Development of novel concepts for microalgae in the Austrian energy system

Published 2014

Citation: Sonnleitner A, Bacovsky D. Development of novel concepts for microalgae in the Austrian energy system, 4. Central European Biomass Conference 2014, 15th-18th of January 2014, Graz, Austria.

Abstract

Microalgae are seen worldwide as a new and promising feedstock for the energy supply chain.
Because of their high productivity and their ability to convert CO2 into biomass, microalgae are a
potential raw material for biorefineries, avoiding the food versus fuel conflict, and contributing to an
increased share of renewable energy. According to the current state of the art the utilization of algal
biomass for the production of fuel, energy and heat seems to be economically not competitive and the
life cycle assessment shows improvement possibilities in energy consumption (project
Algae&Energy:Austria). There are different options for utilization concepts which are technologically
and economically feasible. New concepts need to be developed and synergies with already existing
technologies need to be used.
Challenges along the value chain:
· Supply of water for cultivation
· Supply of nutrients for cultivation
· Energy consumption during cultivation
· Harvesting and processing of biomass
· Investment and operating costs
One possibility to cover the need of water and nutrients in a cost-effective way is the combination of
microalgae cultivation and waste water treatment. The cultivation of algae using different waste water
types common in Austria is technologically possible. In particular municipal waste water and effluents
from breweries and dairies are suitable as substrate. Due to the usage of this synergy the need for
fresh water and artificial fertilizer for algae cultivation decreases substantially and therefore operating
costs are reduced. Promising production concepts were developed and further research and
development needs were pointed out (project SAM).
After producing algal biomass the harvesting and processing steps for further utilization seem to be
difficult. In particular the high amount of water increases the energy expenditure in most of the
conversion pathways. Hydrothermal liquefaction seems to be promising to reduce the energy intensity
through two major factors: First, the conversion takes place in the liquid phase, and no energy
intensive drying of the algal biomass is needed. Second, the entire carbon which is fixed in the algae
can be used for energy production. The main product of hydrothermal liquefaction is a bio-oil, which
can be further processed in existing refinery processes into biogenic motor fuels, plastics and basic
chemicals (project microHTL).
In Austria many scientific research groups and companies are dealing with microalgae in the energy
system. These research and development efforts comprise different topics and approaches, like
different cultivation system designs (open pond, photobioreactor), biotechnological optimization of
microalgae species, the utilization of algal biomass in energetic and material pathways or the
combination of microalgae cultivation with existing technologies. It is of growing importance to
establish a network of Austrian experts and research groups for enhancement of cooperation and
research within the field of algae (project network biobased industry).
Through the optimization along the entire value chain with special regard to novel concepts of
cultivation, harvesting, processing, conversion and utilization, as well as an enhanced network of
Austrian experts and research groups, microalgae can serve as biogenic feedstock for the energy