The Tesla Semi...

edited November -1 in General
My apologies if this topic has come up before in this forum.

I have been thinking over the last few weeks about the unveiling of the Tesla Powerwall and its potential in the United States. And it seems that, while neat, it's somewhat useless as is. For it to truly pay for itself, one must live in a place that has variable day/night rates, and the difference must be enough for the battery to pay for itself over a reasonable amount of time, say 5-10 years. As prices drop, I can see this opening up to more areas of the country, but its initial purchasers would be those believing they are more environmental than what they actually are.
However, the introduction of these in a business environment, i.e. Wal-Mart, may make more financial sense as they use a large amount of energy during the day and can cut back sharply at night, allowing a bank of Powerwalls to cut costs with a reasonable payback time. All of which leads me to ask, why are we limiting ourselves? Why are we not integrating the two ideas into a larger system with a greater impact?

For example, can we not create a semi tractor that runs completely off of electricity? This is where many of you may skip to comment about the massive amount of energy required, far more than that of the Roadster, and storing that much energy is not feasible. But please, let me finish. Hypothetically, we build a semi-tractor with a large electric motor attached to a relatively mild battery, say double that of the Tesla S, so 170 kWh. The semi is attached to a trailer, under which are three more Model S-size batteries, weighing a total of roughly 3600lbs, providing an additional 255 kWh, and wired to the tractor. That is roughly 10% of the max weight a standard semi trailer can legally haul. For a company that hauls bulky items that do not come near the 34-40,000lb limit, this might be a feasible option.

But, that's probably still not enough to haul all that weight very far, and it's not designed to. Most of the energy required by a vehicle is during acceleration and traveling uphill. It takes far less energy to keep a vehicle moving on semi-level ground than it does getting that vehicle up to 65 mph. That is where the solar roadway ( comes in. With an induction charger designed into the roadway , one could charge onboard batteries as you travel down the road. One could, in theory, recharge those batteries and save them for going uphill, passing, or pulling off of the highway to a charging station.

Multitudes of these semis on the road would lead to other helpful changes. Truck stops could be fitted with battery swaps for those that might need it. Rapid chargers could be fitted anywhere trucks might stop: truck and rest stops, along on-ramps, and at major shipping centers. Many of these shipping centers could be outfitted with Powerwall-esque battery stations that hold and distribute solar, wind, or conventional grid electricity to those semis overnight.

Anyway, those are my thoughts on it. Feel free to pick apart as you will…


  • edited November -1
    Solar roadway will never happen. Wayyyyyyy too expensive and i doubt could carry trucks. And inductive charging is very inefficient.

    For the cost of a solar road in energy terms it would be far easier to run overhead wires trolley style and connect them to the grid. Or ordinary solar farms along the road if you like.
  • edited November -1
    Or think about this. A trailer also has 35 square meters of flat roof. Even with current commercial efficiency of 20%, that is 7kW of charging. Now lets say that during an 8 hour winter day you only get an average of 1/3 of that due to angles of the sun that still nets you almost 19kWh. During a 16 hour summer day lets say you get 1/2 of the max, 28kWh. This gives a 10% charge in of itself, and with 5 85kWh packs for 255 kWh, this is roughly 6.5 gallons of diesel equivalent, and since electric drive is 3-4 times as efficient this makes it the equivalent of as much as 26 gallons of fuel, and since rigs get like 2mpg we are talking a MASSIVE 50 mile driving range. So I think we all can agree that even with every tech available right now an electric rig is a bad idea?
  • edited November -1
    The simpler the better. A truck with a dozen Model S sized batteries would work better than trying to put in inefficient charging while driving solutions.

    Tesla Model Semi 1.0 needs at least 300 mile range and a reserve for altitude changes to handle the trips from the Gigafactory to the Fremont factory (258 miles by Google Maps). (timeline approximately 5 years - perhaps a fleet of 100 vehicles to continuously transport batteries.)

    Tesla Model Semi 2.0 needs to double that to 600 for more efficient delivery of cars from the Fremont Factory to all of North America. This will also require a few Tesla co-branded truck stops that have SuperDuperChargers that can charge the dozen batteries in a timely manner.
  • edited November -1
    timeline for model 2.0 would be about 7 -10 years. :)
  • edited November -1
    The solar roadways can hold the equivalent of a 250,000lb truck. As for expense, as they are mass produced the cost goes down like any other electrical device. The savings from the reduced maintenence compared to asphalt should help offset some of not all of the increased cost.
    Solar farms require land. Solar roads use existing land so it serves two functions, not just one.

