Mainly if you want to focus on the applied portions of Renewable energy then you have to pursue engineering courses like BTech Mechanical Engineering, EEE further with a MTech in Renewable Engineering. Now if you want to work in Photovoltaics, Quantum Photoelectronics etc then Physics/ Chemistry followed a MSc-phD program can be a great option for you. So based on your interest in Renewable energy you will have to select the course.

To know more about this you can visit the link below:

https://www.careers360.com/courses/renewable-energy-course

I hope my answer helps. All the very best for your future endeavors!