Biodiesel - Safety and Performance

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Safety and Performance

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The information provided below is a summary of the National Renewable Diesel Demonstration Initiative (NRDDI) program's Final Report with respect to diesel equipment users.

Legend:

  • B2: 2% biodiesel mixed with 98% diesel
  • B5: 5% biodiesel mixed with 95% diesel
  • B10: 10% biodiesel mixed with 90% diesel
  • B20: 20% biodiesel mixed with 80% diesel
  • B100: 100% biodiesel with no diesel content

Warranty

The majority of North American engine manufacturers now endorse up to a B5 biodiesel blend. The Engine Manufacturers Association issued a technical statement indicating biodiesel use up to B5 should not cause engine or fuel systems problems. As biodiesel is more widely tested and used, manufacturers will be in a better position to support the use of higher blends. Warranty coverage of B20 and higher is offered by select manufacturers under specific conditions.

However, similar to using regular diesel, some manufacturers may limit the scope of their warranties by stating that failures from the use of any fuel cannot be attributed to a factory defect. Therefore, the cost of repair under these circumstances (if any) would not be covered by certain warranties.

It is recommended that you contact your engine manufacturer, dealer, or consult your equipment owner's guide for more information on warranty coverage; particularly, if you plan to use blends above B5.

Operability

In general, the NRDDI projects increases the confidence in the use of up to B5 in engines under the conditions encountered, as there were no engine failures reported.

Cold Weather

Like petroleum diesel, biodiesel can form crystals in cold weather which can lead to filter plugging. Laboratory tests show that a biodiesel blend forms crystals at a higher temperature than petroleum diesel. Actual experience with cold weather operations is influenced by many factors including the type of feedstock used as some types of biodiesel form crystals at lower temperatures than others, depending on the feedstock and characteristics of the fuel.

Potential solutions to cold weather problems are similar to those for petroleum diesel. They include using fuel additives and engine block or fuel filter heaters and storing vehicles in a building.

Several studies including the NRDDI projects have shown the successful use of biodiesel blends in cold weather up to a certain low concentration. It is important for the fuel provider to choose the right biodiesel formulation, and the fuel blend level is adjusted, to meet the Canadian General Standards Board recommended temperature specifications for the season and region of use. If you are unfamiliar with this subject it is recommended you discuss cold weather use with your fuel provider.

Cleansing Effect

Biodiesel acts like a mild solvent and has a cleansing effect. It "cleans out" sediments formed over time in equipment and storage fuel tanks which can cause occasional filter plugging, especially in the early stage of switching from petroleum diesel to biodiesel blends. However, when it is used in low concentrations, such as B5, it should not cause major issues. The NRDDI projects did not encounter any engine failures due to the cleansing effect.

In its research, the US National Renewable Energy Lab (NREL) found the cleansing effect should not be an issue with B5 and lower blends. Although, it is still wise to keep some extra filters on hand and monitor potential filter clogging a little more closely at the beginning.

Material Compatibility and Older Equipment

Older diesel engines were not necessarily designed to use biodiesel blends. Certain parts such as seals, gaskets, and connectors made with non-compatible rubbers or metals can be altered if the biodiesel blend is high. Consulting your engine manufacturer or equipment owner's guide (for the specific model-year of the equipment) will help you assess what maximum blend level is recommended. Today, most engine manufacturers accept the use of blends up to B5 without voiding the warranty; however, the blend must always meet industry approved standards.

This following guide (PDF, 1.6 MB) identifies which materials are not compatible with biodiesel (p.23, p.50 and p.51).

NREL has found there have been no significant material compatibility issues with B20 (unless the B20 has been oxidized). NREL found B20 or lower blends minimize most issues associated with materials compatibility. This conclusion provides even more confidence in the minimal effects which can be expected with B5.

In the NRDDI projects, where vehicle model years varied from 1967 to 2010 but most were of model year 1994 or newer, operation on B5 was not shown to cause any significant loss-of service incidents.

It is recommended that you consult your dealer or vehicle guide; particularly, if you plan to use biodiesel blends above B5 in older equipment.

Long-term Effects

Since an increasing number of engine manufacturers are endorsing B5 the NRDDI projects did not generally examine long term effects, such as wear, materials compatibility or longevity and did not find any issues which could be specifically attributed to these effects.

Stationary and Heating Equipment

Although there is limited experience with the use of biodiesel as a heating fuel in Canada, no significant adverse effects from using biodiesel in low-level blends in furnaces and boilers have been reported from initial trials. The NRDDI Imperial Oil project (PDF, 318 KB, in English only) tested biodiesel blends in space-heating furnaces. The results found that biodiesel use in furnaces should not exceed B10 in order to be compatible with existing seals in fuel pumps for late-model equipment. It remains a good practice to contact your furnace manufacturer; particularly, if you plan to use blends above B10.

The use of B5 in power generators in remote northern Canadian locations was demonstrated in both warm and cold seasons in the NRDDI Manitoba Hydro project (PDF, 2.1 MB)without any issues or requiring additional maintenance.

Performance

Power

Biodiesel-powered engines have been shown to deliver similar torque and horsepower as diesel-powered engines.

Fuel Economy

Neat biodiesel (B100) has about 8% less energy content than diesel. As the diesel blend level is lowered, differences in energy content become proportionally less significant; blends of B5 or lower cause no easily noticeable differences in fuel consumption in comparison to diesel.

It is important to keep in mind your driving habits – when and where you drive, how often, the speed you travel, your aggressiveness on the road and other factors – have a lot to do with your vehicle's fuel consumption and costs. Inefficient driving practices can cause a greater increase in your fuel consumption and costs in comparison to switching your fuel from petroleum diesel to a B5 biodiesel blend.

Handling

Storage

All fuels have a limited shelf life. Long-term storage and storage with temperature variations leads fuel to degrade. Although biodiesel has been known to have a shorter shelf life than most petroleum diesels, fuel standards are designed to ensure all fuels have adequate long term performance. Adding proper additives is expected to address long-term storage concerns.

As summer fuel may be less suitable for winter, it remains a good practice to deplete fuel supplies before the season changes to ensure fuel remains appropriate for the expected temperature.

For low-level blends of biodiesel such as B2 and B5, end-users should be able to keep using their existing tanks. However, as mentioned above it is advised to keep extra filters on hand due to biodiesel's cleansing effect.

Safety

B100 is considerably less flammable than petroleum diesel, presents low-pressure storage at ambient temperatures, and is safer to handle and transport.