Algae: green sludge or the energy source of the future?
Sunlight lies at the basis of photosynthesis. It ensures that water and carbon dioxide are converted into glucose and oxygen. On land it makes plants grow, and in the sea it does exactly the same for algae or seaweeds. Trees and land biomass are already being converted into energy on a large scale, but now more and more attention is also going to aquatic biomass.
01The biomass that is sometimes forgotten
When we think of algae, we naturally think of the dirty green sludge where frogs can be found or that completely ruins the swimming pool. So it does not exactly have a great image, but it is crucial for life on earth. It lies at the basis of all food chains. They are the inventors of photosynthesis (your little bonsai or all the greenery outside descends from them) and they are responsible for well over a third of the oxygen supply in the air.
Most algae occur in aquatic environments, but they can also be found elsewhere. Some algae species also occur on tree bark and on stones, or live in symbiosis with fungi. Most algae species get their energy from sunlight, but some species are also mixotrophic (they also take carbon from organic material) or heterotrophic (they have lost the ability to photosynthesise and are completely dependent on organic material). Algae are counted among the oldest organisms on earth. Fossils of algae up to 1,7 billion years old have been found.
02Research into the use of algae as biofuel
That algae can be used as biofuel has been proven many times. For example, the Dutch company AlgaeLink, together with KLM, carried out research into algae kerosene. An agreement was even concluded to research the sustainable production of aviation fuel from algae. Furthermore, a Boeing 737-800 has indeed already flown for two hours on algae fuel. The technology exists, and technically it is perfectly possible.
Wageningen University, for its part, has built the AlgaePARC. In this knowledge centre all knowledge about the use of algae as biofuel is gathered. There are also set-ups for experimenting with algae cultivation. The aim there is to increase the productivity of microalgae, improve the energy balance of cultivation and reduce the energy requirements of algae. They want to achieve this by, among other things, changing the algae density, selecting algae strains that are most suitable for mass production and optimising the reactor design.
ExxonMobile is also carrying out extensive research into the use of algae as biofuel. By 2025 they want to make it technically possible to produce 10.000 barrels of algae biofuel per day. For comparison: we consume more than 90 million barrels of oil per day. To reach their goal, they have already modified an algae strain. Thanks to the modification, the oil content of the algae has more than doubled. To do this, they modified the genetic switch responsible for transforming carbon into oil.
03Pros and cons of using algae as biofuel
Because algae multiply quickly, the yield per hectare is much higher. Compared with maize, up to five times more fuel can be obtained per hectare. In addition, no traditional fertilisers are needed. Moreover, algae do not compete with food (still often produced in places where there used to be forests) and, like other biofuels, they emit less CO2 than fossil fuels. Because algae also take CO2 from the air themselves, the main goal is to ensure that the CO2 emitted is not greater than the CO2 taken from the air. Furthermore, algae need a lot of water, but this does not have to be drinking water. Seawater and even wastewater can suffice. Finally, using them in combination with a power station can create a closed carbon cycle.
In practice there are also disadvantages to using algae as biofuel. The price tag in particular counts against algae: classic energy sources are much cheaper. A litre of algae oil can cost up to €5, and that is many times higher than the price tag of diesel. Experts do want to put this into perspective, however: the price of a litre of algae oil already includes a CO2 reduction, whereas this is not the case with fossil fuels.
In addition, cultivation is labour-intensive and involves large installations that need to be maintained. Moreover, algae do result in much lower CO2 emissions compared with fossil fuels, but there are still emissions of nitrogen oxides and particulate matter. As a result, fuel from algae still has negative health consequences. In any case, biofuel nowadays has a formidable competitor: electric driving. It looks as though the latter will win the day. Nevertheless, algae can be useful for, among other things, aircraft that cannot simply switch to electricity.
Conclusion
Although algae are certainly a promising alternative to classic fuels, the cost remains too high to make it commercially attractive. Further research remains necessary. In the meantime, the technology behind batteries and electric cars is evolving quickly, making it more likely that they will dominate the streets in the short term. As a fuel for aircraft, among other things, algae do still have a lot of potential.
Algae: the green energy of tomorrow? ➜ EnergieAanbieding.nl
Will we all be driving on algae in the future, and will green algae also provide green energy? A lot of research is still needed ᐈ Read more here.
04Frequently asked questions about the use of algae
The role of algae in the energy transition remains unclear. They have a high yield, but it remains difficult to achieve commercial successes with them. Why is this? You will find the answer to this and other questions in this FAQ.
Yes, and research is often carried out into how algae can serve multiple purposes, precisely because this would improve profitability. For example, algae also consist of proteins and sugars. It could be interesting to also use these proteins and sugars in the food industry. This could be used for animal feed, among other things. In addition, algae can also be used for the production of clothing, among other things, where they form an alternative to cotton, but also to polyester and acrylic, for which petroleum is needed. According to experts, as long as textile fibres cannot be recycled permanently, it is the most sustainable clothing material there is. Bioplastic from algae and algae as a meat substitute are also among the possibilities. Finally, algae are also used in cosmetics, as a thickener or as a moisturising element. In each case they have the advantage of being a sustainable alternative to existing raw materials.
Are there also other applications in which algae are used?
This has everything to do with the speed at which they multiply. Algae manage to convert up to 98% of sunlight into energy, whereas for plants this is 12% on average. This is because algae have many protrusions with stacked discs, which in turn contain gamma building blocks. It is one of the reasons why algae are studied so closely: modern solar panels get 20% energy from sunlight. Engineers believe that algae hold the blueprint for super-efficient solar panels.
Why do algae have such a high yield?
The single-celled microalgae with a size of 3 to 50 µm are especially interesting, while macroalgae are less interesting. These microalgae must also be sufficiently fatty. Sargassum, chlorella and gracilaria, among others, are often mentioned. In any case, the yield is still too low to compete with fossil fuels. That is why research focuses mainly on how these microalgae can be genetically manipulated to increase the yield. In the ExxonMobile research, Nannochloropsis gaditana was manipulated.
Which algae are suitable for the production of biofuel?
Researchers speak of more than 50 cost groups. The most important cost groups are installation costs, operating costs and maintenance costs. These include infrastructure costs, the costs of growing the biomass, harvesting costs, dewatering costs and oil extraction. Nutrients such as nitrogen, phosphorus and potassium, CO2, water and electricity also involve costs. Finally, there are also the costs of land use. Many of these costs can be limited, but genetic manipulation, the combination with classic energy generation and the use of waste streams in particular must ensure that algae can compete with classic fuels.
What costs are involved in the production of algae?
This is also being researched. The algae remove heavy metals, pathogens and other contaminants from the wastewater, while the biomass is used for biofuel production. According to a number of experts, this combination is the most plausible commercial application in the short term. However, it requires large areas of land, and moreover the yield is too limited to make a difference globally.
Algae are also used for wastewater treatment. Can this be combined with biomass production?
Yes, increasing the oil content is only one of the steps being taken to improve the genetic structure of the algae. Further optimising photosynthetic efficiency, improving the growth rate, improving temperature tolerance, reducing susceptibility to photo-oxidation and reducing photoinhibition are also being researched.
Can more be optimised than just the oil content?
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