As part of the ambitious goals Brazil committed to at the 21st Conference of the Parties (COP21) of the United Nations Framework Convention on Climate Change, the Ministry of Mines and Energy announced the RenovaBio program in December, 2016. The program proposes to create a regulatory framework to revitalize the biofuels sector, encouraging energy efficiency gains in biofuels production and use, and will recognize that different biofuels have different capacities to contribute to the de-carbonization goals set at COP21. In August, 2017, the Brazilian Government put a tariff rate quota in place for ethanol imports, allowing 600 million liters to enter duty free, with any volume above being subject to a 20 percent tariff. This followed a March, 2017, request by Brazilian ethanol producers to place a tariff on ethanol imports. Producers claim the pace of imports jeopardizes domestic ethanol production; especially in northeastern Brazil, where import volumes have risen significantly due to competitive prices from imported corn ethanol. The United States remains the top supplier of ethanol to Brazil. The Brazilian ethanol-use mandate remains unchanged at 27 percent (E27), whereas the biodiesel mandate increased to eight percent (B8) in March, 2017.