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March 16, 2021   |   Diesel Technology Forum

Policy Insider

DTF Comments to Senate Committee on Energy and Natural Resources

Thanks to their widescale penetration throughout the global economy, continued innovation and investment in advanced diesel engines is essential for achieving near-term and long-term progress in meeting national climate and environmental objectives.

In Re:  Ways to Strengthen Research and Development in Innovative Transportation Technologies with a Focus on Solutions that Decrease Emissions, Reduce Our Reliance on Foreign Supply Chains, and Increase Manufacturing in the United States; Hearing March 16, 2021

Dear Chairman Manchin and Ranking Member Barrasso:

As the Committee considers investments in transportation innovation to decrease emissions and promote U.S. supply chains, manufacturing and employment, we respectfully request and appreciate your consideration of the following:      


Thanks to their widescale penetration throughout the global economy, continued innovation and investment in advanced diesel engines is essential for achieving near-term and long-term progress in meeting national climate and environmental objectives.  Today, diesel engines and fuels are the backbone of the U.S. economy, with one out of every two economic sectors relying on diesel technology to move freight on land, water and rail, to build transportation and energy infrastructure, to generate electrical power, and farm the land, among other uses. 

While zero-emissions solutions for some applications are planned for the future, few are available today, making continued investment in diesel power essential to sustain national progress.  Manufacturers are working to develop new power options for their customers in a number of applications, that could include battery-storage/electrification and hydrogen.  The adoption of these solutions could be well into the future, according to many analysts.  This underscores the importance of continued innovation, investment and progress in advanced diesel engines. 

Heavy-duty diesel engines manufactured in the U.S. in 2019 exceeded 900,000 units, providing over 1.3 million jobs and more than $158 billion in economic value. 

The use of advanced biofuels in diesel engines is growing and is an important opportunity that leverages existing vehicle technology and infrastructure while also delivering meaningful greenhouse gas emissions reductions.  

Advanced Generation of Diesel Technology is Part of a National Climate Solution

The diverse nature and significance of the challenge to reduce global greenhouse gas emissions dictates that it is not a one-size fits all problem, but instead one where many solutions will be needed.  An effective climate policy is also one that balances near term strategies for greenhouse gas emissions reductions alongside investments in future zero-emissions solutions. 



West Virginia


Estimated Size of the Commercial Vehicle Fleet (Class 3-8 commercial trucks)

~ 14 Million



Percentage of Fleet that is Diesel

75.4 percent

75.6 percent

80 percent

Percentage of diesel commercial vehicles in operation that are 2011 and newer that achieve near-zero emissions: national average 43%

43 percent

35 percent

45 percent



By way of background, the Diesel Technology Forum is a not-for-profit educational advocacy raising awareness of the environmental and economic benefits of diesel technology.  Our members represent the leaders in diesel technology including engine, truck and equipment manufacturers, component suppliers and fuel and biofuel producers. 


Diesel Powers Key Sectors of the Economy

When it comes to key sectors of the economy like commercial vehicles, off-road equipment, locomotives and workboats, diesel is the dominant powertrain today.  As manufacturers innovate to introduce zero-emissions solutions to these heavy-duty applications, the latest innovations in near-zero emissions performance from diesel are readily available today.  More efficient diesel engines are available today, that meet stringent fuel economy and tailpipe emissions standards established by U.S. Environmental Protection Agency (EPA), that reduce greenhouse gas emissions and bring clean air benefits directly to frontline communities near freight facilities. 

Domestic Manufacturing Benefits of Diesel Technology

One of out of every two sectors of the U.S. economy relies on heavy-duty diesel engines many of which are manufactured in production facilities across the U.S.  75 percent of commercial trucks are powered by diesel engines, and 97 percent of the large Class 8 trucks are diesel, along with the wide variety of construction and agricultural equipment types and much larger engines that power marine vessels and locomotives. Diesel technology delivers products to store shelves, inputs to factories, completes public works projects and delivers our agricultural bounty to markets in the U.S. and across the globe.

Over 900,000 heavy-duty diesel engines were manufactured in production facilities across the U.S. These engines power the fleet of trucks and equipment that keep our economy moving and tied to global markets. As the economy expands, the need for diesel powered vehicles and equipment expands as well and many of these engines entering the market will have been made in the U.S.

Diesel Engine Manufacturing

Clean Air Benefits of the Latest Diesel Innovations

Today, near-zero emissions diesel solutions are widely available in commercial vehicles and off-road equipment along with large engines that power locomotives and marine workboats. Replacing older generations of technology with these latest advancements can generate big clean air benefits. Beginning in model year 2010, EPA requires that all commercial vehicles meet a stringent standard for ozone forming compounds (NOx) and fine particle emissions (PM 2.5). The combination of catalysts and filters allows these near-zero emissions diesel trucks to reduce emissions by 98 percent relative to an older generation of technology.

Replacing a single older generation Class 8 truck with a new near-zero emissions diesel option available today can eliminate over 2 tons of NOx emissions and 250 lbs. of PM emissions.  As an example of the benefits of these near-zero emissions diesel trucks, PM 2.5 truck emissions in the massive port complex in southern California were reduced by over 80 percent as the Ports of L.A. and Long Beach require all trucks meet near-zero emissions requirements.  In 2005, port trucks were the second leading contributor to PM emissions generating 185 tons per year.  By 2019, trucks were the second smallest contributor generating only seven tons per year.[1]  These are direct and immediate clean air benefits delivered to many communities surrounding the port complex and warehouse districts in southern California.

