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Solar Powered Cars - in our Future?



  • yerth10yerth10 Posts: 428
    Wind energy prices have declined from 18 cents / KWH to 4 cents / KWH making it more affordable, however Solar power is still unaffordable, but it will be cheaper in the future.


    However for extracting Hydrogen or supplying electricity for vehicles, it will be NUCLEAR power which will do the job efficiently as the current nuclear power plants operate for 90 % of the time in a year, whereas SOLAR, WIND, HYDEL

    operate for only around 30 - 50 % of the time in a year.
  • I suspect by the year 2050, most people will be driving short-range EVs (~50 miles) with on-board engines for long-distance. Also known as "serial hybrids".


    Some will have solar roofs.


  • kernickkernick Posts: 4,072
    Here's a good, clear link showing how much solar energy the earth receives.

    Technology can only work to collect the energy at the density it hits. It can and never will multiply the energy. Now since that energy is spread out and many times clouds interfere, so they'd need to be spreadout, all you'd neded to do is cover 10% of the Earth's surface with solar panels. Maybe in northern areas where the sun isn't so direct, 50% solar panel coverage would be needed.
    That'll be pretty tough to do when the world's population starts moving to 20B people and the extra farm land that will be needed to feed 3X the number of people now. Say 5X the energy we use now.

    Look, you seem like a nice person with good intent. But the numbers do not add up. If we don't find a powerful new energy source and it has to be nuclear for that, whether it is 100 or 200 or 300 years, population growth and energy needs will overwhelm any combination of wind, solar, and any leftover fossil fuels. It doesn't matter who's forecasts you use whether growth is a little slower or higher; the high growth is in undeveloped countries,which have proven to overwhelm any attempts to stabilize their growth and provide a decent lifestyle. The end will be the same regardless of when you get there. The future has to be new nuclear technology power.
  • yerth10yerth10 Posts: 428
    Currently this is the energy mix for the World.
    Oil - 37 %
    Coal - 27 %
    Nat-Gas - 24 %
    Nuclear - 6 %
    Hydro - 6 %
    Wind, Solar, Geo-thermal may provide around 1/2 %.

    In the future (2030), Wind & Solar may get around 5 %. That is still important. Every %age point make a difference. Since Oil & Gas prices are increasing, there is a talk about
    other fuels. Its natural.

    Unless something like Fusion comes, we are doomed.
  • "Maybe in northern areas where the sun isn't so direct, 50% solar panel coverage would be needed. "

    That is a bit extreme! We've had Food famines in the past, but it looks like we're going to have an Energy famine in the future.

    Note this wouldn't be a problem is the earth's population was only 1 million humans, instead of 6000 million.

  • yerth10yerth10 Posts: 428
    Yes. Today's food consumption (rice, wheat, poulty, meat put together) is somewhere around 4 billion tons, but the fuels (coal, oil & gas) is around 10 billion tons. Definitely the alternative fuels will be needed.
  • kernickkernick Posts: 4,072
    you: Unless something like Fusion comes, we are doomed.

    me: "Doomed" is rather a strong-word. It has only been the last 100 years or so where large quantities of fossil fuels were needed. Otherwise the human race has grown and developed over the centuries.

    Our "need" for fossil fuels is based on our lifestyle choice. If oil, natural gas, coal, and nuclear energy go away tomorrow, people would adapt, unless we're so psychologically weak as a society that we commit mass murder or suicide. Would we lose all scientific research and development. No! We could still have scientists working on fusion and other advanced technologies. Wood is used now as the primary fuel at some electrical power plants. And we would have wind and solar electricity for other crucial needs. And if you're really worried, start brushing up on your farming skills, how to plow with oxen and how to care for horses. (Hmmm. sounds like an Amish lifestyle.)

    So the only real danger is if there is no "Great" energy source after fossil fuels and our current nuclear fission. I tend to be an optimist, as I see every year, all kinds of new knowledge being discovered.

    I think people ought to be more afraid of scientists finding a new energy source, rather than running out of energy. Say someone creates a nuclear fusion battery, and it's about the size of a watch battery. The fuel is water. Great, right? Well if we worry now about someone using a suitcase nuclear bomb, we'd have much larger concerns if we find an energy source 100 - 1000X more powerful. :-(
  • kernickkernick Posts: 4,072
    And you should think about how much fuel is used to produce that 4 billion tons of food. Fertilizers, tractors and other farm equipment, trains to haul large quantities, delivery trucks, processing plants, packaging, refrigeration and freezing, pasteurization.

    So when you consider how much energy you get out of any bio-fuel, you must subtract off what you put in.
  • robertsmxrobertsmx Posts: 5,525
    Technology can only work to collect the energy at the density it hits. It can and never will multiply the energy.

    True. After all, you can only transform energy, not create it. So, that limits us to whatever is available. But, how much of available energy can you convert today versus tomorrow holds the key, and measured as efficiency. That efficiency is expected to increase with improvements in technology.

