How is Photo2Fuel contributing to sustainable CO2 conversion

The objective of being a climate-neutral continent, at the heart of the European Green Deal, is to reach net-zero greenhouse gas emissions (GHG) as set in the commitment to global climate action under the Paris Agreement. It is not easy to lower the emissions, as the majority of them come from the field of energy production. But in Photo2Fuel we have a mission: to produce biofuels and biochemicals in a sustainable way while lowering emissions. How? Let’s discover it!

CO2 emissions of the energy sector: how can biofuels help

Biofuels are fuels derived directly or indirectly from biomass.  They serve as a renewable alternative to fossil fuels, helping to reduce greenhouse gas emissions and improve the EU's security of supply. 
Biofuels have a variety of applications, such as in transport, electricity and industrial or household heating. Nowadays, most biofuels are used as transportation fuels and by 2030, the EU aims to increase the share of renewable energy in transport to at least 14%, including a minimum share of 3.5% of advanced biofuels, that is fuels derived from non-food biomass. 
However, biofuel production technology needs to diversify to sustainably take advantage of existing waste and residue feedstocks: nowadays, biofuels are mainly obtained after growing and processing different crops for the obtention of sugar or oils, such as beetroots or sunflower.  

Conversion of CO2: how we can obtain biofuels and biochemicals

CO2 is an integral part of the Earth’s carbon cycle, and as such, it is present in land, water and air ecosystems. Unfortunately, when the concentration of CO2 rises above the natural concentration level in the atmosphere, it amplifies the natural greenhouse gas effect, increasing the temperature of the atmosphere for the entire planet. Scientists agree that human activities have been the primary source of the observed rise in atmospheric CO2 since the beginning of the fossil fuel era in the 1860s, with 85%  of all human-produced carbon dioxide emissions coming from the burning of fossil fuels like coal, natural gas and oil-derivatives such as gasoline. In fact, in the third quarter of 2022, the economic sectors responsible for the most greenhouse gas emissions were manufacturing (23%), electricity and gas supply (21%), households and agriculture (both 14%), followed by transportation and storage (13%).

To avoid even more adverse effects from the excessive atmospheric accumulation of CO2, attention has been devoted to lowering the emissions caused by energy production and storing the excess carbon.

So far, most attention from policymakers and industry has been towards the use of Carbon Capture and Storage (CCS)  approach, which involves concentrating CO2 and storing it in geological reserves. However, the Carbon Capture Utilisation or Reuse (CCU/CCR) is as important as the CCS and has the additional advantage of producing commodities that otherwise would come from fossil sources.

How to use CO2 as feedstock

The idea behind Photo2Fuel is simple: why don’t we use the result of fossil fuel emissions as feedstock to produce sustainable energy? Photosynthesis is an example of a biological process existing in nature that converts CO2 into energy that, with some adjustments, can be made artificially. As trees convert CO2 into oxygen, with artificial photosynthesis we can convert CO2 and sunlight into an energy carrier (methane) or a chemical product (acetic acid).

That is why Photo2Fuel aims to develop a breakthrough technology that converts CO2 into sustainable fuels and chemicals employing microorganisms and using only sunlight as an energy source. 

Making a system as an auto-sufficient mini solar plant to produce chemicals and biofuels by applying the organic semiconductors microorganism hybrid system has very few (if none) precedents yet. Thanks to the foundation provided by previous research activities developed by the consortium, such an objective is within reach thanks to the project. To do so, the project partners will develop ambitious, though realistic, advancements with high innovation potential.

In the case of Photo2Fuel, there is a win-win situation: we are going to use the surplus of CO2, therefore reducing it, but we will also help in replacing fossil fuels which produce a lot of CO2.

Using CO2 produced by industry emissions to obtain methane and acetic acid

One of the main advantages of using CO2 as a feedstock with the Photo2Fuel methodology is to obtain sustainable chemicals and biofuels using just sunlight and no other extra energy source. In the auto-sufficient mini solar plant, solar energy will be stored in batteries, so that LEDs lights can be switched on at night or in variable weather conditions. By doing so, the system will be auto-sufficient and the system can run in changing weather conditions and also in dark periods.
This approach will also help with the obtention of a stable conversion of CO2 into the target products.
The innovation behind Photo2Fuel also lies in the use of organic compounds to start photosynthesis and the generation of methane and acetic acid. Organic semiconductors (called polymer dots) and microorganisms (Moorella thermoacetica and Methanosarcina barkeri) will form the basis for the sustainable production of the chemicals.

Impact of carbon capture and conversion on the society

Currently, the awareness from society of the environment’s health is increasing. Europeans desire new technologies that do not harm the environment through contamination and GHG emissions, and that can repair the impacts caused by fossil fuels. Photo2Fuel actively responds to these needs, by delivering a technology that uses CO2 and sunlight as input sources and offers valuable chemical products, while using only organic components (microorganisms and organic polymers), excluding the use of heavy metals or other rare and potentially toxic earth metals. Photo2Fuel also positively impacts society by creating new jobs and business models.

Contributing to new business models: from fossil fuels to CO2 conversion

Photo2Fuel will demonstrate and validate (from a technical, environmental, and socio-economical point of view) innovative technologies for acetic acid and methane production from sunlight and CO2 conversion. High-quality chemicals and biofuels produced with the Photo2Fuel methodology will allow providing flexibility to the power network while decarbonizing carbon-intensive industry emissions. A key step will be to involve different stakeholders from the value chain of energy production, sharing knowledge and understanding the needs of the sector. Photo2Fuel results can be the base for the industrial use of the project technology developments. New processes and advisory services will deliver high competitiveness and growth impacts, thus helping to decarbonise the industry.

Authors
Juan Diego Medrano García, Raul Calvo Serrano (ETH Zurich), Maria Bieringer (TZE), Mara Mennella (KNEIA)