The Sahara Forest project will use seawater and solar power to grow food in greenhouses across the desert. Photograph: Exploration Architecture
The Sahara Forest project represents integrative design at a huge scale. (Integrative design combines multiple design improvements to get an overall improvement that's bigger than the sum of its components.) As it says on the the Sahara Forest project home page:
The project combines two proven technologies in a new way to create multiple benefits: producing large amounts of renewable energy, food and water as well as reversing desertification.
The two technologies are the Seawater Greenhouse, invented by Charlie Paton, and a concentrating solar energy generation capability. The synergies arise in several ways - the energy generation provides the power to run fans to work the greenhouse, while the greenhouse creates excess fresh water for cleaning the mirrors of the generator, for example. The team that's come together to create the project also represents some interesting synergies:
The Sahara Forest post at Treehugger features a long interesting response in the comments by Pawlyn in response to questions raised by other commenters.
This is one of several projects I've read about recently that combine energy generation via visible light with use of the excess heat to achieve much higher solar energy conversion efficiencies. For example, this report in Science Daily last year about a prototype PV/Thermal system that was projected to capture 80% of the energy. While it complicates the mechanicals of the system, it certainly seems to make sense to take advantage of the heat created as a side effect of PV energy collection, especially since the PV cells work better - are more efficient - at lower temperatures. The heat needs to be removed anyway!
So far neither the project's website or news reports about the project have many details about its progress or funding, but it's definitely something to keep an eye on.