The Department of Energy Public Access Plan requires investigators receiving DOE funding to "submit metadata and a link to the full-text accepted manuscript (or the full text itself)" to the DOE's Office of Scientific and Technical Information.
The policy applies to award agreements issued or renewed after October 1, 2014.
The manuscript version required is the final, peer-reviewed manuscript version. The DOE also refers to this as an accepted manuscript. This manuscript is the version of the article that has been accepted for publication and includes all changes made by the author during the peer-review process. It does not include the publisher's formatting.
The time before an article will be freely available to the public is typically called the embargo period.
For the DOE, there is a 12-month embargo from date of publication. Please note that the DOE refers to this as an "administrative interval".