"Can easily replace" - you can easily become the president of the US, it is political problem, etc... It is better to rephrase it difeerently: "At the moment we

"Can easily replace" - you can easily become the president of the US, it is political problem, etc... It is better to rephrase it difeerently: "At the moment we cannot replace fossil fuels with nuclear energy, and we do not know if we ever will be able. Due to different economical and political problems." This would be more honest and would not conceal a valid pint of the author.