The conversation between human and AI assistant.
[|Human|] Given these paragraphs about Natural hydrogen, what are other forms of hydrogen obtained using different processes?
[|AI|] Green hydrogen, which is produced from renewable energy sources, and from grey, brown or black hydrogen, which is obtained from fossil sources or from the electrolysis of water.
[|Human|] 
Given these paragraphs about Natural hydrogen, what are other forms of hydrogen obtained using different processes?