Biofuel for Cat® Generators
Available for over 20 years in some markets, renewable liquid fuels, such as hydrotreated vegetable oil (HVO) and biodiesel, are becoming a more popular choice among customers seeking to reduce the impact of their operations on the environment in the near term.
What is Biofuel?
Biodiesel and HVO are biofuels produced from renewable resources such as vegetable oils, including soybean oil, canola oil, and palm oil, as well as used cooking oils and animal fats. While the resources may vary globally, finished fuel specifications are independent of the feedstock.
What is the Difference Between Biodiesel and HVO Fuel?
HVO and biodiesel are the two main renewable liquid fuels readily available for end users, but they have several differences:
| Biodiesel (FAME) | Hydrotreated Vegetable Oil (HVO) (Renewable Diesel) | |
| Source | Vegetable oils and fats | Vegetable oils and fats |
| Process | Transesterification | Hydrotreating |
| Chemistry | ||
| Product | Oxygenated, ester |
Non-oxygenated, paraffin |
| Replacement for diesel? | Yes, with some cautions | Yes |
| Specifications | ASTM D6751, EN 14214, Cat Spec | EN 15940 |
- Note that hydrotreated vegetable oil (HVO)/renewable diesel (RD) is per diesel fuel specifications except for density. HVO has lower density than diesel fuels.
- Biodiesel and HVO are sourced from the same feedstocks but differ in the processing and in the final product chemistry.
- HVO can be used in both standby and prime applications, whereas biodiesel is better suited to prime applications.
- Both fuels can be used “neat” or blended with conventional diesel to various percentages.
What are the Benefits of Biofuels?
- Although HVO and biodiesel do not significantly reduce CO2 emissions at the tailpipe, switching to biofuels will reduce lifecycle greenhouse gas emissions compared to diesel.
- Lower visible smoke emissions when using biofuels.
- HVO fuel is a drop-in replacement for diesel.
- Running generators on biofuels provides similar performance to diesel.
- Biofuels are available now and are easy to switch to.
- Running on biofuel provides similar rated power output, transient response, start up time, and NOx emissions to running on diesel.
Considerations for Use of Renewable Liquid Fuels
Application
Performance
Availability
Affordability
Maintenance
There is a difference in applicability of biodiesel and HVO for prime and standby power:
| Power | Biodiesel | HVO |
| Prime, Continuous | Blend levels per Caterpillar guidance | Any blend level with diesel |
| Standby | B5 Maximum blend level | Any blend level with diesel |
The differences in applicability of biodiesel and HVO in standby power applications are due to the nature of the fuels. Biodiesel can age with storage and degrade in quality as it ages. As such, it does not support use in standby power applications and, particularly emergency generator applications.
Generator engines fueled by renewable liquid fuels have similar performance to those fueled with conventional diesel but may experience a small decrease in maximum power output. Fuel consumption may also increase due to the potentially lower energy content of the specific renewable fuel being used. The cold temperature properties of both HVO and biodiesel need to be appropriate for the ambient environment of the generator. Your local Cat dealer can talk you through any adaptations that may need to be made to your installation.
Some regions or municipalities, particularly where mandates for renewable fuel use exist, may have abundant availability of biodiesel and of HVO. Other areas may not, which can mean fuels need to be transported to the location if needed. Transport over long distances may reduce the positive environmental impact of these fuels.
Only purchase biodiesel and HVO fuels from reputable dealers selling commercial grade fuels that meet the relevant specifications.
The price of biodiesel blends varies depending on geographic area, base material (corn, soybeans, etc.), supplier, and government tax and other incentives. Although renewable liquid fuels can cost more than petroleum diesel, diesel generator set owners can transition to these fuels without purchasing new engines. In the case of fleets, managers can transition to renewable liquid fuels without acquiring new spare parts inventories.
Detailed guidance on the use of renewable liquid fuels exists, and users should be aware of the differences in the maintenance requirements associated with them compared to diesel fuels and each other.
When switching from diesel fuel to biodiesel for the first time, shorter maintenance intervals are recommended with focus on fuel filters, hoses, pumps, and seals. Always consult your local Cat dealer for guidance and information relating to new or existing equipment.
HVO fuels have similar aging properties to diesel. Biodiesel, however, has a shorter shelf life due to its composition. Shelf life is based on the blend level.
Contamination control measures are critical for application of any fuel, diesel or renewable. Fuels must be protected from water and dirt.
Specifications & Standards
Biodiesel is registered with the U.S. Environmental Protection Agency (EPA) and is legal for use at any blend level in both highway and nonroad diesel engines. In the U.S., the applicable blending spec for B100 is ASTM D6751. B20 blend specs in the US is ASTM D7467.
European fuel standard EN 14214 ensures that biodiesel is suitable for even the most modern engines. EN 16709 describes B20 and B30 biodiesel blends.
HVO fuels must be per EU 15940 spec. HVO fuels also satisfy the diesel fuels specifications ASTM D975 and EN 590, except for density.
Only purchase biodiesel and HVO fuels from reputable dealers selling commercial grade biodiesel.
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