Carbon-dioxide emissions account for nearly 84% of greenhouse-gas emissions, while methane the main ingredient in natural gas makes up 8.8%, according to a recent Environmental Protection Agency report.
There are two main incentives for this, the first being the geological feature that naturalgas is in finite supply and world production of it is thought might peak within the next few decades, and secondly that burning fossil carbon contributes to the atmospheric concentration of CO2, which scientific consensus accords will cause global warming and climate change.
Calpine, which operates 46 power plants and two naturalgas companies in the U.S., is expected to be one of the main builders of big "baseload" power plants in California, which is suffering an energy crisis.