Highway Will Recharge Your Batteries as You Drive | Hacker News Reader

Highway Will Recharge Your Batteries as You Drive

spectrum.ieee.org

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The article suggests that mitigating range anxiety is the primary benefit. But such systems could allow EVs to have much smaller batteries which would lower their cost and increase their efficiency (due to lower weight).

It's wireless charging just like in the old snes game fzero!

I'm very much looking forward to the future of transportation. Here in NYC traffic can be awful. And of course the smell of the gas, vehicle fatalities, lack of parking, and the emissions which cause increased rates of cancer near toll free bridges and heavily trafficked roads are ever present.

Autonomous electric vehicles can offer a solution to all of those issues and they can also allow this city to reclaim a tremendous amount of the space currently used to park vehicles which are just sitting and doing nothing. I like to imagine more bike lanes, more trees, wider sidewalks, and trash piles farther from pedestrians. Ahh, and with air so clean, it shall be a wonderful new beginning for the city if it is executed properly and implemented well with a focus on improving pedestrian life.

A technology like this could mean that autonomous cars would rarely have to leave the road, making them even more useful. Perhaps here in NYC it could just be main drags which can wirelessly recharge the vehicles as they drive over.

As a side note, if they kept the roads green like in the concept picture, that'd be awesome too.

Is there really a measurable increase in cancer rates at toll free bridges versus tolled bridges?

I've heard it before (with a map). I'm having trouble locating that same map but I suppose it'd be possible to come to a conclusion based on a map of high traffic areas in NYC and the rates of cancer using the cancer maps provided by NYS [0].

Unfortunately, I'm at work so that 30 minutes isn't readily available at the moment.

[0] - https://apps.health.ny.gov/statistics/cancer/environmental_f...

It still doesn't solve the problem that private vehicles require n times more space than a fleet of busses or bicycles.

Perhaps people will decide that the flexibility and comfort of private vehicles, especially in a context like the one described where they create much less noise and pollution, is worth them taking up a little more space.

It's easy to fall into the trap of deciding that buses/bicycles are somehow morally better (or worse) than private cars. This is not so -- we should dispassionately judge the tradeoffs instead, ideally with an eye towards allowing individual people to make the choices that fit their needs best.

Electric cars still cost energy (i.e. coal and associated emissions) and private vehicle ownership costs space. If space is at a premium, then your parking space makes the city a little less livable for everyone else. If your power source isn't wind, solar, or nuclear, your emissions are just a few miles outside the city instead of in your tailpipe.

And perhaps the ability to go wherever you want, whenever you want, in comfort, as opposed to having to wait for a bus or ride a bicycle in the snow, is worth more to the people in the aggregate than a little extra space saved by not parking cars. You're assuming everyone has the same preferences that you do.

(And anyway, since we're talking autonomous vehicles here, you could park them together in central locations and then even the space argument mostly goes away.)

Well This is more an ethical problem. Yes, I agree I much rather sit in my car and go wherever I want. But the amoubt of energy required to do this (producing, operating and disposing of the car, and maintaining streets, managing accidents etc.) seems out of proportion, and can't possibly the right of every living person on a planet with 8-10 billion people. And you just have to look at European cities to see that transit can be the more convenient option when space for streets is limited. E.g. i'm living close to a soccer stadium that has no parking lot. Hard to imagine in the US. But the city is criss-crossed wirh subway lines, and it ishence often the fastest way to get to a destination. Then the argument for cars breaks down.

A concern about a rapid increase in EV usage that I see a lot is of having the infrastructure to cope with the increased electricity usage. To that end, wouldn't this be creating even more of a problem?

While 75% efficiency (I assume that's only under optimal conditions) sounds pretty good, that's still a lot of wasted energy. And wouldn't there be some overhead for running these roads while no EV vehicles are on it? Seems like a lot of wasted energy to promote use of something that is supposed to be more environment/energy conscious.

