • Represents 80 to 90 percent of operating hours

This range is the most important for planning continuous load availability.

How eTRU Power Use Compares to Diesel TRUs

Understanding energy demand is only part of the equation. Many facilities also want to know how electric standby compares directly to diesel operation.

Here’s what changes when a TRU runs on electricity instead of diesel:

✔ No fuel burn during idle

A diesel TRU typically consumes close to a gallon of fuel per hour while maintaining temperature. Electric standby removes that consumption entirely.

✔ Lower operating cost per hour

Electricity is consistently less expensive than diesel across most commercial markets, leading to significantly lower hourly operating costs.

✔ Less engine wear

Reduced idling helps extend engine life and cut maintenance costs by reducing run hours.

✔ Cleaner and quieter operation

Electric standby eliminates diesel exhaust and reduces noise, improving working conditions and community impact.

See How Much Your Facility Can Save With Electric Standby

Run the numbers for your operation and compare diesel costs to electric power.

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Why These Power Levels Matter for Infrastructure Planning

Not every trailer operates at peak load simultaneously. Most facilities see a predictable mix:

  • A few trailers in temperature pull-down
  • The majority maintaining temperature
  • Several unplugged, staging, or moving

Understanding this natural diversity helps avoid oversizing or undersizing electrical systems and ensures consistent power availability without unnecessary cost.

Circuit and Power Requirements for eTRUconnect

Electric standby systems rely on clean, consistent power delivery, and that’s exactly what eTRUconnect is designed to support. The system integrates the key electrical requirements needed for reliable TRU operation, including:

  • 480VAC service to provide power to TRU’s
  • 30 A branch circuits sized specifically for electric standby
  • Built-in branch circuit protection for safe, compliant operation
  • Safety-interlocked connectors that automatically cut power during disconnect

These design elements help ensure safe operation, protect equipment, and provide the dependable power TRUs need during both pull-down and temperature maintenance.

How to Estimate Your Yard’s Power Needs

Facilities can get a clear picture of required electrical capacity with a simple three-step approach:

  1. Count Your Connection Points
     Include docks, yard positions, and any planned expansion areas.

  2. Estimate How Trailers Typically Operate
    Most sites have a mix:  some pull-down, some maintain temperature, and some are unplugged or staging. Determine your general mix.

  3. Apply the Expected Power Ranges
    • Pull-down: 15–17 kW
    • Maintain: 8–12 kW

This gives a realistic view of both peak demand and everyday continuous load. Leaving extra capacity helps accommodate fleet growth and future electric TRU technology.

Future Proofing: Planning for What Comes Next

Today’s electric standby TRUs operate within predictable power ranges, but the next generation of battery-electric TRUs will require more capacity, new connector types, and smarter power management. Preparing for these shifts now can help facilities avoid costly retrofits later.

Looking ahead, operations should expect:

  • Higher AC power needs
  • More diverse charging and connector standards
  • Increased demand for monitoring and load management
  • Greater emphasis on scalable infrastructure

Building electrical systems with future capacity in mind allows facilities to transition smoothly as technology evolves, regulations tighten, and more electric-powered equipment enters the market. Electrification is accelerating across the cold chain, and yards that plan ahead will be positioned to support both today’s eTRUs and the fully electric fleets of tomorrow.

Ready to Plan Electrification for Your Facility?

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What Is eTRU and How Does It Support Cleaner Cold Chain Operations?

Erika Thorson

Refrigerated transport is one of the most critical links in today’s supply chain, but it’s also among the most energy-intensive. For decades, diesel-powered transport refrigeration units (TRUs) have been the standard for keeping cargo at temperature in trailers and box trucks.

Now, as fuel costs climb and emissions standards tighten, the cold chain industry is shifting toward a cleaner, smarter solution: electric transport refrigeration units, known simply as eTRUs.

What Is an eTRU?

An electric transport refrigeration unit (eTRU) allows a refrigerated trailer or truck to maintain temperature by plugging into the local electrical grid instead of running its diesel engine.

When connected to a truck shore power system such as ESL Power Systems’ eTRUconnect®, the TRU draws roughly 20kWof electricity, enough to power its cooling system efficiently while idle at a warehouse, terminal, or cold storage yard.

