Drop-in biofuels are hydrocarbon fuels substantially similar to gasoline, diesel, or jet fuels. These fuels can be made from a variety of biomass feedstocks including crop residues, woody biomass, dedicated energy crops, and algae. The goal for drop-in fuels is to meet existing diesel, gasoline, and jet fuel quality specifications and be ready to "drop-in" to existing infrastructure. This minimizes infrastructure compatibility issues, which are a prohibitive barrier to fast commercialization of biofuels like ethanol and biodiesel.
Drop-in fuels are expected to meet existing specifications for diesel, gasoline, and jet fuel. The benefits of drop-in fuels include:
- Engine and Infrastructure Compatibility—Drop-in fuels are expected to be substantially similar to their petroleum counterparts and therefore minimize compatibility issues with existing infrastructure and engines.
- Increased Energy Security—Drop-in fuels can be produced domestically from a variety of feedstocks and contribute to U.S. job creation.
- Fewer Emissions—Carbon dioxide captured by growing feedstocks reduces overall greenhouse gas emissions by balancing carbon dioxide released from burning drop-in fuels.
- More Flexibility—Drop-in fuels are replacements for diesel, jet fuel, and gasoline allowing for multiple products from various feedstocks and production technologies.
History of Hydrogenation-Derived Renewable Diesel
Hydrogenation-derived renewable diesel (HDRD), also known as green diesel or second-generation biodiesel, is the product of fats or vegetable oils—alone or blended with petroleum—refined by a hydrotreating process. HDRD meets the petroleum diesel ASTM specification. This allows it to be legally used in existing diesel infrastructure and vehicles. HDRD derived from domestic biological materials is an alternative fuel under the Energy Policy Act of 1992.
HDRD can be produced from soybean, palm, canola, or rapeseed oil; animal tallow; vegetable oil waste or brown trap grease; and other fats and vegetable oils. Producing HDRD involves hydrogenating triglycerides to remove metals and compounds with oxygen and nitrogen using existing refinery infrastructure. Dedicated hydrotreating facilities that do not use conventional petroleum can also produce HDRD.
Fuel producers are designing HDRD to substitute for or blend in any proportion with petroleum-based diesel without modifying vehicle engines or fueling infrastructure. To be used in diesel engines, HDRD must meet the same ASTM standards as conventional diesel.
HDRD is compatible with existing fuel distribution systems. Blended HDRD can be distributed through modern infrastructure and transported through existing pipelines to dispense at fueling stations.
HDRD fuels can be an alternative to conventional transportation fuels. The benefits of HDRD fuels include:
- Increased Energy Security—HDRD can be produced domestically from a variety of feedstocks while creating U.S. jobs.
- Fewer Emissions—Carbon dioxide captured by growing feedstocks reduces overall greenhouse gas emissions by balancing carbon dioxide released from burning HDRD. Blends of HDRD can reduce carbon monoxide and hydrocarbons. In addition, HDRD's ultra-low sulfur content should enable using advanced emission control devices.
- More Flexibility—HDRD that meets quality standards can fuel modern diesel vehicles. This fuel is compatible with existing diesel distribution infrastructure (not requiring new pipelines, storage tanks, or retail station pumps), can be produced using existing oil refinery capacity, and does not require extensive new production facilities.
- Higher Performance—HDRD's high combustion quality results in similar or better vehicle performance compared to conventional diesel.