Sometimes the best questions come while waiting for a train.
In this case Royal Victoria station on the DLR.
I looked down the platform and I thought...
Where else in London are there pylons?
They're not common in the capital, even round the edges. Most suburban skylines are entirely pylon-free in all directions. And yet in a few places pylons are an intrinsic part of the landscape, like here along the edge of the Royal Docks. These pylons were added when this was a commercial zone and the Thames was a great place to hide unwanted infrastructure, but now they stride through housing estates. So where exactly are the rest?
So I Googled.
From the Mayor's website I learned "London’s electricity comes from the electricity grid. Power in this grid is generated in large power stations outside of London." Hence the need for pylons.
From the Metadyne website I learned "In order to get the electricity to customers the national grid (now run by National Grid plc) transmits electricity across the country in bulk at extra high voltage, the more so to the London area where there is little generation any longer. The network distribution operator (UK Power Networks in London's case) collects electricity at transfer substations and conveys it to distribution substations around the city, then local substations and finally at the standard 240 volts to the street mains and end users."
From Wikipedia I learned that London has 400kV substations at Barking, Beddington, City Road, Crayford, Hackney, Highbury, Hurst, Kensal Green, New Cross, Pudding Mill Lane, Rowdown, St John's Wood, Seven Sisters Road, West Ham, Willesden and Wimbledon (and nearly in London at Elstree, Iver and Waltham Cross). There are also 275kV substations at Brimsdown, Chessington, Ealing, Mill Hill, New Hyde, Redbridge, Tottenham and Warley. However not all of these use pylons, some feed underground cables.
Blue and red are for overhead lines, i.e. pylons. Blue is 400kV and red is 275kV. You can see a ring of red and blue around the edge of London, like the M25 of electricity distribution. Meanwhile green is for underground cables. Almost all of the connections in inner London are green. So now we know where the pylons are, but only roughly.
And then I discovered Open Infrastructure Map. It's a version of Open Street Map but it shows where all the electrical power lines are wherever you live, be that Cheshire, Denmark, India or New Zealand. Solid lines are overhead, dashed lines are underground. This brilliant map allows me to check for overhead transmission lines in full zoomable detail, and indeed allows you too, so I could stop there, problem solved.
But the map doesn't have the Greater London boundary on it, so checking precisely what's in and what's out was tricky. So I turned to an Ordnance Survey map instead and scoured that for pylon symbols to see precisely where they go. And then I made this deliberately poor sketch map to summarise where London's pylons are.
The pylons in my original photo are part of a chain along the Thames from Tilbury to Canning Town via Barking, which then heads up the River Lea to West Ham (by Star Lane station). These pylons used to go further but remediation for the Olympics buried the section from West Ham to Hackney Marshes underground. That improved the Games no end. The rest of the LeaValley pylons, through Tottenham, Enfield and Waltham Cross, remain above ground. A separate chain of pylons runs up the River Roding from Barking to Redbridge.
Most of the pylons looping around London lie just beyond the Greater London boundary. You can see how the ring grazes the boundary to the northwest, especially round Uxbridge and Harefield, with deliberate incursions to Harrow and Mill Hill. Out east a lot of pylons feed into Warley substation, one of the few points of interest in the small London bulge beyond the M25. But in south London the orbiting pylons nudge much closer in a long line from Chessington to Chelsfield (with a spur to Wimbledon and a brief underground gap from Beddington to New Addington). Bexley gets a bonus stripe from Falconwood to Crayford.
So that's where London's pylons are.
And, more importantly, where they aren't.
Sunday update:Russ from Open Infrastructure Map has knocked up some code which generates a precise map of Greater London's pylons. Thanks Russ!
