Open pond systems are generally regarded as a less than viable solution despite the advantages of being very cheap to run and more easily managed than other methods. The reason many people believe open pond algae farming isn’t is a good solution is the difficulty in finding a high lipid algae strain suitable for farming in a certain area that can cope with seasonal change and pH-swings. Another problem is that the algae will have to compete with invasive algae species and other aquatic organisms, including invasive bacteria, that make their way to the ponds.
There are two main types of open pond farming, the mono culture and the combined culture. Mono culture is when you only grow one species of algae in a pond. This method has been found to be sensitive to virus diseases and a single infection can wipe out an entire pond. Combined culture is when you farm several species.
It might seem odd that it is hard to find suitable hardy species of algae since algae seems to thrive everywhere. The truth is however that algae that produce a lot of lipids invest less energy into the production of proteins or carbohydrates and therefore tend to be a lot more sensitive than species with a lower oil content. An alga species that spends all of its energy on growth instead of diverting it to oil production tend to have a larger chance of surviving harsh conditions, unless of course those harsh conditions consist of a lack of nutrients in the environment.
Biodiesel can be made from algae but it is hard to predict how economically viable different methods can be. Most research is currently done by the private sector and although this research is bringing the science forward it is next to impossible to really evaluate the techniques without building and running production units. Many people do believe that it would be possible for biodiesel to take the place of regular diesel and gasoline. Sceptics do on the other hand not believe that biodiesel and algae oil can be made profitable unless we see a lot higher oil prices.
Algae are among the most effective oil crops and studies show that algae can produce up to 60% of their biomass in the form of oil. Micro algae are also the quickest growing crop in the world and grows a lot faster than other alternatives for making oil, such as oil palms and corn. The algae harvest from a singe acre of algae farming can be as high as 20,000 US gallons per year or more than 30 times bigger than the second fastest growing crop. A high yiled combined with a high oil level make algae ideal for producing oil and jet fuel.
Unfortunately, it is still very expensive to process algae into oil. At this point, this cost is what’s preventing algae oil from being an economically viable product. If more efficient, cheaper ways are developed, oil farming might become viable in poor countries with low wages or perhaps even in more developed countries. We do however have a long way to go before we reach that point.
With all the problems related to open pond farming, most scientist are convinced that another solution is needed to avoid diseases and species competition. One such alternative system is closed loop algae farming. Closed loop algae farming means that you grow algae in a closed system (usually made up by tubes) that allows light to reach the algae but prevents other algae species and disease to enter the system. A closed loop system also keeps out bacteria that can compete with the algae. Closed loop systems do work but the problem is to create systems that can produce algae in large enough quantities for a low enough cost. The goal is to maximize the output of each system.
The main problem which closed loop systems is to make sure that the water contains enough sterile CO2 for the algae to grow. If too little CO2 is present the algae wont grow at the desired speed, and if none-sterile CO2 is introduced you run the risk of introducing disease and competing organisms creating the same problem you face in open pond farming. A lot of experiments have been made running the exhaust CO2 from factories through a close loop system and this seems to work very well. It reduces CO2 emissions and hence helps fight global warming. The algae produced can be burned in generators creating energy for the factory to use.
Some experts thinks that the only way to make algae oil farming profitable in the near future is to put the farms near big coal and oil power plants where all the excess CO2 can be used by the farm. This might be worth considering even if it doesn’t make any money as it will reduce CO2 emissions from the power plants. In fact, some believe that it in the future it should be mandatory for power plants to feed the CO2 emissions through a system like this to reduce CO2 emissions.
A possible future use for waste water (sewage as well agricultural) and flood plain run-off is as nutrition in algae farms. Water like this do however contain a lot of bacteria that are harmful to lipid rich algae strains and the waste water would therefore need to be treated before it is used. The water would first have to be processed by bacteria in a process called anaerobic digestion If the water isn’t treated correctly, the algae growth can be stunted and large part of the algae population can die off.
On a related note, the end product from biogas facilities is very easy to process to make an ideal algae farming medium.
One of the main criticisms about algae farming is that it would be a waste of valuable fresh water. This problem is avoided if waste water or salt water is used for the farming, and methods using these types of water are therefore strongly preferred by most scientists. There is however a fear that pollutants and heavy metals in waste water might stunt algae growth and make waste water growing a non-viable alternative. The same can be true when using salt water although the concentration of heavy metals is usually lower in salt water compared to waste water. Some scientist believe agricultural-grade fertilizer is the best way forward but the same heavy metal problems can be found here as well. The solution might be to find and use algae strains that are more resilient towards heavy metals. There are several types of string algae used in open pond farming that exhibit a very high resilience towards heavy metals.
In this clip from Associated Press, John Mone talks to California scientists about the future of bio fuel extracted from “pond scum”. Algae grow fast and take up little land, and some variants can even be grown in salt water. But how soon can we see commercially viable algae bio fuel on the market? One of the hurdles that must be overcome is how to get the oil out of the algae in a cost efficient manner. In the video, AP’s John Mone visits several different algae oil research facilities to take a closer look at the various methods available.
A question many people are asking is whether algae farming and algae oil ever is going to be a economically viable options. Some will say NO, other say “perhaps in time”, while a third group says that it already is. The truth depends a little on what you consider as economically viable. For example, some people claim that algae farming are economically viable even if it operates at a loss if it is cheaper than the alternative: to clean CO2 out of the emissions from a factory by using a filtration systems. To put it in other words: algae farming is economically viable if the cost of running algae farms is a justifiable cost considering the bigger financial picture.
