On this point, I would refer you here.
The relevant text:
My understanding is that you will not get a check in the mail, only the right to carry the excess credit forward. Given the political uncertainty of 2016, I would plan to reduce my withholdings and use up that credit asap, and not carry it forward for very long.
The relevant text:
If the federal tax credit exceeds tax liability, the excess amount may be carried forward to the succeeding taxable year. The excess credit may be carried forward until 2016, but it is unclear whether the unused tax credit can be carried forward after then. The maximum allowable credit, equipment requirements and other details vary by technology, as outlined below.
Comment