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1) What is the cost of construction of a mile of "solar highway" vs. a conventional one?
The solar panel is intended to be laid over on existing roads. Panel grid and the ancillary two channels would be the main expenditure.
I'd expect the cost of new construction of a new road would be the same as conventional -- prep, road base, minus the actual surface treatment.
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Originally Posted by Toyman at Jewel Lake
2) How much power can practically be generated, and can the value of the power make a meaningful offset in the up front cost.
Upfront costs are somewhat offset by reduction of surface maintenance costs for roadway, aboveground cabling, and conventional power plants.
This is an UPGRADE to the existing road system, power grid and data grid. In some areas the value would be immediate and huge, in other areas it might not have as much of an impact.
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Originally Posted by Toyman at Jewel Lake
3) There will be areas (particularly in the north) with a mix of conventional and solar roadways. How do these glass panels stand up to the impact of snowplow blades? To rocks being dropped on them and then driven over by a semi-tractor? To the buildup of sand/gravel used as traction in the winter? To studded tires or tire chains?
The solar roadway is intended to melt snow and ice off it's surface and the surface is high-traction nubbly, so you wouldn't need plows, grit, chains or studded tires. They eveloped and tested them in Idaho with these things in mind.
Transitioning from conventional to solar would be problematic at first when you still have disparate surfaces. Coming onto the solar roadway from an asphalt/gravel road that needs traction devices could damage the panels... I'd be interested in seeing their test cases for this. I'd also like to see their tests in cold temperatures, to see if the awesome impact and load results hold true in the extremes.
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Originally Posted by Toyman at Jewel Lake
4) What kind of resources have to be consumed to build this vs conventional highways?
See #1 above. The question isn't so much a roadway resource issue... what/how much resources would be consumed on the solar roadway vs. conventional power plants, conventional power grid infrastructure, conventional data grid infrastructure, conventional storm water handling, conventional snow removal and road maintenance.
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Originally Posted by Toyman at Jewel Lake
Neat technology and I hope it can prove cost effective. Especially since the company is in my neighborhood.
It seems to offer a lot in an urban area, where both the power distribution facilities are in place and the smart features can be utilized. Would be pretty cool to be able to reconfigure parking in urban areas say for events or to handle routing of traffic around construction or accidents. The lighted sidewalk idea is also cool. I just really queston rather it can ever be cost effective.
Missing answered most of the questions. The weight question was left unanswered. They tested the panels so that they could withstand over 250,000 pounds - since that was the weight of fuel super tankers. Heavier than an abrams tank. If you go to the website, they show a tractor over the panels. They have a video of tractor with a grader going over the panels on the website too.
My rough math which may be off regarding you power generating potential. Each panel right now in full sun generates 32 watts and is a square foot - but once they expand the solar part of the hexagon they said 52 - 72 watts is possible. A note that they were able to reduce the size of the panels for generation 2 panels was noted. So that is a lot of power potential. Again, the sun has to be shining. At least by me, a two lane residential road is 18 feet across, so 1 foot of residential two lane road is 18 sq. ft. 18 x 32 is 576 watts per FOOT. A 4-lane highway each direction, which is common for interstates (8 lanes total) so multiply by 4 or 2304 watts. That is at the low end. A miles of highway is 11,980,800 watts in power generating potential. Meaning no cars, bad panels, or shade in that mile.
It's all conjecture right now - I just hope they are able to get to testing point and it works.
Ohh and think of all the salt, sand, and plowing that will be saved every year by having these panels around. That has to be figured into the ROI. Of course people (plow drivers) will lose their jobs. Maybe they can be trained for panel installation and maintenance.
Missing answered most of the questions. The weight question was left unanswered. They tested the panels so that they could withstand over 250,000 pounds - since that was the weight of fuel super tankers. Heavier than an abrams tank. If you go to the website, they show a tractor over the panels. They have a video of tractor with a grader going over the panels on the website too.
My rough math which may be off regarding you power generating potential. Each panel right now in full sun generates 32 watts and is a square foot - but once they expand the solar part of the hexagon they said 52 - 72 watts is possible. A note that they were able to reduce the size of the panels for generation 2 panels was noted. So that is a lot of power potential. Again, the sun has to be shining. At least by me, a two lane residential road is 18 feet across, so 1 foot of residential two lane road is 18 sq. ft. 18 x 32 is 576 watts per FOOT. A 4-lane highway each direction, which is common for interstates (8 lanes total) so multiply by 4 or 2304 watts. That is at the low end. A miles of highway is 11,980,800 watts in power generating potential. Meaning no cars, bad panels, or shade in that mile.
It's all conjecture right now - I just hope they are able to get to testing point and it works.
Ohh and think of all the salt, sand, and plowing that will be saved every year by having these panels around. That has to be figured into the ROI. Of course people (plow drivers) will lose their jobs. Maybe they can be trained for panel installation and maintenance.
