Oilgae - Energy From Algae
Oilgae is a second-generation type of biofuel made from algae (hence the name). It can be used for creating biodiesel, ethanol, and a number of other types of biofuels, and unlike other crops, algae doesn't have competing fuel and food markets. In addition, algae provides a much higher energy content, so researchers have found that it makes more sense then growing corn to produce biofuels, which is the most popular energy crop in the United States.
Algae has a growth cycle of about a week, depending on the variety, which means that farmers harvest the crop year-round. The best strains are high in fat content and not difficult to harvest. Some farmers use open ponds to grow algae, while others use photobioreactors, or PBRs. Does this sound anything like work on an oil rig or petroleum refinery? Hardly!
PBR systems are much easier to control because they're slowed off from the environment, thus making the water conditions easier to control and preventing contamination. Basically, the algae crop is grow in tanks with access to sunlight or an unnatural light source. If the system is completely closed, sterile CO2 has to be added into the tanks to make it possible for the crop to grow.
While some farmers are still using open pond systems, it is harder for farmers to cultivate high-oil content and large virus-free crops without a PBR system. High-oil species of algae are typically not as resistant to disease or hardy when it comes to changing weather conditions, and they usually also grow more slowly. However, new technology is being explored with wastewater sources for open pond algae farms, and a number of projects are funding oilgae research for both open ponds and enclosed systems in the United States.
If you work on an algae farm, maintaining conditions of the water will be your main task outside of the harvesting process. Every species of algae has specific conditions that must be met for optimal growth, and your daily tasks could include checking water temperature and carbon dioxide levels. In addition, as the algae grows, it will block sunlight to the plants growing deeper in the water, so workers use paddles or run automated paddle wheels to stir the water and ensure that the entire field is getting enough sunlight. Some farmers also add nutrients to the water.
Harvesting is done every two to ten days on an algae farm, depending on the plant species. On smaller farms, workers use microscreens to collect the algae. Some farms using closed systems will interrupt the growing process by cutting off the CO2 supply, which will induce a process called flocculation. The farm dries the algae, at which point it is either shipped to biodiesel or other biofuel plants or oil is created. Farms that create their own oil usually use an oil pres, which crushes the plant kind of like a juicer. Chemical processing can also aid in the removal of oil.