Energy innovation, the contribution of micro-algae

Endesa launched a project - unique in Europe - to use micro-algae cultivation to capture CO2 emitted from a coal power plant

Micro-algae are single-celled aquatic plant organisms which, if properly stimulated, grow much faster than terrestrial plants. This means that they produce a much greater amount of biomass.

For this reason they are subject to in-depth studies for energy aims. In fact, they appear particularly suited for CO2 absorption in biofuel production. They can also have other relevant uses, such as waste water purification and bio-molecule production.

Compared to conventional biomass, many factors favour micro-algae.
Their production does not compete with that of agriculture or forestry, nor does it require a significant use of freshwater. Also, they can grow on marginal land or water surfaces, using brackish water or waste water from various uses.
Their yield is theoretically extremely high: more than 60 tons of dry biomass per hectare each year, saving over 120 tons of CO2.
They reproduce at a very fast rate: some species double their mass several times a day, so that it is possible to envisage a continuous production, without the need for costly and complex logistical systems that collect, transport, process and store. Finally, some micro-algae have a mass consisting of natural fats and oils for up to 50% of their weight, guaranteeing a biofuel production per unit area which is several times higher than the best terrestrial plants that are currently being used, with a lower cost.

Nevertheless, research and experimentation are still in an initial phase. The aim is to optimize every aspect of the supply chain: selection of micro-algae strains and cultivation technology, water quality and treatment as well as light management, temperature, nutrients and the CO2 that must be absorbed for different cultivated species.

Various experiments are taking place worldwide (mainly targeted to biodiesel production), but it is still too early to determine whether harnessing micro-algae will truly be a significant innovation in the energy field in the near future.

In this regard, a very interesting project has been launched by the Enel group to cultivate micro-algae to capture CO2 from the Spanish plant of Carboneras (Almería).

Under the Endesa project, unique in Europe, a pilot plant will be constructed for the cultivation of micro-algae on a surface of 1,000 square feet, which during their growth will capture up to 110 tonnes of CO2/year from plant combustion. From the produced biomass, energy will subsequently be obtained as biodiesel.

The project will use a technology developed under the CENIT CO2 (Consorcios Estratégicos Nacionales en Investigación Técnica) project, launched in 2006 under the patronage of the Spanish Ministry of Science and Innovation.