In short: eTRUs replace fuel burn with electricity, reducing emissions, operating costs, and maintenance, without compromising performance.oom for error. If a shore power connection fails, ships can’t run as planned and valuable cargo could be delayed or put at risk.

Why Electric Standby Matters for Fleets and Facilities

Every hour a diesel TRU idles, it burns close to a gallon of fuel and adds hours of engine wear. Switching to electric standby changes that equation:

  • 50–65% lower running costs compared to diesel
  • 20–30% longer engine life from reduced idle time
  • ROI in 12–18 months 

For distribution centers managing multiple trailers, these efficiencies translate into thousands in annual savings, and a faster path to sustainability compliance.

Check out our eTRU Webinar Series for a deeper look at fleet electrification, compliance planning, and real-world implementation strategies. 

Reducing Emissions and Meeting Compliance Goals

Electrifying TRUs has quickly become a key part of how fleets meet evolving emissions rules.
Agencies such as the California Air Resources Board (CARB) and local air districts (AQMD) are mandating cleaner operations across the supply chain.

Running TRUs on electricity instead of diesel helps facilities align with:

  • CARB’s Zero-Emission TRU Rule:  requiring new zero-emission TRUs by 2031–2035
  • AQMD Rule 2305:  reducing emissions from warehouses over 100,000 sq. ft.
  • Corporate sustainability initiatives linked to greenhouse-gas reduction targets

And there’s a community benefit too: electric standby eliminates noise pollution, improving air quality and working conditions for nearby residents and employees alike.

Sustainability That Pays Back

Electric standby systems aren’t just cleaner and cost efficient, they can generate revenue.

Through the Low Carbon Fuel Standard (LCFS), fleets that replace diesel with electricity earn credits for every kilowatt-hour used, typically worth $0.07–$0.10 per kWh. These credits can be reinvested into additional electrification projects or used to offset operating costs.

Across the U.S. and Canada, utilities also support truck shore power adoption with:

Regional incentives in states like California, Missouri, Texas, and Oregon

Infrastructure rebates covering design and installation

Up to 50% cost coverage on qualified equipment

Safety and Engineering Built for Real-World Use

Cold chain yards are tough environments exposed to weather, heavy traffic, and constant use. That’s why ESL’s eTRUconnect® is engineered for safety, compliance, and durability in the field:

  • UL/cUL Listed and NEC-compliant construction
  • Safety-interlocked connectors that disable power during disconnect
  • Dual drive-off protection that cuts power automatically if a trailer  pulls away.
  • Corrosion-resistant, NEMA 3R enclosures built for harsh conditions

These features protect both operators and equipment, helping facilities prevent downtime, avoid repairs, and maintain continuous operation.

For a deeper look at how eTRU systems operate and what to consider during implementation, check out our guide What You Need to Know About eTRU.

Future-Proofing the Cold Chain

Electrification doesn’t stop with hybrid TRUs. Battery-electric TRUs are the next step, and the infrastructure you install today lays the groundwork for that transition.

Facilities equipped with 240 V or 480 V eTRU systems already have the right platform for tomorrow’s charging systems. By planning ahead, operators can avoid costly retrofits while staying ahead of:

  • Stricter CARB emission mandates
  • Utility capacity upgrades
  • Customer and ESG reporting requirements
  • Future Products and technology that will require additional infrastructure

Forward-thinking facilities that electrify now will be best positioned to meet future standards, and win contracts with sustainability-focused shippers.

Did you know?

A regular eTRU can save about one gallon of diesel every hour when operating on electric standby. That translates to major cost and emissions savings, preventing roughly 20 pounds of CO₂ emissions for every gallon of diesel avoided, with facilities often seeing ROI in about a year.

Powering a Smarter, Cleaner Supply Chain

Adopting eTRU systems is one of the most practical ways fleets can cut emissions, control costs, and meet new regulations, all without disrupting operations.

With over 30 years of electrical engineering experience and more than 300,000 connection points deployed, ESL Power Systems provides proven, safety-certified solutions that help fleets electrify with confidence.

Ready to See What Electrification Could Mean for Your Facility?

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How Ships and Ports Integrate Clean Energy with Shore Power Connections

Erika Thorson

Modern ports are under increasing pressure to reduce emissions, meet regulatory standards, and improve sustainability. A shore power connection, sometimes called cold ironing or onshore power supply, enables docked vessels to plug into the local electrical grid instead of running their diesel engines.