This would only work for bus lanes, but normal cars driving to work are best loaded either at home or better at work, where the energy company can extract energy during the peak times. These charging lanes are way too expensive, and the charger too heavy.

I feel like the next big thing is creating energy out of things we use everyday. Like stairs, doors, floors (especially rooms with children) and overns. We waste energy but this won't happen till we get the efficiency percentages higher and higher.

Carnot had a lot to say about theoretical efficiency WRT input and output temps.

For example if I did the math in my head correctly, the peak Carnot heat engine efficiency of an oven cooling down would be 30%, dropping to 0% as it hit room temp. Only way to boost the theoretical Carnot limit would be to boost the temp... sear more steak, bake less bread, etc.

So if pessimistically it took a tenth of a kilowatt hour to heat up a kitchen oven, you'd get maybe a hundredth of a KWH out of a cooling engine (the rest goes to waste heat). Its going to be hard to environmentally amortize the cost of the heat engine. Spending the resources on better insulation would have a much higher payoff. Similar problem with the structure, you could collect energy off the hydraulic door closer, but it would be way better for the environment overall to dial up the weather stripping and door insulation than to gather a watt or two.

And then the things you are trying to get energy out of need to be used frequently enough to recoup the cost and energy demands of refining and building a more efficient device.

This mentions 75% efficiency, but doesn't say anything about energy transfer rate. How quickly could this charge a vehicle?

One of the linked articles talks about a prototype delivering 100kW to a bus, so it should be in the feasible range.

So that would imply thirty or so KW of heat at 75% efficiency and a hundred delivered. I suppose road icing and snow accumulation would not be much of an issue at those levels.

On hot summer days, during traffic jams, a slowly rolling 30 KW heat source might cause road softness issues, something to think about.

If it's rolling slowly then it won't need anywhere near 30kW, though. Power consumption varies roughly by the third power of speed.

Unless the vehicle is already fully charged, I'd expect it to draw as much power as it can for charging, regardless of its current power consumption.

Sure, but the vehicle is not in charge of how much it can draw.

And the metric that matters is kWh per mile.

> Sure, but the vehicle is not in charge of how much it can draw.

The road determines a maximum, but the vehicle need not draw that much, for instance if already fully charged.

> And the metric that matters is kWh per mile.

That would also depend on vehicle speed; charge obtained per second seems more useful than per mile.

What matters is that your vehicle is x% more charged at the end of the segment, or at least that you used no battery power over the segment. It really doesn't matter if your car isn't charging while you're stuck in gridlock.

Even if it does that (and if this is a problem then you could simply design the system to only deliver enough power to sustain travel) then the car won't be charging for very long before it becomes full.

> Even if it does that (and if this is a problem then you could simply design the system to only deliver enough power to sustain travel)

That seems far less useful; "your charge won't go down in this lane" means the lanes would need to go everywhere, while "your charge will slowly go up in this lane" would mean the lanes could sustain travel over a wide area even if they only appear on major highways.

Also, different EVs require different amounts of power to sustain travel.

> then the car won't be charging for very long before it becomes full.

Depends heavily on the charging rate. Considering that many EVs can take hours to charge with a wired charger...

Right now, EVs are fine for short-distance travel but most EVs have trouble with long-distance travel. An EV's battery will be fine with getting you to and from the highway, and you'll charge wherever you park as well.

Your emphasis on "wired" is kind of out of place here. These wireless chargers will necessarily be able to provide substantially more power than a typical wired charger. A typical wired charger is 10kW or less, while highway inductive charging will need to provide 20-30kW just to sustain highway speeds.

Let's say you draw 30kW no matter what until the battery is full. If you're in a traffic jam, you might be consuming 2kW or so on average, leaving 28kW available to charge the battery. If you're in a LEAF and your battery is completely empty, your battery will be full in less than an hour. And your battery is likely to be well above empty.

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