Which of the following is not the source of Alternate Energy?

Which of the following is not the source of Alternate Energy?

مندرجہ ذیل میں سے کون سا متبادل توانائی کا ذریعہ نہیں ہے؟
Explanation

Thermal energy  is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.