‘Artificial photosynthesis’ can create hydrogen from solar energy

Scientists have developed a simple system which allows solar energy to be stored in the form of hydrogen

A process, called artificial photosynthesis, creates hydrogen which can then be used as a fuel either directly or in the form of methane, or it can generate electricity in a fuel cell for cars.

The scientists from HZB research institute and TU Delft claim this energy also has the potential to be available at night or on cloudy days.

Professor Bernard Dam of the Faculty of Applied Sciences at TU Delft explained: “Our focus has been a ‘cheap and stable’ solution. In this way we have reached a yield of almost 5%.

In other words, nearly 5% of the energy in the incident sunlight is stored in the hydrogen produced. For this type of set-up, that is a record.”

Hydrogen’s primary emission when used is water vapour, and as a result is regarded as one of the best forms of fuel for transport of the future.

But for that its production has to be made affordable, efficient and environmentally friendly. One way of achieving this is through the electrolysis of water, breaking it down into hydrogen and oxygen, particularly if that is done using electricity generated sustainably. Electrolysis is an expensive technique, though, whereas solar is not.

“We’ve just created a cost-effective, highly stable, and highly efficient solar fuel device,” Professor Dr. Roel van de Krol, head of the HZB Institute told RTCC.

“The big advantage of this compared to normal solar cells where you generate electricity and have to store it somewhere [else] – we store it as hydrogen in this device… as a single device,” he said.

Theoretically, a solar-to-chemical efficiency of up to 10% is possible, but de Krol admits his team still have some way to go before they can bring it to market requiring at least a 5% to make it attractive to private investors.

“We’re not there yet, [and] it will be quite challenging. It’s very hard to put a time frame on,” he said. “Our dream is to make large fuels of this technology then instead of normal cells with electrical cables we would then have pipelines of hydrogen.”