It certainly does look like interesting technology. What unfortunately hasn't been discussed is the cost of installation and maintenance. It sounds as if the sub-base (support structure, whatever you want to call it) is at least as complex and expensive as conventional highway construction. On top of that, you have the cost of the circuit boards, components and processing required. The amount of FR4 (circuit board material) and components, is massive. You're talking about more square feed of circuit board than currently produced in the world. Even a simple, 2-layer board has a layer of copper on each side. Just how much of the world's copper production would be required to build say 10,000 miles of road. Electrical components use some fairly exotic and expensive materials-tantalum being just one. The number of LEDs involved...also massive. I hope it works out and can be done cost effectively...but I remain skeptical. I do need to do some digging on sq-ft cost of circuit board production, let alone the exotic glass used.
One of the other questions is just how much power is required to heat the surface for snow melting? Heated driveways have been around for a long time...but are rarely used due to the energy costs. There is a large surface area involved, with large delta T; in any kind of breeze the convective heat transfer will be huge. Even worse, the energy required to melt snow (latent heat) is actually a large figure, let alone the requirement to heat the drainage system and keep it above freezing. If I get some free time over the weekend I'll crack open my heat transfer textbook and run some numbers. Again, love the concept, but question the engineering and economics.
Another concern...the glass appears (and I think the FAQ covered this) to have a fairly coarse textured surface to increase the coefficient of friction (traction). Only thing is...highway traffic is highly abrasive. Tires pick up dirt and stones that grind and polish road surfaces. You can see the wear on even concrete highways. How long would it take to wear down these textured surfaces to polished glass? Can the glass be "recut" to refresh the texture, similar to how grooved highways do?
Rather than an extensive network of solar highways, it seems like it would be more practical in limited, focused applications.
Last edited by Toyman at Jewel Lake; 05-29-2014 at 10:15 PM..
Toyman - Lots of questions to be asked and answered.
I don't have the Electrical Engineering or Mechanical Engineering background to answer them.
If highways are not practical, potentially parking lots and driveways are. My driveway doesn't have to be as robust as the residential street, which doesn't have to be as robust as a highway... As much as I like rooftop solar panels - something that is on the ground that can still be used seems something to pursue. I like the easier to maintain aspect and I am sure if there is a way to keep the sidewalk and driveway snow and ice free for "free" people will like that. The expensive to put in driveway heaters are more expensive to actually run.
Even if all the questions are asked, answered and acceptable to going forward. It is going to be a slow process - and obviously the areas that would benefit the most should be completed first.
A large portion of the panel construction is currently from recycled materials by design. Most of the metals could/would be reclaimed from e-waste and the existing grid transmission lines (and transformers and substations, etc) as it was replaced. There is already a huge amount of the necessary metals in the existing grids that would simply be repurposed during the upgrade. The materials from damaged panels and the power/data cabling in the solar roadway could/would also be reclaimed.
I'm not sure what "exotic glass" is, but the panels are made primarily from plain old recycled glass. They may add mica for increased durability during the first casting. Any self-cleaning compounds would be surface coatings, not intrinsic to the glass. The panel glass can be replaced and reclaimed for recycling when the surface is polished down by traffic. Eventually there would be significant material lost due to this grinding, but luckily silica and mica are abundant and we use glass so pervasively that sources of additional recycled glass would not be difficult.
LEDs are primarily a semiconductor made of silicon or gallium arsenic (neither rare), with doping agents (most not rare) to produce the different colors. The only rare element in the doping agents is indium, which is only necessary for violet; all the other colors can be obtained with other non-rare elements. Violet LEDs could be avoided in the roadway, and the particular wavelength of the other colors could be targeted to use the most abundant source of those doping materials. Needless to say, LEDs are tiny and use extremely small amounts of materials. The components in an entire block's worth of panel LEDs is probably be less than a single by-directional stoplight. The lifespan of LEDs and their electrical efficiency is much higher than any other conventional lighting system used in/on/near our current roadways (most of which would/could be reclaimed and recycled into LEDs). LEDs that are still functioning in a damaged panel could also be reused.
The energy costs of heating the roadway would have much less of an impact if the power used to do so was from a zero-cost fuel (i.e. sunlight). By their calculations, once national, the solar roadway would generate a substantial surplus of power... one budgeted use of that extra power would be winter road heating. Additionally, unlike most heated driveways, the panels are smart... they can sense temperature and precipitation levels and only cycle the heating elements exactly and only when they're needed.
It's a paradigm shift, a total replacement. We'd be transferring the allocation of materials and resources from one application to a more efficient and productive application. We'd be generating power from a zero-cost "fuel" from the surface of a distributed and decentralized system instead of from huge, expensive, centralized power plants. The roadway becomes the transmission lines, thereby replacing the existing grid, and eliminating the need for transformers and substations. The roadway is both the plant and all other parts of the grid, but it can never go entirely down, requires no harvested or transported fuels, requires no additional land, and does not need to be decommissioned at the end of lifecycle. The cost of producing, installing and maintaining the solar roadway needs to compared against the total costs associated with all other power plants, power & data transmission lines, AND winter road maintenance.
