You Do Need power plug adapter while traveling from Netherlands to Ethiopia.

Here is Why You Need An Adapter

The outlet and plug type used in Ethiopia are C, F and G and in Netherlands are C and F. This is how they look like.

Netherlands

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

Type C

Type F

Ethiopia

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

Type C

Type F

Type G