    I'm unsure where you get your numbers, but semis get roughly 5-6mpg, and newer high efficiency models get close to 12mpg.
    Your solar panels on the trailer idea shows exactly why I need road to produce my electricity.

    You're right, induction charging is inefficient, but remember that a truck is being charged the entire time it's on the road. Even if the batteries lost 75% of their charge during a 12 hour trip, there are still those rapid charging stations I mentioned along the road to recharge during the required trucker breaks.
  • edited November -1

    Building costs of the solar road with $0 solar panels is still about 100x tarmac road because everything else it needs. It will be too expensive for road use forever. It could become useful for something like parking lots, but for roads, never.

    Whole idea is just stupid IMO, it would be cheaper to cover a road with solar panel canopy than trying to put it onto road. That's how expensive that is.

    "The savings from the reduced maintenence compared to asphalt"

    reduced??? How about multiplied by a lot. If someone has said that solar road requires less maintenance he/she was telling you direct lie, or has no clue what he is talking about.
  • edited November -1
    Timo plus a million

    Dont need real eatate. Panela in median angled toward sun.
  • edited November -1
    You're clearly right. It will cost more money because it just will. And your lack of evidence that it will cost more is overwhelming.
    The truth is that no one knows what a solar roadway will cost, even the people building it can't say. Nor can they say what it will be in 10 or 20 years. What can be said is that solar roadway panels are designed to last 20-30 years. Asphalts life span is much less than that. If a panel goes bad, it can be replaced without tearing up the area around it. Asphalt needs constant patching and replacing.
    Asphalt provides you NOTHING other than a roadway. It serves no other purpose. It is a graveyard for petroleum. It is a money pit. Solar roadway panels may be able to pay for themselves and may be able to pay for their maintenance.
    But of course, this idea is as foolish as an electric sports car that can go over 200 miles between charges. The technology doesn't exist! It will never happen!
    Oh wait...what forum are we on again?
  • edited November -1
    While Tesla makes a great car and has audacious plans to bring affordable electric transportation to the masses, Tesla is not the answer to every transportation problem. Eliminating 100% of carbon based fuel sources is much more expensive than eliminating the first 80%.

    This hybrid (yes, hybrid) solution developed by a Tesla founding member is optimized for the market that you are describing.

    Optimization of resources (money, fuel, time) needs to be pursued based on the application.
    One size does not fit all.
  • edited November -1
    Unless these solar roads ways can bend, it isn't feasible. How do you deal with hills. Also, presumably ICE will drive on this and as is with ICE cars, when one gets into a wreck and catches fire (oil/gas) how well will the PCV cells hold up?
  • edited November -1
    @al; do some research. Solar roads with infrastructure it requires cost way way too much to ever become feasible.

    It is made using bricks. If one brick gets loose it becomes serious safety hazard. If not from panel itself that hit the cars, then from the pothole and exposed live electrical wires. That <u>alone</u> is enough reason to not ever do that.

    It requires foundation of the road that doesn't move. At all. That's because those bricks can't move, otherwise they become loose or break. That means that before you have put even one bolt into road you have already used more than tarmac road needs. Basically you need to create steel-reinforced concrete road as foundation.

    Then there are wirings, conversions from DC to AC, sensors to detect failed parts, huge cost of personnel that maintain all that and so on.

    Installation of the panels is very very slow process (compared to tarmac road), which translates to way higher cost.

    I haven't even touched the cost of the panels themselves, and already have costs that are many many times higher than ordinary tarmac road.
  • edited November -1
    This makes sense. Have a read.
  • edited November -1
    Wrightspeed turbine generator or fuel cell.

    There are two major obstacles for long range BEV truck:

    a) battery cost
    b) battery recharge rate.

    If semi uses 10x energy compared to Model S, that's 850kWh battery for tiny 250 miles. Tiny for a long-haul truck.

    Using SC 150kW charging 850kWh/150kW ~= 5:30 charging time. That is not feasible. Not for long-haul trucking. No battery tech can change that.

    Electric motors have advantages over ICE, but BEV isn't really feasible for everything. Not without inductive charging. While I think solar road is stupid, inductive charging road OTOH is feasible idea. Magnetic resonant coupling for wireless power transmission is quite effective if the distances are not very big. Not as effective as conductive charging, but advantage is that you don't need to stop at all.
  • edited November -1
    Diesel electric power plants move trains and their cargo, gozillions more weight than any semi-truck, all over the United States. But diesel engines are at best perhaps 40% efficient. Even at that rate, it is better to use the energy to power an electric generator than drive the wheels directly using diesel. That is because the torque of an electric motor vastly outranks that of a diesel motor.

