The transportation sector is a major contributor to greenhouse gas emissions and air pollution. As concerns grow over climate change and environmental sustainability, there is an urgent need to transition to cleaner and more eco-friendly transportation solutions. One area receiving attention is the adoption of alternative fuel commercial trucks, which offer the possibility of reducing the carbon footprint of freight transport. 

Compressed natural gas (CNG) trucks have emerged as a promising sustainable technology, providing comparable performance to traditional diesel trucks while producing lower emissions. With both environmental and potential economic benefits, CNG trucks present an appealing option for fleets looking to “go green”.

The purpose of this article is to compare CNG trucks with standard diesel trucks across a range of factors. By evaluating the pros and cons of CNG trucks, we can better understand why they present an advantageous sustainable transport solution worthy of wider adoption in the trucking industry. The comparison will focus on environmental impact, costs, performance, and challenges associated with transitioning to this alternative fuel technology. With more fleets recognizing the need for sustainable freight transport, understanding the benefits and limitations of CNG trucks is key.

What are CNG Trucks?

Compressed natural gas (CNG) trucks are powered by natural gas stored at high pressure. Unlike diesel or gasoline, CNG needs to be stored in cylindrical tanks at pressures up to 3,600 psi to achieve a usable energy density. 

CNG trucks have an advanced fuel storage and delivery system. The tanks are made of steel, aluminum, or composite materials to safely handle the high pressure. The CNG is then fed to the engine through fuel lines and regulators that reduce the pressure for optimal combustion.

The use of natural gas for transportation has grown in recent years. Major manufacturers like Volvo, Freightliner, and Peterbilt now offer Class 7 and 8 CNG trucks suitable for regional haul, vocational, refuse, and other applications. Fleets are adopting CNG trucks to lower emissions and fuel costs compared to diesel. There are now over 150,000 CNG vehicles on U.S. roads today, with continued growth expected.

Environmental Benefits

CNG trucks provide significant environmental advantages over diesel trucks. Most notably, CNG trucks produce lower greenhouse gas (GHG) emissions compared to diesel. CNG is predominantly methane, which has a lower carbon content than diesel fuel. Studies show CNG trucks can reduce GHG emissions by 15-20% compared to diesel.

CNG trucks also emit far fewer particles than diesel engines. Diesel particulate emissions have been linked to respiratory diseases and increased cancer risk. CNG eliminates particulate emissions almost entirely. 

Additionally, CNG allows trucking fleets to meet tightening emissions regulations. As government agencies impose stricter limits on acceptable tailpipe emissions, CNG provides a compliant solution. The natural gas fuel system reduces smog-forming pollutants like nitrogen oxides to near-zero levels. With environmental regulations only getting stricter over time, CNG enables continued trucking operations.

Overall, the environmental benefits of lower GHG emissions, negligible particulates, and regulatory compliance make CNG trucks an eco-friendly alternative to diesel trucks.

Economic Advantages

Switching to CNG trucks provides significant economic benefits in terms of fuel cost savings, lower maintenance costs, and government incentives.

Fuel Cost Savings

CNG costs significantly less than diesel fuel per gallon. CNG prices have also historically been more stable than diesel prices, insulating fleets from price fluctuations. This allows companies to better forecast and control fuel costs by switching to CNG trucks.

Lower Maintenance Costs

CNG engines generally require less maintenance than diesel engines. The fuel is cleaner burning and reduces carbon buildup and oil contamination. This increases engine life and allows longer intervals between oil changes and tune-ups. CNG trucks save on regular maintenance costs.

Government Incentives

Several government programs provide financial incentives for fleets to adopt NGVs like CNG trucks. These include tax credits, grants, rebates, and low-interest loans. Governments support CNG adoption to improve air quality and reduce dependence on imported diesel. Companies can benefit from thousands in incentives per CNG truck purchased.

Performance Benefits

CNG trucks can match or exceed the engine power and torque of equivalent diesel trucks. CNG engines provide strong acceleration and hill climbing ability, making them well-suited for demanding applications like refuse collection or regional hauling. 

The driving range of CNG trucks has improved significantly in recent years. Latest models equipped with larger fuel tanks can travel 250-300 miles on a fill up. While not yet equal to diesel, this is sufficient for many urban and regional routes. With more fueling stations, range anxiety is diminishing.

Safety is a major advantage of CNG trucks. CNG is lighter than air and disperses quickly in the event of a leak, unlike pooling diesel. The tanks are also highly pressurized and mounted away from potential impact zones. Multiple redundancies in valves and lines ensure CNG systems are inherently safe. This gives CNG trucks a strong safety record.

Infrastructure Challenges

One of the biggest hurdles to widespread CNG truck adoption is the lack of fueling infrastructure compared to diesel. There are limited public CNG fueling stations, making long hauls more difficult. Building a private CNG fueling station just for a small fleet of trucks is often not economically feasible. 

