# The Perspective of Large-Scale Production of Algae Biodiesel
## 3 Production of Algal Biodiesel
### Production Cost Analysis
Oil extraction, pre-esterification, purification, and distributions would account for 15-25%, 10-15%, 2-3%, and 2-3% of the cost, respectively [75]. The cost structure for algae farming in open ponds and photobioreactors is shown in Figures 2 and 3 (based on the investigation of [35; 63]). The analysis shows that the capital costs for the case of open ponds are evenly distributed, while the cost of photobioreactors is dominated by the cost of construction (79% to 82.7%). There are many factors associated with algae production affecting cost-effectiveness: co-products, nutrients, harvest technology, biomass drying, and conversion. System design and algae species are essential but not the only factors. In most cases, the cost of producing biofuels simply depends on the cost of biomass supply. Facilities for mass production of algae and energy use have yet been unbuilt. Therefore, with small amounts of algae that are produced, it is difficult to realistically evaluate the costs of producing more substantial quantities of biofuels from algae. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Feedstock** & **Technology** & **Energy Efficiency Ratio (EER)** \\ \hline Jatropha & Linked transesterification and biogas production. & 3.34 \\ \hline Palm oil & Linked transesterification and biogas production. & 3.58 \\ \hline Marine microalgae &
\begin{tabular}{c} Algae cultivation through PBR 1. \\ Linked transesterification and biogas production. \\ \end{tabular} & 0.07 \\ \hline Freshwater microalgae & Algae cultivation in PBR. & 0.35 \\ \hline Freshwater microalgae & Algae cultivation in ORP 2. & 1.46 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Energy efficiency ratio (EER) for biodiesel produced from the different feedstock. The price for 1 kg of algae ranges from $16.4 for open raceways ponds systems to $33 for closed photobioreactors systems. Several cost estimates are available that look at the increase in size from today's ponds to several acre size ponds. One of those estimates is that for 1 acre of production, 1 kg of algae would cost about $11, but costs could be lowered to about $4.4 by increasing the sizes to 100 acres with today's state-of-the-art [63]. Although this estimate indicates a considerable cost-cutting, it is still too high to compete with existing terrestrial biofuels crops [63]. [PERSON] et al. [77] have analyzed _T. suecica_ algae production on a scale of 1 ha. They obtained a cost of $15.8 kg\({}^{-1}\) biomass produced. At the 100 ha scale, they estimated a cost of about $5.5 kg\({}^{-1}\), which is much more than the $2 kg\({}^{-1}\) that needed to make algae biofuel competitive with petroleum-derived diesel. According to the investigation of References [63; 67; 78; 79], prices of algae biodiesel grown in an open raceways pond (ORP) and a photobioreactor (PBR) can be shown (Figure 4). The average price of algae biodiesel grown in a photobioreactor is $4.93, which is 66% more than in an open-pond system that is $2.97 L\({}^{-1}\).  
Figure 3: Capital cost structure of PBR systems.  
Figure 2: Capital cost structure of open-pond systems.  
Although high biomass productivity and the cultivation of single-strain culture are enabled by using photobioreactor, cultivation is costlier than in open ponds.  
In 2012, a continuous decline in biodiesel prices had been expected in the coming period [80]. Accordingly, the expected price of biodiesel in 2020 was about $1.5 per liter, which unfortunately did not happen. High competition with both systems is first and second-generation biodiesel.