Solar Roadways 4

[rjoto]

I rarely keep up with news but I saw this on CNN and thought it looked really interesting. I'm always skeptical of these "green" visionaries trying to change the world, but this guy's an EE of 20 years, has been working with several universities, the US Federal Highway Administration, and more so it seems to be at least somewhat credible.

He's got a site with some videos explaining the concepts and he's also addressed a lot of potential issues in an FAQ.

The biggest potential issue I see with this is cost, which he briefly brings up in the FAQ but gives no estimate for. But I'm not Electrical or Civil, so I'm sure there are a lot of other potential issues out there that I can't think of.

Anybody else heard about this?

 

[KENAT]

Cost, long term cleanliness affecting power generation, just how much of the grids power can really come from solar panel/how to handle over generation by day V almost none at night, ROI in parts of the country with less sunlight, over heating in parts of the country with lots of sunlight...

I realize the FAQ mentions most of these but from what I read it doesn't give a very robust or quantitative response.

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[TomDOT]

Almost any actual road will be getting at least an order of magnitude more abuse than their parking lot testbed. An actual highway will be at least two orders of magnitude.

Additionally - how much net power are they actually producing, with their powered stripes and heaters sucking down electricity?

If you want to use a parking lot to generate solar power, it will almost certainly be cheaper and more effective* to mount regular solar panels above the cars, with the added benefit of offering shade and weather protection.

Angling the solar panels for drainage is probably interesting as well...

*No pesky cars blocking the sunlight, and you can angle the panels optimally.

 

[imcjoek]

Oh good. The lines will be LEDs and all the panels are wirelessly connected. Hours of entertainment.

 

[TomDOT]

I missed the "wireless charging of electric vehicles while moving" part on the first read-through. Induction, I suppose. A continuous line of induction chargers.

 

[cranky108]

Just thinking, but for induction to work, the car must be moving in relation to the magnitic field (a given).
A car with no energy, and a stationary field (like perminite magnetcs), would recieve no charge.
A car moving at the same rate as the field in moving would recieve no charge.
So the optimal field would be to move in the oposite direction of the moving trafic, which would produce the maximum induction, and a higher relitive frequency to the recieving coil.

One problem is to support the maximum electrical efficency, you need to tune the circuit to react to the driving (no pun intended) frequency. But since the circuit will keep changing it will require an active tuning of the circuit.

If there is a power transfer between the power company (or agent), and the vehicle owner, how do you bill for the energy, or is it assumed a fixed cost? If an electric meter is used, who reads it, and if the power consumed was from more power provider, how is that devided between the providers?
How would a driver know when his energy rate has changed? Would there be even more road side signs for that?

 

[SnTMan]

I would invite anybody considering making roads out of anything but simple pavement to come drive So. Peoria Ave, near my house. You'd think you had square wheels. Looks like more infrastucture problems to me.

Regards,

Mike

 

[crerus75]

Like most of the other technologies that are going to change the world, this one makes me skeptical. I don't know if these questions are stupid, so everyone please feel free to educate me.
-Road grit is abrasive. How long will that surface stay transparent enough to produce usable power?
-What happens to it when somebody decides to spin donuts on it in the middle of an intersection, or rip a handbrake turn?
-How reflective is the surface, and how will the resulting glare, if any, affect people in the surrounding buildings, aircraft pilots, etc.?
-How do you transmit the resulting power through a distribution system that is already overloaded in some high-use areas?
-How do you store or get rid of the excess power? He talks about "virtual storage" (pumping it into the grid during the day and back out at night), but it seems like this would create transmission issues as we shuttle large amounts of energy back and forth.
-He seems to insinuate that significant market penetration could/should force a conversion to a DC current-based grid. Does this seem not only overly optimistic, but wildly impractical to implement to anyone but me?

I like the technology conceptually, but I think implementation will be a mother.

 

[rconnor]

This does seem outlandishly optimistic. I cannot see the incremental cost between this and traditional methods being within the realm of practicality. They didn’t publish any figures on this which only adds to my skepticism.

However, whenever I find myself skeptical about these technologies that offer massive shifts in infrastructure, I think about how England installed a subway system in the 19th century (albeit right at the end of the 19th century). Could you imagine how that conversation would have gone? “You want to do what?!? Dig a bunch of tunnels under our city, with buildings and people above, and have trains go into them to take people around the city? Do you know how much this is going to cost? What about the safety issues? We already have roads and trolleys, why on Earth would we need to build this system? It’s ludicrously expensive, unsafe, untested and unnecessary!”