This shift is more than a compliance requirement. It’s the foundation of port electrification. By adopting shore power, ports cut harmful emissions, reduce noise pollution, and deliver cleaner operations for surrounding communities. For vessels, the benefits are just as important, including lower fuel use, reduced maintenance, and easier compliance with evolving standards like CARB’s Shore Power Rule

The Cost of Getting It Wrong

While the advantages of shore power are clear, the risks of a poor implementation can be costly. Choosing the wrong system or underestimating compliance requirements may result in:

  • Delays and rework if systems fail to pass inspection.
  • Operational downtime when equipment isn’t engineered for heavy-duty port conditions.
  • Unexpected costs from non-standard components or proprietary connectors.
  • Regulatory penalties if ports or vessels fall short of emissions rules.

At a busy port, there’s no room for error. If a shore power connection fails, ships can’t run as planned and valuable cargo could be delayed or put at risk.

What to Look for in a Shore Power Solution

A port-ready solution should be engineered for safety, durability, and compliance. When evaluating a shore power connection, consider:

  • Regulatory compliance: Systems should meet CARB, IMO, NEC 555, and IEEE 80005 requirements.
  • Safety features: Look for interlocked connectors and clear field labeling.
  • Durability of design: Corrosion-resistant enclosures and weatherproof construction are essential.

Plan Your Shore Power Project With Confidence

Download our Commercial Shore Power Brochure to see features, compliance details, and planning tips.

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Planning for Growth and Changing Regulations

Shore power isn’t just about meeting today’s rules. It’s about preparing for the future. Emissions standards are getting tougher, and more ports are moving toward zero-emission operations. By planning with customizable, expandable systems, ports can adapt to new vessel requirements, higher power needs, and stricter regulations without starting over.

Ports that plan ahead also gain an advantage. A strong shore power infrastructure makes them more attractive to shipping lines that are focused on meeting sustainability goals.

How ESL Simplifies Shore-to-Ship Integration

At ESL, we design and manufacture shore power connection systems that streamline electrification without compromise. Our solutions are:

  • Custom-engineered for each facility’s requirements.
  • Built for compliance, meeting CARB, IMO, and NEC standards.
  • Safety-focused, with interlocked connectors and built-in test points.
  • Scalable, with expandable configurations that adapt to future vessel needs.
  • Proven in the field, trusted by commercial, military, and cruise facilities across North America.

With more than 30 years of experience and over 300,000 connection points deployed, ESL helps ports, terminals, and engineering firms integrate shore power with confidence.

Power Your Port with Confidence

Don’t risk delays, downtime, or costly compliance failures. Partner with ESL for a shore power connection solution engineered to meet your specs, emissions goals, and growth plans.

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What Does CARB Compliance Mean for Commercial Fleets and Facilities?

Erika Thorson

California’s CARB regulations have long shaped air quality standards in the U.S., and their influence is growing. As other states adopt similar rules and major retailers prioritize low-emission supply chains, commercial fleets and facilities across the country are under increasing pressure to align. For operations that rely on diesel-powered TRUs or manage temperature-controlled logistics, CARB compliance is now a strategic consideration, not just a regulatory requirement.

What Is CARB Compliance?

CARB, the California Air Resources Board, enforces some of the most aggressive air quality standards in the U.S., including regulations aimed at reducing emissions from diesel engines used in TRUs.

CARB compliance typically refers to:

  • Meeting emission standards for diesel-powered equipment
  • Reducing idling and reliance on diesel generators
  • Implementing zero-emission solutions such as electric standby systems or battery-electric TRUs

For fleets using refrigerated trailers, compliance means transitioning to clean alternatives such as plug-in shore power for temperature-controlled loads at distribution centers, truck yards, and cold storage facilities.

Why CARB Compliance Matters Beyond California

California may be first, but it won’t be last.

States like New York, Oregon, and Washington have already adopted similar emission goals, and major retailers are demanding cleaner supply chains. If you operate across state lines, your non-compliant equipment could soon be sidelined.

Key reasons this matters:

  • Regulatory momentum is spreading nationwide
  • Major logistics partners are prioritizing sustainable fleets
  • Non-compliance can limit bidding opportunities and facility access

Future-proofing isn’t optional—it’s essential.