I agree that costs need to be firmly determined and total power generation figures need to be solidified (preferably per mile). But consider a different perspective:
How many miles of solar roadway could be produced and installed over the existing road system for the price of a single new billion dollar power plant?
How many more miles of solar roadway could be produced and installed, and how many maintained, for the price of operation of a single power plant (estimated at twice the construction costs over it's 30 year lifecycle).
How many more miles of solar roadway could be produced, installed and maintained for the price of surveying, extracting, transporting and refining just the fuel used in a conventional power plant... including all the equipment, manhours and resources necessary?
How many more for the cost of crew, equipment, fuel and materials for winter road maintenance and subsequent spring road repairs?
How many more for the cost of crew, equipment, fuel and materials for locating, diagnosing and repairing the existing transmission lines when there is an unexpected outage?
How many hours would you NOT be without power/phone/internet in such an outage if the entire rest of the grid and transmission lines were still operational even though a tree/rock fell down and broke the panels in that section of road? At the very most, if the cables were also damaged, you would only have a localized outage (at the point of damage) that would be immediately detected and a crew sent to it's exact location for repair while the rest of the surrounding roadway continues to perform -- how much is that redundancy and security worth?
Not to be a wet blanket but coming from an engineering perspective, there are quite a few claims that I find questionable at best. It's a cool idea, just not one that will be feasible anytime soon. As far as solar goes we have much more effective and efficient ways to implement it. Space is not the concern but rather how all that power will be routed and stored once it has been produced.
This video provides probably the best analysis of the whole Solar Roadways idea and reveals a lot of marketing nonsense and inherent flaws that must be handled before it can get any further. I love that these people have passion for what they are doing and their intentions seem to be quite admirable but to say their plans are troubled would be putting it lightly. The cost is a huge factor, with estimates ranging from $40 trillion to $80 trillion, or around $1.5 million a mile or so but that would be if they actually got everything working and they are quite a ways from it.
The whole roadway system becomes an interconnected power grid... so if it's dark or cloudy in one location, power being generated by another portion of sunny roadway will supply the lights etc on the dark/dim portion.
This is incorrect.
The roads would be hooked up to the local electric grid and would draw power directly from the electric grid which is usually backed up by coal, natural gas or nuclear. During the day when the sun is up it would put power into the grid but on cloudy days or when these units were shaded or at night time, it would be pulling power from the grid constantly.
One of my biggest concerns is whether or not this would produce more power than it used. The reason why I have this concern primarily is because panels installed laying flat tend to be pretty inefficient compared to those installed tilting at an angle. This effect becomes more pronounced the further north you go in the U.S.
I've looked at their calculations and there's a lot missing, I don't see any accounting of panel degradation, I don't see efficiency losses based on the inverters they would be using, they seem to be assuming the same sort of production that you'd get with a high end panel situated on a rooftop facing due south in a warm climate. As others have said, its a cool idea but they seem to be pulling the whole South Park gnomes deal with it so far:
Step 1-Invent Solar Roadways
Step 2-????
Step 3-Profit
Supposedly there's a costs breakdown coming in July so that will be very interesting to review to see how feasible this would be, even for smaller scale applications.
Not to be a wet blanket but coming from an engineering perspective, there are quite a few claims that I find questionable at best. It's a cool idea, just not one that will be feasible anytime soon.
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This video provides probably the best analysis of the whole Solar Roadways idea and reveals a lot of marketing nonsense and inherent flaws that must be handled before it can get any further. I love that these people have passion for what they are doing and their intentions seem to be quite admirable but to say their plans are troubled would be putting it lightly.
I found the video entertaining and informative, but it set my teeth on edge every time he said "ash- phalt."
I think his critical analysis was spot on. Most of the claims the fundraisers make need thorough testing to prove out, and several do seem unlikely. But it looks as though the claims are enough to pull in the crowdsourcing bucks they wanted, and that's a kind of success in itself, even if this proves out not to be a viable product for highway use.
And I still think it has some possibility in the home and business market. Parking lots and driveways take up space. Being able to dual purpose, why not. Heck, these might be able to work for roof tiles too, but obviously a different mounting solution must be addressed.
Plus up North the ability to melt snow for "free" has got to be worth something. Even if "free" means dumping power back into the grid for credit later on, since it may draw some power to keep the road warm enough.
The million dollar question is still cost though and that is after the other concerns are all addressed.
Here's another highly skeptical review by an electrical engineer with some additional criticisms. This one cracked me up...
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The bumps on the prototype Solar Roadway glass hexagons are about an inch apart. A car driving at highway speeds moves about 100 feet per second, so the bumps would make a very well-defined tone of about 1 kHz. That's a medium-pitched whine. Get used to it, because you'll hear it ALL THE TIME.
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