The most common and most likely answer to this crossword clue is the 8 letter word PARAFFIN
I've seen this crossword clue in The Times
P
A
R
A
F
F
I
N
More clues leading to the result PARAFFIN
- Trouble keeping half of common people in heating fuel
- Fuel soldier dropped: unpleasant smell returning
- Fuel vessel stopped by pilots following one
- Dad drops bottles very loudly, getting flammable substance
- Fuel problem keeps airmen fidgeting initially
- Fuel made from palm fibres clipped into container
- Air soldier with Forces getting in fuel
- Fuel hurting around half of common people
- Fuel container filled by pilots if on the way back
- Father’s seen fliers, with a section on fish oil
Buddy explains!

The straight part
We know that "Fuel" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fuel = paraffin.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PARAFFIN mean?
PARAFFIN noun- A petroleum-based thin and colorless fuel oil
- Any member of the alkane hydrocarbons.
- Paraffin wax.
- To impregnate or treat with paraffin.
- To embed in paraffin wax.