Unlike passenger vehicles, turnover in the commercial truck sector is relative slow.  After a decade, roughly less than half of all commercial vehicles on the road today do not come with solutions to meet the most recent tailpipe standard.  While zero-emissions solutions are being planned for the future, with a few models in a few smaller truck categories available today, it will be some time before these technologies enter the commercial vehicle fleet in large numbers to generate benefits.  Meanwhile, significant clean air benefits may accrue to communities across the country by transitioning these older and higher mileage commercial trucks to near-zero emissions solutions quickly.

Clean Diesel Progress - Heavy Duty On-Highway (Trucks, Transits & School Buses)

Climate Benefits Are Here Now from More Efficient Diesel Engines and Vehicles

Much like cars, commercial vehicles are now subject to stringent fuel economy and greenhouse gas emissions standards.  A single new Class 8 diesel truck can eliminate almost 10 tons of greenhouse gas emissions in a single year when replacing an older less efficient model.  Just imaging the climate benefits of transitioning many of the nation’s older trucks to new diesel models available on dealer lots today.

Over the lifetime of the fuel economy rule for trucks, between 2021 and 2027, more efficient diesel-powered commercial vehicles are expected to reduce greenhouse gas emissions by over 1 billion tons and save record amounts of fuel.[2]  Beginning this year, a more stringent fuel economy standard known as Phase 2 rules, is required for all new commercial vehicles.  The new rule applies to all truck types from a heavy-duty pickup to a tractor-trailer combination truck.  While engines are expected to become more efficient, a variety of other technologies such as lightweight materials, aerodynamics and innovative transmissions, are designed to boost the fuel sipping properties of the already efficient diesel engines.  Future technologies, like zero-emissions solutions, are expected to be introduced (while a few are available today) in a few truck types, yet the overwhelming majority of these new more efficient trucks will be diesel.[3]

Climate Benefits Can Be Enhanced Through Expanded Use of Biodiesel and Renewable Diesel Fuel

The diesel engine, patented by Rudolph Diesel over 160 years ago, was designed to operate on biofuels.  Today, the same holds true as diesel engines – old and new – may operate on renewable diesel fuel and high-quality blends of biodiesel and in doing so generate substantial climate benefits.  These are fuels that are considered advanced biofuels, capable of reducing greenhouse gas emissions by at least 50 percent and in the case of renewable diesel fuel upwards of 80 percent.  These are low-cost solutions that do not require additional investments in new engines, vehicles or charging stations, unlike other low carbon transportation solutions.

The use of these fuels is already achieving substantial and low-cost greenhouse gas reductions where they are used.  In California, the use of biodiesel and renewable diesel fuel have eliminated the most greenhouse gas emissions cumulatively in the transportation sector between 2011 and 2019, according to the California Air Resources Board.[4]  The benefits of renewable diesel fuel and biodiesel exceed that of electrified cars, trucks and buses by nearly 4-to-1.   

 CO2 Reductions

According to the National Biodiesel Board (NBB), 2.8 billion gallons of renewable diesel fuel and biodiesel were sold in 2019, the last year for which data is estimated.  Between 2018 and 2019, renewable diesel sales grew by 50 percent.  NBB estimates that there are enough readily available feedstocks to produce six billion gallons of these fuels by 2030.

Interest in the sector is expanding as many high-profile petroleum refiners are retooling petroleum facilities to produce renewable diesel fuel.  According to Stratas Advisors, an energy sector consultancy, if actual production equates to announced capacity, renewable diesel production in the U.S. could displace all petroleum diesel fuel consumed in California.[5]  This is a low carbon fuel derived largely from feedstocks in the U.S. and produced by a skilled and well-paid U.S workforce.

Examples of planned renewable diesel fuel investments include:


Thank you for the opportunity to provide these comments.


[1] 2019 Emissions Inventory, Port of Long Beach, https://polb.com/environment/air/#emissions-inventory

[2] https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-phase-2-greenhouse-gas-emissions-standards-and

[3] “Reinventing the Truck”, IHS Markit (2020), https://ihsmarkit.com/products/reinventing-the-truck.html

[4] Low Carbon Fuel Standard Dashboard, California Air Resources Board, https://ww3.arb.ca.gov/fuels/lcfs/dashboard/dashboard.htm

[5] “Overcapacity Looms as More and More U.S. Refiners Enter the Renewable Diesel Market”, Stratas Advisors, June 2020, https://stratasadvisors.com/Insights/2020/06112020LCFS-RD-Investment

[6] https://www.spglobal.com/platts/en/market-insights/latest-news/oil/012821-valero-darling-to-move-forward-with-port-arthur-diamond-green-diesel-project

[7] https://corporate.exxonmobil.com/News/Newsroom/News-releases/2020/0811_ExxonMobil-and-Global-Clean-Energy-Holdings-sign-agreement-for-renewable-diesel

[8] https://www.reuters.com/article/us-hollyfrontier-refining-cheyenne/hollyfrontier-to-convert-oil-refinery-into-renewable-diesel-plant-idUSKBN2383LF


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