Covering roadways with glass solar panels is a terrible idea. Asphalt is durable and flexible. It's OK with getting bits of gravel, glass, or steel ground into it. Solar panels deal badly with such abuse.
Putting solar panels flat on the ground loses 30% of their potential power.
Even ignoring all of that, covering solar panels with cars is a terrible idea.
Oh god... Not another one of these...
There is literally no reason to put solar panels on road surfaces. Go on google maps and look at the surface areas of roads (that are not in a buildings shadow most of the day) compared to rooftops or empty space.
I see one reason,the fact that if you put solar panel in a place where the energy will get consume directly or within a short period then you don't need to take care of storage and transport for it.
Then place them next to the roadway so they can operate efficiently? I don't understand the gimmick here. Again, it's a blender that plays MP3s, a carefully crafted web of buzzwords. Why does everyone want this so badly?
Again I think it is to reduce cost, you just need to add a layer on an area that is already taken care of (snow removed during winter, object and dust removed by cars and maintenance team).
Snow can be removed from rotating solar arrays by simply turning them sideways at sunrise, perfectly clearing them as the sun warms them up. If you're really enterprising you can turn them upside down at night. Can't say the same for the roads anywhere I've lived. Also, those dull grey cement highways used to be gleaming white when they were poured but alas, car tires are black and turn everything they touch black as well.
But you would put just any old solar panels on a road: See what is happening at http://www.solarroadways.com/ - it addresses at least some of the issues you mention.
This isn't a technology problem though. It's a stupid problem. Compare this to building a blender that plays MP3s. Why would you not just cheaply mount the solar panels next to the road? You can still do all the gimmicks with the LEDs and stuff without having to spend time and money making a high traction, durable road surface that doubles as a solar panel. There's nothing to be gained.
You could also just mount the panels above the road and block the sun out of people's eyes while they drive. Less sun hitting people also means less people need to run the AC on the road.
If you don't mount flat you can then do tracking too.
Like you say. Mounting flat is probably the worst way to go from a utility and return standpoint.
It's still true. Solar Power in most of the USA is too expensive unless you factor in government subsidies that has been added to accommodate externalities caused by burning fossil fuels. The technology currently is not cheaper to manufacture then coal/natural gas for most of the USA mainly due to the high investment cost and high maintenance cost of panels. These panels don't last forever and you can expect to replace them once every few (5-10) years. For commercial installs you also need to install rotors which have their own failures and maintenance costs associated with them.
To have solar win against fossils you need an area that is sunny and very dry. You also need very very cheap land. Watt/square meter of land fossils will win in most places within the US.
I'm surprised by how often (and by how many people!) someone suggests roads should be covered with solar panels... Asphalt is very different than glass...
Flexible is actually a negative on the roadway though: it increases rolling resistance. You want something very hard that will not shatter. Cement works very well (asphalt is okay)
There's another way: put solar panels above the road. Especially for big, wide highways, there's a lot of area that's basically not used for anything except cars and trucks to drive over. Cover these with solar panels and now that land isn't just used for transportation, but also a lot of energy generation. On top of that, the cars underneath will be shaded from the Sun, which can be really useful in sunny climates, and would help people use less A/C in their cars, thus saving energy.
The two problems I see with this idea are people complaining about the "view" (which is why it shouldn't be done on some really nice scenic part of a road, but in the middle of an ugly part of the city it should), and the possible problems with wind-loading, especially during storms, though surely this has been dealt with before, as there's a lot of places where they cover parking lots with elevated solar panels like this. For the view problem, they don't even have to cover the whole road with panels, they could just cover some lanes, put them in the median and extending over the inner lanes some, etc.
>though surely this has been dealt with before, as there's a lot of places where they cover parking lots with elevated solar panels like this.
As a side note, you have to consider how in parking lots it is rare to have cars and trucks passing under the panels at 70 Mph, and more generally accidents are usually very low speed.
Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure).
So, more or less it would be needed to build an artificial tunnel (concrete, rather thick) similar to a "snow shed":
> Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure).
I mean, aren't these issues already basically solved? I frequently drive through miles-long tunnels under Boston at 70mph.
A tunnel is already massively over specced for that because it's preventing the tons of soil/rock/building overhead from collapsing down. The forces for cars passing underneath is minuscule compared to that. For a hypothetical covered roadway you want something much cheaper and lighter so it's not mind numbingly expensive to build.
That's true, I didn't fully elaborate on all that but yeah, there's concerns there that wouldn't exist for a parking lot.
However, you bring up a great point with the "snow shed": covering all or part of a road with solar panels like this would also have the side effect of keeping bad weather off the road. How much money would that save in show-shoveling costs, and the costs to society of having roads blocked by snow (and snowplows), and having weather-induced accidents (both rain and snow)? Now, it's probably not feasible to cover every little road in a city with these things, but at least covering major arteries, while probably somewhat expensive due to the engineering challenges you raise, would have some major benefits: keeping the main roads clear even during horrible weather, and also providing a lot of energy from the solar panels.
You have an excellent point there, but the costs are unfortunately way too high to be feasible, not even remotely.
And you have to consider how - in places where there is snow - you have to choose to either forfeit the (possibly little) energy the panels can produce in winter or anyway clean them from the snow anyway.
The good ol' rule of the thumb is that (of course it depends on the country) the cost is 10,000,000 Euro's per km of highway (plain, mainly earthworks), 20,000,000 per km on bridges/viaducts, 30,000,000 per km in tunnels. (the "base" price may of course vary, but the relative proportions remain roughly valid)
An artifical tunnel or sbow shed, besides the solar panels, would be probably 1.5 to 1.7 times the cost of the "simple" highway.
