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.
and accounted through the Integrated Assessment framewok before specific numerical results are
presented and published.
Presenter Response
[1.1] N/C --- [1.2a] Biomass productivity was estimated using a biophysical growth model based on
incoming solar radiation and water temperature determined from local meteorology through energy
balance calculations. Biological input parameters to the model were derived from current literature and
are explicitly described in Wigmosta et al. (2011). As noted the last systematic national water resource
assessment was conducted in 1978. Part of our current effort is to estimate water availability with the
most current information at each potential pond site. [1.2b] We agree that ground-truthing is an important
issue for assessments of resource use and algal biofuel production. We have approached this issue at
several levels including: 1) In the early phases of our efforts in developing the Biomass Assessment Tool
(BAT) we worked closely with J.R. Benemann and D.B. Anderson in developing the conceptual design,
data requirements, and underlying assumptions for the algal growth model which is the foundation for the
biomass production and resource use estimates produced by the BAT. 2) Simulated pond evaporation
rates from our model were compared with corrected pan evaporation data over a range of climate zones.
3) To the extent possible, based on limited published literature values and anecdotal information provided
by J.R. Benemann derived from his direct experiences in algae cultivation, we have attempted to
benchmark our analytical results. For example, our results indicate an average conversion efficiency of
total solar energy to organic mass of approximately 1%. This is consistent with the published value of
1%-3% for observed yields from Williams and Laurens (2010). We also found our calculated national
mean annual vegetable oil production rate of 5775 L/ha/yr is conservatively well below the published
value for current production of 14,000 L/ha/yr by Mascarelli (2009). We have plans, during the summer
months of 2011 to visit several research sites where algal growth experiments are planned or underway
including: 1) PNNL's Marine Science Laboratory where current lab experiments represent different U.S.
regional climates and focus in on both fresh and saline water algal strains; 2) University of Arizona where
focus is on the design and operation of raceway's in arid climates using freshwater species; 3) Texas
A&M (Pecos) to evaluate large-scale pond systems and production strains for biomass and lipids; and 4)
Utah State University where research is focused on cold weather cultivation and alternative nutrient
addition strategies. We will also monitor algal growth experiments at New Mexico State University and
Texas A&M (Corpus Christi). [1.2c] Using the GIS capabilities of BAT, it would be relatively
straightforward to consider the impacts of sea level rise to evaluate the sensitivity of microalgae
production potential to alternative climate change scenarios, particularly related to land availability in the
coastal regions. --- [1.3] N/C --- [1.4] N/C --- [1.5] N/C --- [1.6] We agree with the invaluable need to
ground-truth from the perspective of operators/farmers; please see Response [1.2b]. --- [1.7] We agree
with the reviewer in that it is ideal to model the major factors in multiple stages of the lifecycle process,
as is being done under the INL/PNNL Integrated Assessment Framework (IAF) project. There are
however, clear benefits to the scientific research community to share periodic and logical progressions
within specific lifecycle stages; the current project has benefited from such presentations and publications
from others, and our assumptions, results and contributions have been peer-reviewed by experts in the
field and published in Wigmosta et. al (2011). It should also be noted, that the IAF leverages major
components developed under the current project allowing a model progression to include and represent
the "resource to production to refinery" portion of the lifecycle.
2. Technical Progress and Accomplishments
Please evaluate the degree to which the project has
made progress in its objectives and stated project management plan
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