Equipping the world for new energy sources

As the first and lightest element of the periodic table, hydrogen is a gas that is never found in its pure form. In nature, it only exists in compound form. Most hydrogen is found in water, H2O, where each molecule contains one oxygen and two hydrogen atoms. By splitting water into its hydrogen and oxygen components, the resulting hydrogen can be stored and burned as required to provide carbon-neutral electricity and heat. 

It’s light too. 1 kg of hydrogen contains the same amount of energy as over 2kg of natural gas or almost 3kg of petrol. Hydrogen stored in clever fuel cell systems is what enabled flights into space to begin in the sixties. However, back on Earth, our ambitions of creating more efficient fuel infrastructures are still to become a reality.

Ralf Winterling, Technical Head of Infrastructure at REHAU, is confident that hydrogen will play a central role in future energy supply. “We want to be a driving force in the energy transition. Like many countries, Germany is actively reducing its dependency on fossil fuels and, with that, we are seeing enormous growth in a mix of renewable energies, worldwide.”

Engineering experts at REHAU have been developing hydrogen storage tanks for vehicles of the future for many years. It’s a complicated process that involves fuel cell construction and designing the surrounding distribution infrastructure for hydrogen.

In Argentina, REHAU has developed facilities where surplus electricity from renewable sources can be stored by converting water into hydrogen or synthetic natural gas. Vast storage facilities are available in the natural gas network and in underground caverns, but special multi-layer pipes are needed to safely transport pure hydrogen gas. One of the greatest challenges is preventing permeation, where very small and volatile hydrogen molecules can diffuse through the walls of polymer pipes. REHAU is researching the deployment of hydrogen-compatible pipe systems that incorporate barrier layers to eliminate permeation.

“The major advantage of hydrogen is that it is suitable for transportation as well as for producing electricity and heat. This makes hydrogen the most universal storable energy source of all”, Mr. Winterling says. “Hydrogen produced by wind power or solar power will be like “green crude oil” – in limitless supply, infinitely renewable, and completely emission-free when converted back into electricity and heat.”
As for the near future, Mr. Winterling believes multiple energy approaches will co-exist for some time but that relying on conventional fossil fuel sources will soon become economically unviable.

Other energy options that offer great long-term promise include pumped-hydro power plants and ‘Power-to-Heat’ technologies that convert excess electrical power into stored heat. Amongst its live sites, REHAU has built borehole thermal energy stores (BTES) in Braedstrup (Denmark), Crailsheim (Germany) and Drake Landing (Canada).

In Braedstrup, more than 1,200 residential units, business and municipal buildings are serviced by district heating systems. REHAU ground source probes circulate water heated to 85ºC by solar power at a depth of around 50 meters, effectively turning the ground beneath our feet into a gigantic heat storage system. In winter, this heat energy feeds back into the circulating water and is released to keep residents warm through the coldest months of the year.