Ignoring the massive infrastructural costs and practicalities, but given the efficiency losses of the wireless-charging freeway idea, what would be the benefit of putting solar panels above the freeway and chargers underneath, over just having solar panels on the car instead?
There's not enough surface area on a car to power it in motion though. With a covered roadway you at least get the extra square footage from the empty space between cars. Still probably not feasible but it gets mildly closer.
On the whole idea powering cars wirelessly while they drive just doesn't work on mass scales. It's going to be massively expensive to build it out.
The car and the road are actually parts of a giant dynamo, I guess. Like the car having a coil and under the road a giant magnet, thus generating current in the coil.
Not practical though. Every time someone has done the math for a fully scaled up system (assuming magic technology that doesn't exist) it always has the same answer: Unless the power transfer system is nearly 100% efficient, using it on a typical highway results in the the highway turning into a molten puddle in less than a day.
If you want to run the numbers yourself a Tesla uses 300 watt-hours per mile on the highway. California route 60 sees 337000 cars per day and is 70 miles long. And an amazing power transfer system might be 75% efficient.
I think it might still be useful even if it's not enough to "increase" the charge of the car. Prolonging the driving distance by 50%+ on some highways would still be really beneficial.
Taking the thought to the extreme, it could also be used as a kind of traffic shaping/control system. Have some roads "energised" at specific times to provide an incentive to go a longer way to alleviate chokes or traffic jams.
That gives many people an incentive to take a longer path (whereas current systems/methods for this are kind of driver-hostile as the drivers going the longer route don't get any direct benefit)
The issue isn't the efficiency from the car's perspective—it's what happens to the other 25% of the energy that doesn't go into the car. Hence the molten puddle road comment.
All the more reason to only run it at certain times of the day. Enable it at night, when electricity is cheaper, heat generation is less of an issue, and there's less congestion.
How many millions... billions... would it cost to line all the roads? and then all the lost electricity due to inefficiency? All to give cars a little extra distance?
And then... when Road v2.0 comes out and it all has to get replaced? v3.0? Then flying cars and no one uses roads?
That road has four lanes (two in each direction), so if every vehicle is electric and is using the charger, it needs to dump a daily average 164W/m. For comparison, solar irradiance is 1.3kW/m^2.
Your efficiency calculation is wrong. It isn't 25% of 300Wh, 300Wh is the output. The input is 400Wh, with 25% loss or 100Wh. Not 75Wh as you have. And you have a bunch of other mistakes too.
Along the length of the road, that is 21kWh. At 75% efficiency, that is 7kWh into the road surface per car. Roughly 2.4GWh of energy ($200k worth of electricity) per day lost as heat into the roadbed in total. Assuming 4 lanes and a 3.7m lane width, route 60 is 1.7 million square meters of asphalt and that is 1.4kWh per square meter. (8x more than your number.) Still comparable to solar irradiation though. Asphalt might get a little soft on a busy summer day when everyone is also running their AC but it wouldn't be a molten puddle. If the chargers are only embedded in a narrow strip down the middle of the lane, that section might get very soft.
So at 75% I guess it is practical. But 75% is going to be extremely hard. And the first place this should be installed is Route 1, because it would be a highway-sized snow-melter that also happens to power vehicles.
Now ask yourself why we don't have defrosted highways. Installing roadbed chargers is going to be even more difficult.
100% of the loss does not end up in the road surface mostly it's radiated into space.
As a sanity check at highway speeds it takes ~30HP to maintain speed or a loss of 10HP or 7.5kw over ~60m (distance from one front bumper to next) x ~4m approximate width of a lane = 30w/meter which is a non issue. Lower speeds need less power, but can have more cars.
Further, not every car needs 100% power as batteries are still a thing, this is just for the subset of long distance traffic. And if you limit things to say 75% of a cars power demand that's still 4x the range.
On the plus side, _if_ this sees wide adoption, that Tesla would need less batteries, significantly decreasing its weight and with it its energy use.
Also, the article is a lot more optimistic about efficiency:
"The group used an off-the-shelf, general-purpose amplifier with a relatively low efficiency of about 10 percent. They say custom-made amplifiers can improve that efficiency to more than 90 percent."
That requires too much infrastructure. Just have the cars carry their own grenades. If you can make them tiny nuclear bombs (Californium-251 might enable this) then you could achieve amazing range.
In a far out, sci-fi kind of world, huge solar powered blimps hover in fixed traffic patterns, collecting more solar power than they use, and relay fractional amounts of collected surplus energy down to parasite vehicles, that assume a formation for refueling laser targeting, within the blimps flight pattern.
The cars accept the laser energy in a beam collector, for energy conversion, netting a bonus as recharge, and then resume independent travel as their intended destination requires.
Predictive consumption graphs can estimate optimal routes, for different charge requirements before leaving, optimizing for fastest time, best blimp paths, least energy consumption, traffic congestion avoidance or whatever.
How so? Trains are not all autonomous. Autonomous trains are greatly simplified due to traveling on rails. All trains are inconvenient due to being bound to the railway. They don't solve the last mile (or five) problem: getting to and from the station.
Rail-based navigation is considerably simpler than autonomous driving. The problem is reduced to "how far am I along the track" and "if there is something in my way, it's trespassing on the railway, so make a best effort to detect the obstacle and stop, and beyond that, who cares".
