Critical Review of Microalgae LCA Studies for Bioenergy Production
- PDF / 804,784 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 31 Downloads / 235 Views
Critical Review of Microalgae LCA Studies for Bioenergy Production Franziska Ketzer 1 & Johannes Skarka 1 & Christine Rösch 1
# Springer Science+Business Media, LLC 2017
Abstract The cultivation of microalgae gained high attention within the last years because of their potential to substitute conventional bioenergy crops. To evaluate algal bioenergy production pathways already at an early stage, several life cycle assessment (LCA) studies have been performed, but their results and conclusions vary drastically. Against this background, this review gives a comparative analysis of 16 recent studies. To allow for a comparison, a meta-approach served to uniform the considered systems. System boundaries have been equalized and the energy return on investment (EROI) has been calculated for each study. Depending on the assumptions made on biomass productivity, lipid content, required energy, and the output of the system, the energetic Highlights • System boundaries and processes were adapted in a meta-analysis • Comparison of energy return on investment (EROI) was enabled • Differences of results from 16 microalgal LCA studies, focusing on bioenergy, were identified • Explanations for varying energy inputs and outputs were given and discussed • Bottlenecks in algae-to-energy systems are summarized Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12155-017-9880-1) contains supplementary material, which is available to authorized users. * Franziska Ketzer [email protected] Johannes Skarka [email protected] Christine Rösch [email protected] 1
Karlsruhe Institute of Technology, Institute for Technology Assessment and Systems Analysis, P.O. Box 3640, 76021 Karlsruhe, Germany
performance was assessed. Large variations from 0.01 to 3.35 for the EROI could be derived. Keywords Life cycle assessment (LCA) . Microalgae . Bioenergy . Meta-analysis . Energy return on investment (EROI)
Introduction Microalgae are considered to be a promising feedstock for several purposes [1]. They can be used as raw material to produce high value products, e.g., for pharmaceutical applications, as fine chemicals or in human nutrition. To achieve economically viable products and to conquer bulk markets like the bioenergy sector, microalgal application has been studied in biorefinery contexts lately [2]. Microalgae can have high oil or carbohydrate contents that can be converted to liquid fuels like biodiesel or bioethanol, as well as gaseous energy carriers such as biogas (biomethane) [3]. Some algal species are even suitable to produce biohydrogen [4]. Consequently, algae-to-energy systems are considered to be a promising solution to overcome the energy vs. food dilemma, as they can be grown in absence of fertile soil in technical systems, so-called photobioreactors (PBRs). In general, algae can be produced in two different production systems open ponds or closed PBRs. Basically, the choice of the production system depends on economic-driven decisions and the final target product. I
Data Loading...
