Nature serves as a model for this technology for obtaining drinking water. Plants and animals show how it works: a 30-metre-high Canary Island pine tree at the altitudes of La Palma or Hierro can “comb out” about 50 litres per day from the fog with its long needles thanks to the trade winds. The dune grass in the Namib Desert manages 4 litres per foggy night. This is also where the 2 cm tall fog drinker beetle lives. It stands against the fog clouds with its head down. When the condensing water drops on the slanted body have reached a size of about 5 mm, the water runs down the grooves on the beetle’s back to its mouthparts. The amount of water absorbed corresponds to about 40 % of its body weight.
After many years of research and testing, Peter Trautwein (aqualonis GmbH) has developed the so-called CloudFisher for the WaterFoundation: an effective and durable fog collector to convert moisture from the air into clean drinking water in areas with high fog density. It is the first fog collector that can withstand high wind speeds of up to 120 km/h. It is quick and easy to install, requires no energy and is extremely low-maintenance. All materials used are food-safe. Thanks to its performance, the CloudFisher guarantees countless people high-quality drinking water that meets WHO standards at low cost.
Thanks to its performance, the CloudFisher guarantees high-quality drinking water that meets WHO standards at low cost for countless people. The extracted water can also be used in agriculture and for livestock breeding, reforestation projects and commercial purposes.
Possible areas of application for the CloudFisher are dry mountain and coastal regions with high fog and wind occurrence, such as in Ethiopia, Australia, Chile, Eritrea, Iran, Colombia, Morocco, Namibia, Nepal, North America, Oman, Peru, Spain, South Africa, Tanzania or Yemen.
m²The wind pushes the fog through the vertical net. The smallest droplets stick to the special fabric and unite to form large drops. These run down into the collection channel due to gravity. From there, the fog water flows through pipes into a reservoir.
Depending on the region and season, the daily water yield is between 6 and 22 litres per square metre of net.
But also during monsoon seasons, which follow the fog season from November to June, e.g. in Eritrea, the meshes are used to collect water, supplemented by horizontally attached polyethylene sheets. Depending on its purity, the rainwater obtained can be used as drinking water or for agriculture and watering livestock.
Every fog project begins with meteorological data collection on wind speed and direction, relative humidity and temperature, precipitation and the amount of water collected. These findings are used to decide whether the location is worthwhile for producing water from fog and how the collectors will be optimally aligned with the wind.
Fog collectors in Eritrea:
In 2007, the first 20 fog networks were set up together with the project partner FogQuest. 10 collectors each in the villages of Nefasit and Arborobue, which are located at an altitude of over 2,000 metres.
CloudFisher Pro in Morocco:
The largest installation in the world has been in Morocco’s Antiatlas Mountains since 2018. With the fog nets, 22 litres are “harvested” per square metre on an annual average. With 31 CloudFishers (1,686 m² net area), that makes 37,092 litres per fog day. This means that the 16 villages with approx. 1,300 inhabitants have 12 litres of water per family member per day at their disposal.
More about the project: https://www.wasserstiftung.de/en/morocco-mount-boutmezguida/
CloudFisher Pro, Mini und Complete in Tansania:
In Babati district, 14 schools with about 4,000 pupils benefit from 14 CloudFisher collectors (1 CF Pro, 5 CF Mini, 8 CF Complete) since 2022.
Learn more about the project: https://www.wasserstiftung.de/en/tanzania-qameyu-umagi/
CloudFisher Complete in Bolivia:
In the highlands of the Andes, a fog collector system with 14 CloudFisher collectors has been installed in the community of Alto Veladero for the local farming families, two schools and neighbouring settlements in 2022/23 – a total of around 1,000 people.
Learn more about the project: https://www.wasserstiftung.de/en/bolivia-alto-veladero-sivingalito/
4i-mag / Online-Magazin für Technologie, 21. Januar 2021
Drinking water scarcity – harvesting fog amidst arid conditions
PBS News Hour, July 31, 2019
(Public Broadcasting Service/US-TV-Netzwerk)
How scientists are harvesting fog to secure the worlds water supply (7 Minuten)
CloudFisher turns fog into drinking water in morocco’s driest regions
What is fog?
In our context, fog describes the phenomenon of small water droplets (1 to 40 micrometres in diameter) dispersed in the air. Fog is a kind of cloud that touches the ground or mountain terrain. Fog can be dense and reduce visibility to far less than one kilometre.
What does fog collection mean in general?
Fog collection describes the process of water harvesting or production from fog. For this purpose, large arrays of mesh, so-called fog nets, are arranged vertically in places where wind drives fog through them. The water sticks and accumulates in the mesh fibres and drips down into a collection and pipeline system.
