Sunday, June 12, 2011

Land transport without fossil fuels

When there are lots of people living on the moon or on Mars they'll probably like to have the same freedom to travel in their own personal vehicles that most of us in wealthier countries enjoy on Earth today, in fact, some sort of efficient transport across the surface of each planet is going to be crucial to development.

If we make the assumption that battery technology is never going to equal the energy density of petroleum fuels, and given the extra demands that are likely to be made on the energy systems of surface vehicle simply because of the environment they have to operate in, it would be useful to have a system that uses electricity but with which each vehicle would have a virtually unlimited electricity supply.

On the face of it that sounds impossible - without going nuclear - but it's actually pretty easy to do, all it requires is a roading system that has a reticulated power system that feeds each vehicle while it's traveling on longer journeys, and all that would require is a two rail fence down the middle of the major roads with the top rail being the positive, and the bottom rail the earth (think I'll stick with "earth" rather than try to be clever with "Lunar" or "Mars") each vehicle would be equipped with nothing more complicated than a couple of trolley poles to give unlimited range. To keep costs and hazards down, vehicles would still have batteries for emergency and just to cover the few tens of kilometers of unpowered minor roads, and the few kilometers of the driveway.

Thinking about it, it might even work on this planet.


  1. In fact I think it will not only work on this planet, but we will see it in the next decades. Think about it--governments are trying to create incentives for driving electric vehicles. The motivations for these incentives will continue in the decades to come; even if half the population drives electric, it will still be desirable to increase that proportion further. One incentive might be free charging energy, which could be transferred in special lanes akin to the "HOV" lanes on busy highways. I imagine governments might first experiment in cities like Los Angeles.

  2. I've been pushing this idea for months now on any blog that had a post on the subject of EV's, I just thought I'd put it on the Moon for a change.

  3. Hello Andrew,

    I think the idea would be more successful as a trolleybus style system, with, for example -240V and +240 V on a pair of cables. Many of these are in operation, but not as extensively as you propose.

    I’m not sure however about the application on Earth for passenger cars. Main issues I see:

    Height: The wires (rails) would have to be about15 feet high for trucks. Makes for a long pole.
    Peak load: Cars operate about 2-3 hours a day, going in and out of town (40 km average distance). Connecting them all at the same time would increase the already critical problem of peak demand in cities. Utilities are interested in electric cars and batteries because they spread out demand and your proposal would do the opposite.
    Billing: How does the electricity supplier charge car owners? And what about when you change states?
    Snow: The ground rail would fail in heavy snow conditions, and snow plow operators would rip’ em apart.

    One application that might work would be using the cables for long distance trucks on highways. They usually run on a single lane, have space for batteries for the off road maneuvers and the analogy with existing trolleybuses would make the system easier do develop.

    The cable material we discussed for the moon rotovator would come in handy as structural material for a very high speed flywheel energy storage system. Since it is about 10 x stronger than existing carbon fibers, it should allow flywheels to store energy densities 10x higher, as high or higher than the best batteries, with a much longer operating life and 0 maintenance for magnetic bearings and no disposal problems.

    Trolley trucks, intercity buses, on main roads only, with rotovator cable flywheels and twin overhead cables. What do you think?


    Michel Lamontagne

  4. Hi Michel,
    Height: The wires (rails) would have to be about15 feet high for trucks. Makes for a long pole.

    There would be two heavy rails on uprights down the middle of the road, the top rail powered, it would be about 1.2 meters tall with the trolley poles extending from the left side of vehicles (in countries that drive on the right side of the road).

    Peak load: Cars operate about 2-3 hours a day, going in and out of town (40 km average distance). Connecting them all at the same time would increase the already critical problem of peak demand in cities.

    40 km is actually the distance for battery power that I had in mind, vehicles traveling greater distances than this usually have a major road (highway or motorway) included in their journey. Vehicles would typically charge at home over night, start their journey on battery, and only go onto the powered roads for longer trips, in this way we get the best of both world, charging a night, small battery size, but still have the ability to make long trips.

    Billing: How does the electricity supplier charge car owners? And what about when you change states?

    With wireless digital communications billing is pretty easy. As to metering, diesel cars in this country are taxed for road use with a hub meter, it's not hard to forget to pay the bill, but if you do it for too long you'll get caught, metering could be based on distance traveled on the powered system x vehicle class, if thats easier than measuring kWh's.

