Sundrop Fuels plans to build a plant in Louisiana that will make gasoline from natural gas and include a demonstration plant for turning paper-mill byproducts into "green gasoline." The cost to build the plant is estimated at $500 million. The company has chosen IHI E&C International Corp. as the contractor. Construction is expected to start later this year. The project is "the first of four renewable gasoline "megaplants" that will produce more than 200 million gallons of biofuel a year.