Mainly because it uses water available on the sea: salt, brackish or polluted water. All the need for energy is fulfilled by sun power. Having in on a land would add complexity with the pipes. Moreover scarcity of water and cultivable land are the main obstacles to meet the quantitative and qualitative shifts of the world’s demand. Most of the potentially arable land is concentrated in a few geographical areas, and it is extremely scarce in many of the regions with high population growth rates, such as North Africa and the Arabian Peninsula. The solution it is also modular and flexible and the capability to move it could be really useful in some circumstances.