To make hydrogen you must have water and a lot of free/cheap energy.
In Tunesia they have a lot of sun and the possibity to make the effective solar mirror sytems to give close to free solar energy source. About the water, they must bring in the seawater because there is not to much groundwater, it gives some problems, the water must be transported to the desert area where the solar systems will be build, but thats most a question about energy, and energy can be close to free in these solar systems if they are build in big scale, about the salt in the seawater there is different ways to work with that problem they will all need energy, but in this case there will be a lot of free energy to run the processes.
In the north sea there is a lot of hydrogen projects based on the many existing and comming windmills in the sea, still based on the idea of you must have free/cheap energy and water to make hydrogen. On windy days there already now is problems to get away with all the energy, in some situations they must stop the windmills or pay to get of with the energy. And they are going to build many times more wind mills so here there is cheap/free energy avaible already and the water is just to take it where it is needed. The countries in the north sea area already have decided to build hydrogen factories out in the sea, now its only a question about time before the first sea hydrogen will come.
In the energy perspective Hydrogen is Green, in the polution perspective there needs some new tecnic solutions before its 100 % clean, but compared to using fossile energy, hydrogen already now is much more clean.
Is hydrogen a source for ever or only a step on the way to a green planet, I dont know, but I know the climate on the planet is getting crazy, and we need to stop using fossile energy as fast as possible.