[gruez]

>the backup power is generated from methane (aka 'natural gas') which has very high power density and very low capital cost compared to the steam turbine either in a coal or nuclear plant.

Doesn't natural gas power plants also use turbines to generate electricity? How can it be cheaper than the steam turbine portion of a coal/nuclear power plant?

[tuatoru]

Combined cycle gas turbine generators use a steam turbine as a second, downstream method to recover exergy from the exhaust of the main gas turbine.

CCGTs are expensive. Simple gas turbines that are used to meet daily demand peaks are relatively cheap; as GP said they're basically stationary jet engines.

To me it's kind of bizarre that money is so cheap at present, but somehow it's still too costly to use it to invest in things with a delayed payback.