What is Clean Diesel?

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First and second generation bio-based diesel fuel help improve air quality, reduce emissions and make diesel part of our sustainable future.

The new generation of clean diesel technology, ultra-low sulfur diesel fuel, cleaner engines and advanced emissions control technology, provides both environmental and economic benefits to the U.S. As policymakers look to promote cleaner, more fuel efficient technologies, its use will grow along with other competitive alternatives. Diesel engines were originally invented to run on vegetable oils. Today, most diesel engines can run on high-quality blends of biodiesel with little modification as well as next-generation, drop-in renewable diesel fuels which offer even further benefits. This flexibility of the diesel platform can accelerate the introduction of these renewable diesel fuels across the economy.

Greater use of diesel technology would help the U.S. reduce petroleum consumption and improve energy security. The U.S. EPA estimates that America could save up to 1.4 million barrels of oil per day - an amount equivalent to the oil we currently import from Saudi Arabia - if one-third of U.S. cars, pickup trucks and SUVs were diesel-powered.

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Diesel technology's future value is further is enhanced by its suitability for hybrid applications and its readiness to utilize a diverse range of first and second generation renewable and biodiesel fuels.

Diesel Hybrid Technology

Diesel hybrids hold the promise of significant efficiency gains for commercial vehicles. By combining a smaller, fuel-efficient clean diesel engine with an advanced electric or hydraulic system, hybrid buses and delivery vehicles have demonstrated significantly improved fuel economy, along with reduced exhaust emissions and enhanced performance. 

Adding hybrid technology to already fuel-efficient diesel engines for passenger vehicles has been demonstrated in a concept car format. It combines the fuel efficiency of diesel over gasoline, the performance premium of a diesel generator's ability to accelerate an electric motor, and the efficiency gains of using electricity seen in gasoline hybrids such as the Toyota Prius. Diesel hybrids have large potential fuel economy gains, but vehicle cost could also be high.

Renewable Diesel Fuels and Biodiesel

While virtually all the renewable diesel fuel being produced in the U.S. today is biodiesel, next generation renewable diesel fuels, which offer additional economic and environmental benefits are quickly being developed. The Department of Energy's Energy Efficiency and Renewable Energy Biomass Program is working with the private sector to further increase the availability of advanced biofuels to improve energy security, stimulate the economy and create green jobs.

A key federal policy for renewable fuels is The Renewable Fuel Standard (RFS). The RFS program was originally created under the U.S. Energy Policy Act of 2005, which established the nation's first renewable fuel volume mandate. The original RFS program required that 7.5 billion gallons of renewable fuel be blended into gasoline by 2012. Under the Energy Independence and Security Act of 2007, the RFS program was expanded to include diesel, in addition to gasoline. Taken together, RFS provides a significant incentive for the production of biodiesel and advanced biofuels. In 2014, biodiesel producers supplied over 1.2 billion gallons. In June 2015, the U.S. Environmental Protection Agency proposed to expand the amount of bio-based diesel fuel to 1.9 billion gallons by 2017.

Diesel drivers have the option to fill up with blends of biodiesel at the pump. Most new and existing diesel vehicles and equipment are compatible with lower level biodiesel or renewable diesel fuel blends-between 5 and 20 percent, depending on manufacturer warranties, and even some 100 percent blends. Systems are also being developed to allow stationary engines to operate on a mixture of diesel and natural gas.

Commitments to use more renewable fuels within the military are strong. The Army is seeking to use 25 percent renewable energy by 2025 while the Navy is hoping to use renewable fuels for 50 percent of its energy needs by 2020. The Air Force is also planning to fly on a 50-50 blend of renewable and conventional fuels by 2016. Based on current estimates, achievement of the Navy and Air Force goals would result in the purchase of over 700 million gallons of renewable fuels each year.

For more information about Renewable Diesel Fuels and Biodiesel download Diesel Powers the U.S. Economy: Providing High-Paying Jobs, Exports and Long-Term Productivity Gains in the Nation's Fundamental Sectors the full report with appendices includes more specific information in the appendices.



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What is Clean Diesel?

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