Embedded in all positive claims for gas is an essential assumption: that it replaces other more polluting fuels. But what if it also turns out to replace the panoply of alternative energies, including solar, wind, hydro, and nuclear? In Canada, where shale-gas development is well advanced, only a small fraction of electricity is generated from coal; most comes from hydropower or nuclear power. In the U.S., competition from cheap gas was recently cited by the owners of the Vermont Yankee Nuclear power plant as a factor in their decision to close down. And while the evidence may be somewhat anecdotal, various reports suggest that cheap gas has delayed or halted some renewable power projects. It stands to reason that if people believe natural gas is a “green” alternative, they will chose it over more expensive renewables.