Carl Sagan pointed out that the energy gaps between Kardashev's three types were so enormous that a finer gradation was needed to make the scheme more useful. A Type 1.1 civilization, for example, would be able to expend a maximum of 1017 watts on communications, a Type 2.3 could utilize 1029 watts, and so on. He estimated that, on this more discriminating scale, the human race would presently qualify as roughly a Type 0.7.