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Policy

Meeting the Climate Challenge

As transportation sources of greenhouse gas emissions are the leading category, we need ready-to-go solutions today to cut our carbon diet as we invest in solutions to deliver zero-emissions in the future.


Whether it is achieving net-zero carbon emissions or deep decarbonization, we need an all-hands-on-deck approach to cut greenhouse gas (GHG) emissions now and in the future to meet the climate challenge. As transportation sources of GHG emissions are the leading category, we need ready-to-go solutions today to cut our carbon diet as we invest in solutions to deliver zero-emissions in the future. Looking at big things that move like trucks, buses, equipment, locomotives and marine vessels, there are diesel solutions ready today to help meet the climate challenge to help cool a warming planet. From much more efficient engines to the uptake of low carbon biofuels, diesel solutions are ready now to contribute to meeting our climate goals.

Carbon dioxide, the most abundant greenhouse gas, may endure in the atmosphere between 300 to 1,000 years, according to the National Aeronautics and Space Administration. What is emitted today will hang around as a heat trapping gas for quite a while. To meet the challenge of the climate crisis, we should do what we can now to cut these emissions as innovative zero-emissions solutions are planned for the market place tomorrow. Waiting for emerging technologies will do little to address the cumulative effects of GHG emissions.

The transportation sector is the leading source of GHG emissions. Cars, pickup trucks and SUVs are the leading category of transportation sources of GHG emissions while bigger while big things that move, like trucks, buses, railroads and marine vessels, represent about 30 percent of transportation emissions.

Transportation Sources of GHG

While zero-emissions solutions for cars and light-trucks like pickup trucks and SUVs are available today – and more are just around the corner – we may need to wait a while for similar options to be available for the fleet of big things that move. As zero-emissions solutions, like battery-electric and hydrogen fuel cell options, are on the drawing board, it may be some time before these options are adopted in large numbers to generate benefits along with a build-out of recharging or refueling infrastructure to support their continued adoption.

Meanwhile, there are low carbon options ready today to contribute to immediate term GHG emissions reductions in a big way.  Introducing these ready-to-go solutions for the heavy-duty freight sector should be a part of any net-zero carbon strategy.   

  1. Cutting Carbon Emissions From the Freight Sector With Efficiency
  2. Making the Switch to Biodiesel and Renewable Diesel Fuel
  3. Black Carbon Reduction from Advanced Diesel Engines

Cutting Carbon Emissions From the Freight Sector With Efficiency

The freight sector runs on diesel. Diesel fuel is the most energy dense transportation fuel and the inherent efficiency of the diesel engine is the most productive means of transferring energy density into work. This explains why 97 percent of commercial vehicles run on diesel and almost every locomotive and marine vessel. As noted above, commercial vehicles are responsible for about 24 percent of GHG emissions and the larger Class 8 tractors make up 60 percent of all commercial vehicle emissions.  We can do a lot very quickly to reduce emissions by replacing older engines with more efficient diesel options.

energy density graph

Much like cars, fuel economy standards are now required of the large variety of commercial vehicles from heavy-duty pickup trucks, to vocational trucks like cement mixers and utility trucks to full-size Class 8 tractor-trailer type trucks. The first phase of those rules kicked-in in 2014 while the second and more stringent fuel economy standard will kick-in in 2021. For a typical Class 8 long haul truck, these standards adopted jointly by the U.S. Department of Transportation and the U.S. Environmental Protection Agency (U.S. EPA) will result in a 25 percent improvement in fuel economy over the lifetime of the rule. 

To meet these requirements, a variety of technologies will be used to make these vehicles more efficient. Diesel engines will become more efficient while other solutions will help make the fuel-sipping diesel engine consume less fuel and reduce GHG emissions while also maintaining near zero emissions performance for criteria emissions particulate matter and oxides of nitrogen.

Learn More - Diesel’s Shrinking Share of Emissions Inventory

Between 2007 and 2030, these technologies will save 1.5 billion tons of carbon dioxide emissions and save 150 billion gallons of fuel. These benefits are equivalent to removing all cars, pickup trucks and SUVs on the road today for a year and half or making them all zero-emission vehicles.

Even as zero-emissions solutions are expected to become available in the marketplace soon, diesel technology is still expected to deliver the overwhelming majority of these benefits over the next ten years. While a few alternatives exist today and others are expected to hit dealer lots soon, research confirms that diesel will still be the predominant technology and fuel type powering commercial vehicles.

Strategies to decarbonize the freight sector should consider options to encourage the owners of older commercial vehicles to replace less efficient equipment with new. Replacing a single older Class 8 tractor with a new more efficient diesel option can eliminate almost 29 tons of GHG emissions. As we wait for zero-emissions solutions to prove out in the lab and in the marketplace, let us not forget what can be done today by advancing low carbon solutions available on every commercial truck dealer lot today.

