Exelon Generation said on Monday that it is preparing to refuel its Byron and Dresden nuclear power stations as a result of action taken by the Illinois legislature to enact a comprehensive energy bill.

The Illinois Senate approved an overhaul of the state’s energy policy with a key part of the package keeping the Byron nuclear power station operating just hours before Exelon had planned to begin shutting down two reactors at facility – with plans to close two more units at Dresden later this year.

The new bill promises $694m in support for economically struggling nuclear power sector. Nuclear power plants are generally older and much more expensive to operate, but also offer carbon-free electricity generation.

The bill still needs to be signed by Illinois governor J.B. Pritzker, but he said he would do so “as soon as possible”. Mr Pritzker said in a statement shortly after the bill’s passage the state is “making history by setting aggressive standards for a 100% clean energy future”.