Michaux's paper starts with the assumption that it would take about 4 weeks worth of batteries to survive the Finnish winter, and therefore every grid in the world will need 4 weeks worth of batteries.

Despite a writing a hundred page paper covering basic details of existing power generation technologies, he devotes only about a paragraph to establishing that assumption.

Additionally, there is a section dedicated to ocean shipping. Routes are currently chosen to minimize costs, traveling long distances on bunker fuel. Running those same routes on batteries would be prohibitively expensive. Instead of concluding that in the future we will do ocean shipping differently because the cost minimization will work out differently, Michaux simply adds that to the tab of batteries that we would need to decarbonize.