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.