Honestly, because I was under the impression that transmission loss was a real thing. If I'm wrong, I'm wrong.
Ah, yeah it's a scale thing. Of course losses in any energy system are a thing, it's just that transport losses in wide-area synchronous electricity systems aren't a particularly big concern when on the continental scale at which American, European or Australian grids operate. As I said, we're talking 10% in Australia and 6% in Europe. As long as there's transmission lines, it doesn't matter a whole lot where any particular power source is located.
Judging just by where electricity grids are interconnected, the limiting distance for transmission losses seems to be "completely unpopulated and unused area several hundred kilometres wide" (ie, a desert or an ocean). However some people seem to be seriously looking at long distance transmission of solar power across the Mediterranean, so who knows?
Well, I sit corrected.
I had my information from someone who worked in the electricity generating industry in the UK.
He was bewailing the use of gas for generating electricity and then transmitting it through the national grid. He claimed this was a bad idea because in his words "electricity is leaky". While losses from gas transmission are minimal. He favoured using gas for domestic heating rather than electricity.
Or he could have been someone who drifted in off the street and just spouted nonsense. This happens to me more than I would have thought possible in a previous existence.
It did make some sense to me, though. Conductors have a resistance, and they will lose energy through heat (if nothing else). Or else why do people search for and value superconductors?
Transmission losses from gas are supposed to be somewhere around 1 or 2 percent which is indeed lower than electricity transmission losses of 6 percent (within the UK, I suspect you're too small to get serious distance-based losses, rather than just the inherent losses from stepping electricity up and down from transmission to distribution to end user).
However he was
probably talking about the fact that you have to burn the gas to
get electricity in the first place and that carries a lot of heat loss. A new combined cycle plant might achieve 60% thermal efficiency, meaning if you put in 100 TJ of gas you get 60 TJ of electricity leaving the plant. Open cycle is a fair bit lower again - maybe around 35%.
He's almost certainly right, too, that gas heating and cooking would also be cheaper for consumers than electricity.
One other concern, though is that with natural gas, losses are leaks of methane. And while burning natural gas is pretty clean, methane leaked without burning is a very potent greenhouse gas. For example, a study in the US suggests that leakage rates are higher than previously expected, to the extent that the actual global warming impact of American gas wipes out the emissions reductions which could be gained from converting vehicles from petrol or diesel to natural gas.
I think the question of whether natural gas use by households for heating and cooking is cleaner than electricity will depend on where a system gets its electricity from. In Australia it will certianly be cleaner because we burn so much coal. UK electricity is half as dirty as Australia's, I haven't done that maths.
