INTERESTING FACTS ABOUT HYDROGEN

ADVANTAGES

WHY USE HYDROGEN?

Hydrogen can look back on a long tradition as an energy source and chemical raw material. Its high energy content - corresponding to about 3.5 l of oil at a weight of 1 kg - characterized it early on as the ideal fuel where weight plays a dominant role in front of the volume: to lift a balloon or zeppelin and later as a fuel for space vehicles. In the first half of this century, the entire gas supply was based on city gas, a coal gas that is more than half hydrogen. It was only with the development of oil and gas deposits that hydrogen was gradually pushed out of the public supply networks. In 1992, almost 3 billion m3 of city gas (and about a third of it in the old federal states) was used in the private household and small consumer sector in Germany. This corresponds to around 10% of natural gas use in these areas. While the displacement of hydrogen as an energy source with decreasing use of coal in the energy sector took place, there are long-term good chances for it to return if its advantages of regenerative generation and the absence of carbon are in demand. But why should this demand increase again in the future? The big quantum leap in the local emissions balance is already being achieved by switching from petrol and diesel to natural gas. Hydrogen has advantages beyond the existing and envisaged emission standards. Use can therefore only make sense where there are other advantages besides the local low emissions. As a secondary energy source, hydrogen offers the opportunity to gradually change from CO2-emitting to CO2-free traffic while maintaining the application technology by changing the energy source shares.

STRATEGIC MEANING

The basis for a long-term change is the concern about the finiteness of fossil energy resources, on the one hand, and the requirement to drastically reduce all (and in particular also climate-relevant) emissions. It is irrelevant whether the finite nature of the resources or the ability of the atmosphere to absorb pollutants dictate action. It is only against this background that hydrogen is of strategic importance in connection with renewable energy generation.

• for storing energy,
• to transport energy and
• as a pollutant-free mobile energy source.

If one accepts these considerations, the long lead times until the acquisition of relevant market shares require an early continuous development, testing and demonstration, which must be started today.

The entry into a large-scale hydrogen energy industry is also seen as an important option if the contribution of fluctuating power generators (wind energy, solar energy) reaches such an extent that electricity supply and demand can only be adjusted via a storage facility. Simulation calculations with the key data of the German electricity industry show that this is necessary with a share of renewable energy sources of around 20 - 25% of the electricity mix, although this limit cannot be seen rigidly. As a "storage medium" for electricity, hydrogen has the most attractive properties today: Compared to storing electricity in batteries, the material expenditure is many times lower. This application variant is practiced in a small style in the self-sufficient solar house of the Fraunhofer Institute for Solar Energy Systems. Unneeded solar electricity is used there stored in a 5 m3 hydrogen tank and optionally used for heating support, cooking or to generate electricity in times of weak solar supply. If one wanted to store the same amount of energy in accumulators, a lead accumulator of more than 40 t weight and 100 m3 volume would be required.

NO POLLUTANTS

Regardless of these long-term options, hydrogen offers itself as a pollutant-free fuel for traffic applications, whereby road vehicles are initially seen to reduce emissions in city centers, but in the long term all modes of transport could be affected, be they ships, trains or planes. However, the advantages of freedom from pollutants and the low fuel weight are offset by a large tank volume and tank weight, which imposes restrictions on the range and payload of small vehicles.

In addition to these three large areas, the progress made in developing fuel cells as an early niche application has also made hydrogen generation possible. The prerequisite for this, however, is that the manufacturing costs can be moved into the range of the costs of conventional technologies. The global efforts of the leading companies in this field indicate that large-scale market entry can be expected around the turn of the millennium. If expectations are met here, the fuel cell (similar to photovoltaics) could initiate a revolution in the entire energy industry early in the next century whose dynamics and dimensions should be comparable to the displacement of the transistor by microelectronics and their effects on the entire media and communication sector.

If one now pursues the strategy of establishing hydrogen as an energy source in the long term, the early "niche applications" in the transport sector or via the fuel cell are the first markets. In the area of conventional hydrogen generators from chemistry, a cost-effective introduction and testing can take place in a first phase. This could open up an economic market entry within the next five to ten years, which could be expanded in the medium term via imported hydrogen and other hydrogen sources (e.g. biomass gasification).

Next time I will deliver some insights ino the characteristics of H2

#SAFETYINSIGHTS