Case 26: Greenhouses without heating or irrigation

The market

Controlled organic farming, also known as greenhouse farming, has quadrupled or quintupled in the last decade, growing from a marginal but traditional agricultural activity to a global industry worth over $100 billion. The area of ​​greenhouses, both plastic and glass, has reached 630,000 hectares, with 443,000 hectares in Asia alone. The Mediterranean region boasts over 100,000 hectares, with Spain leading the European region at approximately 55,000 hectares. The area around Almería and Murcia (Spain) covers 200 square kilometers. The Netherlands may have the highest percentage of agricultural land covered, with approximately 0.25% of its total land area consisting of greenhouses. The Netherlands has approximately 9,000 greenhouses operating on over 10,000 hectares, employing around 150,000 people and generating €4.5 billion in revenue from fruits, vegetables, plants, and flowers, 80 percent of which is exported. Turkey is rapidly becoming one of the world's leading producers of greenhouse tomatoes, with an output of over 6 million tons. In recent years, China has become the largest operator of controlled environmental agriculture. Its soilless farming practices include the use of coal ash, peat moss, vermiculite, coconut fiber, sawdust, and rice hulls mixed with organic fertilizers, including mineralized pig manure. These Chinese techniques, already described by Marco Polo in his journal, are inexpensive and adapted to local conditions, explaining the product's competitiveness. This opened the market to innovation, and a portfolio of alternative propellant chemicals, ranging from hydrocarbons (propane, butane), hydrofluorocarbons (HFCs), dimethyl ether (DME), and compressed propellant gases (carbon, air, nitrogen, and nitrous oxide), entered the market. Last year, approximately 15 billion containers of propellant gas were sold worldwide, with Europe leading the market with a production of over 5 billion units. Steel aerosols account for 3.6 billion units. If all of them were recycled, this would produce enough steel for over 160,000 cars. Propellant gases represent a technological platform that covers a wide variety of products: asthma inhalers, cleaning products, insect repellents, air fresheners, food products, disinfectants, paints, fire extinguishers, shaving creams, automotive care products, aviation, and microelectronics. Personal care products consume the majority of propellants, especially hairsprays and mousses. However, food products, particularly whipped cream, are experiencing steady growth. Conversely, propellant use in paints and finishes is declining. Revenue generated by consumer aerosol products in the United States at wholesale prices reaches approximately $15 billion, and nearly $40 billion worldwide.

Innovation

The scarcity and cost of water force producers to use large quantities of pesticides. In response, greenhouse design has evolved since the beginning of 2000 toward a completely closed system—as have the building controls—allowing farmers to fully control energy, humidity, and productivity, thus reducing their reliance on chemicals. Agriculture has simultaneously evolved toward hydroponics in an artificial substrate composed of sand, perlite, rock wool, and volcanic gravel. This latter option was already used in the floating gardens of the Aztecs. Earthstone Inc. (USA) now offers recycled glass transformed into foam through the injection of CO₂.

Charlie Paton, a British designer with no prior experience in agriculture, observed during his frequent trips to Morocco an unproductive land bordered by the Atlantic Ocean on one side and a vast desert on the other. He sold his lighting business and dedicated his life to designing and implementing a simple and economical way to grow food in the desert using abundant saltwater. Seawater is evaporated to create cool, humid conditions inside. Some of the evaporated seawater is condensed into freshwater to irrigate the crops. Dry desert air entering the greenhouse is then cooled and humidified by seawater trickling over the first evaporator. As the air leaves the growing area, it passes over the second evaporator, where seawater is also poured. This water has been heated by the sun in a network of pipes, making the air warm and humid. When warm, humid air reaches the cold surface, the cool water condenses.

The cool, humid conditions of the greenhouse allow crops to grow with minimal water. When crops are not stressed by excessive transpiration, yield and quality improve. The operating cost is a fraction of the material, financial, and environmental costs of traditional greenhouses. It offers an income opportunity in coastal areas worldwide that currently rely on reverse osmosis as their only source of drinking water for human consumption or agriculture. The system also works well in conjunction with power generation infrastructure, particularly where heat needs to be dissipated, as is the case with concentrated solar power plants, by utilizing the waste heat produced to increase freshwater production. This innovation does not consume freshwater but instead produces potable water. It is a prime example of the blue economy principle: using what you have, moving from scarcity to abundance.

The first cash flow

Charlie then founded Seawater Greenhouse Co. Ltd. and privately invested for over 15 years in three pilot plants to prove the concept: Tenerife, Canary Islands (Spain) in 1992; Al-Aryam Island, Abu Dhabi (United Arab Emirates) in 2000; and near Muscat, Oman, in cooperation with Sultan Qaboos University in 2004. He used only prevailing sea winds, fans, and simple off-the-shelf evaporators to convert seawater into freshwater, creating a humid environment in which virtually any plant can grow. In late 2009, Seawater Greenhouse completed a recapitalization with private investors and signed its first commercial project in South Augusta, Australia.

The opportunity

The potential for growing crops with simple inputs like nutrients, sunlight, and seawater is enormous. It is now proven viable to cultivate lettuce, tomatoes, a wide variety of fruits, vegetables, herbs, and flowers, and even produce high-quality sea salt in the desert. This profitable business model generates multiple revenue streams through a simple process that mimics the hydrological cycle, where seawater heated by the sun evaporates, cools to form clouds, and returns to the earth as rain, fog, or dew. This represents a huge platform for entrepreneurs worldwide. There is a window of opportunity to make this a mass-market production system anywhere in the world, since hydrological cycles can be replicated without restriction at any altitude. And instead of working solely with salt water, a variant of the same technological platform would allow the use of contaminated water, ensuring purification through evaporation and condensation cycles that exploit differences in temperature and humidity. Adding to this the vortex technology of Curt Hallberg and his team at Watreco in Sweden, described in the first case, we can see how predictable results from physics can move our societies from hunger to self-sufficiency by utilizing unusable land, ensuring profitable social and environmental development.