Green Plains Renewable Energy Inc., North America's fourth-largest ethanol producer, today announced the pricing of its offering of $100 million in convertible senior notes due 2018, which was increased from a previously announced $75 million aggregate principal amount. The Omaha-based company said it intends to use the net proceeds of the offering for general corporate agreements, but may use a portion of the proceeds to acquire or invest in additional facilities, assets or technologies or retire existing debt.  Green Plains, which distributes about 1 billion gallons of ethanol annually, is a joint venture partner with BioProcess Algae LLC, which was formed to commercialize advanced photo-bioreactor technologies using algae. It currently operates a demonstration plant in Shenandoah, Iowa.