Common Misconceptions About CARB Compliance

“This only affects California.”
 False. Other states are aligning with CARB. Operating nationally means preparing now.

“We have to replace our entire fleet.”
 Not necessarily. Many facilities can meet requirements with retrofits, shore power access, or dual-voltage capabilities.

“Compliance will cripple our operations.”
 In truth, the right infrastructure can increase operational efficiency, reduce fuel costs, and even improve safety at the dock.

Think Compliance Is Too Costly? See the Real Numbers

Use our calculator to uncover how shore power can reduce diesel use, maintenance, and emissions—while keeping your fleet CARB compliant.

Estimate your ROI

How to Stay Compliant Without Overbuilding

Too many fleets overspend chasing compliance. But smart planning and flexible infrastructure can reduce costs while still meeting requirements.

Here’s how:

  • Shore power systems like ESL’s eTRUconnect® allow electric TRUs to plug in when parked, reducing emissions, fuel use, and idling.
  • Dual-voltage systems support both 480V and 240V, accommodating mixed fleets without complex rewiring.
  • Modular, daisy-chain capable setups can power multiple units from one input, simplifying deployment and scaling with demand.
  • Break-away safety features and integrated compliance markings streamline inspection-readiness.

How ESL Helps Clients Align With CARB Requirements

At ESL, we help fleet operators and facility managers design smarter infrastructure that meets CARB requirements—without blowing the budget.

With over 30 years of experience, our solutions are:

  • Purpose-built for electric and hybrid TRU power
  • UL/cUL Listed with safety interlocks and rugged enclosures
  • Tested and proven in high-volume logistics environments
  • Custom-configured to your exact dock layout, voltage, and usage needs

Whether you’re just starting your compliance journey or looking to retrofit existing infrastructure, we provide the guidance, hardware, and ongoing support to move forward with confidence.

The Bottom Line

CARB compliance isn’t going away. But it doesn’t have to derail your operations.

With the right partners and technology in place, fleets and facilities can reduce emissions, lower costs, and stay ahead of evolving regulations.

Let’s Build the Right Compliance Solution for Your Fleet

Request a custom quote today and get the specs, pricing, and insight to move forward strategically.

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Understanding the Electrical Differences Between Reefer Containers and eTRUs: Why Precise Identification Matters

Erika Thorson

Generic terms like reefer, van, or freezer are often used to describe a variety of refrigerated equipment, but each type can have different electrical requirements. To ensure we quote the correct product, it’s important to understand exactly what kind of equipment will be plugged in.

Reefer Containers: The Ocean and Intermodal Workhorses

Reefer containers are typically used for ocean or intermodal shipping and come with a built-in cord and a male pin-and-sleeve plug, usually 440/480V 3-phase, 32A (IEC 60309). These cords are often visible coiled in a tray or hook on the container’s side. The container itself is a self-contained metal unit, similar in appearance to a standard shipping container, often 20 or 40 feet long.

Electric Transport Refrigeration Units (eTRUs): The Overland Option

Electric Transport Refrigeration Units (eTRUs), on the other hand, are usually mounted on trailers or trucks. Instead of a cord, they are equipped with a male inlet mounted on the unit’s exterior. The cord with the female connector is provided at the power source (dock, pedestal, or building).

Visually, eTRUs blend into the body of the trailer or appear as nose-mounted units on the front wall. At first glance, they may look like conventional diesel-powered TRUs, but the giveaway is the small inlet plate or recessed power port replacing the familiar fuel tank.

Quick visual differences:

  • Reefer Containers: Large, box-like units with a coiled power cord and male plug. Often have corner castings for stacking/shipping.
  • eTRUs: Mounted on trailers, often with no external cord. Look for an inlet plate or recessed power port on the side or front of the unit.

Why This Matters for Electrical Quotes

It’s important to note that not all containers or eTRUs use the same standard configuration. Some may have non-standard connectors or voltages depending on origin, manufacturer, or retrofit. Since pricing and product selection can vary significantly depending on the required connector or receptacle, confirming the exact electrical configuration — including voltage, phase, amperage, and plug type — helps avoid misunderstandings and ensures a safe, cost-effective solution.

Photos of the connection point, nameplate data, or equipment specifications are very helpful in making the correct selection.

If you’re looking for further assistance or ready for a project quote, Contact our team now!

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