You Do Need power plug adapter while traveling from Åland Islands to Greenland.

Here is Why You Need An Adapter

The outlet and plug type used in Greenland are C, E, F and K and in Åland Islands are C and F. This is how they look like.

Åland Islands

In Åland Islands, outlets of type C and F are in use.

Type C

Type F

Greenland

In Greenland, outlets of type C, E, F and K are in use.

Type C

Type E

Type F

Type K