I read the report. Outside heat comes to play twice. First, the reactor holding the iron oxide (rust) is kept at 400 C. Later, steam must be made to oxide the iron and liberate the hydrogen. The reports claims about 11 percent thermal efficiency, which they wave off with plans of better insulation.
Not impressed if the goal is to store, not make, hydrogen.
It would be a question as to how efficient they can make it when optimized. It has the advantage of the main stock of iron never disappearing once you have it.