On: Dutch brewery burns iron as a clean, recyclable fu...

[knolax]

Well I think in this case the iron is feeding a furnace so it's not going through a heat engine, it's just giving off heat.

[ncmncm → knolax]

Right, conversion of iron to rust yielding heat is 100% efficient, less only the work needed to move the rust out of the way.

If you wanted to convert that heat back to electricity, there would be losses, but nowhere near as much as some people are saying. 1800 degrees minus ambient is a very big delta T. You are not bound to a closed cycle, so Carnot does not apply. So it is likely 80+% would be achievable, maybe over 65% round trip.

[socialdemocrat → knolax]

Yes and anyway you could use combined heath and power systems to get higher efficiency.

[fastball → socialdemocrat]

Not sure I follow.

[hinkley → fastball]

Cogeneration. It's common in cogeneration for heat to be a secondary output that makes the overall system profitable, but isn't the primary output.

[fastball → hinkley]

But in this case heat is the primary output.