I see what your point is regarding the convenience of using a car. What could be more convenient than leaving your house, getting in your car, then being dropped at your destination? But this doesn't take into account the cost of the entire infrastructure needed to make it work flawlessly. On the other hand, the train goes faster, and benefits from economies of scale. A tightly knit network of trains would beat a transport system made of autonomous cars.
IMO, the future is likely not individuals in their autonomous cars. It's a ubiquitous autonomous ad-hoc ride sharing network, which will features some of the good parts of trains and buses, and some of the good parts of Taxis or individual cars. Popular routes will likely be populated by lots of large vans and buses of various sizes, all autonomous, and there might be interchange points where you get dropped off for a minute or two before an autonomous car comes to pick you up for the last few miles. Other people might already be in that car and going the same direction, or be waiting for you. Once there's a critical mass of ridership, you can get some really efficient usage of the system, and route capacity as needed.
I did some napkin math on this a while back[1]. It's interesting.
> IMO, the future is likely not individuals in their autonomous cars.
I think people will still want their own personal cars, because...
> some of the good parts of trains and buses, and some of the good parts of Taxis
...they won't want to get the car with the drunk vomit urine and heavily graffitied and torn up interior.
I can see how you could - via the hailing app or whatnot - send the car off as "undesired because XYZ" - and maybe it would go somewhere to get refurbed, but after a while, with so many refurbs, the companies will either give up, or they will make concessions (allowing for so much damage until it is deemed "needing repair" and cleaning it up as best as they can otherwise).
People might also want personal cars as a quicker convenience, and also as a status symbol. There's also those who might want to ride around in a personalized custom car, much like people do today.
> I think people will still want their own personal cars, because...
I'm not making a case people won't have their own cars, I just think it will be less common, and extremely less common to have two or more for a family.
> ..they won't want to get the car with the drunk vomit urine and heavily graffitied and torn up interior.
It's not like you don't know who was in the car that caused the problem, and can't have the whole day recorded for proof. Charge a cleanup fee, include video as proof. If it requires immediate cleaning and must be pulled off the road, charge them for the average income for that time as well. If it's in the agreement for the ride, you can auto charge the account/card as well, since that's how they paid in the first place.
I think that's plenty of incentive to cut down on people not treating your vehicles well because there's no driver to call them out.
> People might also want personal cars as a quicker convenience, and also as a status symbol.
Sure. For the same reason people buy $100k+ cars. That's a somewhat small segment of the market.
> There's also those who might want to ride around in a personalized custom car, much like people do today.
Insurance will likely start to make that expensive. Sure, it will happen, but I think it will be less common. It's already an expensive hobby.
The cleanup problem really isn't, in my opinion. Riders get tracked in a way that's hard to avoid (since your account is tied to your CC), so when cars get sent off, the company can tag the previous passenger and identify outliers, who can then be forced to pay a surplus fee per ride, covering the extra costs.
I had worked for compagny train 10 years ago and they told me that all vehicles train will be autonomous in 2015. They have only one and it still not working. They prefer to put driver that play on their phone, because people need to work. This is the world where we life. Sad and stupid.
I don't understand why the industry is completely focusing on electrical vehicles. It is not inherently clean energy, unless we change how we produce it.
What about the fuel cells driven cars? In my opinion it is still a valid option. You refuel hydrogen and produce water at the end.
Writing this, I recognized that it is probably short-/middle-term money, because electrical cars are quicker to develop (incl. infrastructure).
How do you think the hydrogen is produced? Currently it's either a product of petroleum or produced by using electricity to split water. So your argument of electricity not inherently being clean energy applies to hydrogen as well.
Assuming you use electricity to split water to power your fuel cell, you've basically just made an even more complicated way to use electricity to power your car. So at that point, just simplify it and just use a battery and a motor.
Small nit to pick, its produced more from steam reformation of methane:
"There are four main sources for the commercial production of hydrogen: natural gas, oil, coal, and electrolysis; which account for 48%, 30% 18% and 4% of the world’s hydrogen production respectively."
Whether or not the energy is "clean" now should not keep us from working toward advancements in this area. We all know that we want "clean" energy, and many people are headed that direction, but this is a massive object to redirect and it will take time. Be patient and keep encouraging the production and use of clean energy. It will happen. :)
Perhaps not inherently clean, but even in the worst case they're wildly more efficient than their standard ICE cousins, worst case scenario you're getting an equivalent of 36 mpg, best case scenario 112 mpg. A power plant of any variety is many times more efficient than your car engine.
Given that power grids everywhere are turning more towards renewable energy, this efficiency will only grow. The cleaner the grid, the cleaner the stuff that runs on the grid.
As for Hydrogen, lack of infrastructure is a major issue, on the production side as well as distribution. Producing hydrogen from natural gas produces CO2, producing it from water is slow and requires electricity, once again you're tied to the grid. There are further issues, found a good list of them here: https://cleantechnica.com/2016/06/10/hydrogen-fuel-cell-cars...
because one person with enough personality can create a market if the product is compelling enough. I think a range extender with sufficient battery for average daily use is key; granted I am bias as I own such a car,the Volt.
Longer range battery powered cars suffer from high weight for range and long charging time. Even the charging times of a Tesla are not truly viable in long trips; its 45+ minutes to get full. A thousand pounds, long charge, and very high capacity loss in cold weather are not the big negatives. Add in even hilly terrain hurts them too.
I think after the honey moon is over those who select an EV as their only car; a lot of those buying into the 35k-50k cars may only have one vehicle; will soon find its limitations irritating. I would not mind a Bolt,but only as a second car. 200 to 300 miles is not enough and the charge time, again even in Tesla, is not acceptable
I also own a Chevy Volt. It's my only car. The biggest improvement is the fact that I almost NEVER have to go to the gas station, and every trip I've taken has had each leg within a Model S's top range.
