Doesn't the bulk user upload do that? I can never remember!...
Sending an email on account creation
What you are trying to do should work.
Please go and vote for https://tracker.moodle.org/browse/MDL-19390 They have said maybe with more votes this will be added.
Hello Derek, I did see that page and even when the password is omitted in the csv file it still fails to send an email for me, so I'm not sure if that information is incorrect or there is something else going on. I see now that this has been a bug for quite some time but I voted for it anyway.