    The cable material we discussed for the moon rotovator would come in handy as structural material for a very high speed flywheel energy storage system.

    An outfit called Power Tree Corp is working on large scale flywheel energy storage, though I'm not sure they've got anything up and running yet.

    I think spaced based solar power will happen, and a flywheel energy storage system might be an option to stabilize power from them, especially if the solar power satellites are in low sun synchronous dusk to dawn orbits using switching systems to move power around to meet peak demand, especially as, because global population is spread so unevenly across time zones, peak demand periods are not smoothed very well even across the whole globe.

    Cheers, Andrew Worth

  5. There is a safety issue with this system that limits it to major roads as the powered fence (I'll emphasis it's a two rail fence not overhead cables) would not be something for pedestrians to navigate. You'd also have to have vehicles wanting to turn off onto minor roads and driveways on the left disconnect and pull off to the right, and then go though an underpass, or go on to major intersections and back track.

  6. Hello Andrew,

    Why the emphasis on the fence?
    In Canada, even at 1.2m, i'm afraid it would pass part of winter under the snow bank... Overhead cables seem safer. And you can get twice the voltage for half the danger. Three lanes highways also seem troublesome.
    But perhaps one of the greatest problems is that diesel and gas are still just too cheap. Around Montreal, railways and suburban trains are still diesel, even though the're a natural for electric power. The train company just doesn't want to be bothered with the infrastructure.


    Michel Lamontagne

  7. Hello Andrew,

    Driving on the moon = no aerodynamic drag and very low friction (directly proportional to G) so a battery can go a long long way... with regenerative braking and flywheel storage even further. But turning a corner without skidding though, that would be a challenge!

    The rail might actually come in quite handy, at this point, but not for the same reason!

    Michel Lamontagne

  8. Why the emphasis on the fence?

    I may be wrong but it seems cheaper and simpler, to put it overhead you'll need taller uprights, and have lots of unsightly wires. I had the thought that with trolley poles sticking out the side of vehicles and contacting the fence would give you the start on a simple self steering system, and I had in mind the fence itself being heavy enough to be a crash barrier (I know an electrified railed fence doesn't sound like a good idea for that).

    There's also the point you raised that 15 feet is a long way up for trolley poles from cars, I'd be looking at poles that slid out laterally only a couple of feet and fully retracted when not in use.

    But on the Moon the nearest gas station could be 1000km away! One of the terrific things about building roads on the Moon would be no rain, and of course on corners you'd just camber the road however much was needed.

    On multi-lane roads here on Earth you'd just have a fence on the left of each lane.

    I don't have to deal much with snow where I live, but I would have thought 1.2 meter deep snow would stop traffic no matter what the motive power source!

  9. Hello Andrew,

    The snow from the middle of the road is piled up on the sides, higher and higher, where it sits until spring (hiding the rail). If you google 'snow bank' images, you'll get a good idea. I have a 1,4 to 2m snow bank in front of my house every year.

    Passing from lane to lane would be tough.

    In Quebec, we can just barely afford to keep up the existing infrastructure, so adding a whole other level of stuff to maintain... I'm hoping for better batteries.
    There are some existing flywheel UPS systems that might serve as seed technology for car rated power flywheels, specialy with rotovator materials.


    Michel Lamontagne

  10. Michel, my rails are in the middle of the road, not the sides.

    I'd be wanting the system to be self steering and navigation, everything would move at the same speed and lane changing would only happen at motorway on ramps and exits.

    It's a heavy railed fence down the middle of the road, the trolley poles themselves work to prevent vehicles colliding with it, how much maintenance can there be?

    Also you have electric cars vs infernal combustion engine cars, that should mean less time and money maintaining vehicles.

    I'm hoping for better batteries.

    Everybody seems to be hoping for better batteries, which usually means better by a couple of orders of magnitude. Reminds me of the line "nuclear fusion is the power of the future - and always will be." Sometimes you just don't get what you hope for, but good luck with that anyway.



  11. Hello Andrew,

    It’s an extended form of ‘Personal rapid transit’ then?

