The United States won't meet some biofuel mandates under the Renewable Fuel Standard unless new technologies are developed or policies change, a report says.

The standard mandates minimum use levels of conventional biofuels such as ethanol, biomass-based diesel fuel and cellulosic biofuels produced from wood, grasses, or non-edible plant parts by 2022.

A report from the National Research Council, requested by Congress, said production of adequate volumes of biofuels are expected to meet consumption mandates for conventional biofuels and biomass-based diesel fuel but whether and how the mandate for cellulosic biofuels will be met is uncertain.

Unless the production process is unexpectedly improved, production scaled up and policy uncertainties removed, the capacity to meet the renewable fuel mandate for 16 billion gallons of cellulosic biofuels will not be available, a release from the National Science Foundation said Tuesday.

The study was sponsored by the U.S. Department of Agriculture, U.S. Department of Energy and U.S. Environmental Protection Agency.