On the other side we have more pessimistic analyses that say that algae oil wont become a viable alternative before the oil price hits $800 per barrel. Studies of this type do however usually have to work with the very small amounts of data available in the public domain outside the research companies and it safe to assume that the actual coast of making algae oil and when it can become economic viable is much lower as the companies, for reasons of competition, often need to keep their breakthroughs to themselves before they are ready to reveal new innovative systems and discoveries.
Some believe that we are a long way from being able to create viable photo bioreactors that can operate at a profit in developed countries but that it might already be possible to operate them profitable in poor countries with low wages. In high wage countries it seems hard to make algae oil that can compete with petroleum products any time soon.
One of reasons why it is so difficult to say whether or not algae biofuel will be economically viable or not is the speed with which this research field is moving forward and all the new and more efficient ways of farming algae, producing oil, improving algae strains etc that are discovered . Right now, just a few small breakthroughs may be enough to radically change all calculations.
Photobioreactors are the most widely researched method for developing biofuel from algae. A photobioreactor is a system in which nutrient rich water is pumped through transparent plastic tubes subjected to sunlight. This creates an ideal environment for algae and allow for very quick growth.
You can see an example of a photobioreactor in the video below.
This system might be the one most widely researched by companies at the moment, but it is also a more complicated method compared to simply growing and harvesting algae in open ponds. It is also a considerable more costly method than open farming. At this point you might wonder why so much research efforts are focused on this more complex and expensive method, when open water farming is cheaper and less complex and makes it possible to turn marginal lands such as deserts into productive land. This question is not easy to answer, but one reason is that a photobioreactor can be used to clean the exhaust from factories while creating energy – a sellable product. This could make it profitable for companies to manage their pollution levels in a whole new way. Another reason is the drawbacks discovered in other methods such as the disease problems that can decimate algal populations living in open ponds.
A problem in developing a good photobioreactor is that you need to match a design with an algae species that produces a lot of lipids (from which we get the oil) and is suitable for the area the photobioreactor is meant to be placed in. A photobioreactor suitable for one algae species is not necessarily optimal for another species. This is one of the reasons why some sceptics believe that this will never be a viable technology.
Different types of algae are harvest in different ways. Macro algae is easier to harvest than micro algae and can be harvested more energy efficient. One way of harvesting macro algae is to simply have a net installed in the pond and raise it to bring the algae up and out of the water. The algae are then harvested using mechanical cutters similar to lawnmowers. This process was earlier done by hand. You can usually harvest macro algae like this 3-4 times each season by simply lowering the net again after harvesting and allowing the algae to grow back. It should however be said that the first harvest usually is the biggest one while the subsequent harvests tend to be smaller and smaller.
Micro algae are smaller and harder to harvest. It is also a more energy requiring process. Micro algae are the type of algae primarily grown in photobioreactors. There are several ways to harvest them; some are one step processes while others require two steps. Examples of common methods include >settling or flotation, centrifugation and filtration. All processes uses flocculation in one way or another to get algae cells to clump together forming larger clumps that can be harvested. Exactly how hard a micro algae species is to harvest and how energy consuming it is to do so depends on the size of the species in question. The smaller the algae, the harder the harvest.
Micro algae and especially very small micro algae are usually the most fast growing kinds of algae and therefore among the most attractive to farm. They are however also the hardest to harvest so you need a balance between algae size and growth rate to find an optimal algae to farm. A more efficient way to harvest micro algae could enhance the viability of algae bio fuels by miles.
In order to turn algae into bio fuel, the oil must be extracted. One of several interesting methods currently being investigated is ultrasonic extraction of algae oil into water. In this video you will be able to see algae oil extracted from algae using Industrial Sonomechanics’ (ISM) high-gain Barbell horn. The output diameter is 65 mm and the vibration amplitude is 100 microns.
This video basically shows how ISM’s 4 kW ultrasonic reactor system works, although on much smaller scale. The ISM system is based around the Barbell horn, an ultrasonic reactor, a magnetostrictive transducer, and a flow-through reactor chamber.
Algae bio fuel – also known as oilgae, algal fuel, or algaeoleum – is a type of biofuel derived from algae. Several companies and governments are currently funding research project focused on making algae bio fuel an economically and environmentally feasible alternative to fossil fuels. Ecological concerns and high oil prices have worked together to shine a spotlight on algae as a potential source for biodiesel, biogasoline, bioethanol, biomethanol, biobutanol and other types of biofuels for the 21st century.
Microalgae is currently the main focus for algae bio fuel research, chiefly due to its less complex structure Several species of microalgae are also noted for their high oil content and capacity for growing really fast. A microalga is smaller than 0.4 mm in diameter and the group includes famous members like the Cyanobacteria (blue green algae) and diatoms. Macro algae can on the other hand grow really large; the seaweed that makes up the vast kelp forests of the northeastern Pacific is one notable example.
Algae fossil fuels and carbon dioxide
Unlike fossil fuels, the use of algae bio fuel does not introduce more carbon dioxide to the atmosphere. Fossil fuels that are brought up from the ground and combusted increase the amount of carbon dioxide in the atmosphere since the carbon they contain have been hidden away underground for millions of years. Algae will on the other hand absorb existing carbon dioxide from the atmosphere as they grow. When algae bio fuel is combusted carbon dioxide is released into the air, but never more than what the algae absorbed from the air during its lifetime. Right now, the burning of fossil fuels produces roughly 21.3 billion tonnes of carbon dioxide per year. Estimations show that about 50 percent of this can be removed from the atmosphere by natural processes such as plant growth, but the remaining 50 percent – a whopping 10.65 billion tonnes – stays in the atmosphere.