Is it possible to harness gamma rays for energy?

Every nuclear power plant uses heat from gamma rays in addition to kinetic energy of nuclear fission products and neutrons. When a uranium nucleus fissions into two daughter nuclei fragments, about 0.1 percent of the mass of the uranium nucleus appears as the fission energy of ~200 MeV. read more

A single gamma ray is hard to convert, it's not a lot of energy. But you can I suppose shine it on a series of atoms which will reemit lower wavelengths, and use a photosynthesis cycle once it's low energy, that's pretty efficient. read more

So, yes, it should be technologically possible (one day) to effectively harness the energy. Also, we may devise some meta-materials which might be able to red-shift gamma rays into the ultraviolet or infrared ranges where we can use existing solar cell technologies. read more