CEP Clean Energy Partnership CEP-FAQ
CEP Clean Energy Partnership CEP-FAQ

FAQ – Key questions and answers at a glance

We have compiled the most frequently asked questions from many conversations and encounters, and answered them with our positions in mind.

If you don’t find what you’re looking for here, please feel free to send your questions to us using the contact form.

Why hydrogen?

Hydrogen can play a key role as part of the transition to renewable energy – as a fuel and an energy carrier. One prerequisite for the use of renewable energies is a powerful electricity network that can absorb power fluctuations from volatile energy sources. Large amounts of energy can be stored in hydrogen and converted back into electricity again when needed. This is done most efficiently on board a fuel-cell vehicle. Using hydrogen as a fuel produces no harmful emissions – just a little water vapour. Produced from renewable sources, hydrogen will make a major contribution to the energy transition, and enable zero-emissions mobility.

Where does hydrogen come from?

Hydrogen (H2) is the most abundant element in the universe and is available in practically unlimited quantities – but almost exclusively in a chemically bonded state. Hydrogen production is carried out using various methods that vary in terms of their potential for reducing CO2 emissions and current production costs, among other things.

The CEP is increasingly concentrating on carbon-neutral hydrogen production through water electrolysis using energy from renewable sources, and the production of hydrogen from biomass. But carbon dioxide emissions can also be reduced using hydrogen from natural gas: When this is used in fuel-cell vehicles, CO2 emissions are up to 30 percent lower than those produced by modern diesel vehicles (comparison value 120 g CO2/km).

Isn’t hydrogen dangerous?

Hydrogen is no more dangerous than other energy sources. Any leaking hydrogen evaporates immediately. If, in a worst-case scenario, the hydrogen ignites, it burns upwards very quickly. It creates no dangerous heat radiation above the accident site, as petrol or kerosene do. Hydrogen is nontoxic, odourless, and non-corrosive. With proper handling, hydrogen gas presents no danger. The CEP only uses state-of-the-art technology that meets the most stringent safety requirements.

How much electricity/water is needed to produce 1 kg of H2 by electrolysis?

To produce hydrogen by electrolysis directly at the filling station, the CEP currently requires about 55 kWh/kg H2 of electricity at an assumed rate of efficiency of > 60 percent.

To produce 1 kg of hydrogen, nine times the amount of water is necessary, i.e. nine litres.

How is hydrogen stored? Doesn’t it diffuse through the tank?

There is a widespread belief that hydrogen diffuses through materials and escapes from tanks. Although hydrogen molecules are very small, for over a hundred years now it has been transported and stored in steel cylinders at pressures of 200 bar and up without problems. The problem of diffusion in metal containers is practically negligible, as it occurs at such a slow rate.

In modern composite-material bottles such as vehicle fuel tanks, which consist of a plastic core wrapped in carbon fibre, the rate of diffusion is higher, but also negligible in practice, otherwise these tank systems would not be permitted. The car manufacturers’ safety concepts ensure that tanks, pipes and valves must be completely sealed, so hydrogen vehicles can safely enter tunnels and underground car parks.


The Clean Energy Partnership is one of the most important international projects to test hydrogen as a fuel. It revolves around the development of technical standards – from production to swift, safe fuelling to the operation of hydrogen-powered vehicles.

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