    With a proper battery swap solution, a fully electric semi truck designed as such from the ground up -- would positively demolish a diesel truck. Imagine either one electric motor per axle... Or one per wheel on the truck itself. The improvement in traction from being all wheel drive would be impressive.

    Just one of Tesla Motors' electric drive units surpasses the horsepower and torque of some truck engines. So having three-to-six of them on tap would make the hauling of no issue. Because of the mass involved, a considerable amount of capacity would have to be on hand. The question really is how far you would want to travel on a single charge.

    1 gallon of diesel fuel holds 40.7 kWh of energy. If a semi-truck typically travels six miles per gallon, that is 6.7833~ kWh per mile expended. Assuming an electric motor could perform the same work using 20% as much energy, that comes to 1,356.66~ Wh per mile. But since only about 40% of the energy expended by a diesel motor goes toward motion, then an electric motor might use 542.66~ Wh per mile. That is certainly a whole lot. But it means a 600 mile range may be achieved with a 362 kWh battery pack, if you include about 10% battery protection. And that is around half the range a typical longhaul driver would find adequate.

    So, actually... An 850 kWh battery pack capacity would make for a formidable semi-truck. I figure a range of ~1,400 miles would not be out of the question.
  • edited November -1
    Well, Red, if that is 10 model S packs. Call it 10000 lb. Dont forget that trucks pay taxes based on weight so that weight comes out of payload.... plus the weight limits on bridges.
  • edited November -1
    Well, the presumption is that this wouldn't be done until after energy density had doubled from 2009 levels. So, that would be 2019 or later. Thus, the battery pack would weigh half as much as today. If we wait until 2029, then an 850 kWh battery pack would weigh only 2-1/2 times as much as today's 85 kWh version. Still hefty, but without the gigantic ICE and its myriad of accessories it would still be a worthwhile tradeoff. Especially since diesel fuel is bound to be in the <i>"Twelve bucks a gallon! Please pay before you pump!"</i> range by then.
  • edited November -1
    Actually, you're on to a Billion Dollar's idea over here. Here's how it can actually work.

    1. Tesla starts designing a semi to be used for transporting lithium to the GF and batteries from the GF to the car factory. It uses the same charger standard as the Model S and has solar panels on its roof.
    2. Tesla builds those trucks and the necessary superchargers to cover their routes.
    3. If the savings are worth it on the long-run, Tesla would build a factory dedicated to making semis and building the charging infrastructure would be done by someone. If the truck transportation business goes electric there will definitley be companies willing to invest in charging stations.
    4. The recomended truck driver's rest intervals will make these 30-45 min stops every 4 hours no problem at all and the efficient driving habits of them will mean doing the math as if the S85 gets 350 miles of range if you know what I mean.
    5. Diesel is expensive and new aerodynamic trucks get 8-10 MPG which is 30-50% better than older trucks. However, trucks are very expensive and the ROI of buying a newer one is not worth it for many businesses. That's why you see older trucks relegated to less interstate use if you notice. This means an electric truck has many potential buyers.
    6. Internal combustion systems are pretty expensive on trucks, the bigger the electric motor the more savings you have over an equivalent ICE. So even with 850kWh "which would mean a 1000 miles+ range, way more than needed" that's $212,500 based on powerpack's $250/kWh. Mercedes Actros goes up to $300,000!
  • edited November -1
    I pictured something with four or six battery packs, stacked two high and two to three length-wise. The truck front would resemble a bullet train, with the trailer replaced by a flatbed for loading cargo boxes. The vehicle would sacrifice the bending joint between tractor and trailer and gain aerodynamics, with the same cornering abilities as a bus. It would have an add-on tail behind the cargo box, one that slides forward or back until snug against the cargo, forming a tapering tail.

    Batteries could be recharged by connecting each to a supercharger at a specially designed large truck stop charging station, or by battery swaps. Battery swap stations at a truck stop seem in the long run one of the most sensible solutions, even if it's something Tesla is having a tough time doing. (Tesla is great at doing the impossible, revolutionizing everything from electrification of cars to autonomous driving, but for some reason this one seems to be stumping them a little.)
  • edited November -1
    SolarRoadways <- are the "Tesla" of roads. Tesla + SolarCity, actually.

    It never ceases to amaze me that on a forum of Tesla enthusiasts there are so many that so quickly dismiss Solar Roadways as "impossible", just as 200 mile per charge EV's were "impossible" to accomplish too :)

    The simplest, and most powerful reason I always give to the those that "Grin" but don't "Shine" is this . . . Elon Musk & Bill Gates made significant contributions to their incredibly successful (over 2.25 million and STILL counting, now in it's "forever funding" format - IndieGogo campaign. If THEY think it's worth pursuing, then I think it's worth pursuing.

