In Oulu, hydrogen is made using only sunlight

A solar hydrogen panel breaks down water molecules into hydrogen and oxygen using only sunlight. The method is called photocatalysis.

Inside the panel is water and a catalyst that absorbs sunlight and accelerates the chemical reaction of water decomposition.

Technical the development started at the University of Oulu about ten years ago. In 2022, the technology was tested in a laboratory, where hydrogen was successfully produced using artificial light for a few months.

Now the panel got to do real work in the open air.

The device is the first of its kind in Finland, and a rarity in the world, says the University researcher Samuli Urpelainen from the University of Oulu.

“Only a handful of reactors like this that have been taken to the field can be found in the world.”

Sentences is an odorless, tasteless and invisible gas that produces only water vapor when burned. That is why it is planned to be one alternative to fossil energy sources.

Hydrogen is enough because it is the most common element in the entire universe. The problem is that the usable hydrogen occurs attached to other elements. So hydrogen cannot be directly collected from anywhere, it has to be prepared.

In the most common method, it is split from fossil fuels, such as natural gas, the hydrogen and carbon contained in which are separated from each other with hot steam. Carbon is usually released into the air as emissions.

Greener the method is electrolysis, where hydrogen is produced from water using renewable electricity.

However, a lot of electricity is needed. The University of Oulu calculated that if all the hydrogen used in the EU were to be produced by electrolysis, hundreds of thousands of new wind turbines would have to be built.

“The third option is the photocatalysis we are researching. It works like electrolysis, but without electricity,” says Urpelainen.

The difficulty of photocatalysis has been finding a sufficiently efficient catalyst material.

If the material does not work well, the sun’s energy is wasted. The charges created by the light have time to disappear before they cause chemical reactions. In this case, energy is released mainly as heat and radiation.

In addition, the material should react to light wavelengths in the widest possible range of visible light. So far, many effective materials have worked best with UV radiation, which reaches the earth’s surface relatively little.

Expensive and rare metals are often used as catalysts, the availability of which is problematic. The University of Oulu has studied more common raw materials, such as nickel found in Finland and molybdenum sulfide obtained from granite.

The panel test use will continue throughout the summer.

The purpose is to compare different solar conditions, catalysts and energy production between a hydrogen panel and a standard solar panel. The actual production of hydrogen is initially low.

“In the square meter panel, we are talking about milliliters per day. Higher outputs can be achieved when newer and better catalysts are introduced. They are now being tested in the laboratory,” says Urpelainen.

According to him, hydrogen panels could expand to industrial use in the early 2030s. Commercialization is already being done by the spinoff company Zun-H, founded at the University of Oulu, which started operations at the turn of the year.

For hydrogen is in demand especially in places where electrification is difficult.

According to Urpelainen, the panels could be exported, for example, to villages in developing countries that are located beyond the reach of the electricity grid. Now they burn coal and wood.

The energy from the hydrogen panels would be used with a fuel cell, and the only emission would be water.

In Finland, the users of hydrogen panels could be apartment building companies, which would collect hydrogen on the panel during the summer and use it in the winter, when the energy demand is at its highest.

The advantage of hydrogen compared to other renewable energy sources is its storability. Solar and wind power can be obtained when it’s sunny and windy, and electricity can be stored in batteries in industry for hours or at most days. Hydrogen is an energy store already in itself.

“I believe that hydrogen will play an important role in the green transition in the future. If we think further, solar hydrogen could even be used in industry, for example in the production of plastics, fuels and steel. Versatility is an advantage here.”