The efficiency drops significantly at both ends compared to the pure use of electricity from renewable energy systems such as photovoltaic (PV) or wind power.
Why should one accept this without any need? Here, as in the case of so-called digitalisation, it is apparent that technical possibilities are not promoted in a targeted manner according to their optimal application, but as an end in themselves. What sense does it make to produce electricity in northern Germany using wind power or in North Africa or PV/solar-thermal power plants somewhat more efficiently than locally, if the intermediate energy source H2 more than nullifies these advantages through conversion losses? Add to this costly infrastructures such as H2 pipelines and logistical efforts such as the tanker transport of hydrogen from North Africa – a real bang idea of the lobbyists, which Altmaier joyfully anticipates – or vice versa?
In addition to the energy-political fallout, Altmaier and his supporters seem to be striving for a new dependence on Arab states. If at some point in the interest of decarbonization they disengaged from oil and gas supplies of this region, they want to replace this with supplies of (then no longer entirely) “green” hydrogen. We do not even want to get into about the necessity of using energy produced on the African continent there and thus promoting its economic development.
Electrolysis for grid stability
The concept is completely wrong for only an energy system transformation with maximum decentralization can offer the highest efficiency and security of supply at the lowest complexity and cost and follow the premise Energy is generated where it is needed. This does not mean at all that H2 would be uninteresting as an intermediate energy source. On the contrary, it is ideally suited as a (decentralized) long-term storage and load controller in the grid. If, therefore, H2 production is not demanded as an end in itself, but regenerative electricity surpluses are converted into H2 by electrolysis, it can be used excellently despite its lower efficiency. Therefore one would not have to shut down PV and wind power plants or export green electricity to Eastern Europe in order to get it back as coal-fired electricity when the opportunity arises. In addition to short-term battery buffering, electrolysis is also ideally suited as an easily and quickly adjustable load to ensure grid stability – better than was ever the case before renewable energies (RE).
Consequently, it would be more effective for the energy transition and climate protection if the billions in subsidies were not invested in ostentatious large-scale projects of H2 production plants and superfluous transmission and distribution grid expansion but in the massive expansion of local battery and H2 long-term storage facilities. Ultimately, every decentralized RE plant should have storage facilities to enable maximum utilization of energy on site while minimizing grid volatility. This would also eliminate the need for the assertion, repeatedly made by renowned researchers that RE plants are fundamentally volatile.
Integrate H2 technology sensibly!
Making it mandatory to equip all newly installed PV systems with battery storage systems that are appropriate to their kWp output is therefore urgently required, as well as the promoting the retrofitting of old systems and to make H2 generators or long-term storage systems marketable and promote them in various scales. They have already been developed.
This applies both to small electrolysis units of a PV-supported household power supply, which can be combined directly with compact stationary fuel cells for “cold” reverse power generation, and to wind farms, which use Power2X to convert their overproduction directly into industrially usable energy sources instead of switching off wind turbines. So what is stopping us from integrating H2 technology into a decentralized energy transition in a meaningful way and from abandoning prestigious but useless or even counterproductive large-scale technological projects?
In passing, we should also look at the share of transport in the planned extensive hydrogen economy. One may look with envy at the Japanese supremacy in fuel cell vehicles (if one can even talk about such a supremacy in this niche technology), but one does not necessarily need to follow suit. As already mentioned above, the conversion processes are very much at the expense of efficiency, which is much higher in purely battery-powered electric vehicles. Moreover, H2 technology in the vehicle is more resource-intensive and bulkier than pure battery power.
The decisive argument in favour of fuel cell vehicles, namely the longer range due to the much higher energy density of hydrogen, will no longer be effective in a few years, because both the further development of lithium-ion batteries and new battery technologies promise significantly higher storage capacity per kg. This would render obsolete the construction of a separate H2 tank infrastructure, which will take many years and will incur considerable costs. Under certain circumstances, H2 technology could be useful for trucks, buses or ships in the mobility sector.