Together with an account at HPC2N you will also get an email address. However, you cannot log in to read it at HPC2N so it will need to be forwarded to your home/other email. This email address will be pulled from SUPR by HPC2N, and will be used by HPC2N to determine where to send you any information.
Thus you must make sure to keep the email address given in SUPR updated and valid. You can change it from this page: SUPR personal information.
Note that HPC2N requires you to give a working email address, and that your account may be disabled if mail sent to it starts bouncing.