I'd like to use an alternative email address for alert notifications

You can use alternative email if you'd like to receive your alerts notifications to another email address. Simply check the Send plain text box in the alert settings dialog and specify an email address that you'd like to use. 

Note that some providers (e.g., T-Mobile and Verizon) offer this service for personal use only and might limit the number of messages you can receive. Please make sure to specify terms and conditions from the provider beforehand.