Fog water harvesting on the verge of economic competitiveness

Abstract

Fog water harvesting has proven to be a successful means to provide water in dry regions for decades. So far, economic considerations have been focused on the sheer construction cost of a fog collector, and the idea of fog water harvesting as a business model has largely been neglected. However, paying attention to this aspect could be a further step to the sustainability of fog harvesting projects. This short report is dedicated to two crucial elements of economic competitiveness of fog water harvesting: (i) maximizing the efficiency of fog water collectors and (ii) the development of a simple business model that introduces fog water harvesting as an economically competitive investment as an alternative to centralized water delivery. For the first part (i), a field study was conducted in the outskirts of Lima (Peru). In preparation of the subsequent constructive upscaling of new fog collector prototypes, a design study was performed to find the most effective fog collector structure. Five prototypes of collectors with different shapes and collecting materials were tested at a small scale, followed by an upscaling of the three most promising setups to full scale fog collector devices (Fig. 1, No. 1–3). Additionally, a three-winged screener called Astropod (No. 4 in Fig. 1) was introduced as an improved instrument for the evaluation of water yield by fog water harvesting. The Astropod permits measurements of the favourable wind directions for fog water collection and the absolute amount of collected fog water at the same time. The results of the efficiency study (Tab. 1) revealed that the Eiffel device is the most suitable fog water collection system, reaching the maximum absolute yield of up to 2,650 litres per day during the peak fog season. Therefore, it was chosen for the follow-up projects, also due to its robustness and comparative simplicity. The successful implementation of the first set of fog collectors caused an increased awareness among local communities in the project area about using these systems. Joint efforts, including substantial financial contributions of the community members allowed for two follow-up projects, each one largely performed FOG WATER HARVESTING ON THE VERGE OF ECONOMIC COMPETITIVENESS