Going to the gas station constantly is an inconvenience that most people simply don't notice until they get an electric car.
So would I rather take a 15-40 minute lunch break on a road trip every 3 hours on the maybe one road trip beyond 200 miles I'd go on every year or have to travel to the gas station 50 times a year? Obviously the latter involves a lot more wasted time.
Oh, and charging speed is improving. No reason, fundamentally, you couldn't engineer a battery that charges, say, 100 miles in 5 minutes or 200 miles in 10 minutes. Tesla AND others (VW, etc) are planning/testing 350kW charging, which would help enable that speed.
As far as cold weather: balooney. I've lived in cold weather states for most of my life. Conventional vehicles have a huge disadvantage in that they don't even start AT ALL in some conditions whereas electrics have zero problem. And since they're already plugged in, you can pre-heat them before you leave (without burning gas, mind you).
Hilly terrain is actually much better with electrics since you have PLENTY of torque and regenerative braking means you're not going to overheat your brakes like you would in a conventional vehicle.
Also, electric is the great "virtualisation layer" of energy. Once it's electric, you roll. Every energy can be converted to electric.
People will argue that running on the iron directly is more efficient, but on a large scale, electric wins. It already won, it's just not apparent yet.
1) It IS inherently cleaner than conventional even without a major switchover, for two reasons:
. a) A central power station can be much more efficient than a small internal combustion engine, even using the same fuel. A good natural gas power station can get above 60% efficiency (caveat: LHV... but even using HHV value for natural gas, still above 50%), whereas internal combustion engines are around 15-25%, although can be even worse. This difference is much greater than any transmission or round-trip charging losses.
. b) Regenerative braking only (practically) works with electricity. This already makes electric cars cleaner, since they can recapture kinetic energy while braking. In conventional cars, this is all wasted as heat. A side benefit of this is electric car brakes last way longer.
2) We ARE changing over. Coal used to be >50% of our electricity, now it's on the order of 30%, and usually is dwarfed by natural gas at 33%. Natural gas per unit /thermal/ energy gives off a lot less CO2 than coal and still significantly less than gasoline or diesel. And natural gas plants are also very clean burning with almost no ash and soot (which can cause global warming in other ways, besides asthma and lung cancer, etc). And it's easier to make really thermally efficient natural gas plants than it is for coal. HOWEVER, even natural gas is now over-shadowed by clean energy (now at 36% of power) from nuclear, wind, hydro, solar, and geothermal combined (in that order). So now over a third of electricity is essentially carbon-free. This means that electricity on average is actually less carbon intensive in the US than if it were all produced from natural gas alone, which makes it even cleaner than if it were all centrally-burned petroleum, which makes it cleaner than if it were small internal combustion engines.
3) Fuel cells (let's take hydrogen for example) have major problems. The MAIN being the terrible round-trip efficiency. Electrolysis of hydrogen from water using electricity (this is basically the best case scenario, realistically) is 40-60% efficient. Fuel cells are themselves only 40-60% efficient. Then you add in the significant amount of energy needed to compress and transport the hydrogen (transportation is comparable to transmission losses from electricity, but sometimes worse), and the total efficiency is somewhere between 20-35%. Batteries are around 80-90+% efficient, and you can do even better if you're careful. That means you're ALREADY only able to travel a fourth to a third the distance in a fuel cell car for the same amount of electricity generated. That's insanely bad when you think of it. This is the main problem.
4) Fuel cells are actually much more expensive. They require high pressure storage and transfer. The fuel cells themselves are expensive, too.
5) Hydrogen itself has problems. There are material compatibility issues. A good lithium ion battery using a silicon chemistry can actually have a higher volumetric energy density (when you include the lower efficiency of fuel cells) than hydrogen, meaning you can make a more compact electric car or put a bigger battery in the same space. Hydrogen is also insanely flammable, with a very high flammability range in air. It makes explosive mixtures with air very easily. It also causes embrittlement of metals.
6) Electricity distribution is already ubiquitious due to the electric grid. Most people can charge at home (and even more if apartments just run out an outdoor outlet to parking spaces). That means people almost never need to go out to a filling station. It's only needed on long trips, and even then only after exhausting the internal battery. Many hotels/motels already have RV charging (and many allow EV charging), so on a multiday trip could start out each day with a full "tank" without any trips at all. And there's already been a lot of work installing charging stations all over the country, including very fast charging roughly equivalent to the ...
Fuel cells and batteries are fundamentally pretty similar. Fuel cells require that you put in a lot of not necessarily clean energy in a central place to generate hydrogen, then distribute that hydrogen to vehicles, which then use it to drive in a way that doesn't produce further pollutants. The same can be said of electricity. You generate it in a not necessarily clean way, distribute it to vehicles, they use it without polluting further.
Cleanliness isn't really any reason one way or the other but there are other differences. Energy density of hydrogen fuel cells is higher than Lithium ion batteries so vehicles can travel further. On the other hand, physically moving hydrogen is relatively expensive and infrastructure to do so doesn't currently exist while distribution of electricity is a thoroughly solved problem and is relatively efficient.
Should also be stated that a significant amount of energy is lost in carrying electricity over distances (over power lines and while at rest in batteries), which is not the case for H2.
I would consider our transmission of electrical energy to be very efficient. To transmit power thousands of miles and only lose a few percent is remarkable.
