Fog Water Collection for Local Greenhouse Vegetable Production in the Atacama Desert

Abstract

Agricultural production in the Atacama Desert is restricted by extreme aridity and poor soil quality. Between 18 degrees S and 30 degrees S, low stratocumulus clouds regularly cover the southeastern Pacific Ocean reaching the Coastal Cordillera. Thus, marine fog is constantly present in the coastal areas of the desert. Fog can be harvested using fog collectors. However, limited information is available with regards to the variability of fog presence throughout the year and along the coast of the desert. Combining fog water harvest with hydroponic production under greenhouse facilities presents an alternative for sustainable and local fresh food production. In this article, we analyze the potential of fog water collection in two sites (Alto Patache and Falda Verde) distant by about 1000 km within the Atacama Desert. Additionally, in both locations, the environmental conditions within greenhouse structures, the potential energy requirement for environmental conditioning (including the energy production from photovoltaic panels) and the water requirements of vegetable crops under greenhouse conditions were modeled. The annual average of fog water collection registered was 2.9 and 3.3 L per day per m2 in Alto Patache and Falda Verde, respectively. During the most demanding season for crop evapotranspiration, 2.13 m2 of fog collectors can supply the water required for 1 m2 of greenhouse crops. The energy required for water and air pumps in the hydroponic systems can be supplied with photovoltaic systems including eight PV modules and a battery storage capacity of 9.4 kWh. In conclusion, the present study sheds light on the possibilities of massive water collection from fog to be used in local and sustainable food production in the Atacama Desert.