Reasons to transport and store hydrogen
The generation of the renewable electricity required for the production of green hydrogen is usually exposed to strong fluctuations
- especially when primarily wind and solar energy are used. These
fluctuations occur both during the course of days (e.g. PV systems do
not produce electricity at night) and over the course of months or years
(e.g. due to the weather, in Germany wind turbines generate
significantly more electricity in the winter half-year than in the
summer half-year). Therefore, the storage of green hydrogen is necessary
to guarantee a constant delivery of hydrogen to
individual consumers and to ensure the general security of renewable
energy supply. In this context, long-term storage facilities with a
large volume/storage capacity for hydrogen are of special importance
when considering future energy systems based entirely on renewable
energy sources.
The energy supply of most of the
European industrialised countries, and of Germany in particular, is
currently highly dependent on the import of fossil fuels.
The figure below shows Germany's primary energy consumption in 2019
broken down into the different energy sources. Domestic primary energy
sources are lignite and renewables. These two “domestic energy carriers”
currently cover only about a quarter of total primary energy
consumption.
In order for Germany to achieve its climate goals (greenhouse gas
neutrality by 2045), fossil primary energy sources will have to be
almost completely replaced in the coming decades (as explained in
Chapter 1.2 and
Chapter 1.3).
Although a complete replacement of these fossil energy sources with
renewable alternatives produced exclusively in Germany is
technologically possible, there are several reasons why part of the
energy demand will most likely be covered by
imported renewable energy carriers.
Due to its high population density, Germany has relatively little free
land that can be used exclusively for the generation of renewable
energy. Land use conflicts, for example with nature conservation or
residential development, and resistance from affected local inhabitants
(NIMBY-Effect) are already causing considerable delays in the
realisation of projects for the construction of wind or solar farms. In
the worst case, project plans can even fail completely for the reasons
mentioned. Other regions in the world have a significantly higher unused
potential for renewable energy generation than Germany. This refers not
only to available land, but also in particular to the availability of
wind and solar energy as well as hydropower, bioenergy and geothermal
energy. For example, a solar module in the south of Algeria generates
almost twice the amount of energy compared to an identical solar module
in Northern Germany due to the particularly high solar radiation in
North Africa.
For the reasons mentioned above, it is likely that a global trade in renewable energy sources
will emerge in the future. Densely populated countries with high energy
consumption - such as Germany - will probably act as importers in this
market. Countries that have a high availability of renewable energy,
e.g. wind and solar, and enough space to build large-scale production
facilities will be able to export green energy. Gaseous and liquid
energy carriers can be transported over long distances much more easily
than electricity. Therefore, it is likely that this global trade of
renewable energies will be based on green hydrogen and / or its
derivatives. In this chapter, you will learn how green hydrogen can
first be stored and then transported and what the so-called derivatives
are about.