The EL is intended to replace scriptlets in modern JSP pages. As such, they really have little to do with each other. Scriptlet variables become local variables in the service method of the servlet created on behalf of your JSP. The EL has no access to these variables.
Rather, the EL operates upon scoped variables -- that is, objects placed in one of the context scopes: page, request, session or application.
Typically, scoped variables are created by the page controller for a JSP via the setAttribute() method of the appropriate scoped context.