There are several studies that indicate it would cost the United States trillions of dollars to transition to an electric system that is 100-percent renewable. Costs range from $4.5 trillion by 2030 or even 2040 to $5.7 trillion in 2030--about a quarter of the U.S. debt. The lower estimate results in a cost per household of almost $2,000 per year through 2040. The $4.5 trillion cost does not include the stranded cost of the oil, natural gas, and coal technologies that would be disrupted. Costs can be greatly reduced by allowing nuclear as part of the non-carbon emitting mix and allowing natural gas to generate 20 percent of the electricity. Allowing existing nuclear plants to operate would save about $500 billion. Also, moving the goal to 2045 or 2050 would help to reduce costs by allowing advanced technologies to be developed and commercialized.
A spokesperson for Wood Mackenzie, who was in charge of one of the studies indicates, "In areas of the country that have a decent mix of wind and solar potential, those places can probably get to 50% renewables without struggling. Above 50%, the challenge of ensuring reliable grid operations starts to take off." No large and complex power system in the world operates with an average annual wind and solar generation level greater than 30 percent. Another issue is that installers of wind turbines will be faced with NIMBY (not-in-my-back-yard) challenges.
