How many kW's of gas can a 1" pipe handle? (ish)
It'll be very "ish" as it depends on the length of the run, whether it's steel or copper, how many bends there are etc etc. Also, gas pipe is generally quoted in discharge rates of cubic metres per hour. Having said that, it can be converted.
I've consulted my calculator and worked out that, for pipes between 3 and 30m long, with no bends, the answer is between 50 kW and 193 kW. Ish.
Hope this helps