DESERTEC - A solution for the global climate and energy challenge

DESERTEC - A solution for the global climate and energy challenge

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  • Craig Embleton
    Craig Embleton
    The company name is only visible to registered members.
    Extending Desertec concept to CO2 sequestration.
    Hello All

    I have completed a thesis that uses data produced by the DLR to look at CO2 sequestration: “What is the potential for reducing atmospheric CO2 levels through solar-desalinated irrigated vegetation of the Sahara and Arabian deserts?”

    The full thesis can be downloaded here: http://www.greenfrontier.org/thesis-completed-what-is-the-po...

    I believe it shows that the Desertec concept - expanded - can do so much more than mitigate CO2 emissions by electricity production.

    In my thesis I investigated the potential of using solar-desalinated water to irrigate the MENA region in order to grow vegetation in the Sahara and Arabian deserts, with the proposal being that this vegetation would lower atmospheric CO2 by creating a net carbon sink. Having investigated a range of species I chose Eucalyptus grandis x urophylla to model this proposal, due to its relatively well-researched growth rate and water requirement and high transpiration ratio.

    I calculated how much carbon could be sequestered in the vegetation and soil of a Eucalyptus grandis x urophylla forest, on an estimated area of 8.4 million km2 across the MENA deserts. I calculated the water required to irrigate the trees and the electricity needed to provide the water through desalination of seawater, mostly through reverse osmosis, and to supply the water to the trees by pumping it across the desert in pipes.

    I then reviewed how much electricity could be generated using concentrating solar power in the MENA region from studies undertaken by the DLR and related this to the electricity requirements of region in 2050 and the electricity requirements to desalinate the seawater to irrigate the trees. I found that there would be a great deal of surplus energy generated, beyond that required for the desalination and irrigation processes. I then calculated the area of land required for the parallel troughs or linear Fresnels used to provide the electricity from the land use efficiency of the CSP units and the direct normal irradiation falling on an area of land. I also looked at the costs, benefits and possible sources of income from the project, including the provision of food beneath the linear fresnels.

    Results from my thesis suggest that a forest of Eucalyptus grandis x urophylla occupying 8.4million km2 of MENA deserts could be capable of sequestering 8 – 14.3GtCyr-1 in the vegetation and upper-soil profile. Non-land-use-change anthropogenic carbon emissions are currently 8.7Gtyr-1. The forest would require 7,560 – 8,400km3 water yr-1 for irrigation, which would require 56,144 – 62,553TWh electricity yr-1 to desalinate. Electricity could be supplied by CSP units covering 324,532 – 579,194km2. Major project costs included CSP units, RO plants and pipework. Benefits included ecosystem services, timber and carbon credits.

    I have researched a great deal of additional material that did not make it into the final version of my thesis, including a large chapter on the role that people could play in the project. This chapter reviewed the number of people currently living in poverty in the world and the increase in world population predicted over the next 40 years. I then investigated the potential of the transformed MENA deserts to host thriving human settlements by reducing the area of land dedicated to Eucalyptus grandis x urophylla production, in order to host these human settlements including food production. I looked at the use of permaculture to serve the needs of these people (settlers) including the use of biointensive gardening and forest gardening and how much carbon this form of gardening could sequester. Preliminary calculations indicate that using intensive permaculture techniques the MENA desert could be partitioned into 400 million permaculture smallholdings, each with an attached forestry micro-plantation, capable of supporting up to 4 billion people.

    I then developed a model whereby these settlers could take responsibility for individual micro-areas of Eucalyptus grandis x urophylla forest (1 hectare per settlement) and in exchange receive payment and title deeds to their land. A mixed forest would be preferable to a monoculture of Eucalyptus grandis x urophylla. Growth rates, water requirements and transpiration ratios of a range of species would need to be practically assessed.

    I removed these sections on advice of my thesis supervisor as they contained too much speculation for an academic thesis. However in the bigger picture they are highly relevant to the purpose of poverty elevation and providing the land necessary to absorb the world population increase before the predicted stabilisation is reached around 2050. I am in the process of reintegrating these sections as a post-thesis addendum.

    I am now investigating ways to progress the work I have done in my thesis to practical study. My first degree is in Applied Biology and I have several years of biological field trials experience. Last year I gained a Permaculture Design Certificate that I took in the village of Al-Jawaseri in the Dead Sea valley Jordan near a project known as ‘the greening the desert’ site. I believe that permaculture environmental restoration through planned biological succession and human settlements will play a large role in future work and I have established an organisation -http://www.greenfrontier.org/ - to implement these and other ideas further.

    If anyone has any advice or contacts that I could approach to progress this into practical studies I would greatly appreciate it.

    Best wishes

    Craig Embleton

    Skype: craigembleton
    • 16 Feb 2011, 4:29 pm