I guess the Ministry of Trade, Industry and Energy is considered a very powerful ministry?

That's how it's described on Namuwiki.
It says that even now, with the resource/energy duties and the Korean Intellectual Property Office gone, it is still more powerful than the Ministry of Land, Infrastructure and Transport or the Ministry of Environment.
It also says that if the special judicial police for technology leaks currently being pushed through passes, it will be second only to the Ministry of the Interior and Safety.