For login to TNEB portal you must need a valid user ID and password. If someone doesn’t have user id and password, he/she need to register TNEB portal first.
For fresh registration a valid email address and valid consumer ID require. While registering user need to choose or select a unique login name and then need to provide some information about electricity connection. On successful registration an email sent to user email id which contains a verification link. User need to click on this link, the click will verify the email address and then user redirected to login screen. For login, user needs to put login id and password on login screen.
Login id/name cannot be modified in any case; similarly you can’t modify consumer number. Still if a user requires changing in login id or consumer number, he/she need to delete the entire account and do a fresh registration.