It is on the basis of this fundamental principle that the idea to produce renewable energy was born, thanks to a modern version of the solar fireplace. In the past, especially in warm regions, solar fireplaces were used to cool down houses by exploiting thermal convection. Air heated by the sun inside the fireplace rose to the exterior and sucked in the colder air in the interior, thereby creating circulation in a room that was otherwise hot and closed. 
The entrepreneur Roger Davey came up with the idea of using this principle to produce enough energy to run a medium-sized town. Davey is thinking of building in the Arizona desert – where the air is very hot – an 800-metre-tall solar tower with 32 turbines at its base, moved thanks to the flow of hot air. It has been calculated that this plant would generate almost 200 MegaWatt, sufficient for 100,000 homes.
Technology allows the construction of an enormous plant. What are the positive aspects? A large amount of energy generated with no pollution at all and without using large quantities of water, as solar panels do since they must be washed after a period of time. Moreover, this plant works constantly unlike solar plants that stop at night and on cloudy days and wind farms that stop on days with no wind.
The greatest obstacle is certainly the material to be used for such a tall tower. Davey and his team have planned to use cement to build a heavy and stable tower, fibres would make it too light and "mobile". It is expected to take two and a half years to make up for the CO2 emissions linked to construction.