The BBC has an article on a green building being built in China, The Pearl River Tower - The Green Tower Of Guangzhou City.
Rising high through the polluted air of Guangzhou City in southern China is a 71-storey tower block which, according to its designers, will be the most energy-efficient in the world.
Among a host of features designed either to make or save energy, the one that caught my eye was the shape of the Pearl River Tower itself.
It is built in a curve, facing the prevailing winds. And it has been deliberately sculpted to increase the speed of that wind and force it through slots in the building where wind turbines will be located.
Now, on many buildings, wind turbines are a waste of space because there's so much turbulence in cities. I heard an apocryphal story about a Japanese firm that installed a turbine which needed electric power to keep it turning to save the face of its would-be-green owners.
But the American architects of this tower - SOM - insist that their experiments in a wind tunnel show this building will generate economically viable wind power.
The vertical axis turbines will be located in the mechanical floors mandated by the Chinese government as emergency muster floors, so no usable office space will be lost.
SOM claims that by thinking carefully about the use of space combined with energy-saving and energy-generating technology, they have been able to make unprecedented gains, so this building will potentially create as much energy as it uses.