Reviewer Comments - EERE

2011 Algae Platform Review – Reviewer Comments
Reviewer Comments are direct transcripts of commentary and material provided by the Platform’s
Review Panel. They have not been edited or altered by the Biomass Program.
conditions that prevent membrane fouling, the cost changes to $2.03 x 10E-5 per gallon for the filtration
process or $243.80. No CapX were included in any of these estimates. We recognize that these
preliminary calculations need significant refinement, but they provide an initial basis to warrant further
investigation both from cost and experimental perspectives. Due to the combined complexity of the
estimation and space limitations, we are open to discuss this further with reviewer. We do not fully agree
with this comment that the presenter had a technology that “he can make work” for this particular
application. Once again we apologize for any misperception that this is a technology in search of an
application. We carefully evaluated costs for different filtration methods and came down with the two
scenarios and further we provide the costs per gallon in the above examples which are surprisingly
insensitive to method, but the level of solids (%solids) varies vastly ( Scenario 1 = 50 – 60%, Scenario 2
= 15 – 20%) . We hope to consume much less than 15% of total energy, but need to optimize the
debottlenecking separation of water and algae, thus the focused effort. Basically, it is not economic to
filter all of the water in the raceway so a pre-concentration must be performed. There are three main
approaches to pre-concentration: 1) full volume evaporation (used as a pre-concentration step much as
does the salt industry, but the algae will probably eat up their stored oils to survive these types of
scenarios thus rendering them nearly useless to us for oil production), 2) gravity assisted
flocculation/settling, and 3) air (or other gas) assisted floatation. All of these methods are commonly
utilized in industry (food processing, mining, etc.). We have selected gas assisted flotation due to its
consistent results, speed, high concentration ratios, and energy efficiency. We are pursuing very smallscale
studies with several varieties of algae to understand how the systems will perform before going to
the expense of purchasing a full scale rotary membrane unit. We have read a number or TEA articles and
will continue to consider the techno-economic feasibility of the cross-flow membrane technology.
Project: 9.2.2.3 National Renewable Energy Laboratory
Title: Efficient use of algal biomass residues for biopower production with nutrient recycle
Presenter: Eric Jarvis
Presentation Date: Friday, April 08, 2011
Criteria Avg Score Std Deviation Count
Approach 5.43 1.18 7
Progress 4.57 1.92 7
Relevance 5.43 1.40 7
Critical Success Factors 5.43 1.40 7
1. Project Approach
The project performers have implemented technically sound research, development, and deployment
approaches and demonstrated necessary results to meet their targets
The project performers have identified a project management plan that includes well-defined milestones
and adequate methods for addressing potential risks.
Reviewer Comments
Reviewer: 1 Criteria Score: 4
The Problem is worthy of study. The approach is worth evaluating. Do not culture your own algal
biomass! Partner with someone or get big quantities from actual industrial concerns. Improve the
effectiveness of the approaches. Decide what the deliverables will be and design the program to deliver.
Page 142 of 223