Asked 10th Jan, 2014
  • Boundless Impact Research and Analytics

How would you define drop-in (or non-drop-in) alternative fuel?

What's the best definition you've seen? I would like to use an existing government policy or national lab/academies report. Or, how could I improve these two draft definitions below?
To start, the US Energy Policy Act of 1992 still seems to be the authority on "alternative fuel." (Thank you EERE for making this list easy to find.)
Methanol, ethanol, and other alcohols
Blends of 85% or more of alcohol with gasoline
Natural gas and liquid fuels domestically produced from natural gas
Liquefied petroleum gas (propane)
Coal-derived liquid fuels
Fuels (other than alcohol) derived from biological materials (including pure biodiesel (B100))
My first stabs at "drop-in" and "non-drop-in." (Thank you CAAFI for getting me started.)
Drop-in Alternative Fuel:
An alternative fuel that is completely interchangeable and compatible with a particular conventional (typically petroleum-derived) fuel. A perfect drop-in fuel does not require adaptation of the fuel distribution network or the vehicle or equipment engine fuel systems, and can be used “as is” in vehicles and engines that currently operate on that particular fuel. Some alternative fuels may become “drop-in” only after blending with conventional fuel to a certain prescribed proportion.
Non-drop-in Alternative Fuel:
An alternative fuel that is not completely interchangeable and compatible with a particular conventional (typically petroleum-derived) fuel. A non-drop-in fuel requires adaptation of (or special treatment within) one or more components of the existing fuel distribution network or the current fleet of vehicle and equipment engine fuel systems. Some alternative fuels must be carefully segregated from conventional fuels, while others may be safely blended with conventional fuels. Some alternative fuels may remain “non-drop-in” even after blending with conventional fuel.

All Answers (2)

3rd Apr, 2014
Antje Klitkou
Nordic Institute for Studies in Innovation, Research and Education
There is a gradual difference between drop-in and non-drop-in alternative fuels: ad a low blend of petroleumm with bioethanol (ca. 5%) conventional internal combustion engines need no adaptation, while at higher blends such adaptations are required.
1 Recommendation
13th Nov, 2021
Abu Yousuf
Shahjalal University of Science and Technology
Drop-in fuel: replaceable with existing fuels, no need modification of engine or distribution system.
Non-drop-in: need some modification to adapt the new fuels
1 Recommendation

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