Sahara Forest

LOCATION: Norway and Jordan

SUMMARY: Since the dawn of civilisation, forests have been shrinking and deserts have been growing, primarily as a consequence of human activity. The trend continues to this day. During the evolution of the earth, the growth of plants was primarily responsible for creating the moderate climate that we enjoy. The converse is also true: the loss of vegetation is exacerbating problems of climate change.

The purpose of our scheme ‘The Sahara Forest Project’ is to reverse the trend of desertification, grow food crops and, through the climatic benefits produced by revegetation and carbon sequestration, to address climate change. The project combines two proven and economically viable technologies, the Seawater Greenhouse and Concentrated Solar Power (CSP), for the first time.

The Seawater Greenhouse is an ingenious technology that creates a cool growing environment for food crops in hot arid regions and is a net producer of distilled water from seawater. Designed by Charlie Paton with three pilot versions built, the scheme essentially mimics the hydrological cycle in miniature. Seawater is evaporated from cardboard grilles at the front to create cool humid conditions within the greenhouse and is then condensed as distilled water at the back.

CSP concentrates the sun's heat to drive steam turbines and produce zero-carbon electricity. A 300km by 300km square of the Sahara desert would be sufficient to generate all the world’s electricity needs. The two technologies are powerfully synergistic: They both work best in sunny regions, the Greenhouse produces surplus de-ionised water that CSP plants need to maintain maximum efficiency while CSP produces large amounts of surplus heat that can be used to increase the amount of seawater evaporated and thereby extend the area of land that can be irrigated.

Other attempts at revegetating deserts have generally been based on unsustainable sources of water (either finite ground water or energy intensive desalination) whereas our proposal will be a net producer of clean water in some of the most water-stressed parts of the planet. The scheme has the potential to reverse desertification, produce large amounts of renewable energy, zero carbon food and water and create conditions for self-sufficient communities.

PROBLEM SPACE: The process of desertification is a classic example of a failing system that leads to a whole range of other impacts including water shortages, resource conflicts and exacerbated climate change.
The Sahara Forest Project would have the restorative effect of returning areas of desert to forested land and sequestering substantial quantities of atmospheric carbon in new plant growth and reactivated soils. The scheme is based on two proven technologies that together can create large amounts of renewable energy, zero carbon food and fresh water in some of the most resource-constrained parts of the planet. The idea is replicable in many desert regions and, if created on a scale comparable to some of the large existing greenhouse developments, would produce significant local and global climatic benefits. We believe the scheme represents a major step in the transition from a carbon economy to a closed loop solar economy.

SOLUTION: The Seawater Greenhouse process has been tested and proven with three trials in Tenerife, Abu Dhabi and Oman. We have a wealth of measured data that allow us to accurately predict how the technology will perform under any realistic climatic conditions.
CSP is a mature technology and there are a number of projects currently in operation, with many more being planned. Similarly to the Seawater Greenhouse, the technology is well-understood in terms of its climatic requirements, productivity, scaling and commercial viability.
The innovative nature of our proposal is in the way that we combine these technologies to produce highly beneficial synergies. This proposal has been proven at a concept level and now needs to be explored in further detail to demonstrate the environmental, social and economic benefits. This will involve the following studies:
• Developing a thermodynamic model to help optimize the process in different climates
• Running climatic models in order to assess the impact of large-scale revegetation and seawater evaporation in hot arid regions
• Researching and developing economic models that inform optimum scaling and procurement methods.
• Advancing proposals from the three Seawater Greenhouse trial schemes that show how local expertise can be developed such that the scheme can be run in a way that yields the greatest benefits to the local population.
• Detailed assessment of the commercial opportunities for extracting useful elements and compounds from seawater such as calcium carbonate, magnesium chloride, sodium chloride and minerals for use in enriching the desert soils.
The results from these studies will guide detailed designs for specific applications. We would use the prize money to carry out this development work. Proving the environmental, social and economic benefits in greater detail would increase the likelihood of this solution being replicated around the world.

CONTACT: [email protected]