THE GND IS TOO CAUTIOUS:

Transitioning to a clean-energy grid should happen by 2035, the study advises, with at least 80% of that adjustment completed by 2030. For the purposes of Jacobson's study, his team factored in presumed population growth and efficiency improvements in energy to envision what that would look like in 2050.

Jacobson first published a roadmap of renewable energy for all 50 states in 2015.

This recent update of that 2015 work has a couple of notable improvements.

First, Jacobson and his colleagues had access to more granular data for how much heat will be needed in buildings in every state for the coming two years in 30-second increments. "Before we didn't have that type of data available," Jacobson told CNBC.

Also, the updated data makes use of battery storage while the first set of calculations he did relied on adding turbines to hydropower plants to meet peak demand, an assumption that turned out to be impractical and without political support for that technology, Jacobson said.

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