ST. PAUL, Minn. - The 16 big flasks of bubbling bright green liquids in Roger Ruan's lab at the University of Minnesota are part of a new boom in renewable energy research. Driven by renewed investment as oil prices push $100 a barrel, Ruan and scores of scientists around the world are racing to turn algae into a commercially viable energy source. Some varieties of algae are as much as 50 percent oil, and that oil can be converted into biodiesel or jet fuel. The biggest challenge is slashing the cost of production, which by one Defense Department estimate is...