Seawater Greenhouse
Encyclopedia
The Seawater Greenhouse is a technology that enables the growth of crops in arid
regions, using a greenhouse
structure, seawater
and solar energy. The technique involves pumping seawater (or allowing it to gravitate if below sea level) to an arid location and then subjecting it to two processes: first, it is used to humidify and cool the air, and second, it is evaporated by solar heating and distilled to produce fresh water
. Finally, the remaining humidified air is expelled from the greenhouse and used to improve growing conditions for outdoor plants. The technology was introduced by British inventor Charlie Paton in the early 1990s and is being developed by his UK company Seawater Greenhouse Ltd. The more concentrated salt water may either be further evaporated for the production of salt and other elements, or discharged back to the sea. The Seawater Greenhouse can be seen as one response to the global Water crisis
and Peak water
.
and the Qattara Depression
where hydro schemes have been proposed to exploit the hydraulic pressure to generate power, e.g. Red Sea - Dead Sea Canal.
developed by Charlie Paton's company Light Works Ltd, now Seawater Greenhouse Ltd.
The first pilot project commenced in 1992 with the search for a test site which was eventually found on the Canary Island of Tenerife.
A prototype Seawater Greenhouse was assembled in the UK and constructed on the site in Tenerife.
The results from this pilot project validated the concept and demonstrated the potential for other arid regions.
The original pilot design has then evolved into a lower cost solution using a lighter steel structure similar to a multi-span polytunnel. This structure is designed to be cost effective and suitable for local sourcing.
This design was first tested and validated through a second Seawater Greenhouse that was constructed on Al-Aryam Island
, Abu Dhabi
, United Arab Emirates
in 2000. In both cases, crop production in terms of quality and quantity has been outstanding.
The year 2004 saw the completion of a third pilot Seawater Greenhouse near Muscat, Oman
. In collaboration with Sultan Qaboos University
, providing an opportunity to develop a sustainable horticultural sector on the Batinah coast
.
These projects have enabled the validation of a thermodynamic simulation model which given
appropriate meteorological data, accurately predicts and quantifies how the Seawater Greenhouse
will perform in other parts of the world.
In 2010 Seawater Greenhouse built a new commercial installation in Australia
. The enterprise is now independently operating as Sundrop Farms Pty Ltd
.
cool air. The process recreates the natural hydrological cycle within a controlled environment. The front wall of the building is a seawater evaporator. It consists of a honeycomb lattice and faces the prevailing wind. Fans control air movement. Seawater trickles down over the lattice, cooling and humidifying the air passing through into the planting area.
Sunlight is filtered through a specially constructed roof. The roof traps infrared heat, while allowing visible light through to promote photosynthesis. This creates optimum growing conditions – cool and humid with high light intensity. Seawater that has been heated in the roof passes through a second evaporator creating hot saturated air which then flows through a condenser.
The condenser is cooled by incoming seawater. The temperature difference causes fresh water to
condense out of the air stream. The volume of fresh water is determined by air temperature, relative humidity, solar radiation and the airflow rate. These conditions can be modeled with appropriate meteorological data, enabling the design and process to be optimised for any suitable location.
The Seawater Greenhouse evaporates much more water than it condenses back into freshwater. This humid air is `lost´ due to high rates of ventilation to keep the crops cool and supplied with CO2. The higher humidity exhaust air provides some benefit to the cultivation of more hardy crops downwind of the greenhouse.
This phenomenon could enable the cultivation of biofuel crops in the area surrounding the Seawater Greenhouse.
as its demand for power is proportional to sunlight. .
The use of pesticides is reduced or eliminated as the seawater evaporators have a biocidal effect on the air that passes through them.
can be used to help create and enrich the surrounding soil, or alternatively digested to produced bio methane, albeit with less, but still significant quantities of soil nutrients.
is a scheme that aims to provide fresh water, food and renewable energy in hot, arid regions as well as re-vegetating areas of uninhabited desert. This proposal combines the Seawater Greenhouse and concentrating solar power (CSP) working in synergy. CSP is a form of renewable energy
that produces electricity from sunlight using thermal energy to drive conventional steam turbines. It is claimed that, together, these technologies will create a sustainable and profitable source of energy, food, vegetation and water.
The team behind the Sahara Forest Project comprises experts from Seawater Greenhouse Ltd, Exploration Architecture, Max Fordham Consulting Engineers and the Bellona Foundation
.