We essentially distinguish here between two types of fog collectors – the simple 1st generation fog collector developed by Canadian NGO FogQuest (founder and director Bob Schemenauer), and the technology 2.0 fog collector (CloudFisher) developed by the WaterFoundation together with the German industrial designer Peter Trautwein (aqualonis GmbH).
What are the necessary conditions for fog collection?
The prerequisites for fog collection are fog and wind. Dew and humid air alone are not sufficient to collect water. Whether local conditions are suitable for harvesting fog must be identified by means of scientific assessment and by performing pilot studies using a small test collector. Validated methods exist.
For what purpose is fog water collected?
The main purpose of fog harvesting nowadays is drinking water supply. Beyond that, the water can also be used for irrigation, plants, livestock and crop farming. A number of current projects include farming aspects, but plugging the gaps in drinking water supply is the dominant application. Another positive effect is an overall reduction in the use of contaminated water resources.
How does a simple (FogQuest) fog collector work? What are the pros and cons?
This fog collector uses very simple and affordable meshing that is put up between two poles. The collector is easy to construct and comparatively cheap. It collects a moderate amount of fog water. Unfortunately, this technology is very prone to being destroyed in windy conditions – occurring quite often in mountainous regions where fog harvesting works best. Furthermore, aspects such as food grades and damage by strong solar radiation are often underestimated in very simple and cheap constructions.
What are the main differences between the two types of fog collectors?
The main differences between the two types are the mesh composition and quality, the collector construction (frames, grids, water gutters, etc.) and the price. The CloudFisher is more efficient and has the more sustainable construction, while simple collectors are easier to construct and cheaper. Wind conditions are a key element when deciding which technology should be used or is more successful.
How large are fog nets and how are they typically arranged?
The FogQuest fog collector has a 40 m² net surface, the net surface of a CloudFisher measures 54 m² and has a height of 6 metres. Since wind and fog are the conditions necessary for fog collection, fog nets are typically arranged on the windward slopes of mountains where they are directly oriented towards persistent winds. Orientation is a key factor because diverging by only 30° from the wind direction results in a 25% lower yield. To reduce obstructions to the wind, it is useful to spread a number of collectors over a certain area instead of placing big ones close to each other.
How much water can be collected?
Water collection yields vary a lot depending on local conditions and year. The annual average yield of simple collectors is around 5 litres per square metre, whilst the CloudFisher average, in Morocco for example, is more than 20 litres per square metre and fog day. The daily yield per installation depends on the technology used, the weather conditions and the size of the fog collectors. Since the quality of water droplet density, etc. varies a great deal, pilot studies (see above) are necessary.
Is electricity required for fog collection?
No electricity is required to collect fog. Fog collection is a passive technology that combines weather conditions (wind) and physics (gravity).
What are the initial steps in starting a fog collection project?
After securing an enabling environment (people in need, administration, regulation, commitment of beneficiaries; even better: involvement of the community, etc.), feasibility of fog collection in the desired area must be assessed. To do this, climate conditions must be measured and small test collectors installed (see above).
Is the collected water clean and declared potable?
Yes, since atmospheric water is normally free of bacteria and contamination. It is safe. In all existing projects, fog water has met WHO drinking water standards. As with all other water sources and systems, pipes and storage facilities must be cleaned regularly. Also, contamination by bird droppings for example must be prevented.
Is it possible to collect rain?
Yes, fog collectors can also collect rain – when the rain arrives with wind and so falls at an appropriate angle.
What are the average costs for a fog collection project?
The costs for a project vary greatly and depend on the technology selected, and the size and yield required. According to FogQuest, a simple 40 m² fog collector costs about USD 1,500 producing an average of about 200 litres of water per day. A 54 m² CloudFisher, like that in Morocco, produces an average yield of about 1,200 litres of water per fog day costs about €11,000.
Where can I buy the materials required for a fog collector?
The main suppliers of fog nets are FogQuest (simple nets) and aqualonis GmbH (CloudFisher type). For further information, refer to their websites (www.fogquest.org and www.aqualonis.com).
Is fog collection sustainable?
As long as the fog collectors are maintained properly and the systems are kept clean, fog collection can be a very sustainable solution. The CloudFisher nets in particular can operate for many years. Moreover, fog collection does not have any harmful environmental impact and can foster socioeconomic factors such as female labour force participation and education through saved time.
Is it possible to provide enough water for a city?
No, since water demand in cities is much too high for a fog collection system. The design is very well suited for remote mountain communities and smaller villages. In Morocco, the world’s biggest fog net plant with 31 CloudFishers provides water for 16 small villages.
What are the key benefits?
What are the key downsides?
What represent obstacles to implementation?