The Biofuel Obligation Scheme, which was introduced in 2010, currently obliges that the amount of biofuel brought to the market is not less than 4.166% of the relevant disposal of petroleum road transport fuels. Biofuels are defined as liquid or gaseous transport fuels produced from biomass. In 2011, the biofuel obligation resulted in 145 million litres of biofuel being placed on the market. The rate of obligation will increase over time and by 2020 it will require suppliers of road transport fuels to make certain that even higher volumes sold are biofuel. This will ultimately create a market size approaching 500 million litres of biofuel.