Seawater Agricultural Hydrogen

The key to cheap regenerative hydrogen

Our mobility must be converted quickly to renewable energies. Renewable hydrogen is an important core technology here. In contrast to batteries, only Power2Gas provides the necessary energy density and thus range, transport and storage capability, as well as the fast refuelling required for broad-scale implementation. Especially the fleet of hundreds of thousands of trucks on the roads lends itself to a quick conversion, as they not only have a high consumption but also very long running times and high transport capacities. In this way, the new technology can pay for itself quickly and the hydrogen filling station network to be expanded does not have to be as tightly knit as would be necessary for private vehicles.

As soon as the technology is established and thus cheap enough, private vehicles and the associated infrastructure can follow suit.

But a major hurdle on the road to regenerative hydrogen mobility remains:

The price!

Hydrogen electrolysis requires very large amounts of energy over a very long period of time. In addition, this energy must be very cheap in order to compete with chemically produced hydrogen or diesel at a competitive price.

A possible key technology to achieve such a quantum leap in the cost of solar power is called IrrigationNets. It is a seawater cooling system for solar power plants and agriculture. These special cooling systems can use seawater to produce very large quantities of cold salt-free humid air.

In this way, in the Mediterranean region, where there is sufficient solar radiation, the efficiency of solar power plants can be increased by up to 20% due to cooling. Furthermore, the service life of the modules can be extended by up to 30%. This effect is noticeable over the entire service life of the modules and ensures a slower loss of power due to aging and thus also a considerable additional electricity yield in the first 20 years.

Synergy effects with agriculture

However, the actual cost jump is due to the synergy effects in local agriculture. Due to ever higher temperatures and longer periods of drought, agriculture is suffering worldwide. Here, too, the new seawater-cooled solar power plants are helping.

On the one hand, under the somewhat higher solar plants, agriculture can continue to be operated in water-saving partial shading. This means that no arable land is lost for food. Instead, the area is used twice and the cultivation safety and yield are increased.

But also on the surrounding fields, the additional cooling and humidity provide a greenhouse feeling without greenhouses and thus lead to about 30% higher yields.

For this service in agriculture, the solar investor receives a profit share of the additional yields in agriculture. Furthermore, the solar power plant is allowed to use the farmland free of charge and the area is actively managed and thus guarded. All this reduces the electricity production costs. But that alone is not enough, because you not only have to produce the electricity cheaply, but also consume it completely. Only if the electricity can be sold can the power plant pay for itself even at low electricity prices.

Due to the well-known bell-shaped power curve of solar power plants, this is not an easy task. Although most electrolysis processes can now be dynamically adjusted in terms of consumption, here too the expansion of capacity is limited by the costs and the lower full-load periods that would be required for a larger expansion. It is therefore necessary to integrate staggered consumers and a certain battery capacity into the local smart grid.

Cheap surplus electricity and staggered consumers

The main part of the power plant's electricity production is sold primarily to the local power grids and, with a normal electricity price, provides a large part of the amortisation.

Hydrogen production is kept at a low level during these high-price periods in order to avoid burdening the electrolysis plants by switching on and off. If there is a favourable surplus of electricity over lunchtime, hydrogen production can then be increased from approx. 10% to 100%.

The next consumption stage, which only runs at midday, is then the hydrogen compression and cooling for the production of liquid gas. In this way, these large consumers, which can convert very large amounts of energy in a short time, can use the very high output curve of a solar power plant without the need for extremely large additional storage tanks.

Desalination storage air conditioning systems

A major consumer in these regions is also the air conditioning systems of large buildings. Air conditioning systems in particular are worthwhile for the targeted consumption of cheap surplus electricity. With the help of large water tanks, ice can be produced in these tanks and the energy can thus be stored for later consumption during the course of the day. Ice production is also a form of seawater desalination, as the ice is practically salt-free. After storage, only the remaining highly concentrated salt water has to be drained off first and used for cooling the building. Only then is the ice melted and the drinking water is fed into the drinking water supply after use for cooling. Normally, desalination by icing would not pay off due to the high energy consumption. However, if ice has to be produced for storage anyway, desalination is practically a free side effect.

Waste heat utilisation

Another important key component in the production of regenerative hydrogen is the use of waste heat from electrolysis and hydrogen compression. With the help of ORC (Organic Rankine Cycle) plants, electricity can be generated from the waste heat. In principle, the ORC process is a normal turbine-driven power plant, except that these power plants use a different working fluid instead of water, and thus manage with much lower temperatures of only 300°C. This is a waste heat level, which is very easily achieved, especially with gas compression. Compression plants that generate up to 400°C of waste heat have already been tested here.

Transition technologies

Especially the conversion from gasoline to hydrogen depends on high investments due to the required infrastructure and supply logistics, but it is also connected with various supply gaps and thus start-up difficulties. This is where transitional technologies can help. For example, Wankel Super Tec GmbH offers a special hydrogen engine that can be operated with hydrogen as well as with a variety of classic fuels. In addition, the engine can also run on hydrogen of low quality, while fuel cells require 99% pure hydrogen, which is more expensive to produce.

Conclusion

The technologies we need for a conversion to regenerative hydrogen mobility are already available today. Only the development of the necessary infrastructure must be pursued consistently and is a social task which the various states should pursue together. Parts of this infrastructure are even already available. For example, the gas tankers which currently still ship liquefied gas from America to us already exist. OPEC should also make urgent investments in the new energy markets to compensate for the then declining demand for oil.

Author:

Volker Korrmann

ewind Betreiber- und Vertriebs- GmbH

Baldersheimer Weg 111

12349 Berlin

www.IrrigationNets.com