Algae: the basis for renewable energy generationMaría José Cuetos, Environmental Department , Bureau Veritas Training .
The Hubbert Peak theory, also known as oil depletion and widely accepted by the scientific community, predicts that global oil production will peak and then decline as quickly as it grew. This peak is believed to have already been reached in 2006.
With this in mind, wouldn't it be better to focus on other energy sources that are alternatives to oil and can be used instead of fossil fuels ? For example, biofuels.
Many critics point out that ethanol extracted from sugar cane crops that power most of the cars in Brazil or oil extracts from crops such as soybeans, sunflowers and olives require large areas of land and compete with land used to produce food. However, this is only the case for first-generation biofuels, which appeared more than 20 years ago and are produced from raw materials of edible origin (sugars, starches and vegetable oils from soybeans, sunflowers and palms).
Second-generation biofuels already exist, which use student data non-edible raw materials (lignocellulose, waste oils, microalgae, non-edible virgin oils), which do not compete with arable agricultural land and whose production is more efficient and with a higher energy yield per hectare. In particular, I would like to highlight the use of algae for the production of biodiesel.
Algae are photosynthetic organisms that, like terrestrial plants and some photosynthetic bacteria, use the sun's energy to create organic matter from atmospheric CO2 and water. Microalgae are generally more efficient at converting solar energy into lipids, the building block that will later be transformed into biofuels.
Microalgae do not compete with agricultural land and food production (which allows reducing the environmental impact of biofuels produced from land plants). Although the selection processes for strains with the highest yields, the cultivation method and the extraction of triglycerides need to be further improved, their use has great advantages:
Microalgae are capable of producing 30 times the amount of lipids per unit of land surface, compared to terrestrial oilseed crops.
Greater lubricity, better combustion, with low persistence in the environment and lower risk of explosion
Algae pulp (after oil extraction) can be used in the food and pharmaceutical industries because it also contains sterols that can be used as building blocks for hormones.
Microalgae are the most primitive form of higher plants, due to their simple cellular structure. Among them, the best for this use are green algae ( Chlorophyceae), and diatoms ( Bacillariophyceae ) are also good candidates, but the limiting factor is the need for silicon for their growth and lipid production, while green algae only require nitrogen for growth.
Although they can be grown in open growth ponds, it is vertical production in photobioreactors , where algae are exposed to sunlight in transparent tubes, that has been developed by biofuel companies to produce algae faster and more efficiently .
Current research in this field focuses on genetic engineering to improve lipid extraction performance, as well as on its nutritional and pharmaceutical interest, such as polyunsaturated fatty acids (EPA, PUFA, DHA), vitamins, essential amino acids, minerals, pigments (phycobilins, carotenoids, etc.).