Andres Clarens & Lisa Colosi Discuss Algae-to-Energy Systems
Fast Breaking Paper Commentary, December 2010
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Article: Environmental Life Cycle Comparison of Algae to Other Bioenergy Feedstocks
Authors: Clarens, AF;Resurreccion,
EP;White, MA;Colosi, LM |
Andres F. Clarens & Lisa M. Colosi talk with ScienceWatch.com and answer a few questions about this month's Fast Breaking Paper paper in the field of Environment/Ecology.
Why do you think your paper is highly
cited?
One of the key contributions of this paper is that it allowed people to think quantitatively about some of challenges and opportunities associated with algae biofuels. Algae have been studied as a source of energy for many years and, in some ways, our paper echoed work performed in the 1980s and '90s.
But our work provided a fresh perspective because it interpreted the challenge through a life cycle lens, and this allowed a larger audience to grapple with the most significant obstacles for large-scale algae deployment. We highlighted these using an uncertainty analysis as reported in the figure shown here.
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Tornado plots reveal the extent to which energy use (left) and greenhouse gas (right) emissions for algae cultivation are sensitive to changes in input parameters (vertical axis). The results show that algae energy content (high heating value), the source and dosage of fertilizers, along with the CO2 source are the most important inputs driving the results. |
Of all the inputs to the model, three seemed to emerge as the most important in driving the impacts: 1) the high heating value of the algae, effectively their lipid content; 2) the source of carbon dioxide, and whether or not it comes from a virgin hydrocarbon source as most industrial grade CO2 does; and 3) the source of nutrients since the production of these is so resource intensive.
The high heating values of the algae have been discussed widely and we found our results to be consistent with this focus. But almost as important were the sources carbon dioxide and nutrients, and this discussion had not been previously emphasized in the literature.
Does it describe a new discovery, methodology, or synthesis of knowledge?
The paper makes contributions in terms of methodology and synthesizing knowledge. There is some methodology involved because it is one of the first published studies to apply a life cycle framework to algae biofuels while simultaneously trying to bound the uncertainty of the analysis. Our paper exposed a few of the challenges associated with doing this type of analysis, e.g., burden allocation of carbon dioxide. There is also a synthesis element to our work since our model is based heavily on the results of demonstration scale studies.
Would you summarize the significance of your paper
in layman's terms?
Coauthor Lisa M. Colosi.
We performed a systems-level analysis of algae-to-energy systems and found that in many ways it is better to use corn or switchgrass to make energy than algae. This is surprising because many believe that algae represent a better way to produce energy than these traditional land-based crops. There are a few important ways in which algae are better: They use less land for the same unit of energy, and they can be grown in wastewater, which would have other environmental benefits.
How did you become involved in this research, and
how would you describe the particular challenges, setbacks, and
successes that you've encountered along the way?
Our research group has expertise in life cycle assessment, and, being in a Civil and Environmental Engineering Department, we know a good deal about wastewater treatment techniques. Looking at this problem, we realized there were a lot of insights we could bring to bear.
Where do you see your research leading in the
future?
The algae-to-energy field is very active and there are constantly new developments being reported. We are trying to model those and provide updated life cycle results. Our modeling conclusions have also led to some laboratory-based experiments that we hope will be valuable down the road.
Do you foresee any social or political
implications for your research?
Biofuels and politics have been closely coupled in the past and I hope that
future expenditures by the government to develop alternative energy
technologies are based on sound science. There haven't been any direct
impacts of our work on politics to date but I know that the US Department
of Energy is aware of some of the challenges that we have highlighted and
are looking for solutions like the rest of us.
Andres F. Clarens
Assistant Professor
Civil and Environmental Engineering
University of Virginia
Charlottesville, VA, USA
Lisa M. Colosi
Assistant Professor
Civil and Environmental Engineering
University of Virginia
Charlottesville, VA, USA
KEYWORDS: BIODIESEL PRODUCTION; FLUE-GAS; CO2 FIXATION; MICROALGAE; BIOFUELS; ETHANOL; ENERGY; CULTIVATION; GENERATION; RECOVERY.