Chemical energy generally deals with the refineries and such sector so you should be thorough with the NCERT 12 th chemistry.
It is a very good branch to opt ton one of my favourite branches . You have very good opportunity in future in foreign . In India you won't fetch a good job though if you aren't in a psu.

Hi
as your  taking chemical engineering you should be good at knowing  common salts & charechterestis of the chemical reactions. You have to study the basics in organic,analytical and chemical terms