Canary marine microalgae: Key allies in decarbonisation

Microscopic organisms called microalgae can transform CO₂ emissions into biomass with a wide range of industrial applications—from biofuels and biomaterials to bioactive compounds and biofertilisers. Like higher plants, these microalgae perform photosynthesis, capturing CO₂ (e.g., from power plant emissions) and converting it into valuable resources while releasing oxygen. 

Thanks to its geoclimatic conditions—mild, consistent year-round temperatures, abundant sunlight, and high solar radiation—the Canary Islands are ideal for microalgae cultivation. For over thirty years, the ITC’s biotechnology department has been studying microalgae while optimising the technical, economic, and environmental viability of growing, harvesting, and processing these microorganisms.

The pilot project with Endesa

Aligned with its goal of achieving full decarbonisation by 2040, Endesa continues to prioritise sustainability. Therefore, it seeks innovative solutions that integrate the power of nature with scientific developments.

To test the potential of native Canarian marine microalgae for direct CO₂ capture from power plant emissions, Endesa temporarily provided ITC with a plot at the Juan Grande thermal power plant. Here, a pilot system for cultivating microalgae is connected directly to the plant's exhaust stack.

Funded by the Cabildo of Gran Canaria Island through the BIOASIS platform (via SPEGC) and supported by the regional government’s BLUEACT project (Next Generation EU), the research also benefits from the following R&D&i projects: THINKINAZUL (funded within the PRTR by the Ministry of Science and the government of the Canary Islands) and ACUICONECTA (85% co-financed with ERDF funds via Interreg MAC 2021–2027 programme). 

How do microalgae convert CO₂ from a power plant?

Through photosynthesis, microalgae incorporate CO₂ from combustion gases and convert it into biochemical compounds like lipids, proteins, carbohydrates, and pigments, effectively capturing carbon.

Meanwhile, as ambient CO₂ concentrations are insufficient for industrial-scale microalgae cultivation, marine plant aquaculture requires a continuous input of inorganic carbon—typically gaseous CO₂—a requirement that emissions from direct combustion fulfil.

Estimates suggest up to 200 tonnes of CO₂ are needed to produce 100 tonnes of microalgae biomass. Therefore, this aquaculture approach—by capturing CO₂—could derive its carbon from power plant gases. In parallel, it boosts its economic viability. 

Following the capture of combustion gas emissions, the resulting biomass can also be used for bioenergy. This approach can drastically reduce the carbon footprint of both the energy and aquaculture sectors. Alternatively, its use in biomaterials or agricultural substrates could enable long-term carbon sequestration, contribute to mitigating climate change effects, and even generate carbon credits.

The ‘blend’ concept in marine microalgae production

Microalgae not only capture CO₂ from combustion gases—they can also process the discharges and effluents most damaging to the marine environment (e.g., wastewater and desalination brine). This helps bioremediate these harmful effluents, thus reducing their ecosystemic impacts.

ITC’s technological research developed the ‘blend’ concept. This approach combines these effluents with the aim of seeking to ensure the technical, economic, and environmental viability of the microalgae production process. The result is a nutrient-rich, seawater-salinity medium ideal for growing diverse microalgae strains. This way, a broader biodiversity of marine microalgae—with potential for various industrial applications—could benefit from the nutrients in wastewater within a marine environment thanks to the salts present in the brine. 

This innovative mixture concept, along with the capture of combustion gas emissions from thermal power plants, represents a totally new methodology across water cycle treatment, CO₂ capture, and marine plant biomass production. Implementing this methodology would eliminate the need for imported fertilisers by leveraging the inorganic nutrients from the islands' major wastewater discharges. This would result in reducing costs and minimising marine pollution by releasing only algae-treated water with natural salinity back into the environment.

The result is an innovative system for producing marine microalgae, designed around a more sustainable, circular, integrated water-cycle concept. It can be replicated in the Canary Islands and worldwide, producing substantial economic and environmental benefits. Among the advantages, we can find biofuels and other market-relevant products, the conservation of the marine environments, the reduction of the carbon footprints, and the boosting of a bioeconomy that benefits vulnerable communities.

Future plan: biomass, aquivoltaics & a Just Transition

The Endesa–ITC pilot project at the Juan Grande thermal power plant will evaluate the operational feasibility of this solution for producing biomass with multiple applications. It involves combining the capture of its combustion gases (from future biofuels) with the mixture of these discharges at Endesa’s plants undergoing transition. As a result, it presents a cutting-edge and sustainable technology for decabornisation and energy transition.

Important to know is that microalgae cultivation doesn’t require fertile land—it takes place in ponds and using degraded and/or non-fertile soils. Thus, it opens the possibility of creating a medium-term for Endesa and ITC to set up a 12-hectare demonstration plant on degraded and/or infertile agricultural soils, serving to integrate CO₂, wastewater, and brine. This facility would reduce GHG emissions while contributing to addressing other challenging pollution sources on the islands. Simultaneously, it would create valuable resources, including biofuels. This new pre-commercial scale plant would be energy self-sufficient, powered by photovoltaic panels that also act as windbreaks—ushering in the concept of ‘aquivoltaics.’

Treated water could then be reused to irrigate nearby wetlands with the aim of recovering their environment and landscape. This approach would therefore contribute to the preservation, protection, conservation, and restoration of these connected areas—designated as having very high natural value in the current plan. Moreover, the wetland itself would serve as another CO₂ sink. The aquaculture activity would generate jobs, contributing to diversifying the Canary Islands' economy. This aligns with one of Endesa's major strategic pillars for complete decarbonisation: to develop a plan that preserves the social and economic context, committing to a just transition.