How much combined cycle natgas plant has been built recently, and how much planned? What's the capital outlay picture on this, compared to other sources? Is it as cheap to build as gas-fired peaker plant?

Wikipedia seems to have faith in gas:

Combined cycle - Wikipedia, the free encyclopedia

The turbines used in Combined Cycle Plants are commonly fuelled with natural gas , which is found in abundant reserves on every continent.^{[citation needed]} Natural gas is becoming the fuel of choice for private investors and consumers because it is more versatile than coal or oil and can be used in 90% of energy applications.

Heh.