The long-awatied notice of proposed rulemaking on the Renewable Fuels Standard will be issued Tuesday morning at 10:00 Eastern time by the Obama administration.

The announcement will be made jointly in a press conference by Secretary of Agriculture Tom Vilsack, Secretary of Energy Steven Chu and Environmental Protection Agency Administrator Lisa Jackson who will discuss President Obama’s commitment to advance biofuels research and commercialization under the rule.

EPA is required under the 2007 Energy Bill to consider ‘significant indirect emissions’ when determining greenhouse gas emissions for fuels under the so-called RFS-2 program. The new RFS requires new corn ethanol plants and new cellulosic ethanol plants to produce a fuel that emits fewer life-cycle greenhouse gasses relative to regular gasoline and that indirect land use changes should be figured into that.

However, methods for calculating such ‘indirect land use changes’ – such as from forest or grassland to crops – are not yet adequately developed, and therefore many are arguing they should not be used in calculating the emissions. “Otherwise, we’ll exclude some good biofuels and stifle the investment that is so essential to our national renewable fuels strategy,” says Senator Tom Harkin (D-IA), who was one of a group of senators who asked the EPA not to propose regulations assuming that greater U.S. biofuels use would increase carbon dioxide emissions.

The Renewable Fuels Association has already scheduled a press conference for one hour after the administration’s formal announcement to comment on the proposed rulemaking.