[uc_banana]

Assuming you live on a motorway and your local streetlight used 500W, and was converted to an LED that draws practically nothing, that frees up....about enough juice to add 20 miles of range over 12 hours. No wonder no-one bothers with this scheme.

[the8472]

That's merely the capacity that was freed up, it doesn't account for additional spare capacity in the wires. And I said "overnight and at the workplace", which should cover more than 12 hours. Maybe it's a bit tight but it should be enough to alleviate charging stops on most days. If you're going to make longer trips then may be a stop by a fast charger may be needed.

[jjk166]

There isn't additional spare capacity in the wires that were designed only to power the light. While they almost certainly are rated for a bit more juice to deal with intermittent power surges and an appropriate factor of safety for design use, you still need that buffer for any application that draws 500W, so you can't persistently run above that level.

And if you're charging when you park at home and at work, unless you find someone who works at your home and sleeps where you work, that's going to be around 2 streetlights per car, and even that's assuming 100% street parking with optimally arranged streetlights. For context, there are currently about 6 cars per streetlight in Europe, and their current total power consumption of 35 TWh/yr would be able to provide 20 miles of range per day to just 16% of that number of cars. Of course streetlights aren't normally running 24/7, but even if you triple the power usage (which the streetposts might not even be able to handle) you're still at less than half of what you'd need at a minimum. There's really no way around building substantially more charging infrastructure.

[uc_banana]

>additional spare capacity in the wires

1. What additional spare capacity? Why would any particular electrical installation (here, streetlights) be designed for about an order of magnitude more carrying capacity?

2. One of the original motivators for near-universal lighting of roads was to use the night-time baseload of power stations that could not be turned off (ie, nuclear and coal). Now that we use much more intermittent sources, this "free" energy just doesn't exist. It may be that switching to energy-efficient street lighting just makes up for this shortfall, leaving no spare power.