Dear Mark: Robert Tulip’s conclusions about the “inefficiencies" of existing microalgal cultivation methods as analysed by Beal et al. in the manuscript, "Economically competitive algal biofuel production in a 100-ha facility: a comprehensive techno-economic analysis and life cycle assessment,” are his interpretations, not ours. We have conducted very rigorous techno-economic analyses and life cycle assessments of many potential line-ups, and we are very encouraged by the results for a few of them. I think that Robert’s reading of our manuscript was selective, with him only seeing in it the results that confirmed his preconceptions. Since our manuscript is currently under review, I shared it with him under the condition that he not share or distribute it yet. Once it has successfully passed through the peer-review process, I would be pleased to share it with all interested parties. I would like to point out that productivity rates to date exceed the DOE’s targets for 2018, and we envision algal biofuels that will be cost-competitive with fossil fuels once we derive the full value from potential co-products. One of our manuscript’s conclusions is that algal biofuels are unlikely to be cost competitive with fossil fuels (especially heavily subsidized ones) without deriving value from additional co-products. From our calculations, using “defatted” algal biomass as a nutritional supplement in animal feeds, while assuming the commodity price for soybeans of $400/MT, results in a biofuel price of ~$8/gallon. This greatly undervalues the algae, which has a far superior amino acid profile and other nutritional benefits (e.g., high omega 3 fatty acid content) relative to soybeans. Using “defatted” algal biomass as a supplement in fish feeds, while assuming the going commodity price of $1500/MT, results in a biofuel price of ~$2.50/gallon. The prospect of using algae directly in human nutrition has even greater economic benefits. There are lots of promising directions to go from here, so I am disappointed that Robert has chosen to portray our findings in an unfavorable light. For the purpose of scaling arguments, I would also like to point out that cultivating algae in an area the size of Wyoming can produce enough biofuel to meet the entire annual liquid-fuel transportation demand for the US while simultaneously producing an amount of protein 5.7x the annual global soy protein production. I believe these numbers, based on demonstration-scale field trials, should be a reason for optimism.
Sincerely, Chuck Greene On Nov 8, 2014, at 8:51 AM, [email protected]<mailto:[email protected]> wrote: Response to comments from Mark Capron Hi Mark Thanks for your comments. My view is that microalgae is the best option for carbon dioxide removal as a geoengineering method to stabilise the global climate, and that the submarine storage and processing concept I have presented here should be the most economical and technically feasible approach. Here is a summary. Considering how carbon can best be managed in a form that is made commercially sustainable by its value as saleable commodities, my concept is that temporary deep ocean storage of algae presents a method able to make emission reduction irrelevant to climate stabilisation, by producing energy at a cost below the production cost of fossil fuels. The inefficiencies of existing algae methods are analysed by Beal et al in their paper Economically competitive algal biofuel production in a 100-ha facility: a comprehensive techno-economic analysis and life cycle assessment. Charles H. Green kindly sent me this paper in response to my comments on his [X] post<https://groups.google.com/forum/#!topic/geoengineering/z3kwcBNQsSY> on the efforts of the Algae Biomass Organisation. Beal et al have also written [X] Energy Return on Investment for Algal Biofuel Production Coupled with Wastewater Treatment<http://www.ingentaconnect.com/content/wef/wer/2012/00000084/00000009/art00002>. Another typical paper on algae yield and energy return on investment is [X] Reduction of water and energy requirement of algae cultivation using an algae biofilm photobioreactor<http://www.utexas.edu/research/cem/algae_images/03_12%20reduction%20of%20water.pdf>. The methods described in these papers are nowhere near cost effective as biofuel production systems able to compete with coal and gas without carbon tax subsidy. A completely new technological paradigm is needed. I preface my comments on the potential for such transformative technology by saying that the concepts described below are untested and are solely my personal ideas. I would warmly welcome any suggestions on testing methods or discussion on my assumptions. [X]NASA’s OMEGA system<http://www.energy.ca.gov/2013publications/CEC-500-2013-143/CEC-500-2013-143.pdf>, using floating plastic bags at sea to grow algae, presents a basis for a far more efficient biofuel production method than algae ponds or photobioreactors, due to its ability to tap into oceanic energy. The OMEGA system as described by NASA must be augmented by three important innovations which together promise a new technological paradigm that will be cost competitive. These factors are: 1. use of tide, current and wave power to move CO2, nutrient, algae and water; 2. initial co-location with abundant sources of CO2, nutrient and expertise and suitable hydrogeology; 3. use of produced algae to make more factories using methods such as [X] bioplastic<http://algix.com/>. These methods offer potential to drive capital and operating expenditure down way below existing biofuel models in order to enable cost competitiveness against fossil fuels when replicated and expanded to achieve efficiency of scale. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
