I've been researching this myself and came across a few things.
It seems that binding in that way is somewhat deprecated in favor of using computed properties or aliases. Check out the comments on the answer for this SO question:
What's the difference between Ember.computed.alias and an Ember.binding?
Or more specifically the comments on this github issue: https://github.com/emberjs/ember.js/issues/1164#issuecomment-23200023).
Part of the reasoning seems to be an aversion to using global/absolute paths. Also you probably don't want to bind to the class definition, but an actual instance of the class. I'm not quite sure what your utility class is, but if it were a controller the idea would be something like this:
export default Em.ObjectController.extend({
needs: ['utility'],
aliasedVariable: Ember.computed.alias('controllers.utility.variableOnUtility')
});
Check out the answer for this SO question: Ember.js: data-binding between controllers
Also this section of the ember guide:
http://emberjs.com/guides/controllers/dependencies-between-controllers/