As the pursuit of 100% renewable energy becomes more popular in the United States, some scientists fear that it could be more expensive and less efficient than previously thought, according to Inside Climate News. A new study, conducted by 21 prestigious energy researchers, suggests that renewable energy, like wind, solar, and hydro, will be most efficient and cheapest if combined with nuclear power and carbon capture technology.

The scientists believe that directly replacing fossil-fuel power plants with renewable energy will take too long and cost an exorbitant amount to implement. The study argues that carbon capture technology will allow some fossil-fuel plants to continue to operate while wind, solar, and hydro are economically expanded, and nuclear will produce the energy that is lost from coal and natural gas. The study has had mixed reviews, scientists taking both sides of the debate.