    BTW, many of you forgot (or ignored) all the subsequent EXTRA money that is saved/created from ancillary purposes. No snow removal. Fewer accidents (with dynamic road information updated instantly). Powerlines (and their infrastructure and maintenance) become a thing of the past. Not to mention the 20-25 year estimated lifespan <- no one knows for certain of course, until actual long term real world tests are run, could be more, could be less.

    Then of course there's the potential for FREE <- or at least incredibly CHEAP energy > replacing ALL of the country's utility providers when coupled with vast amounts of Tesla PowerPaks (of the MegaWatt variety) installations <- which I imagine, would facilitate SuperChargers EVERYWHERE!!!

    Elon himself already explained what VERY LITTLE amount of square footage of solar panels would be needed to run the WHOLE country (and world), and what an even smaller amount of battery (footprint) would be needed to house that energy for daily use.

    Solar Roadways are literally "paving the future with sunshine" <- WHY that is NOT their ACTUAL slogan, I'll never know.

    Keep Grinning, my friends, but remember to Shine on (you crazy diamond-shaped <- not really but kind of > solar road panels) too :)
  • edited November -1
    "no snow removal" = "uses 10x more energy in a day than it produces in a year". It isn't enough to just melt the snow, you need to keep the water from freezing, so even in no snow situation you would need to keep road above freezing temperatures.
  • edited November -1
    Solar roadways are not impossible, just insanely expensive, and because that impractical.
  • edited November -1
    Solar roadways are a very silly idea. Much easier to just mount solar panels beside the road.

    Snow? Well you could build a canopy (slanted to catch sun and shed snow) far more cheaply than solar road. Would be expensive but not as bad as the solar road.

    plus... glass is hugely energy intensive. Build a whole road out of glass? Please. Would never ever ever come out energy positive.
  • edited November -1
    Most gains are incremental in nature. Tesla's growth plans and approach from an expensive prototype roadster to a luxury sedan to the affordable third generation were only made possible once the cost/benefit equation could be balanced for each. The main goal of Tesla and other companies thinking along similar lines is to reduce our dependency on oil and a fossil burning based economy. Tesla is only just beginning. It will take years of growth and all of their attention to successfully manage what they already have on their plate.

    Wrightspeed can be viewed as a Tesla spin off by a founding member that saw a huge opportunity to reduce fuel usage in the trucking industry by a considerable amount. There is enough room for both companies and many others. They are not competitors, but allies working toward the same goal while carving out separate market niches. Elton Musk has always said that his competition is ICE vehicles and not EVs, BEVs, EREV's or hybrids. They all help to reduce the use of oil.

    Developing infrastructure is expensive. Any investment by Elon Musk and Bill Gates in Solar Roadways is to develop technology that might make sense 10 or 20 years down the road AFTER a major conversion to EVs is the norm, not the exception. In the mean time, the United States spends over 3 Billion Dollars a year importing oil. Eliminating that expense would cut our annual trade deficit by more than half. All opportunities to reduce that demand through efficiencies gained by conversion towards electrics should be pursued.

    Personally, I would hate to see Tesla move away from their core competencies. I'd prefer to see them branch out to pick up trucks, cargo vans, and the like first. Elon Musk is a showman and has captured the imagination of millions. He chases the commercial markets that offer the best opportunities for growth and subsidies. I'd prefer to see Wrightspeed be successful in parallel to Tesla in its own right so that both could convert the entire transportation industry more quickly than Tesla could on its own without Tesla running the risk of trying to do even more things at the same time and not being as successful because they've over-diluted their focus, their brand and their talent.
  • edited November -1
    Solar roadway is a solution in search of a problem and due to very large energy inputs in manufacturing and installation will never make sense in an energy sparse world. If energy were cheap enough to make it practical there would be no need for solar.

    Tesla cars answered a real problem- fossil fuels bad but people still want personal mobility.

    So solar road is never going to happen unless some politicians decide to do a Potemkin village.... total waste.
  • edited November -1
    Tesla cars answered a real problem: ICE cars suck. In soooo many ways. Noisy (it's gasoline exploding), jerky (transmission), comparably poor handling (high center of gravity, worse torque control), smell bad (exhausts), has less room (ICE+transmission+exhaust takes lot of space) and you need to go to gas station every now and then just to keep it going (which is worst of them all).
Sign In or Register to comment.