The federal audit court said the decision was based on "evidence of fraud" in the tender process for the US$6bn Angra 3 nuclear power project in Rio de Janeiro.
The open season calendar was modified in December and runs from March 1 this year to February 28, 2018.
Chile's LPG imports rose 15% in January, even as imports of other fossil fuels were down.
Power generation on the coal and natural gas-dependent northern SING grid fell 17% in February.
The BASF subsidiary cited low costs in Argentina as driving growth in output and reserves, even through the current low oil price environment.
Brazil's state-run oil company said it would pump an additional US$600mn into exploration and production projects over the next five years after posting a fourth quarter profit.