Yes, you can apply right away. By second year you already know the subjects that cover your course and you can choose your internship accordingly.
Yes, you can register again. Also you have gone through the same procedure once thus there are chances of an improved performance.
EnTC interns are offered variety of responsibilities with the basic being system analysis and its design, testing, system integration etc. Generally, interns assist the EnTC engineers and shadow them for time management and operations on a real-time project. Activities like documentations, internal team interactions and company related trainings are additional responsibilities for the EnTC intern.