Economic forecasts are for natural gas to rise 20-25% by next winter, in part due to competing demands for its use to generate electricity.
Since the 1990s, natural gas use in Arizona has grown seven-fold. [right: coal-fired plants are black triangles, gas-fired plants are orange. Hydroelectric are blue diamonds. Credit, DOE-EIA]
Power utilities are reluctant to build new coal-fired plants because of uncertainties over controls or costs of greenhouse gases, especially carbon dioxide.
Natural gas plants are cheaper and quicker to build than coal plants. This is a trend across the country.