My name is Barry Prentice from the University of Manitoba in Canada.

I had the easiest job in the world today.

I introduced the host of the conference.

So everyone knows who Christophe is and I don't think I have to spend a long time introducing

him except as an esteemed professor and also the gentleman who has made all of this possible.

So with that very short introduction Christophe, I'm going to return to you to come and give

your presentation on the airships.

Thank you very much that you are all here and attending this conference.

I was very happy about your talks on the first day and what I have learned and I'm also actually

on the second day to see what further talks will be and in particular

for example

what

kind of solar cells we should put on our airships.

My talk is about influence of clouds to solar powered airships and this conference is in

particular about challenges for commercialization and therefore I would like to make a motivation

of my talk in this direction.

In my opinion

there are two important reasons why we need new technologies in aviation and

one is we can see that from the current political situation in Europe

we must try to be independent

of energy resources from outside of Europe.

That means we should not use and import so much oil and natural gas which is usually

for standard aviation needed and that somehow means and implies we need electric mobility.

And I think for this there is a lot of chances for commercialization.

And the second of obviously is the climate change.

It is well known that aviation leads to CO2 emissions but it's not only the CO2 emissions

it additionally are other emissions which happen by burning gas fuel and there are publications

which show that these other effects coming from water vapor and contrails might be 5%

in total of the influence on climate change.

And that also strongly implies we should use a technology which is not burning a fuel

therefore also some kind of e-fuels might be not the optimal choice.

We have also seen that yesterday in the talk of Mr.

Berninger.

So what we need is electric mobility and then the question is how can we come to electric

mobility?

What we need is electric energy and the first thing is we can have solar power

we can have

anything based on green hydrogen or electric battery and there are problems.

What we also have seen from a talk yesterday to use hydrogen in an airplane is very difficult

from a technical point of view and the gas tanks are very large from the volume so this

is difficult and it certainly will also be expensive.

So this is critical in particular since we need green hydrogen and we currently already

have problems to use and to get enough green hydrogen in other areas in the industry in

Europe where it's actually much easier to use green hydrogen.

So in other areas it's difficult to do

it's unlikely we can do it in aviation.

Another thing is electric batteries.

When you have a very small airplane you can use an electric battery but as soon as it

is large it's not working and also to use solar power

we have seen also in the presentation