Comment by Xylakant
3 hours ago
Did I miss something or does the article not even say how much gas they need as an input to generate the 42MW? I see they deride conventional turbines for needing cooling, but the reason they do is to increase the temp differential between hot and cold end of the turbine because some clever fellow named Carnot figured out that the amount of energy you can extract depends on this. Instead it seems that they just full-tilt run a supersonic turbine and blow the hot exhaust with all its energy into the air. So what’s the efficiency of this?
Indeed. My understanding of modern powerstation gas turbines is that they all basically run _at_ the Carnot efficiency eta = (1-T_cold / T_hot) and that rather than chasing marginal gains in how close to that theoretical limit you actually are the biggest differentiators are on maintenance intervals and reliability, which collectively have quite a large effect on eta...
> how much gas they need as an input to generate the 42MW
If you don't have a pipeline, the lower bound is something like 10 LNG tanker trucks per day for each turbine at 42MW. Natural gas is incredibly efficient to transport in liquid form so you could theoretically get away with this for a little while.
The question I’m asking is slightly tangent to how to feed the required gas. It’s “How many MW of gas do I need to feed in to get one MW of electricity.” And they’re pointedly avoiding any statement about this.