Right now, quite expensive, as the fuel is custom-fabricated in small batches. But one of the major advantages of the type of fuel Miley and his collaborators are that only a tiny fraction of the fuel is "nuclearly active" (Palladium or nickel), with the rest of the lattice comprised a zirconium oxide ceramic "skeleton". In the case of Palladium, it is NOT consumed, but only provides a mechanism (whatever that might be) for the deuterium atoms to react. In the case of Nickel, the nickel "is" consumed, but only in minute amounts.
The other advantage of Miley/Arata's fuel is that it "should" allow much higher operating temperatures than a metallic nickel nanopowder substrate as used by Rossi, Defkalion, and Piantelli.
I doubt that it will cost any more than fuel elements for, say, a fission reactor.
Interesting. I recently watched a video of researchers from the University of Nottingham, who have developed a method of producing metal nanoparticles using supercritical water in a setup that can produce them continuously, rather than in batches. If they can adapt that kind of technology to these specific type of particles, the process could be streamlined.
http://www.youtube.com/watch?v=6zurHSq4CB4&feature=results_video&playnext=1&list=PL32CC4F98E910EE75
“I doubt that it will cost any more than fuel elements for, say, a fission reactor.”
Maybe, but the fission fuel produces a lot of power even though the fuel is expensive. The fuel for this type of reaction could be much cheaper, but if the power produced is much less, it could still end up being less efficient.