    Fun with maintenance:

    The rail:
    Rails, especially horizontal ones on isolators, will eventually sag when carrying important amounts of current. The spark at the contact point, that is at a few thousand degrees, will evaporate the rail surface and promote corrosion. The spark will also create ozone, adding to pollution problems.
    Aluminum and copper rails will corrode and wear out from friction.
    Steel rails will last longer but will still rust.
    The isolators (bushings) will stain and crack, leading to short circuits.
    Connectors from rails to conductors will crack from vibration, thermal expansion, and salt (at least here, where it is used for deicing the roads)
    Rails will be fed from substations, which occupy ground area that has to be paid for. Substations need a caretaker.
    Transformers must be replaced every 50-70 years. There will be thousands of these, especially for steel rails.
    People will steal the copper ground wires to sell for scap ( I kid you not, a real problem for Hydro Quebec).
    Switches, breakers, fuses all require maintenance and replacement. Insulation, especially for wires exposed to the sun, will crack and fail eventually.

    The controls:
    The software will become obsolete and have to be replaced. The electronics as well. Control cabinet wiring will cook in the sun and heat, and have to be replaced.
    Standards will evolve, and the original controls will have to be replaced to conform with ISO xxxxx.

    The posts will shift in the ground, suffer floods, frost, collisions and general wear and tear. Galvanic corrosion will destroy the bolts holding them in place. Concrete will fail from water infiltration and CO2 contamination.
    Shoddy contractor work will have to be corrected.
    Bridges will have to be widened, or otherwise modified. It will be discovered that the existing bridges structures of xx% of the bridges do not correspond to modern building codes and that they must be entirely rebuilt.

    After a major pileup leading to 20 deaths, 10 years after implementation, a commission will show that lives would have been saved if the concrete posts has a built in failure point made from an aluminum z-bar. These will be implemented after a major redesign forces the foundations of 45% of the poles to be rebuilt.

    The lateral trolley posts cannot be strong enough to stop 1 ton cars, at 100 km an hour, from swerving into the rail.

    There will have to be an access space behind the rails for safe maintenance, and maintenance tunnels. This space will fill up with junk blown in by the wind, and get choked with weeds, that must be removed. Good summer jobs for students!

    That being said ;-)

    I totally agree that electric cars will be much simpler to maintain than internal combustion engines and are much more efficient.

    An order of magnitude for improvement in batteries would be great, two is too much to hope for, but I’d be happy with just twice as good! If they lasted more than a few years, that would be good as well. I’ve worked in a lead acid battery recuperation plant. Not a nice place. I can imagine the fun they will have with lithium…

    What do you think of the ‘Better place’ switching station solution? Charge the battery for short distances, switch batteries for long trips?


    Michel Lamontagne

  12. Hi Michel,
    I think if the maintenance problem was of the scale you imagine; the subways would've all failed, the present electrical reticulation system would have collapsed, and the supports on all our bridges would have fallen over. None of these things would have been worth building as these maintenance problems you describe are the same maintenance issues that have to be dealt with everyday with any mechanical and electrical system.

    If the cost of maintaining electrical reticulation systems was large we'd all be running our homes on our own domestic diesel generators.

  13. Hello Andrew,

    With all that maintenance for fuel trucks, refineries, wells, pipelines, it’s a wonder they would get the generator fuel to us at all!

    As an aside, these days, we have 14 major repair projects for the Montreal area highways, the main exchanger west of the city will have to be demolished and replaced, two main bridges to the south shore are so damaged by rust that they will have do be rebuilt completely in the next ten years, and one of them is the same model that collapsed in the US a few years ago. We are rebuilding every single concrete overpass on our main highways since one of them collapsed and killed 4 people. Sigh. Poor maintenance; and ice.

    Getting back to the rail system : It takes about 8000 people to maintain the local electrical distribution system in Quebec for 7 million people. Up to 15% of the cost of electricity. My guess is that the electricity or the rails would cost about that much more. Not the end of the world, but not trivial! Plus another 10% to finance the construction of the rail system. So a 25% premium on grid electricity.

    Technically, I have no doubt the rail could be made to work. That’s not really my point. It’s just that it represents a new infrastructure for energy delivery and I’m skeptical it’s required. I don’t see the business case, either. Why pay extra for electricity if you can charge up at home? Even better, if you leave your car plugged in, the utilities will pay you for access to your battery during those peak minutes that they have to pay at ten times the base cost.


    Michel Lamontagne

  14. Well it'll swing on the price of oil, concerns over carbon, and battery cost and efficiency.
    If we see the rest of the world trying to follow the Western example in personal transport it'll have to be electric in one form or the other, battery capacity and cost have been an impediment for 100 years, I'll be surprised if that changes anytime soon. So I see it as a quantifiable known verses an unquantifiable unknown.