A core-shell nanotube array for artificial photosynthesis
(PHYSorg.com Nanotechnology)

The average global energy consumption of transportation fuels is currently several terawatts (1 terawatt = 1012 Joule) per second. A major scientific gap for developing a solar fuels technology that could replace fossil resources with renewable ones is scalability at the unprecedented terawatts level. In fact, the only existing technology for making chemical compounds on the terawatt scale is natural photosynthesis.