; or (B) nuclear power. (d) Technical assistance The Secretary of Energy shall ensure that Department of Energy national laboratories offer to provide technical assistance to each covered entity carrying out a project assisted with a grant under the program. (e) Report Not later than two years after the establishment of the program, and on an annual basis thereafter, the Secretary shall submit to Congress a report containing— (1) an estimate of the amount of funds disbursed under the program; (2) an estimate of the energy conservation achieved as a result of the program; (3) a description of challenges encountered in implementing projects described in subsection (c)(1); and (4) recommendations as to additional legislative measures to increase the use of renewable energy in Puerto Rico and the Virgin Islands of the United States, as appropriate. (f) Authorization of appropriations There are authorized to be appropriated such sums as may be necessary to carry out this section. 3. GAO study and report (a) In general (1) Study and report Not later than 180 days after the date of enactment of this Act, the Comptroller General of the United States shall— (A) conduct a study regarding renewable energy and energy efficiency in Puerto Rico and the Virgin Islands of the United States; and (B) submit to Congress a report containing— (i) the findings of the study; and (ii) related recommendations. (2) Components The study conducted under paragraph (1) shall consider, in relation to Puerto Rico and the Virgin Islands of the United States, the potential— (A) to modify existing electric power systems to use renewable energy sources; (B) to expand the use of microgrids