The scale of the proposed scheme is such that very large quantities of seawater will be evaporated. By using locations below sea level, pumping costs are eliminated.
Among planned activities are one pilot project in Jordan and one in Qatar
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
regions, using a greenhouse
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...
structure, seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
and solar energy. The technique involves pumping seawater (or allowing it to gravitate if below sea level) to an arid location and then subjecting it to two processes: first, it is used to humidify and cool the air, and second, it is evaporated by solar heating and distilled to produce fresh water
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
. Finally, the remaining humidified air is expelled from the greenhouse and used to improve growing conditions for outdoor plants. The technology was introduced by British inventor Charlie Paton in the early 1990s and is being developed by his UK company Seawater Greenhouse Ltd. The more concentrated salt water may either be further evaporated for the production of salt and other elements, or discharged back to the sea. The Seawater Greenhouse can be seen as one response to the global Water crisis
Water crisis
Water crisis is a general term used to describe a situation where the available water within a region is less than the region's demand. The term has been used to describe the availability of potable water in a variety of regions by the United Nations and other world organizations...
and Peak water
Peak water
The term Peak Water has been put forward as a concept to help understand growing constraints on the availability, quality, and use of freshwater resources...
.
Applicability
The technique is applicable to sites in arid regions near the sea. The distance and elevation from the sea must be evaluated considering the energy required to pump water to the site. There are numerous suitable locations on the coasts; others are below sea level, such as the Dead SeaDead Sea
The Dead Sea , also called the Salt Sea, is a salt lake bordering Jordan to the east and Israel and the West Bank to the west. Its surface and shores are below sea level, the lowest elevation on the Earth's surface. The Dead Sea is deep, the deepest hypersaline lake in the world...
and the Qattara Depression
Qattara Depression
The Qattara Depression is a depression in the north west of Egypt in the Matruh Governorate and is part of the Libyan Desert. It lies below sea level and is covered with salt pans, sand dunes and salt marshes. The region extends between latitudes of 28°35' and 30°25' North and longitudes of 26°20'...
where hydro schemes have been proposed to exploit the hydraulic pressure to generate power, e.g. Red Sea - Dead Sea Canal.
History
The Seawater Greenhouse project dates back to 1991 when the concept was first researched anddeveloped by Charlie Paton's company Light Works Ltd, now Seawater Greenhouse Ltd.
The first pilot project commenced in 1992 with the search for a test site which was eventually found on the Canary Island of Tenerife.
A prototype Seawater Greenhouse was assembled in the UK and constructed on the site in Tenerife.
The results from this pilot project validated the concept and demonstrated the potential for other arid regions.
The original pilot design has then evolved into a lower cost solution using a lighter steel structure similar to a multi-span polytunnel. This structure is designed to be cost effective and suitable for local sourcing.
This design was first tested and validated through a second Seawater Greenhouse that was constructed on Al-Aryam Island
Al-Aryam Island
Al-Aryam Island is an island off the west coast of Abu Dhabi in the United Arab Emirates. It was formerly known as Bu Khushaishah. It contains the royal palaces and horse ranches which belong to the ruling family, the Al Nahyans. Access is strictly prohibited to the public...
, Abu Dhabi
Abu Dhabi
Abu Dhabi , literally Father of Gazelle, is the capital and the second largest city of the United Arab Emirates in terms of population and the largest of the seven member emirates of the United Arab Emirates. Abu Dhabi lies on a T-shaped island jutting into the Persian Gulf from the central western...
, United Arab Emirates
United Arab Emirates
The United Arab Emirates, abbreviated as the UAE, or shortened to "the Emirates", is a state situated in the southeast of the Arabian Peninsula in Western Asia on the Persian Gulf, bordering Oman, and Saudi Arabia, and sharing sea borders with Iraq, Kuwait, Bahrain, Qatar, and Iran.The UAE is a...
in 2000. In both cases, crop production in terms of quality and quantity has been outstanding.
The year 2004 saw the completion of a third pilot Seawater Greenhouse near Muscat, Oman
Oman
Oman , officially called the Sultanate of Oman , is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It is bordered by the United Arab Emirates to the northwest, Saudi Arabia to the west, and Yemen to the southwest. The coast is formed by the Arabian Sea on the...
