Monday, April 30, 2012

Vortex towers could vegetate deserts

Plans to bring water and vegetation to deserts through vortex towers and biochar

Vortex towers are typically seen as ways to produce electricity. They could also help to vegetate deserts, in a number of ways. 

The vortex towers that I envisage would be a cross between the and the Solar Tower by Making a spiral groove inside the surface of the tower could enhance the vortex updraft effect. This has all been discussed for years, e.g. in the Economist Sept. 29, 2005. 

Vortex towers can produce huge amounts of electricity, that can be used for purposes such as:

  • Desalination of sea water and transport of the resulting fresh water into the desert

  • Capturing CO2 from ambient atmosphere and capturing CO2 produced in the process of making biochar. The CO2 could be used for cloud seeding, carbon building material and char (see below). 

  • Surplus water could also be sprayed into the sky, using the vortex tower's updraft, to further induce cloud formation to create both albedo change and rain.

  • Split the water into hydrogen and oxygen, by means of electrolysis. The hydrogen could then be used as fuel, or to produce ammonia by drawing nitrogen from the air. The ammonia could then be used to produce fertilizer.

  • Carbon that is captured from the atmosphere could be turned into char, similar to biochar, with its benefits as a soil improver and as a safe way to store carbon. This char could be applied to the soil simultaneously with olivine dust and fertilizer as produced in the way described above. Application of such fertilizer together with char could not only reduce the need for fossil fuel-based fertilizers, it can also reduce runoffs that cause N2O emissions and dead zones in the sea, since the char will improve retention of fertilizer in the soil. The carbon could even be combined with ammonia to produce urea, and all this fertilization would benefit vegetation growth. 

Apart from producing electricity, a vortex tower could also push dry, hot air high up into the sky. Some of that heat would escape into space, while the updraft could also establish an air circulation pattern in which hot air would move, high up in the sky, towards the ocean. Simultaneously, as part of this air circulation pattern, air from above the ocean would be drawn - closer to the ground - towards the vortex tower. This air circulation could bring cold and moist wind into the desert, which would benefit vegetation growth.

The benefits of vegetating desert are many; it would take CO2 out of the atmosphere, it could produce food and vast areas could be made suitable for many plants, animals and people. By selling land for settlement, projects to vegetate the deserts could pay for themselves, as part of the Biochar Economy

Projects that involve afforestation, water desalination, biochar production, olivine grinding and building of vortex towers don't require access to high-tech equipment or scarce resources. This means they can be started at many places around the world, with many global benefits.

Forests have many benefits. Trees take carbon out of the atmosphere to grow. Trees can provide food and building material. Forest waste can be turned into biochar. Forests can have a cooling effect by shading the soil, thus preserving moisture. Furthermore, forests release volatile organic compounds that can have beneficial effects, as follows:
When you're walking through a forest you can smell a kind of piny odour and that's because of these other compounds, volatile organic compounds. And they're things like isoprene, monoterpenes.

When they're released into the atmosphere they undergo reactions with a class of compounds called oxidants and that's things like ozone. Following those reactions they're able to form tiny particles in the atmosphere.

While they're present in the atmosphere they can kind of interact with incoming solar radiation - the energy from the sun essentially and kind of perturb its path so that it doesn't make it to the earth's surface and scatters it.

Additional to this is the role that these particles play in brightening the clouds that are above the forests. And they do this because when they're in the atmosphere they grow and they get to a certain size where they're able to form cloud droplets. And the more of these droplets that there are in a cloud the whiter and brighter that it becomes. And that means that it will reflect away more of the incoming solar radiation that's falling on that particular part of the earth's surface.
[italics part edited from National Environment Research Council, May 18, 2011, podcast and transcript

Read more at:
Afforestation - bringing life into the deserts

Earlier posted at knol (meanwhile discontinued by Google) by Sam Carana, October 12, 2011.