Although the analogy isn’t a perfect match (different economic situation, much cheaper labour but less developed technology), I think it highlights that “crazy” ideas of old are now routine today….even still, I can’t shake the opinion that this is pie-in-the-sky thinking. Certainly some neat ideas though. I’d be very interested to see test projects in parking lots (although I agree with TomDOT, canopy still solar farms in parking lots are likely more well suited) and sidewalks/outdoor malls.

 

[cranky108]

FYI, the grid is not a battery. For every bit of energy that is put into it, it is used are the same rate. Also for every bit that is taken out of it, it must be generated somewhere.

Granted there is a small portion of stored energy, but with efficenciey rates around 50%, they aren't very viable except as play things.

Educate you. The electric transmission system, commonly called the grid, is not a storage system. It transmits energy, from producer to consumer, nothing more. No more magical than the drive shaft in your car.

I do like the idea of softer roads, as it will make tires last longer, but will it effect traction?

 

[beej67]

No power would be generated in Atlanta between 3:30pm and 6:30pm on weekdays.

Just saying.

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[cranky108]

Would underground sections produce much energy from cars headlights?

I guess with over head street lights, if they can keep me up at night, they can generate some energy.

 

[TomDOT]

cranky, the amounts produced from those sources would be.... negligible. Like 0.01% of sunlight, if it is even enough to activate the panel.

 

[cranky108]

My point is, any solution will be assumed to be universal, and applied everywhere. You should know that.

 

[JohnRBaker]

One of the ideas I read about was using the idea of induction charging with something like city buses. An electric bus would leave the yard in the morning fully charged and then at each bus stop there would be an induction charging unit installed in the pavement where the bus would be sitting when loading and unloading passengers. While this was going on, the bus could be at least partially recharged. Even with only getting a small charge at each stop this could still extend to range of the bus and since in many places, when a bus is running on time, they must actually delay leaving each stop so as to not get ahead of schedule so this extra time could be used to increase the level of charge. They could also schedule extra 'charging stops' as needed during the course of the day's route. Granted, this is not the same as a full-time electrified roadway, but it could provide for an albeit specialized implementation. The same could be done with delivery vehicles making regular stops at retail stores where a designated unloading/charging location could be set-up in say the alley or reserved loading/unloading area near the retail stores. And it could apply to school buses as well.

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[cranky108]

And if there were no people getting on or off at some stop, they would have to stop anyway.

Proposed, make induction recharging at every stop light, as they are normally red and we have to stop anyway for the full cycle.
One problem is it would cause induction heating on metal parts that may not be intended as recharging elements. Sort of bad for gas trucks.

Woulden't it be strange to see for example milk trucks stoping at bus stops?

Would the electric rate be the same for cars as for homes? Or would road taxes be added to car electric rates?

 

[SnTMan]

No road taxes on NG. Yet.

Regards,

Mike

 

[TomDOT]

The infrastructure cost of putting an inductive charger at every traffic signal would be ridiculously high, with ridiculously low usage rates.

Other than edge cases, like a bus - most vehicles spend the vast majority of their time parked. Much, much, much cheaper with much higher potential usage to just install more charging stations in parking lots. Once we have enough electric cars to warrant it, anyway.

There are plenty of SAE J1772 Level 2 stations here in Austin, and most surrounding small cities have at least one.

There is also a Tesla Supercharger on the way to other major cities in Texas (San Marcos, on the way to San Antonio. Columbus, on the way to Houston. Waco, on the way to DFW. Corsicana and Huntsville on I-45)

...but even that's mostly un-needed. Most commuters can simply charge overnight at home, and not use public charging the vast majority of the time. It's like a cell phone - simply charge overnight at home, maybe top it off at work. You don't go to some dedicated charge station at the phone store and wait while it charges.

 

[cranky108]

Question: What is the cost to charge an electric car at one of these charging stations?
What is the tax surcharge to charge a car at home to offset the road taxes?

Why is exempting some cars from road taxes a good thing?

 

[TomDOT]

Cost at the charging stations is variable. A fair number of them are free, such as all Tesla stations.

Tax surcharge: Some states have an electric vehicle tax for roads (not many) - most electricity is taxed @ home, though it is not generally directed at roads.

The absolute number of electrics on the road today is tiny. I'm sure the taxes will be taken care of when they have a larger share.