. In collaboration with Sultan Qaboos University
Sultan Qaboos University
Sultan Qaboos University, located in the city of Al Khoudh, in the Capital Region of Muscat, Oman, is the only public university in the Sultanate of Oman. Named after Qaboos bin Sa’id Al ‘Bu Sa’id, the Sultan of Oman, the university opened in 1986. At the time, it comprised five colleges:...
, providing an opportunity to develop a sustainable horticultural sector on the Batinah coast
Al Batinah Region
Al Bāţinah is one of the regions of Oman.Al Batinah Region, otherwise known as Al Batinah, occupies an important location on the coast of Gulf of Oman. It lies between Khatmat Malahah in the north and Ras AL Hamra in the south and confined between the Al Hajar Mountains in the west and the Gulf...
.
These projects have enabled the validation of a thermodynamic simulation model which given
appropriate meteorological data, accurately predicts and quantifies how the Seawater Greenhouse
will perform in other parts of the world.
In 2010 Seawater Greenhouse built a new commercial installation in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. The enterprise is now independently operating as Sundrop Farms Pty Ltd
.
The process
The Seawater Greenhouse uses the sun, the sea and the atmosphere to produce fresh water andcool air. The process recreates the natural hydrological cycle within a controlled environment. The front wall of the building is a seawater evaporator. It consists of a honeycomb lattice and faces the prevailing wind. Fans control air movement. Seawater trickles down over the lattice, cooling and humidifying the air passing through into the planting area.
Sunlight is filtered through a specially constructed roof. The roof traps infrared heat, while allowing visible light through to promote photosynthesis. This creates optimum growing conditions – cool and humid with high light intensity. Seawater that has been heated in the roof passes through a second evaporator creating hot saturated air which then flows through a condenser.
The condenser is cooled by incoming seawater. The temperature difference causes fresh water to
condense out of the air stream. The volume of fresh water is determined by air temperature, relative humidity, solar radiation and the airflow rate. These conditions can be modeled with appropriate meteorological data, enabling the design and process to be optimised for any suitable location.
The Seawater Greenhouse evaporates much more water than it condenses back into freshwater. This humid air is `lost´ due to high rates of ventilation to keep the crops cool and supplied with CO2. The higher humidity exhaust air provides some benefit to the cultivation of more hardy crops downwind of the greenhouse.
This phenomenon could enable the cultivation of biofuel crops in the area surrounding the Seawater Greenhouse.
Other benefits
If carbon-neutral PV panels were available, the Seawater Greenhouse could be carbon neutral in its operations. Unfortunately, current methods of PV production are not perfect. The electrical energy it requires to operate pumps and fans is best produced by solar PVPhotovoltaics
Photovoltaics is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material...
as its demand for power is proportional to sunlight. .
The use of pesticides is reduced or eliminated as the seawater evaporators have a biocidal effect on the air that passes through them.
Fuels production
The Seawater Greenhouse produces biological residues. This biomassBiomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
can be used to help create and enrich the surrounding soil, or alternatively digested to produced bio methane, albeit with less, but still significant quantities of soil nutrients.
Spin-off projects
The Sahara Forest Projectis a scheme that aims to provide fresh water, food and renewable energy in hot, arid regions as well as re-vegetating areas of uninhabited desert. This proposal combines the Seawater Greenhouse and concentrating solar power (CSP) working in synergy. CSP is a form of renewable energy
Renewable energy
Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...
that produces electricity from sunlight using thermal energy to drive conventional steam turbines. It is claimed that, together, these technologies will create a sustainable and profitable source of energy, food, vegetation and water.
The team behind the Sahara Forest Project comprises experts from Seawater Greenhouse Ltd, Exploration Architecture, Max Fordham Consulting Engineers and the Bellona Foundation
Bellona Foundation
The Bellona Foundation is a multi-disciplinary international environmental NGO based in Oslo, Norway. Founded in 1986 by Frederic Hauge and Rune Haaland as a direct action protest group, it has since blossomed into a recognized technology and solution-oriented environmental champion with offices on...
.
The scale of the proposed scheme is such that very large quantities of seawater will be evaporated. By using locations below sea level, pumping costs are eliminated.
