The construction that you're asking about is usually limited to "so" and "such". For example:

The room was such a mess that we spent all day cleaning it.

As with your example #1, the predicative expression can be fronted for emphasis:

Such a mess was the room that we spent all day cleaning it.

Because they don't use "so" or "such", your examples 2, 3, and 4 are incorrect.

Your example #5 sounds incomplete because we normally expect "that . . ." to follow:

So confusing was the question that no one answered it correctly.

In informal contexts, it is common to omit the subordinate clause. However, in that case we'd normally use standard word order and emphasize "so":

The question was so confusing!

The nonstandard word order in example #6 makes it sound awkward. We would normally write:

Korea's production was 400 billion kWh, and its consumption was slightly lower.

By the way, if you search this site for "so that" "such that" you will find several discussions of this construction.

The construction that you're asking about is usually limited to "so" and "such". For example:

The room was such a mess that we spent all day cleaning it.

As with your example #1, the predicative expression can be fronted for emphasis:

Such a mess was the room that we spent all day cleaning it.

Because they don't use "so" or "such", your examples 2, 3, and 4 are incorrect.

Your example #5 sounds incomplete because we normally expect "that . . ." to follow:

So confusing was the question that no one answered it correctly.

In informal contexts, it is common to omit the subordinate clause. However, in that case we'd normally use standard word order and emphasize "so":

The question was so confusing!

The nonstandard word order in example #6 makes it sound awkward. We would normally write:

Korea's production was 400 billion kWh, and its consumption was slightly lower.

By the way, if you search this site you will find other discussions of this construction, such as so...that / to the extent that / such that do they all interchangeable? and "such that" & "such as to", "so...that" &"so...as to", "such...that" &"such ...as to".

The construction that you're asking about is usually limited to "so" and "such". For example:

The room was such a mess that we spent all day cleaning it.

As with your example #1, the predicative expression can be fronted for emphasis:

Such a mess was the room that we spent all day cleaning it.

Because they don't use "so" or "such", your examples 2, 3, and 4 are incorrect.

Your example #5 sounds incomplete because we normally expect "that . . ." to follow:

So confusing was the question that no one answered it correctly.

In informal contexts, it is common to omit the subordinate clause. However, in that case we'd normally use standard word order and emphasize "so":

The question was so confusing!

The nonstandard word order in example #6 makes it sound awkward. We would normally write:

Korea's production was 400 billion kWh, and its consumption was slightly lower.

The construction that you're asking about is usually limited to "so" and "such". For example:

The room was such a mess that we spent all day cleaning it.

As with your example #1, the predicative expression can be fronted for emphasis:

Such a mess was the room that we spent all day cleaning it.

Because they don't use "so" or "such", your examples 2, 3, and 4 are incorrect.

Your example #5 sounds incomplete because we normally expect "that . . ." to follow:

So confusing was the question that no one answered it correctly.

In informal contexts, it is common to omit the subordinate clause. However, in that case we'd normally use standard word order and emphasize "so":

The question was so confusing!

The nonstandard word order in example #6 makes it sound awkward. We would normally write:

Korea's production was 400 billion kWh, and its consumption was slightly lower.

By the way, if you search this site for "so that" "such that" you will find several discussions of this construction.