Alternatives for when your institution doesn't provide you an e-mail address
Some scientific organizations like ieee provide an life-long (or membership-long) e-mail adress which can be used in an academic context. The advantage is, that it will stay valid even if your affiliation changes. The downside is, you will collect spam forever ;-). 

In our university, all students are in a dedicated "firstname.lastname@student.our-university.de" scheme, and they are deleted a few months after graduation. This does not help for long-term communication issues, but allows access for restricted content during the time of study.

In general, I believe your institution should provide an e-mail address due to many reasons (e.g. authentification, ease of communication, etc.), honestly it is hard to imagine how we would run our institution without.