Re: unlike your typical UK green energy project
Actually, 400kV transmission lines are much more efficient than you seem to imply. Because it is such high voltage, very little current is needed for a LOT of power, and the resistive losses which go as I^2 R are very low.
The high-voltage part of the transmission system is on average about 99% efficient i.e. 1% is lost in transit between the power station (say, Drax up north) and the load (say, Birmingham). To send the power all the way from Drax down to London would cost you no more than another 0.5%. But the lower the voltage, the more that tends to be lost in transmission, even over a short distance.
What worries me the most about the Green Energy transition though, is low-voltage local distribution. I.e. what happens when each house on a street needs 40 Amps for their EV charger, 40 Amps for their Heat Pump, and 40 Amps for an electric shower? The answer is that the underground electric cable, often rated at 400A, overheats. And even when they are not on fire or exploding, these low voltage underground cables are often very warm, which is a lot of lost energy, often 5-10%. If the gas grid lost as much energy in transit, you'd smell it everywhere and there would be major fires and explosions.
But these losses are off-meter (though they are part of the reason that electricity costs 4-5 times more than gas per kWh) so you can spend a fortune on your heat pump and electric SUV and kid yourself that you are saving the planet.
Drifting somewhat offtopic, but What really grinds my gears is when people like BBC radio presenters start to imply that there is some sort of problem with nationwide electricity transmission, when actually it's the one part of the system that works really well. This morning they were spouting some bollocks about Nuclear Small Modular Reactors (SMRs), saying that the idea behind them is that they can be placed near to towns and cities for efficiency, but wouldn't this be terrible for safety! This is absolute hogswash. FUD at best, and deliberate anti-nuclear propaganda at worst. SMRs would of course be located in the usual nuclear sites for safety, defensibility etc., but instead of having 2x 500MW reactors, you would have 20x 50MW reactors. This makes them much cheaper and faster to build and maintain. That is all.