Energy News Monitoring

Hydrogen is a commodity which is easily produced by means of electrolysis and transformed back into electricity using fuel cells. It can be generated almost anywhere with the help of renewable energy sources and also employed in private households to provide a reliable power supply. Moreover, hydrogen is a suitable storage medium for solar and wind energy. Its advantage over common batteries is its improved storage density as well as life span.

Now (2021), scientists at Fraunhofer ISE are developing a domestic hydrogen production system using a small wind turbine and electrolyser. For this reason, in the first step of the project a new propeller design was created that can be made to rotate even by a light breeze. Furthermore, the size of the wind blade was reduced by 30 percent compared to conventional ones and a fibre composite used as construction material. The fibre-reinforced composites were created by placing fibre strips in a mould and hardening them with a resin. This task was performed automatically by a fibre placement machine. Even though the rotor blades were designed for weaker wind speeds, they can handle stronger winds as well, as they are flexible enough to automatically turn out of strong winds and thus avoid damage, which makes cost-intensive controlling mechanisms superfluous. The wind turbines will be tested outside in the following months.

The second part of the project will involve constructing a light and safe tank for hydrogen storage. Conventional hydrogen tanks used in large-scale industrial applications are made of steel to safely contain this highly explosive material. The material used for a domestic environment has to be much more flexible, but as safe as its industrial counterparts to enable the successful production of household energy. The design will encompass carbon fibre strips on a cylindrical body to form the corpus of the tank. The strips will be coated with resin, so that when they harden they can endure hundreds of bars of pressure. Sensors will be integrated into the tank to detect leaks to make the device safe for the end user.

Practical implementation of domestic hydrogen production from green sources and subsequent energy storage is a fairly recent development. In 2019, scientists at Katholieke Universiteit Leuven designed a solar panel that could transform sunlight directly into hydrogen with the help of the moisture in the air. The prototype used the water vapor and split it into hydrogen and oxygen molecules. The solar panel used was 1.65 meters long and had a power output of about 210 watts. 15 percent of the solar energy received were converted into hydrogen. The next step of the study will be to test the prototype in real-life conditions at a house in the rural town of Oud-Heverlee. An underground pressure vessel will be used to store the hydrogen during the summer months, which could then be used for heating the house in the winter. If this small-scale system works properly, more panels could be installed at the house or a larger neighbourhood system built to allow other families to use “green” hydrogen.

In 2020, scientists used a small-scale solar PV thermal electrolyser system and analysed its performance in converting sunlight to hydrogen with the help of numerical models and experiments. They calculated that annual amounts of electrical and thermal energy from the PV/T electrolyser system would reach 556.8 kWh. The amount of hydrogen produced, meanwhile, was calculated as 4.49 kg for the PV/T system. The electrical, thermal and total energy efficiencies of the PV/T system, obtained daily on an hourly basis, were analysed and amounted to 12–13.8%, 36.1–45.2% and 49.1–58.4%, respectively.

Using hydrogen for energy production has several advantages: hydrogen is renewable. It is an abundant resource which does not release harmful by-products into the atmosphere. In fact, hydrogen is clean enough for it to be converted into drinking water for astronauts after it has been used. Hydrogen is very dense in energy and able to produce a lot of power. It is more powerful than most fossil-based fuel resources which means that less hydrogen is needed to perform the same tasks. This is one of the reasons why hydrogen is used in in many areas – to fuel spaceships, aeroplanes, boats, cars and in fuel cells.

This new domestic energy production system is a promising candidate for promoting the energy transition. But before it can be launched onto the market, extensive further research will have to be carried out to ensure safe and sustainable energy production.