An artificial leaf to capture the sun? Solar Fuels will transform our society's energy use

Solar energy is the most abundant energy resource on Earth. Capturing and storing just a small percentage of solar power would be sufficient to meet all energy demands for the foreseeable future. For this to succeed, solar power needs to be transformed into another energy form or fuel which can be incorporated in our daily energy needs.

Leading sunlight-capture technologies are very efficient in transforming sun irradiation into electricity or heat. However, these energy forms are very difficult to store or transport. Batteries or hot fluid tanks are far from ideal to match the power demands of our large cities, industries, housing and transport systems.

Our objective and our challenge is to discover a technique that will completely substitute fossil fuels.  The solution is simple: to set up an industrial process able to transform sunlight, water and carbon dioxide into fuels. Fossil fuels are critical to provide us with all our energy needs.  But they are limited, not equally distributed worldwide, and their use and extraction have a serious negative impact on the environment, locally and globally. Substitution of the word "fossil" by the desired term "solar" could also solve all energy demands: by being recyclable, sustainable, abundant, and readily available in small or large scale, whenever the sun shines. Even in the absence of sunshine, solar fuels would be easily transportable to reach everywhere and everyone.

This is why A-LEAF is an ambitious project. It is multidisciplinary and aims to establish basic principles to advance the pursuit of capturing sunlight, and using its energy to convert carbon dioxide into valuable chemicals and fuels. Technically, such a device is viable. But, beyond scientific excellence, our project is looking for inexpensive, easily accessible, abundant, environmentally friendly materials and processes to develop a green, clean, cost-affordable, scalable, and profitable device.

If we want to tackle societal challenges, we need to understand these challenges from all perspectives, and not exclusively scientific. This idea is at the heart of our A-LEAF initiative. The terms "energy" and "crisis" appear to be inseparable. For multiple reasons, we have been living in an energy crisis during the last centuries. Arguably, a sustainable energy cycle would be very beneficial for all stakeholders. An environmentally neutral, clean, abundant, constant, delocalized energy supply would have a tremendous impact, beyond the energy market, and could at the same time promote societal progress, without leaving any one behind (continent, country, town, individual).

How will it work?

The project has brought together an amazing consortium of world leaders in related disciplines, from hardcore physicists to system engineers, in order to define the best way to build a solar to fuels device, able to absorb light via a silicon-based multi-junction.  Our project will review the molecular regime of chemical reactions as well as the up scaling of fuel production stacks.

The light absorbing component will be connected to an electrode, made from nickel and iron, able to use the energy of the sun to split water into oxygen, protons and electrons. Oxygen will be released into the atmosphere, and protons and electrons will be transferred onto a second electrode, made from carbon and copper, where they will be combined with carbon dioxide to produce fuels.

We firmly believe we are working in the direction of progress. Pushing scientific knowledge beyond the state-of-the-art, while looking for technological significance, and innovation potential. But even in failure, we will prevail if our initiative helps to bring others on board to the road for solar fuels, as a real societal (and economical) alternative. Not only a dream, nor a hoax.