I tend to wonder what happened with the Powerball technology - which was essentially a "solid-state" method of hydrogen storage for automobiles (note that the following link has an invalid https cert - proceed at your own risk):
Even so - to me the idea seemed reasonable. Furthermore, there's a place in the United States almost nearly perfect to set up a production/recycling system. I have yet to find an objection to why this process (or the location - aside from possible EPA or endangered species red tape) couldn't work.
If you've ever been there, you probably didn't stop (unless it was for some gas or fast food). It's a "grand intersection" - you have at least one main railroad line, two highways, and one or more high-tension power lines going thru the area.
To the east, is Barstow and Daggett - testing grounds for the Solar One array:
Powerballs are based on sodium hydride pellets, which are manufacturer using a complex process - part of which involves molten sodium (!) with hydrogen gas (!) bubbled thru it. Molten sodium has been used as a means for solar concentrators to move heat from the array to the heat exchangers for steam (it can even stay molten thru the night, continuing power generation with no sun input). At least, that's what I understand.
I've also heard (and maybe I've misunderstood?) that the Powerball system can also be done using sodium borohydrides - for which you would need borax. Guess what is also nearby?
Just to the west is Boron, California (famous for the "20 mule team"):
So - if borohydrides can work - you have that supply (I believe it still is mined there).
Now - hydrogen - where to get that? Well, we need water, but we're kinda in the middle of a desert here. However, not too far away is a pretty good source of water - the Colorado River (plus various lakes and reservoirs). There might also be briny ground water that couldn't be used for drinking or agriculture, but would work ok for this purpose).
So - assuming we have all of this - we can make hydrogen somewhat simply, using a couple of different methods:
1. We could use an old method to create it, using solar as part of the energy input and steam generation; this was a method used in the 1800s to create hydrogen for gas ballooning enthusiasts:
I won't pretend to understand this - but the usage of coal in the process concerns me (mainly the CO production) - I'm not sure all of that is re-captured in the process of conversion.
2. We could use solar power to heat up steam enough so that it dissociates into hydrogen and oxygen:
Well, exactly the same problem applies to hydrogen-fuelled cars – almost all hydrogen production is still done using steam-reforming of fossil fuels, leaving CO2 as a byproduct. It might be possible to ramp up more carbon-neutral methods of production, but you face the same problem with electricity, so…
Your sentimemt is totally wrong. Hydrogen is jusy as dirty as battery technology, you have to produce the hydrogen some way, and producing and expending hydrogen fuel uses far more energy than charging amd discharging batteries.
It moves a lot of mass out the the end of the suspension system that comes with a lot of problems for handling. Also with the motor on the hub all of the shocks directly hit the electric motors where they don't in a normal car setup with motors and drive shafts and the bearings in the motor have to directly bear the weight of the vehicle.
Because in hub motors are generally a bad idea. The more weight you shift to the unsprung portion of the suspension, the worse handling, ride quality over rough surfaces, and energy economy gets. Even worse, the geometry of an efficient induction motor is a cylinder, and you can add torque by lengthening the cylinder. With an in hub motor you need either axial flux or to bond in permanent magnets, both of which complicate manufacturing.
On the other hand, a universal joint and a drive shaft are about as straightforward and reliable as it gets. You can still have a motor per wheel and size is not as restricted.
Long story short: in hub motors don't make sense unless you're very space constrained, like on an e-bike.
You can build a good enough demo to get press. Once the vehicles are out there as a product for a couple years the flaws will be clear.
This has been proposed before. GE had an old patent for a split-transformer system with half the transformer in the road. In the 1980s, CalTrans had an electric bus in Berkeley which recharged at each stop using half a transformer buried in the road. It's easier to do today, because power control semiconductors are much better.
It needs a lot of infrastructure in roads. That's really expensive and a huge maintenance headache.
The wireless power people need to get to a standard charging pad that Just Works, and get it widely deployed.
> It needs a lot of infrastructure in roads. That's really expensive and a huge maintenance headache.
Is it any more expensive or more of a headache than all the externalities, costs, and dangers of the alternative? At this point in time, societies all massively subsidize the fossil fuel industry at great cost to everyone but it's so spread out its hidden from view. I'm curious, if there is ever a realignment of costs from society at large to the oil companies, would the wireless charging roads look far more viable?
94 comments
[ 1.8 ms ] story [ 166 ms ] threadPutting solar panels flat on the ground loses 30% of their potential power.
Even ignoring all of that, covering solar panels with cars is a terrible idea.
[1] https://www.youtube.com/watch?v=obS6TUVSZds
If you don't mount flat you can then do tracking too.
Like you say. Mounting flat is probably the worst way to go from a utility and return standpoint.
To have solar win against fossils you need an area that is sunny and very dry. You also need very very cheap land. Watt/square meter of land fossils will win in most places within the US.
I'm not for or against, just that coke bottle glass is not the only way
The two problems I see with this idea are people complaining about the "view" (which is why it shouldn't be done on some really nice scenic part of a road, but in the middle of an ugly part of the city it should), and the possible problems with wind-loading, especially during storms, though surely this has been dealt with before, as there's a lot of places where they cover parking lots with elevated solar panels like this. For the view problem, they don't even have to cover the whole road with panels, they could just cover some lanes, put them in the median and extending over the inner lanes some, etc.
As a side note, you have to consider how in parking lots it is rare to have cars and trucks passing under the panels at 70 Mph, and more generally accidents are usually very low speed. Besides the "normal" resistance to wind, if you want to build a sort of half-pipe covering a highway you need to consider the pressure induced from the inside by high-speed moving objects and the possibility to resist accidents (preventing an 18 wheeler from completely crash a - say - 100 m section of the half-pipe in case of an accident needs a rather sturdy structure).
