Power higher initially, after raising of low energy (5)
I believe the answer is:
oomph
'energy' is the definition.
(oomph can mean energy or excitement)
'power higher initially after raising of low' is the wordplay.
'initially' indicates taking the first letters.
'after' means one lot of letters go next to another.
'raising' says the letters should be written backwards (in a down clue, letters go up).
'of low' becomes 'moo' (I can't justify this - if you can you should believe this answer much more).
The first letters of 'power higher' is 'ph'.
'moo' written backwards gives 'oom'.
'ph' put after 'oom' is 'OOMPH'.
Can you help me to learn more?
(Other definitions for oomph that I've seen before include "Informal energy or enthusiasm, usually in a girl" , "Go" , "sex-appeal" , "15 [SEXINESS]" , "vital quality" .)