How micro algae can help solve the Ghg emissions problem
Algae pond - photo credit ChadoNihi Free Images - Pixabay
Welcome to the seventeenth edition of my weekly blog where I take a closer look at the policies adopted by individual countries in their efforts to meet the requirements of the Paris Agreement. Particular attention is paid to the role that Carbon Capture, Utilisation, and Storage (CCUS) research and technologies are playing in the drive to meet these requirements.
This week I explain what algae cultivation is, the different methods of cultivation, and how it can be used to generate biofuels from captured CO2 emissions. I also look at innovative algae cultivation companies such as Pond Technologies and Aljadix and the technologies they are using.
A good starting in explaining algae cultivation is first, to remind ourselves what photosynthesis is. Photosynthesis is a natural, two cycle process where green plants and some bacterias convert the energy created by light with carbon dioxide into a usable chemical energy in the form of a sugar, otherwise known as glucose. The first cycle is known as the light cycle, where sunlight is changed into a chemical energy. During the second cycle, called the Calvin cycle, the CO2 is turned into glucose.
Algae cultivation process
Similarly to plants, algae use sunlight for the process of photosynthesis. The microalgae convert sunlight into chemical energy. Using solvents or sound waves, scientists can breakdown the cell structure of the algae in order to extract oil. This oil is further processed at a biorefinery into biofuel. In the future, this process could be performed at a traditional oil refinery. According to the US department of energy, algae cultivation has the potential to produce up to 60 times more biofuel per acre than land-based plants such as sugar beet and sugar cane.
Methods of algae cultivation
Approximately 100,000 different strains of algae exist in saltwater, fresh water, and waste water. There are two main methods for the cultivation of algae:
Open ponds can form naturally(lakes, ponds and lagoons etc.) or artificially (man-made ponds and containers). Algae cultivation occurs in ponds known as raceways where algae, water, and nutrients navigate around a shallow water circuit that allows the sunlight to fully penetrate the algae. Closed ponds are a variation on open ponds where the raceway is cover by a greenhouse. This is a more efficient means of cultivation as CO2 is less likely to emit during the process. Spirulina is typically cultivated in a closed pond system.
Photobioreactors are closed equipment as opposed to a closed system. This is a controlled environment where algae grow more quickly than ponds as carbon dioxide, water supply, light, temperature levels are better controlled. Photobioreactors are more efficient in the use of space and in production levels, however, they are more expensive to install.
Pond Technologies (@Pond_Tech)
Pond Technologies are situated in Markham, Canada and as mentioned before are semi-finalists in the NRG COSIA Xprize competition. In association with Natural Resources Council (NRC) Canada, they have a pilot project in place at St Mary’s Cement an hour West of Markham where they use a photobioreactor on site. The Co2 generated at the cement plant is used as a ‘raw material’ for the photobioreactor. The photobioreactor is located in a covered room on site that uses flashing LED lights to mimic the day/night light cycles which facilitate the rapid growth of Algae. Such photobioreactors can be used at any heavy industry where smoke stacks are used such as Oil & Gas, aluminum smelters, power plants etc.
Aljadix based in Switzerland is also an NRG COSIA Xprixe semi-finalist.Their offering is a carbon negative biofuel made on a sea surface platform 200m long by 100m wide. It is an eco-friendly concept as no land of fresh water space is used. 1 km2 of microalgae of production can generate up to 10 million litres of biodiesel and 1,000 tonnes of an inert carbon hydochar per year, making it a carbon negative enteprise.
Although algae cultivation is in its relative infancy as a CCUS technology, it’s potential is very obvious for all to see. For example, if you can generate 60 times more biofuel per acre versus planted based biofuels then you stand to make a dramatic saving on land use overall. Also, the fact that algae cultivation can be carbon negative makes this process all the more enticing and you can construct a pond or photobioreactor on site at an oil refinery, thus saving on transportation costs relating to captured carbon. Algae cultivation is an exciting technology and one to watch.
Next week’s blog will profile Finland and their efforts to meet their CO2 emissions reduction targets.