So, more or less it would be needed to build an artificial tunnel (concrete, rather thick) similar to a "snow shed":
https://en.wikipedia.org/wiki/Snow_shed
http://wsdotblog.blogspot.it/2014/03/the-i-90-snowshed-retir...
The "lighter" metal/lattice ones are only used usually for railways.
I mean, aren't these issues already basically solved? I frequently drive through miles-long tunnels under Boston at 70mph.
However, you bring up a great point with the "snow shed": covering all or part of a road with solar panels like this would also have the side effect of keeping bad weather off the road. How much money would that save in show-shoveling costs, and the costs to society of having roads blocked by snow (and snowplows), and having weather-induced accidents (both rain and snow)? Now, it's probably not feasible to cover every little road in a city with these things, but at least covering major arteries, while probably somewhat expensive due to the engineering challenges you raise, would have some major benefits: keeping the main roads clear even during horrible weather, and also providing a lot of energy from the solar panels.
And you have to consider how - in places where there is snow - you have to choose to either forfeit the (possibly little) energy the panels can produce in winter or anyway clean them from the snow anyway.
The good ol' rule of the thumb is that (of course it depends on the country) the cost is 10,000,000 Euro's per km of highway (plain, mainly earthworks), 20,000,000 per km on bridges/viaducts, 30,000,000 per km in tunnels. (the "base" price may of course vary, but the relative proportions remain roughly valid)
An artifical tunnel or sbow shed, besides the solar panels, would be probably 1.5 to 1.7 times the cost of the "simple" highway.
On the whole idea powering cars wirelessly while they drive just doesn't work on mass scales. It's going to be massively expensive to build it out.
Nice idea.
If you want to run the numbers yourself a Tesla uses 300 watt-hours per mile on the highway. California route 60 sees 337000 cars per day and is 70 miles long. And an amazing power transfer system might be 75% efficient.
Taking the thought to the extreme, it could also be used as a kind of traffic shaping/control system. Have some roads "energised" at specific times to provide an incentive to go a longer way to alleviate chokes or traffic jams.
That gives many people an incentive to take a longer path (whereas current systems/methods for this are kind of driver-hostile as the drivers going the longer route don't get any direct benefit)
And then... when Road v2.0 comes out and it all has to get replaced? v3.0? Then flying cars and no one uses roads?
So, I don't see the problem?
Along the length of the road, that is 21kWh. At 75% efficiency, that is 7kWh into the road surface per car. Roughly 2.4GWh of energy ($200k worth of electricity) per day lost as heat into the roadbed in total. Assuming 4 lanes and a 3.7m lane width, route 60 is 1.7 million square meters of asphalt and that is 1.4kWh per square meter. (8x more than your number.) Still comparable to solar irradiation though. Asphalt might get a little soft on a busy summer day when everyone is also running their AC but it wouldn't be a molten puddle. If the chargers are only embedded in a narrow strip down the middle of the lane, that section might get very soft.
So at 75% I guess it is practical. But 75% is going to be extremely hard. And the first place this should be installed is Route 1, because it would be a highway-sized snow-melter that also happens to power vehicles.
Now ask yourself why we don't have defrosted highways. Installing roadbed chargers is going to be even more difficult.
As a sanity check at highway speeds it takes ~30HP to maintain speed or a loss of 10HP or 7.5kw over ~60m (distance from one front bumper to next) x ~4m approximate width of a lane = 30w/meter which is a non issue. Lower speeds need less power, but can have more cars.
Further, not every car needs 100% power as batteries are still a thing, this is just for the subset of long distance traffic. And if you limit things to say 75% of a cars power demand that's still 4x the range.
I'm picturing future roads looking like massive Scalectrix tracks...
Also, the article is a lot more optimistic about efficiency:
"The group used an off-the-shelf, general-purpose amplifier with a relatively low efficiency of about 10 percent. They say custom-made amplifiers can improve that efficiency to more than 90 percent."
Correct me if I am wrong.
In a far out, sci-fi kind of world, huge solar powered blimps hover in fixed traffic patterns, collecting more solar power than they use, and relay fractional amounts of collected surplus energy down to parasite vehicles, that assume a formation for refueling laser targeting, within the blimps flight pattern.
The cars accept the laser energy in a beam collector, for energy conversion, netting a bonus as recharge, and then resume independent travel as their intended destination requires.
Predictive consumption graphs can estimate optimal routes, for different charge requirements before leaving, optimizing for fastest time, best blimp paths, least energy consumption, traffic congestion avoidance or whatever.
Rail-based navigation is considerably simpler than autonomous driving. The problem is reduced to "how far am I along the track" and "if there is something in my way, it's trespassing on the railway, so make a best effort to detect the obstacle and stop, and beyond that, who cares".
I see what your point is regarding the convenience of using a car. What could be more convenient than leaving your house, getting in your car, then being dropped at your destination? But this doesn't take into account the cost of the entire infrastructure needed to make it work flawlessly. On the other hand, the train goes faster, and benefits from economies of scale. A tightly knit network of trains would beat a transport system made of autonomous cars.
I did some napkin math on this a while back[1]. It's interesting.
1: https://news.ycombinator.com/item?id=13177836
I think people will still want their own personal cars, because...
> some of the good parts of trains and buses, and some of the good parts of Taxis
...they won't want to get the car with the drunk vomit urine and heavily graffitied and torn up interior.
I can see how you could - via the hailing app or whatnot - send the car off as "undesired because XYZ" - and maybe it would go somewhere to get refurbed, but after a while, with so many refurbs, the companies will either give up, or they will make concessions (allowing for so much damage until it is deemed "needing repair" and cleaning it up as best as they can otherwise).
