Post by neil on Nov 6, 2020 9:00:04 GMT
I came across this story of a Dutch brewery using iron as a carbon-neutral fuel for its energy production. They burn iron powder into iron oxide (rust) in their furnace. The iron burns at about 1800⁰C, hotter than coal or natural gas, so it's easy to extract the energy. It produces no waste gas, only absorbing oxygen to make the rust. Once the iron's burnt, the rust is collected and taken to a renewable electricity source (e.g. wind or solar farm). The electricity is used to electrolyse the rust back into metallic iron, liberating the oxygen.
All in all, you have a clean, closed fuel cycle. The iron is reused many times (I'm not sure how much is lost in each cycle), no carbon is released, and the energy is from a renewable source. It's a way of storing renewable energy that doesn't need expensive rare earths in batteries, or cryogenic storage for hydrogen (or heavy metal hydrides for Blue Planet). The efficiency isn't great, but its better than letting the energy go to waste.
All in all, you have a clean, closed fuel cycle. The iron is reused many times (I'm not sure how much is lost in each cycle), no carbon is released, and the energy is from a renewable source. It's a way of storing renewable energy that doesn't need expensive rare earths in batteries, or cryogenic storage for hydrogen (or heavy metal hydrides for Blue Planet). The efficiency isn't great, but its better than letting the energy go to waste.
