Solar Downdraft Tunnel

Solar downdraft tower generate electricity on the fascinating principle of cooling air at 1.3 Kilometers high creating a strong downdraft to drive turbines

 Klaus Lackner at Columbia proposed such a system for ambient carbon capture.  The proposed tower use salt water to cool warm, dry air, causing it to fall. This convection current driving turbines, capturing  45% of the thermal potential energy and more than recovers the pumping energy. Israeli researchers estimate that a large plant around 1.3 Km high could generate enough electricity at prices equivalent to hydropower.  A 3000 foot project is planned for Arizona.     See article on Treehugger 

Here is a Youtube video describing the concept

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 This is different than the solar updraft towers which heat air causing it to rise examined by Australia-based 
Enviromission.


Cost for various plant configurations grabbed from Youtube frame shot (Old numbers that appear not to be inflation-adjusted)

Southwest airlines wins Environmental award

Southwest Airlines wins environmental award as they realize that saving fuel can be quite lucrative, similar to what Amory Lovins has been saying.  Unfortunately, cheaper flights mean more demand for air travel and we could face a Jeavon's Paradox.  Herman Daly notes that the market cannot define the appropriate scale of an economic system or industry in relation to the ecosystem, it can only allocate factors of production.

One barrier to the renewable energy is cost. I came across an interesting article on the ost of renewable energy on Clean Technica. It argues that renewable electricity, while currently costing more now, will be cheaper than fossil fuel facilities.

 With the rate of introduction of renewables continuous till 2030, and the goals being met, the average price of electricity generated from a mix of renewable energy sources will be at an average of 7.6 cents per kWh by 2030. The trend at that time will continue to be downward. At the same time, the price of “conventional” fossil-fuel-powered electricity generation will already be at approximately 9.0 cents per kWh. That means that renewable electricity supply will be cheaper by 2030 or earlier

Source: Clean Technica (http://s.tt/1961e)

In Germany, and also in British Columbia, most generation facilities are also old.  Electricity in the future, regardless of the source will cost more than today, renewable or conventional.  This means a narrower cost difference or even cost equivalence for renewable energy.  Similar conclusions have been found by Jacobson as well as researchers examining the Danish City of Aalborg.

Renewable Electricity Supply to be Cheaper by 2030 (via Clean Technica)

  Macro-Economic Benefits An increasing number of countries have formulated policies to introduce renewable energy sources into their electricity supply in order to combat global warming or to decrease their dependency on imported fossil fuels. A positive side effect of this development has been the…