People might also want personal cars as a quicker convenience, and also as a status symbol. There's also those who might want to ride around in a personalized custom car, much like people do today.
I'm not making a case people won't have their own cars, I just think it will be less common, and extremely less common to have two or more for a family.
> ..they won't want to get the car with the drunk vomit urine and heavily graffitied and torn up interior.
It's not like you don't know who was in the car that caused the problem, and can't have the whole day recorded for proof. Charge a cleanup fee, include video as proof. If it requires immediate cleaning and must be pulled off the road, charge them for the average income for that time as well. If it's in the agreement for the ride, you can auto charge the account/card as well, since that's how they paid in the first place.
I think that's plenty of incentive to cut down on people not treating your vehicles well because there's no driver to call them out.
> People might also want personal cars as a quicker convenience, and also as a status symbol.
Sure. For the same reason people buy $100k+ cars. That's a somewhat small segment of the market.
> There's also those who might want to ride around in a personalized custom car, much like people do today.
Insurance will likely start to make that expensive. Sure, it will happen, but I think it will be less common. It's already an expensive hobby.
This is a "America v/s Europe" problem.
If you design suburbs so that houses are clustered around Train Stations, then trains are a huge asset.
If you design suburbs around the car, then no, it won't work.
Writing this, I recognized that it is probably short-/middle-term money, because electrical cars are quicker to develop (incl. infrastructure).
Assuming you use electricity to split water to power your fuel cell, you've basically just made an even more complicated way to use electricity to power your car. So at that point, just simplify it and just use a battery and a motor.
"There are four main sources for the commercial production of hydrogen: natural gas, oil, coal, and electrolysis; which account for 48%, 30% 18% and 4% of the world’s hydrogen production respectively."
https://en.wikipedia.org/wiki/Hydrogen_production
http://www.ucsusa.org/clean-vehicles/electric-vehicles/emiss...
Given that power grids everywhere are turning more towards renewable energy, this efficiency will only grow. The cleaner the grid, the cleaner the stuff that runs on the grid.
As for Hydrogen, lack of infrastructure is a major issue, on the production side as well as distribution. Producing hydrogen from natural gas produces CO2, producing it from water is slow and requires electricity, once again you're tied to the grid. There are further issues, found a good list of them here: https://cleantechnica.com/2016/06/10/hydrogen-fuel-cell-cars...
Longer range battery powered cars suffer from high weight for range and long charging time. Even the charging times of a Tesla are not truly viable in long trips; its 45+ minutes to get full. A thousand pounds, long charge, and very high capacity loss in cold weather are not the big negatives. Add in even hilly terrain hurts them too.
I think after the honey moon is over those who select an EV as their only car; a lot of those buying into the 35k-50k cars may only have one vehicle; will soon find its limitations irritating. I would not mind a Bolt,but only as a second car. 200 to 300 miles is not enough and the charge time, again even in Tesla, is not acceptable
I also own a Chevy Volt. It's my only car. The biggest improvement is the fact that I almost NEVER have to go to the gas station, and every trip I've taken has had each leg within a Model S's top range.
Going to the gas station constantly is an inconvenience that most people simply don't notice until they get an electric car.
So would I rather take a 15-40 minute lunch break on a road trip every 3 hours on the maybe one road trip beyond 200 miles I'd go on every year or have to travel to the gas station 50 times a year? Obviously the latter involves a lot more wasted time.
Oh, and charging speed is improving. No reason, fundamentally, you couldn't engineer a battery that charges, say, 100 miles in 5 minutes or 200 miles in 10 minutes. Tesla AND others (VW, etc) are planning/testing 350kW charging, which would help enable that speed.
As far as cold weather: balooney. I've lived in cold weather states for most of my life. Conventional vehicles have a huge disadvantage in that they don't even start AT ALL in some conditions whereas electrics have zero problem. And since they're already plugged in, you can pre-heat them before you leave (without burning gas, mind you).
Hilly terrain is actually much better with electrics since you have PLENTY of torque and regenerative braking means you're not going to overheat your brakes like you would in a conventional vehicle.
People will argue that running on the iron directly is more efficient, but on a large scale, electric wins. It already won, it's just not apparent yet.
1) It IS inherently cleaner than conventional even without a major switchover, for two reasons:
. a) A central power station can be much more efficient than a small internal combustion engine, even using the same fuel. A good natural gas power station can get above 60% efficiency (caveat: LHV... but even using HHV value for natural gas, still above 50%), whereas internal combustion engines are around 15-25%, although can be even worse. This difference is much greater than any transmission or round-trip charging losses.
. b) Regenerative braking only (practically) works with electricity. This already makes electric cars cleaner, since they can recapture kinetic energy while braking. In conventional cars, this is all wasted as heat. A side benefit of this is electric car brakes last way longer.
2) We ARE changing over. Coal used to be >50% of our electricity, now it's on the order of 30%, and usually is dwarfed by natural gas at 33%. Natural gas per unit /thermal/ energy gives off a lot less CO2 than coal and still significantly less than gasoline or diesel. And natural gas plants are also very clean burning with almost no ash and soot (which can cause global warming in other ways, besides asthma and lung cancer, etc). And it's easier to make really thermally efficient natural gas plants than it is for coal. HOWEVER, even natural gas is now over-shadowed by clean energy (now at 36% of power) from nuclear, wind, hydro, solar, and geothermal combined (in that order). So now over a third of electricity is essentially carbon-free. This means that electricity on average is actually less carbon intensive in the US than if it were all produced from natural gas alone, which makes it even cleaner than if it were all centrally-burned petroleum, which makes it cleaner than if it were small internal combustion engines.
