The marketControlled environmental farming, also known as greenhouse farming has grown four to five fold over the past decade moving from a marginal yet traditional farming activity into an +$100 billion dollar business worldwide. The amount of land covered by greenhouses, both plastics and glass reaches 630,000 hectares of which 443,000 in Asia alone. The Mediterranean covers over 100,000 hectares, with Spain as the European leader with an estimated 55,000 hectares. The region around Almeria and Murcia (Spain) covers 200 square kilometers. The Netherlands has perhaps the highest percentage of farm land covered with approximately 0.25% of the total landmass as greenhouses. The Netherlands has around 9,000 greenhouse businesses that operate on +10,000 hectares, employing about 150,000 workers, generating €4.5 billion worth of fruits, veggies, plants and flowers, of which 80 percent is exported. Turkey is fast emerging as one of the world’s leaders of greenhouse tomato farms with a production in excess of 6 million tons. In recent years China has become the largest operator of controlled environmental farming. Its soilless farming includes coal cinder, peat moss, vermiculite, coir, sawdust, rice husk mixed with organic fertilizer, including mineralized pig manure. These Chinese techniques, already described by Marco Polo in his journal, are low cost and adapted to local conditions explaining the competitiveness of the produce. This opened the market to innovation and a portfolio of alternative propellant chemicals, ranging from hydrocarbons (propane, butane), hydrofluorocarbons (HFCs), dimethyl ether (DME), compressed propellant gases (carbon, air, nitrogen and nitrous oxide) came to market. Last year, approximately 15 billion containers of propellant were sold worldwide, with Europe leading the market with a production of +5 billion units. Steel aerosols account for 3.6 billion units. If everything was recycled empty, it would produce enough steel for over 160,000 cars. Propellants represent a technology platform that covers a wide variety of products: asthma inhalers, cleaning products, insect repellents, deodorants, food products, disinfectants, paints, fire extinguishers, shaving creams, automotive maintenance products, aviation and microelectronics. Personal care products consume most of the propellants, especially hairsprays and foams. However, food products, especially whipped cream, are showing a steady increase. In contrast, the use of propellants in paints and finishes is declining. Revenues generated by consumer aerosol products in the U.S. at wholesale prices are approximately $15 billion and nearly $40 billion worldwide.
The scarcity and cost of water forces the growers to use a lot of pesticides. As a response greenhouse design has evolved since early 2000 towards a completely closed system – just like building controls – allowing the farmer full control over energy, humidity and productivity, reducing the dependency on chemicals. The farming evolved simultaneously towards hydroponics in an artificial substrate ranging from sand, perlite, rockwool and volcanic gravels. This last option was already applied in the floating gardens of the Aztecs. Earthstone Inc. (USA) now offers recycled glass, converted into a foam thanks to the injection of CO2.
Charlie Paton, a British designer without track record in farming observed during his frequent trips to Morocco an unproductive soil with the Atlantic on one side, and a vast desert on the other side. He sold his lighting company and committed his life to design and implement a simple and cost-effective way to grow food in the desert using abundant salt water. Seawater is evaporated to create cool humid conditions inside. Part of the evaporated seawater is condensed as fresh water to irrigate the crops. The dry desert air going into the greenhouse is then cooled and humidified by seawater which trickles over the first evaporator. As the air leaves the growing area, it passes through the second evaporator over which seawater is flowing. This water has been heated by the sun in a network of pipes making the air hot and humid. When the hot and humid air hits the cool surface, fresh water condenses.
The cool and humid conditions in the greenhouse enable crops to grow with little water. When crops are not stressed by excessive transpirations yield and quality improve. The cost of operation is a fraction of the material, financial and ecological cost the traditional greenhouses require. It offers an opportunity for income in coastal zones around the world that now have to opt for reverse osmosis as the only access to potable water for human consumption or farming. The system also works well in combination with power generating infrastructure, especially where there is a need to remove heat as is the case with concentrated solar power facilities, using the waste heat generated to increase freshwater production. This innovation does not consume any freshwater, instead it produces potable water. It is a fine example of the Blue Economy principle: use what you have, evolve from scarcity to abundance.