ABSTRACT

Autotrophic Production of Algal Biofuel: What is the best technology line-up
Skye Thomas-Hall,
Cellana LLC, Kailua Kona, HI, 96740, USA

Microalgae have the potential to produce 10-20 times more biofuel feedstock per unit area than any terrestrial bioenergy crop. However for this to be economically viable, three important technology stages need to come together: i) cultivation of high lipid species must be relatively contamination free and highly productive (ideally AFDW in excess of 30 g m-2 d-1); ii) the biomass needs to be harvested quickly using energy efficient technology; and iii) the harvested algae should be processed into stable products before value is lost.

Cellana LLC was formed in 2008 with the primary aim of developing the technology pathway to make algal biofuels economically viable. Cellana’s 2.5ha Kona Demonstration Facility (KDF) is located on the Big Island of Hawaii and has been producing high quality algal biomass since 2009. The production can be tailored to customer needs for different fractions of the algal biomass, including lipids for biodiesel, protein for animal feed, essential fatty acids (i.e. EPA, DHA) and accessory pigments (e.g. lutein, ß-carotene, lycopene etc) for the nutrition and cosmetic industries. Cellana’s KDF is primarily a research facility, designed to test many algal species simultaneously (up to 12) in realistic outdoor conditions. The large scale hybrid system can grow 2 species simultaneously and has excellent flexibility that enables cultivation conditions to be optimized for each individual strain. The facility is also set up to test a variety of harvesting and dewatering techniques on each species grown at demonstrations scale (up to 780,000L).

Presented is an overview of strain selection at small scale (lab <1 L) and mid scale (outdoor 200 L). Growth parameters that can be altered for optimizing cultivation at mid scale and large scale (60,000 – 130,000 L). The majority of the presentation is on harvesting and processing techniques used by Cellana and in the wider algae industry, focusing on cost versus efficiency of methods trialed at Cellana’s Kona Demonstration Facility (KDF). Best handling and storage practices are also presented along with data analysis specifically focusing on lipid quality.