Algae biofuel can reduce vehicle lifecycle CO2 emissions 50 to 70 percent compared to petroleum fuels when using an Energy Return on Investment (EROI) model. "With significant emissions reductions, a positive energy balance, nutrient recycling and CO2 reuse, algae-based fuels will be a long-term, sustainable source of fuels for our nation," Mary Rosenthal, ABO's executive director, told Hybrid Cars.
The study, with the easy-to-remember names of, "Pilot-scale data provide enhanced estimates of the life cycle energy and emissions profile of algae biofuels produced via hydrothermal liquefaction (HTL)," comes from a new peer-reviewed paper published in Bioresource Technology. Authors of the study did a lifecycle analysis of an algae cultivation and fuel production process currently used at pre-commercial scales by Sapphire Energy.
Field data for the study came from two of Sapphire's New Mexico facilities – one in Las Cruces and the other in Columbus – that grow and process algae into Green Crude oil. Sapphire's Green Crude can be refined into gasoline, diesel or jet fuel. Once the fuel reaches commercial scale, it's expected to produce biofuels with lower greenhouse gas emissions and EROI comparable to first-gen biofuels. That EROI is also expected to be close to petroleum and three times higher than cellulosic ethanol. The findings also give Sapphire's system kudos for recycling nutrients and producing significant energy savings during the process.
First-gen biofuels in the US are made up mostly by corn-based ethanol, which makes up to 10 percent of "normal" gasoline and, in some cases, up to 15 percent. The flex-fuel-vehicle specific E85 is made up of 85 percent biofuel and 15 percent petroleum product.