We proposed the WEA scheme to supply electricity, freshwater, and ammonia, which are essential for human beings, and analyzed the case of applying the WEA scheme to inland cities in arid/semi-arid regions by using solar power (PV), seawater, and pipelines. It was found that allocating PV electricity to seawater desalination is advantageous for reducing LCCO2 emissions in lowland areas, while one to ammonia synthesis is more advantageous in highland regions. And even when supplying cities located in extreme highlands and inland areas, it was found that adjusting the distribution of the three products can reduce overall LCCO2 emissions.