Advances in photovoltaic technology have led to the development of thin, flexible solar cells. It's possible to build a tent out of them, and the US Army is considering acquiring and using such portable structures:

The TEMPER Fly is a roughly 16-by-20-foot tent structure able to generate 800 watts of electricity. A QUADrant is a smaller variant of the TEMPER Fly, able to generate 200 watts of power, and the Power Shades range in size and are capable of generating up to 3 kilowatts of exportable electrical power, Tucker said. The PV integrated military shelter items use a lamination process to combine the PV materials into the textile substrate, Tucker explained. The US Army News Service spoke with Steven Tucker, an engineer working on the project:

“Alternative energy sources are really going to shine in mission scenarios where you don’t want to use a generator because you don’t want the noise or heat signature that goes along with it, or where re-supplying that generator with fuel doesn’t make sense,” said Tucker.

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