Home fueling, which is possible with gasoline or diesel vehicles, is not practical with CNG. Installing a natural gas line to fuel vehicles at home would be extremely costly. This means CNG vehicles need access to public or private refueling stations, which are still scarce in many regions.

The upfront investment required for CNG stations is high, so there is reluctance to build more. But without adequate fueling infrastructure, fleets can’t confidently adopt CNG trucks. It’s a chicken and egg situation that slows CNG truck growth.

Overcoming the infrastructure challenge requires coordinated efforts between trucking companies, policy makers, natural gas suppliers, and station builders. Financial incentives and partnerships can make station investments more viable. Governments can also mandate station construction along major trucking routes. But this infrastructure limitation remains a key barrier to mass CNG truck adoption currently.

Higher Initial Costs

One of the main challenges for adopting CNG trucks is their higher upfront costs compared to diesel trucks. This is primarily driven by two factors:

CNG Truck Purchase Price 

The base price of a new CNG truck can be $30,000 to $50,000 more than a comparable diesel truck. This is because CNG trucks require additional fuel storage tanks, more robust fuel lines and injectors, and special CNG engines. These components increase manufacturing and material costs for OEMs.

However, government incentives can help offset the higher sticker price. Tax credits, grants, and other subsidies are available in many regions to encourage CNG adoption. With incentives, the price premium over diesel trucks reduces substantially.

Fuel System Costs

Besides the truck itself, a complete CNG fuel system requires compressors, storage tanks, dispensers, and other infrastructure at fleet yards, weighing nearly $500,000 to $1 million. Larger fleets with high fuel consumption can justify this investment, but smaller fleets struggle to recover these expenses.

The high initial cost hurdle limits CNG truck adoption, especially for small private fleets with tight budgets. But as more fleets switch to CNG, infrastructure costs should decrease over time with economies of scale. Fleet managers should account for long-term TCO savings beyond just upfront costs.

Operational Hurdles

Adopting CNG trucks comes with some operational challenges that fleet managers need to consider.

Training Needs

CNG trucks require specially trained technicians and drivers. Technicians need training on maintaining and repairing CNG fuel systems. Drivers need instruction on fueling procedures and handling the trucks safely. Lack of trained staff can make it difficult to transition and operate a CNG fleet. Companies may need to invest in technician training programs or hire those with CNG experience.

Maintenance Requirements

More frequent maintenance is required on some CNG truck components versus diesel trucks. The fuel storage cylinders need to be inspected every 3-5 years to check for damage. Fuel lines and seals need to be replaced more often. Engine oil may need to be changed more frequently as well. Maintenance facilities need to be upgraded to handle CNG systems. The costs and labor associated with additional maintenance should be factored in when evaluating CNG trucks.

Case Studies

There are several real-world examples of fleets transitioning to CNG trucks and finding success:

– The City of Los Angeles operates one of the largest municipal CNG fleets in the world, with over 1,000 CNG refuse trucks. They reported 40% lower greenhouse gas emissions compared to diesel. Fuel and maintenance savings allowed them to recoup the higher vehicle cost in under 3 years.

– UPS operates over 6,000 CNG vehicles. They highlighted a 75% reduction in particulate matter and 5-11% reduction in GHG emissions per mile compared to diesel trucks. Fuel cost savings offset the higher vehicle cost.

– Waste Management transitioned 18,000 trucks to CNG. They expect to reduce emissions by 15% across their fleet. The program was supported by state funding and federal tax credits to offset the cost.

– AT&T partnered with Clean Energy to transition over 8,000 vehicles to CNG. They aim to reduce emissions by 49% by 2025. The program is supported by $21 million in state funding.

– Ryder System operates over 5,000 CNG trucks across their rental and leasing fleet. They partner with manufacturers to make new CNG trucks available and install fueling stations.

These examples showcase how major corporations and municipalities have implemented large-scale CNG truck fleets and realized environmental and economic benefits. The transition requires upfront investment and infrastructure, but the long-term payoff can be substantial.


In summary, CNG trucks offer considerable environmental benefits with lower emissions compared to diesel trucks. They also provide economic savings through reduced fuel and maintenance costs. CNG trucks can match or exceed the performance of diesel while enhancing safety. 

However, wider adoption faces challenges like lack of fueling infrastructure, higher upfront vehicle costs, and operational considerations around range and refueling. But these hurdles can be overcome through continued investment, innovation and strategic planning. Many fleets have already implemented CNG trucks successfully.

With its clean-burning properties and cost-competitiveness, CNG technology shows great promise for sustainable freight transport. The trucking industry should continue exploring and adopting CNG trucks where feasible to reduce environmental impact and operating costs. Government incentives could further accelerate this transition. Overall, CNG trucks present a viable alternative to traditional diesel trucks worthy of consideration.