Making the Switch to Biodiesel and Renewable Diesel Fuel

Diesel engines are capable of operating on a variety of advanced biofuels to deliver significant reductions in GHG emissions. Biodiesel and renewable diesel fuel are considered advanced biofuels by the U.S. EPA that are capable of reducing GHG emissions by at least 50 percent. In the case of renewable diesel fuel, greenhouse gas emissions may be reduced by more than 80 percent.

These fuels are derived from a variety of waste residues including soy and animal fats. The U.S. produced 3 billion gallons of biobased diesel fuel including biodiesel and renewable diesel fuel in 2020. Most modern diesel engines are capable of operating on high quality blends of biodiesel up to 20 percent, or B20, with some new models approved to operate on blends up to 30 percent. Renewable diesel fuel is derived from the same feedstocks as biodiesel but is refined using a different chemical process to generate a fuel that meets the same engineering specification as petroleum diesel fuel. This means that renewable diesel fuel may be used as a substitute to petroleum-based diesel fuel.

California is the leading consumer of biodiesel and renewable diesel fuel consuming almost one out of every four gallons of the fuel supplied in the U.S. In 2019, the California Air Resources Board found that these fuels have generated the greatest reduction in transportation emissions among all the many fuel and technology types. Since 2011, biodiesel and renewable diesel fuel cumulatively eliminated more than 32 million tons of carbon dioxide. This compares to just over 10 million tons of carbon dioxide eliminated from the use of battery electric vehicles.

CO2 Reductions - CA

In 2020 alone, the California Air Resources Board estimates that almost 7 million tons of GHG emissions were eliminated simply by switching from petroleum diesel to biodiesel and renewable diesel fuel. This is equivalent to taking almost 1.5 million cars off the road for a year, or converting them to a zero-emissions option. In 2020, just over 105,000 new all-electric cars were sold in California, according to the California Energy Commission.

Fleets across the country are switching to these fuels and realizing significant benefits without incurring significant costs required of other alternative fuels. The San Francisco Municipal Transportation Authority has been using renewable diesel fuel in its fleet of over 600 buses to reduce carbon dioxide emissions by over 10,000 tons. Florida Power and Light now uses biodiesel in its fleet of over 3,900 utility vehicles to reduce carbon dioxide emissions by 6,700 tons.

The benefits of fuel switching are low cost and truly low carbon. These fuels are derived from waste animal and vegetable feedstocks and need no investments in new engines, vehicles or equipment as diesel engines old and new may use these fuels. Biodiesel and renewable diesel fuel may also do not require additional and expensive investments in recharging or refueling infrastructure as these fuels may take advantage of the existing fuel infrastructure.

Strategies to decarbonize the freight sector should consider low cost and significant immediate term benefits from fuel switching. While all eyes may be focused on the success of future zero-emissions technologies, let us not forget what can be achieved overnight from the use of low carbon fuels derived from waste feedstocks.   

Read More - Biofuels

Black Carbon Reduction from Advanced Diesel Engines

While carbon dioxide is the most abundant greenhouse gas, there are other greenhouse gas forming compounds known as short lived climate pollutants (SLCP). One of these pollutants is black carbon and it is upwards of 900 times more potent than carbon dioxide. Unlike carbon dioxide, eliminating man made emissions of black carbon is relatively easy including the contribution from older diesel engines.

Black carbon, also known as soot, is generated by the incomplete combustion of fuels including contributions from forest fires, charcoal stoves and diesel engines. Soot is emitted and rises in the atmosphere where it soon falls on polar ice. The black particles trap solar heat and contribute to melting polar ice.

Eliminating diesel sources of black carbon emissions is very cost effective and many countries across the globe are adopting cleaner fuel standards and tighter regulations on tailpipe emissions that will nearly eliminate diesel’s contribution to black carbon emissions.

The U.S. has been a success in developing and deploying diesel technologies that will reduce black carbon emissions by 91 percent between 2005 and 2030. Clean diesel technologies that control black carbon emissions will be an important strategy to meet ambitious climate goals as more countries adopt cleaner diesel fuel standards and tailpipe emissions regulations.

Read More - Climate Change, Black Carbon & Clean Diesel

The leaders in diesel technology are ready to meet the climate challenge. After all, we cannot wait to cut emissions and contribute to the climate diet. When it comes to technologies that power trucks, trains, ships and equipment, zero-emissions solutions are on the drawing board. Today, we can do a lot to reduce emissions quickly by replacing vehicles, equipment and engines with much more fuel-sipping diesel solutions while relying on low carbon advanced biofuels to help get us on the path to net-zero emissions in the future.

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Policy Overview

Hot Issues

"I don’t have concerns
with diesel technology in general"

When asked during the Congressional hearings on the VW situation about its random vehicle audit of all light-duty diesel, Chris Gundler, U.S. EPA Director of the Office of Transportation & Air Quality, replied:

“I don’t have concerns with diesel technology in general. I don’t expect to find widespread problems but we are going to be taking a very close look.”

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