You Do Need power plug adapter while traveling from Ireland (Eire) to Sweden.

Here is Why You Need An Adapter

The outlet and plug type used in Sweden are C and F and in Ireland (Eire) is G. This is how they look like.

Ireland (Eire)

In Ireland (Eire), outlets of type G are in use.

Type G

Sweden

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

Type C

Type F