Among planned activities are one pilot project in Jordan and one in Qatar
YouTube channel
Watch Seawater Greenhouse videos hereAwards
The technology has won a number of awards including:- Clinton Global Initiative 2010 Commitment, the Bellona FoundationBellona FoundationThe Bellona Foundation is a multi-disciplinary international environmental NGO based in Oslo, Norway. Founded in 1986 by Frederic Hauge and Rune Haaland as a direct action protest group, it has since blossomed into a recognized technology and solution-oriented environmental champion with offices on...
commits to implement the first realization of the Sahara Forest Project (2010) - The Buckminster Fuller Challenge Finalist - Sahara Forest, The Buckminster Fuller Challenge, (2009)
- “Power Generation & Water Solutions Innovation Award”, 2009 Power Generation and Water Solutions awards, Dubai (2009)
- St Andrews Prize for the Environment, University of St Andrews and ConocoPhillips, (2007)
- The Tech Award, Technology for the benefit of Mankind, Tech Museum of Innovation, San Jose CA, (2006)
- Global annual Institute of Engineering and Technology (IET) award for Sustainability, Institution of Engineering and Technology, (2006)
- A special environmental award was made for the Seawater Greenhouse, which (distils) seawater for use (in agriculture) in arid climates, Galvanizer association, (2001)
- Design Museum Sense Award for best practice in sustainable industrial design and architecture, Design Museum, (1999)
Articles & Blogs
- "Sea breezer" Seawater Greenhouse featured in "Water Wars: fight the food crisis", Antenna exibition, Science Museum in London (2011)
- “Growing vegetables in the desert is a cinch with the help of a giant solar still that turns water from the sea into fresh water and cool air. Fred Pearce steps inside the seawater greenhouse”, NewScientist, (2002)
- “Engineers race to steal nature's secrets. Giant wind turbines based on a seed, and desalination plant that mimics a beetle”, The Guardian (2006)
- "Seawater Greenhouses Produce Tomatoes in the Desert", Blog by Renee Cho, 2.18.2011 The Earth Institute, Columbia University
See also
- AgroforestryAgroforestryAgroforestry is an integrated approach of using the interactive benefits from combining trees and shrubs with crops and/or livestock.It combines agricultural and forestry technologies to create more diverse, productive, profitable, healthy and sustainable land-use systems.-Definitions:According to...
- Water crisisWater crisisWater crisis is a general term used to describe a situation where the available water within a region is less than the region's demand. The term has been used to describe the availability of potable water in a variety of regions by the United Nations and other world organizations...
- Concentrating solar power
- DesertecDesertecDESERTEC is a concept proposed by the DESERTEC Foundation for making use of solar energy and wind energy. This concept will be implemented in North Africa and the Middle East by the consortium Dii GmbH, formed by a group of European companies and the DESERTEC Foundation...
- Ecological engineering methodsEcological engineering methodsEcological Engineering Methods is when researchers try to tap biologically-based energy sources. Some projects include engineering new organisms that produce hydrogen from water and sunlight in environmentally friendly ways with no waste products, and transforming the way man interacts with the...
- Evaporation pondEvaporation pondEvaporation ponds are artificial ponds with very large surface areas that are designed to efficiently evaporate water by sunlight and exposure to the ambient temperatures.- Uses :...
- EvaporiteEvaporiteEvaporite is a name for a water-soluble mineral sediment that result from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporate deposits, marine which can also be described as ocean deposits, and non-marine which are found in standing bodies of...
- Green Sahara
- Open pan salt makingOpen pan salt makingIn Europe virtually all domestic salt is obtained by solution mining of underground salt formations although some is still obtained by the solar evaporation of sea water. Salt is extracted from the Brine using vacuum pans, where brine is heated in a partial vacuum in order to lower the boiling...
- SalternSalternSaltern is a word with a number of differing meanings. In English archaeology, a saltern is an area used for salt making, especially in the East Anglian fenlands....
- Peak waterPeak waterThe term Peak Water has been put forward as a concept to help understand growing constraints on the availability, quality, and use of freshwater resources...
- Adaptation to global warmingAdaptation to global warmingAdaptation to global warming and climate change is a response to climate change that seeks to reduce the vulnerability of natural and human systems to climate change effects. Even if emissions are stabilized relatively soon, climate change and its effects will last many years, and adaptation will...
- Solar desalinationSolar DesalinationSolar desalination is a technique to desalinate water using solar energy. Solar desalination in the modern era extends back to the early 1950s when simple solar stills were studied for remote desert and coastal communities...
- Solar humidificationSolar HumidificationThe solar humidification-dehumidification method is a thermal water desalination method. It is based on evaporation of sea water or brackish water and consecutive condensation of the generated humid air, mostly at ambient pressure...