I am trying to find out the required power and torque of the motor for the bike for optimum cost.(mass approximated as 200kgs)

I have approached like this :

Calculated Rolling resistance taking Crr as 0.3 (for sand ) (is it correct)

Calculating grade resistance for upto 30 degrees

Calculating acceleration for considering 3m/s2 as required acceleration

Calculating aerodynamic drag (comes in the range of 20 N)

Then adding all to get total tractive force.

How to get the power now , I have tried multiplying with peak velocity (100kmph) but I am getting around 50kW . Is my answer correct ? Is getting a 50kW motor feasible? Or motor with how much power should I need to buy , considering in market all range of motors are available