Here, we propose the water-electricity-ammonia (WEA) scheme as one of the sustainable systems to selfsufficiently supply water, electricity, and ammonia from a renewable source. The WEA scheme is composed of the following three principles: electricity is generated by renewable energy; desalination and water transportation inland are carried out by the electricity; ammonia is synthesized using nitrogen in the air and hydrogen evolved by water electrolysis using the transported water and the generated electricity. The electricity and water have to be allocated to these three products appropriately depending on the needs. In recent years, WEF "nexus" approach has received global recognition for the interdependencies between water, energy, and food. We propose this WEA scheme to settle the demands from the WEF sectors by producing the three products from renewable sources.