Does anybody have any insight about this course? What is its value in comparison to the oil and gas LLM

I don't think there's much difference. It's mainly a question of how you want to brand yourself.

Just look at the courses, they are almost identical, except for some low carbon and renewable classes you get in the Energy Law LLM:

http://www.abdn.ac.uk/study/courses/postgraduate/taught/oglps/
http://www.abdn.ac.uk/study/courses/postgraduate/taught/energy_professional_skills/