The world needs more renewable energy sources. Different types of algae are a good alternative. The years of development is now starting to bear fruit globally as pilot testing facilities and commercial plans. Neste Oil keeps a keen eye on the commercial development and is involved in several R&D projects all over the world.
Biofuel producers have been interested in algae for several years now. Ideas have proceeded from the laboratory to field tests, and lately to small-scale pilot testing facilities. Commercial production can start in the near future. Why are biofuel producers so interested in algae?
the enthusiasm towards algae is easy to understand when you compare algae with the yield of vegetable oils used in the production of biofuels. For example the annual yield of rapeseed oil is around 1.2 metric tons per hectare.
"With algae, it is realistically possible to reach annual production levels of up to thirty tons of oil per hectare," says Neste Oil's algae researcher and project manager Pauliina Uronen. This means that the yield per hectare can be many times the yield of traditional vegetable oils.
"The algae being used are microscopic and they divide and grow very quickly. Many of them can be harvested even daily," explains Päivi Lintonen, Business Development Manager at Neste Oil. Together with Pauliina Uronen, they share the responsibility of Neste Oil's algae projects.
Algae capture energy from the sun
In addition to being highly productive, algae are also otherwise close to ideal raw material for biofuels. Pauliina Uronen explains that in addition to water, algae need sunlight, carbon dioxide and nutrients to grow. Many species of algae live in sea water, which means that they can be grown in saline water. Some projects even use wastewater.
A special advantage in the cultivation of algae is the fact that they can be grown in areas that cannot be used for agriculture. Algae can be grown almost anywhere on the Earth, as long as there is enough sunlight.
Algae also grow naturally in lakes and seas but not in the density required for fuel production. Furthermore, not all types of algae are suitable for fuel production. For example, cyanobacteria and macroalgae– such as kelp – do not accumulate lipids, which is why they are not preferred. There are plenty of good alternatives, however.
"There are tens of thousands algae species. Many of them produce lipids and can thus be used as feedstock for renewable fuels," Uronen says.
The actual cultivation of algae is a complex challenge, though.
Final breakthrough still being expected
Algae are grown in several stages (see below: Cultivation of algae is a four-stage process).
"The algae cultivation technologies as such are already functional. The question is how to make the entire business model feasible," Päivi Lintonen explains. Lintonen notes that it is a complex process that requires competence not only in agriculture but also process technology.
"At present, people are expectant: who will make the next step and start commercializing the production? We may only need a single company that could make the large investment. That would improve trust and give a nudge forwards for the entire sector."
Where does Neste Oil currently stand in terms of the utilization of algae? Uronen says that Neste Oil started investing in algae oil at an early stage.
"We have grown algae ourselves and done research. We have, for instance, found algae species that are better than those mentioned in the literature. We have also completed field tests in several countries with our partners. We know what the actual status is, which means that we are in a position to assess commercial partners. We don't have to rely on their word alone. Our own results are important, because we have been able to use them to make our own preliminary calculations on the greenhouse gas emissions, and now we know which stages of the process may consume most energy. In the R&D the focus should be on feedstocks that have the potential to have clearly lower greenhouse gas emissions than the current regulations allow.
"We are ready to buy some right away"
Neste Oil supports the commercial scale production by signing conditional off-take agreements with algae companies, for instance. Such agreements have been signed with American companies Cellana and RAE.
However, Neste Oil does not wish to comment on which specific techniques will be used to producethe algae. "Our message is that we are ready to buy some algae oil right away," Lintonen says.
Uronen says that the intensive collaboration in Neste Oil between research and business ensures availability and usability of the final product.
One should still remain realistic, however. "We do not want people to start believing that algae would offer the solution to the global fuel problem within the next five to ten years," Lintonen says. "Neste Oil uses more than two million metric tons of renewable raw materials per year. Algae oil production for fuel purposes will probably start with a few thousand hectares and few tens of thousands of tons per year. This is an insignificant amount in terms of the global fuel production, but you must start with something."
The production volumes may increase in the years to come, and algae oil may become an important raw material of Neste Oil's renewable diesel. In any case, the world may be getting a new, genuinely promising renewable energy source.
Cultivation of algae is a four-stage process
The interesting cultivation process of algae consists of four stages.
1) Cultivation – in a photobioreactor or pond?
"There are currently pilot facilities of several different types," Päivi Lintonen explains. "Some facilities grow algae between plates or in transparent tubes or sacks, while others have opted to grow their algae in large open ponds."
The different techniques have their unique benefits and challenges. "Growing algae in a tube is more expensive, but the tube protects the algae. An open pond is more affordable, but more susceptible to impurities and organisms feeding on algae."
Many challenges familiar from agriculture affect the cultivation of algae as well. "Open ponds, in particular, are at nature's mercy. Threats range from heavy rainfall to desert sandstorms. The pond may be infected with pests or a microbe that feeds on algae – or the algae may get a plant disease", Lintonen says.
2) Lipid production – starting with simple means
Small algae species divide quickly, but how can they be pushed to produce the actual raw material, lipids? Pauliina Uronen says that one widely known method is to simply remove nitrogen from the water. That prevents the algae from dividing, which causes them to start accumulating lipids.
"Some cultivators combine different cultivation methods. One challenge in the cultivation process is yield optimization, meaning the point in time when the transfer from growing algae biomass to producing lipids is made," Uronen explains.
3) Harvesting – a lot of water with some algae in it
One slightly surprising challenge in the cultivation of algae is the harvesting process. "Algae are very small plants residing in a large quantity of water. This is why harvesting of algae is expensive," Uronen explains.
This poses another challenge to the optimization of production: the denser the algae population, the less light single algae cells receive, but a denser population is easier to harvest.
4) Separating oil – other useful products also collected
When the algae have been successfully harvested, there is still another process to complete. The oil must be separated from the algae. "Rationally thinking, around 20–30% of the total algae biomass might be oil," Uronen says.
Another valuable product can be collected from algae as well. "A large share of the algae biomass is protein. It can be used as fish feed, for example: after all, algae are the natural food of fish."
The cultivation of algae has lot of challenges and questions. "The main focus usually lies in the development of the growing stage. The entire process should be studied, however." Uronen points out.
Algae oil is still clearly more expensive than other alternative feedstocks for renewable diesel. However, once production facilities are opened, algae oil may become an excellent and competitive raw material for the production of biofuels.