Biofuel production has increased in the US due to government policy of energy independence and security. Ethanol can be produced from a variety of crops including grain, sugar, cellulose, and oil seed crops. The primary biofuel crop in the US, corn, uses less water than some crops but more than others. Producing corn for biofuels in the US has resulted in less irrigation water application to crops, since corn is irrigated with less water than the crops it has replaced, such as cotton. By 2030, water withdrawals for biofuel crops are projected at 4% of the total worldwide, but will be 22% of the total in the US, or 2-3 times that amount depending on irrigation water application to cellulosic ethanol crops.