Algae Biofuel B Greg Mitchell Scripps Institution of

Algae Biofuel B. Greg Mitchell Scripps Institution of Oceanography University of California, San Diego gmitchell@ucsd. edu With contributions from Sempra Utilities, Earthrise Live. Fuels, Inc, General Atomics Neste Oil and The Scripps Research Institute

Algae are photosynthetic organisms CO 2 + H 2 O + Light Energy Biomass Algae very diverse: microscopic to giant kelp Efficient, rapid growth, can double biomass in a day Produce 50% of oxygen but are less than 1% of all plant biomass Few species have been studied for biofuel potential Chlorophyceae Dinophyceae Bacillariophyceae 2

Ethanol and Biodiesel Feedstocks Must Be Expanded if They are to Contribute Substantially Reliance on food crops undesirable – and Limiting Cellulosic ethanol could be part of the solution Ethanol and biodiesel needs a non-food feedstock Algae Can Play that Role: Can be grown on non-arable land in saline water

Unique Potential of Algae Biodiesel Yield per acre • Soybean Based Biodiesel will never contribute more than a few percent of the possible US diesel fuel market • ~20 million acres of algae would supply ALL US transportation fuel – Small fraction of current land use – US currently uses ~970 million acres for crops & grazing Crop Gal/Acre/ yr Of Oil Soybean 48 Peanuts 113 Rapeseed 124 Coconut 287 Palm Oil 635 Algae 15, 000 4

ALGAE BIOFUEL – REDUCED GLOBAL WARMING & LOWERED ENVIRONMENTAL IMPACTS • Algae requires CO 2 for growth therefore fuel is carbon neutral • Possible integration to achieve low-cost CO 2 sequestration and nutrient remediation • Uses all nutrients, minimizing eutrophication • Biodegradable, so minimal issues with accidental spills /leaks • Uses underutilized land, e. g. deserts • Yields >10 x those for land plants so much less land is needed • Can grow in salt, or brackish water • Can produce high yields of – Lipids for biodiesel – starch / polysaccharides for ethanol 5

Encouraging Cost Projections Analysis by General Atomics 6

Evaluation of various Biofuel Options Sempra Utilities Option Rate Impact GHG Impact Market Readiness/ Issues Biogas Manure, Wastewater, Stillage Neutral to slight negative based on scale High Ready Now; Needs scale Microalgae Neutral to slight negative High 5 Years; Land requirement; Tech. development Energy Crops- Switch grass, willow hybrid poplar TBD Medium to High 5 -10 Years; Yields need to improve; land requirement and logistics issues Biomass Pyrolysis and gasification – Forestry Residue Negative Medium Needs significant development and scale economies for commercialization

Engineering a Photosynthetic Hydrocarbon Mix Steve Mayfield The Scripps Research Institute Potential to convert light energy directly to fuel molecules