This would be nice and dandy if the marginal cost of fossil fuels was higher than that of renewables . However , this may never be the case and it shouldn ' t be the goal to achieve 100 % renewable energy . Certainly we ought to make efforts to fully incorporate the externalities associated with the carbon emissions from fossil fuels , but it is still possible for them to be a more efficient option than renewables . Committing themselves to renewables over fossil fuels is just wasting money that they desperately need to use elsewhere and dooming them to stay among the world ' s poorest countries . Can we please end the idea that fossil fuels are inherently worse than renewables . All energy sources have costs , including costs to the environment and human health and it would be stupid to totally write off a valuable source of energy even if it could cause global disaster if it is used on a massive scale .