3) Fuel cells (let's take hydrogen for example) have major problems. The MAIN being the terrible round-trip efficiency. Electrolysis of hydrogen from water using electricity (this is basically the best case scenario, realistically) is 40-60% efficient. Fuel cells are themselves only 40-60% efficient. Then you add in the significant amount of energy needed to compress and transport the hydrogen (transportation is comparable to transmission losses from electricity, but sometimes worse), and the total efficiency is somewhere between 20-35%. Batteries are around 80-90+% efficient, and you can do even better if you're careful. That means you're ALREADY only able to travel a fourth to a third the distance in a fuel cell car for the same amount of electricity generated. That's insanely bad when you think of it. This is the main problem.
4) Fuel cells are actually much more expensive. They require high pressure storage and transfer. The fuel cells themselves are expensive, too.
5) Hydrogen itself has problems. There are material compatibility issues. A good lithium ion battery using a silicon chemistry can actually have a higher volumetric energy density (when you include the lower efficiency of fuel cells) than hydrogen, meaning you can make a more compact electric car or put a bigger battery in the same space. Hydrogen is also insanely flammable, with a very high flammability range in air. It makes explosive mixtures with air very easily. It also causes embrittlement of metals.
6) Electricity distribution is already ubiquitious due to the electric grid. Most people can charge at home (and even more if apartments just run out an outdoor outlet to parking spaces). That means people almost never need to go out to a filling station. It's only needed on long trips, and even then only after exhausting the internal battery. Many hotels/motels already have RV charging (and many allow EV charging), so on a multiday trip could start out each day with a full "tank" without any trips at all. And there's already been a lot of work installing charging stations all over the country, including very fast charging roughly equivalent to the ...
Cleanliness isn't really any reason one way or the other but there are other differences. Energy density of hydrogen fuel cells is higher than Lithium ion batteries so vehicles can travel further. On the other hand, physically moving hydrogen is relatively expensive and infrastructure to do so doesn't currently exist while distribution of electricity is a thoroughly solved problem and is relatively efficient.
So to beat that, you have to use less than one fuel cell to transport 19 other fuel cells. I honestly have no idea whether that's easy or not.
https://www.eecbg.energy.gov/hydrogenandfuelcells/pdfs/28890...
Forbes had an article about it which started with a bit of skepticism about the system:
https://www.forbes.com/forbes/2003/0120/092.html
Even so - to me the idea seemed reasonable. Furthermore, there's a place in the United States almost nearly perfect to set up a production/recycling system. I have yet to find an objection to why this process (or the location - aside from possible EPA or endangered species red tape) couldn't work.
The location? Kramer Junction, California.
https://www.google.com/maps/place/Kramer+Junction,+CA+93516
If you've ever been there, you probably didn't stop (unless it was for some gas or fast food). It's a "grand intersection" - you have at least one main railroad line, two highways, and one or more high-tension power lines going thru the area.
To the east, is Barstow and Daggett - testing grounds for the Solar One array:
https://en.wikipedia.org/wiki/The_Solar_Project
So plenty of sun to power things with.
Powerballs are based on sodium hydride pellets, which are manufacturer using a complex process - part of which involves molten sodium (!) with hydrogen gas (!) bubbled thru it. Molten sodium has been used as a means for solar concentrators to move heat from the array to the heat exchangers for steam (it can even stay molten thru the night, continuing power generation with no sun input). At least, that's what I understand.
I've also heard (and maybe I've misunderstood?) that the Powerball system can also be done using sodium borohydrides - for which you would need borax. Guess what is also nearby?
Just to the west is Boron, California (famous for the "20 mule team"):
https://www.google.com/maps/place/Boron,+CA+93516
So - if borohydrides can work - you have that supply (I believe it still is mined there).
Now - hydrogen - where to get that? Well, we need water, but we're kinda in the middle of a desert here. However, not too far away is a pretty good source of water - the Colorado River (plus various lakes and reservoirs). There might also be briny ground water that couldn't be used for drinking or agriculture, but would work ok for this purpose).
So - assuming we have all of this - we can make hydrogen somewhat simply, using a couple of different methods:
1. We could use an old method to create it, using solar as part of the energy input and steam generation; this was a method used in the 1800s to create hydrogen for gas ballooning enthusiasts:
http://www.sciencedirect.com/science/article/pii/S0378775399...
I won't pretend to understand this - but the usage of coal in the process concerns me (mainly the CO production) - I'm not sure all of that is re-captured in the process of conversion.
2. We could use solar power to heat up steam enough so that it dissociates into hydrogen and oxygen:
On the other hand, a universal joint and a drive shaft are about as straightforward and reliable as it gets. You can still have a motor per wheel and size is not as restricted.
Long story short: in hub motors don't make sense unless you're very space constrained, like on an e-bike.
You can build a good enough demo to get press. Once the vehicles are out there as a product for a couple years the flaws will be clear.
It needs a lot of infrastructure in roads. That's really expensive and a huge maintenance headache.
The wireless power people need to get to a standard charging pad that Just Works, and get it widely deployed.
Is it any more expensive or more of a headache than all the externalities, costs, and dangers of the alternative? At this point in time, societies all massively subsidize the fossil fuel industry at great cost to everyone but it's so spread out its hidden from view. I'm curious, if there is ever a realignment of costs from society at large to the oil companies, would the wireless charging roads look far more viable?