# The Perspective of Large-Scale Production of Algae Biodiesel
## 5 Conclusions  
In the past decade, algae biofuels have attracted the attention of the public and the scientific community for environmental and other reasons. Various factors produce a beneficial and negative impact on the further development of this area. The results of the SWOT analysis indicate essential strengths, weaknesses, opportunities, and threats.  
1. Essential strengths are as follows: * Algae productivity is higher compared to most effective crops. * A large number of algae species can be farmed. * The CO2 footprint of algae biodiesel is smaller than conventional diesel.
2. Essential weaknesses are as follows: * Biodiesel production from algae is an extremely energy-intensive process that, in some cases, results in a negative energy balance. * Production costs are significantly higher compared to the production of conventional diesel.  
The water footprint is large.  
Essential opportunities are as follows:  
Optimization of the biodiesel production process by introducing less energy-intensive technologies.  
Application of post-harvest water recycling.  
Application of CO2 from flue gases for algae cultivation.  
Linking algae cultivation and wastewater treatment and biogas production from algal biomass residues.  
Increasing local employability.  
Essential threats are as follows:  
Promotion of the use of other renewable energy sources in transport such as hydrogen.  
Encouraging the use of battery-electric cars.  
The production of biogas from algae is economically more profitable than the production of biodiesel.  
Production of biodiesel from lignocellulosic raw materials has ecological advantages over production from algae.  
The policies of many countries are to reduce the production and sales of diesel cars.  
Based on these strengths, opportunities, weaknesses, and threats, stakeholders and policymakers can better understand the issue of biodiesel production from algae and thus make better decisions about investing/not investing in specific research related to improvements in biodiesel production technology and microalgae cultivation.  
The key challenges in mass production of biodiesel from algae appear to be high infrastructure, operational, and maintenance costs, along with serious competition from the use of electric cars.  
Progress in minimizing/reducing the energy, water, and land-use footprints needs to be a primary objective of enhancing larger-scale algal biodiesel production.  
Considering the seriousness of the listed threats, and progress made in the last decade, the author's opinion is that it is not to be expected that large quantities of algae biodiesel will be used in transport soon.  
However, possible perspectives in the production of biodiesel from algae can be found in the following:  
* Linking biodiesel production and wastewater treatment,
* Algal biomass-based co-products can provide the necessary revenue to reduce the net cost of biodiesel production,
* Developing and applying less energy-intensive technologies for the biodiesel production process,
* Application of algal biodiesel for blending aviation fuel which would lead to a reduction of CO2 emissions from air transport.  
Conceptualization, investigation, methodology, data curation, writing--original draft preparation, visualization, and writing--reviewing and editing, M.B.; writing--reviewing and editing, and data curation, N.S. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflict of interest.