Recently, the potential of microalgae for the production of carbon-neutral biofuel has begun to be recognized. The oil content and productivity of algae are much higher than those of agricultural oil crops like rape seed or oil palm, yielding theoretically 10 to 100–fold more oil per growth area. Furthermore, microalgae cultivation does not require arable land or clean fresh water, as culturing takes place on land using open ponds, closed photobioreactors, or a combinations of them.
SUBMARINER is carrying out an assessment of the potential for microalgal cultivation as a source of bioenergy in Finland. More specifically, we are reviewing the physical and biological constrains of production in the Baltic Sea region. This includes modeling the availability of light for algal growth as well as the effects of temperature and light on the lipid yield. Based on this information we will be able to estimate lipid production of Baltic Sea microalgal species and give recommendations regarding whether further screening activities should be carried out.
We are also assessing the suitability of various cultivation methods for Baltic Sea region conditions. The proposed pilot scale facilities, located in Helsinki, consist of 100 L -scale photobioreactors built for this purpose. Suitable species of algae will be grown to estimate biomass production under northern Baltic climatic and light conditions throughout the year.
Growing microalgae in waste streams
An important fraction of microalgae culturing costs is due to inorganic nutrients required by algae, that is, fertilizers. Using waste streams with available nutrients, for example municipal waste waters, can reduce the price of end products, while also contributing to the recycling of nutrients and ultimately reducing the nutrient load to natural waters.
Growing algae in wastewater streams is a relatively old idea. Work on this topic was already conducted back in the 1950's but eventually chemical treatment and bacterial degradation of wastewater became the norm in wastewater treatment. Algae are, however, able to remove a high percentage of the bioavailable nutrients. The added value of removing nutrients by algal cultivation is obvious; additionally the produced algal biomass has several potential end uses ranging from high valuable compounds to bioenergy.
SUBMARINER is thus also working to estimate the potential resources available for algal growth in waste streams in Finland (nutrients, CO2). We will carry out an estimation of available waste streams in a pilot area (a waste water treatment plant in Espoo), model algal production scenarios (including amount of production, space required, reduction of nutrients) and conduct a pilot study of waste stream usability.