Conceptual cost of an integrated micro-algal biomass-to-liquids facility

Abstract

An order­of­magnitude cost estimate was conducted on a new integrated biomass­to­liquids (BtL) process that produces 2.6 million litres of biodiesel per year from micro­algal biomass harvested from the Hartbeespoort Dam. The total capital cost of the new BtL facility was estimated at $10.4 million or $19/bbl of biodiesel. The most expensive part of the new BtL facility is the extraction unit to produce micro­algal oils through thermochemical liquefaction, which contributed over 44% of the total capital cost. The biodiesel production unit contributed 37% of the total capital cost. Harvesting costs contributed only 19% of the total BtL capital cost, compared to 20­30% for other BtL harvesting processes used world­wide. The total annual operating cost of the new BtL facility was estimated at $2.5 million per year or $117/bbl. The largest contributor to the operating cost is the extraction unit, with 42% of the total operating cost. The biodiesel unit contributed 40% of the total operating cost. Harvesting costs contributed only 18% of the total operating cost of the BtL process. The most probable lifecycle cost of the new BtL facility was estimated at $136/bb