  As a result of the 2021 United Nations Climate Change Conference (COP26),
several countries committed to phasing down coal electricity as soon as
possible, deactivating hundreds of power plants in the near future. CO$_2$-free
electricity can be generated in these plants by retrofitting them for iron
combustion. Iron oxides produced during the process can be collected and
reduced back to metallic iron using H$_2$, in a circular process where it
becomes an energy carrier. Using clean energy in the recycling process enables
storage and distribution of excess generated in periods of abundance. This
concept uses and scales up existing dry metal cycle technologies, which are the
focus of extensive research worldwide. Retrofitting is evaluated here to
determine feasibility of adding these material requirements to markets, in the
context of current plans for decarbonization of steel industry, and policies on
hydrogen and renewable electricity. Results indicate that not only for a single
power plant, but also on larger scales, the retrofitting plan is viable,
promoting and supporting advancements in sustainable electricity, steel
industry and hydrogen production, converging necessary technological and
construction efforts. The maturation and first commercial-scale application of
iron combustion technology by 2030, together with developing necessary
reduction infrastructure over the next decades, would pave the way for
large-scale retrofitting and support the phasing out of coal in many regions.
The proposed plan represents a feasible solution that takes advantage of
existing assets, creates a long-lasting legacy for the industry and establishes
circular energy economies that increase local energy security.
