From rocket science to propelling the energy transition
High-flying
hydrogen
„Fly me to the moon …“
Unconfirmed rumours state that when Frank Sinatra wrote this song in 1964, he was thinking not of a love affair, but of hydrogen. After all, it was alkaline fuel cells that powered NASA’s Apollo missions into space during the 1960s – and produced power, heat and even drinking water on board. Indeed, the Apollo 11 Moon landing, which Sinatra no doubt enjoyed with a scotch in hand as he sat in front of his television in Palm Springs on 20 July 1969, was only possible thanks to liquid hydrogen and oxygen. Conventional batteries would have been too heavy.
H2 is the stuff space travel dreams are made of. In outer space there are no gas stations, no electric charging points and no roadside rescue to help out with a spare canister in case of fuel shortages. Rockets, space ships and manned stations like the ISS can therefore only be equipped with propulsion technology that is thoroughly reliable and safe, that saves space and weight, and that functions autonomously — propulsion technology that many people on our planet still don’t see making a breakthrough: fuel cells.
„Let me play among the stars …“
In unmanned spacecraft like satellites or probes too, regenerative fuel cell systems will be used to generate power in future. It is in fact solar cells that are responsible for this, but the energy produced cannot be stored adequately because large batteries are too heavy. Hence, it has only been possible thus far to explore primarily the sunny sides of celestial bodies.
Nevertheless, Airbus and the German Aerospace Centre (DLR) are now developing reversible fuel cells that can be refilled with small quantities of hydrogen and oxygen transported on board. During periods when the craft is flying in shadow, these can be used to produce power, while during periods spent in sunlight the solar power is used to split the water once again into hydrogen and oxygen.
„Let me see what spring is like on Jupiter and Mars …“
Some people, like Frank Sinatra, sing about visiting Mars, but others are actually working on making it a reality. If, in a perhaps not so distant future, people are to make the trip to the planet 56 million kilometres away and then perhaps even live on Mars, then one thing is essential: water.
On board humanity’s greatest mission, water could be split into hydrogen and oxygen using electrolysis thanks to solar cells. In a fuel cell, this produces power, heat – and again water, and this closed cycle of power, heat, air and water could be used to sustain life on Mars. Research into such closed systems is being fostered intensively by the DLR.
Before we begin lift-off to Mars, however, some international aerospace agencies are looking to the Moon once again. Japan’s JAXA, for example, has now commissioned Toyota to develop a Moon rover — and of course they’ve used fuel cell technology. The brief was for the rover to provide accommodation for four astronauts, making it a kind of campervan for what must be the most fascinating campsite imaginable. Its planned range is up to 10,000 kilometres, which is to be made possible by a combination of solar cells and fuel cells.
„In other words, please be true …“
Back to Earth, and let’s get grounded for a minute. It’s quite true that hydrogen as a cleaner energy carrier not only has a future in space travel, but undoubtedly also in more earthly applications — as a long-term storage system for power and heat, and in mobility and industry. The technologies have existed for decades, and have been explored and continually refined to this day. In other words, hydrogen is no longer just rocket science: With H2 as a binding element, sector coupling is set to take off.
„The best is yet to come“
Openness to new technologies is a fundamental prerequisite for a successful energy transition. Such technologies include natural gas, green gas, hydrogen, methane, sun and wind — plus ways of linking them up intelligently across all sectors. On the other hand, the energy transition must incorporate existing and socially accepted energy infrastructures too. Long-established pipelines, like the 12,000-km network OGE operates in Germany, do not lead to protests from citizens’ initiatives. They remain usable today and, unlike electrical power lines, do not have to be planned and built over decades.
Thus, with our help, renewable energy will be available wherever it is needed in the near future. That’s what OGE considers to be intelligent sector coupling: a sector coupling that combines both gas and electricity networks and thus makes renewable energy available sustainably in all sectors of consumption.
The best – and here we agree with Sinatra – is yet to come: namely increasing the proportion of green gases like hydrogen or synthetic methane and thus replacing natural gas, a fossil fuel. The key to this is power-to-gas technology, which makes it possible to make green gas using renewable energy. In industry too, power-to-gas technology plays a pivotal role. Thus, the green hydrogen produced using power-to-gas has tremendous potential for reducing CO2. Currently hydrogen is produced primarily using fossil energy carriers like crude oil, coal or natural gas. According to calculations by the German Energy Agency (dena), simply shifting to hydrogen from power-to-gas systems could save 5.64 million tons of CO2 every year.
In summary
Back in the 1960s, Frank Sinatra sang about travelling to the Moon and to Mars, while on Earth fossil fuels were being consumed like never before. It’s high time for a new chart-topper: hydrogen.
