Deming believes that alternative energy technologies are not sufficiently evolved to add significantly to the world energy budget in the immediate future, arguing that "wind and solar power are . . . intermittent, expensive, unreliable, and incompatible with the existing power grid infrastructure . . . cannot be used directly for transportation. In contrast, fossil fuels are abundant, reliable, and inexpensive energy sources." He believes "the largest mistake would be to start to move away from petroleum, a proven and economic energy source, to more speculative and expensive sources," pointing out that "natural gas is . . . abundant, relatively inexpensive and environmentally benign," and that "nuclear power has the potential to provide large amounts of power for very long periods of time if low-grade uranium is used in breeder reactors."