    A laid back approach isn’t going to help in technological improvements that would be necessary for the future. And solar energy is going to be a part of it, not the end of it. Alternative energy transformation methods involving nuclear (limited), wind (limited), hydro (limited) power will also have a role to play.
  • gagricegagrice San DiegoPosts: 28,850
    And solar energy is going to be a part of it,

    Can you show me evidence where solar collectors are any more efficient today than they were 20 years ago? Are they any cheaper than they were in the 1980s? It still costs in todays dollars about $10k to put a system on your roof to supplement the power grid. With only a 5 year warranty. I already went this route in Havasu back in 1984. Even with the big tax credit it was a loss. The sun eats those collectors up in a few years and you are faced with a big bill to replace the panels. Solar is a "pie in the sky" to help with our energy problems.
  • yerth10yerth10 Posts: 428
    kernick wrote

    "So when you consider how much energy you get out of any bio-fuel, you must subtract off what you put in. "

    The cost of Bio-fuels include all those energy put in.
    America's Corn based Ethanol yields roughly 1.3 units for every unit in.
    Brazil's Cane based Ethanol yields even more and that is why that country have an extensive usage of that fuel.
    This year the Flex Fuel Vehicles are expected to capture 50 % of their market.

    At $ 1.8 / gallon of gasoline, E85 = gas.
    I dont know exactly about B20.

    Also please note that Oil does not come in if you put a straw. In USA, we have to go more than a kilometer depth to get it, infact if they drill 1000 wells, they get Oil in only 500 wells.
    The amount of energy that is needed to drill will be enormous.
  • larsblarsb Posts: 8,204
    Solar is progressing, and will make great strides in the next few years:
  • robertsmxrobertsmx Posts: 5,525
    Development around solar energy hasn’t stayed put since the 1980s. A lot of new technologies have been developed, are being used, and are being developed. And believe it or not, some companies are using solar cell panels on the roof of their manufacturing plants to cut down production costs by lowering electricity costs purchased from traditional grids.

    The efficiency has gone up but it is nowhere close to where it could be in the future. And cost has gone down. Honda announced its iteration of solar cell technology in 2002 with a 40% reduction in manufacturing costs (and is using its CIGS solar cell panel to partly supply power its manufacturing facilities, as well as in hydrogen extraction from water (HES/HES-II). Here is an excerpt:

    Honda has marked its presence on the PV scene by announcing their development of a solar cell enabling a 40% production cost reduction. The new cell, to be set up at Honda's production bases at home and abroad, will go on sale in cooperation with housing makers as early as fiscal 2003, Honda officials have said. One cell measures 1 square meter and is made of a thin film of copper indium gallium diselenide. Honda officials said they will soon start using new cells at a factory in Shizuoka Prefecture and that they expect the cells to produce a total of 100,000 kilowatt-hours of electricity a year in January next year, when it will be using a total of 1,000 such cell units there.

    Here is another illustration of what you ask for:

    Solar Power Companies Reach New Heights in Efficiency
    The solar power industry produces a wide variety of products, but every manufacturer tends to focus on two important metrics: the cost of the devices and their efficiency at converting sunlight into electricity. Several companies have recently claimed to break barriers in the latter measurement, commonly referred to as conversion efficiency. Most recently, SunPower Corporation announced that its A-300 crystalline silicon solar cell has achieved an efficiency of 21.5 percent—that is, it converts 21.5 percent of the sunlight hitting it into electricity. According to SunPower, that's a world record for five-inch silicon solar cells, which typically achieve efficiencies of 12 to 15 percent. DOE's National Renewable Energy Laboratory confirmed the cell's efficiency. Back in May 2003, the A-300 made news with a conversion efficiency of 20.4 percent. See the SunPower press release.

    Technology continues to evolve.
  • Solar powered cars are great food for thought for those whose thought processes are unencumbered by the realities of physics and the earth's astronomical relation to the sun. It's nice to dream of technological breakthroughs that will overcome present limitations, but there are natural limiting conditions that no technology can alter.

    The Sun's power reaches the Earth's surface at a density of approximately 1.4kW/sq Meter. This is the maximum available on a surface normal to the Sun and may be diminished by atmospheric conditions. Present silicon PV cells operate at around 10-12% efficiency, but suppose a wondrous technology were developed to convert all of the available solar energy to electrical energy and suppose further that the vehicles' electrical-mechanical conversion efficiency was 100%, is there enough power from the Sun to drive such a vehicle?

    Consider first, how much power does a vehicle require? This is not a simple question since the answer varies with the size, shape and mass of the vehicle and how it is to be operated. For an alternative to succeed in the market, however, it must be competitive with the vehicles that it seeks to replace so let's assume a vehicle similar to present 4 door sedans as a "mainstream" model. That suggests a vehicle of around 3200lbm, 0.32cd, 24sq-ft frontal area and a plan area of about 100sq-ft. We must assume that some form of energy storage is available to handle peak requirements (acceleration, hill climbing) since the 150hp+ of present vehicles obviously is not available from the sun (100 sq-ft=9.29sq-m corresponding to 13kW(17.4hp) maximum sun power). Also, the solar vehicle will not be operated exclusively at high noon on a clear day in the tropics which suggests additional energy storage needs. Now, all this energy storage suggests lots of batteries and/or capacitors or ?, which threatens our size/mass assumptions, but we're assuming magic technology so let's dismiss that concern.

    So we'll consider only steady state, level ground, windless conditions; what will that 17hp from the Sun do for us? Given the vehicle assumptions above, it will sustain a maximum cruising speed of about 57mph. If we were to attempt to keep up with 70mph traffic, we would need about 50% MORE power! In reality, we must operate at lesser average speeds in order to return to storage the energy required to accelerate to our steady state speed, otherwise we must have another source of power to suplement solar energy, in which case, we don't have a solar car, we have a solar/? hybrid.

    Consider further that to capture the entire 17hp available at high noon at the equator on the equinox, the entire 100sq-ft plan area must be perpindicular to the Sun, which suggests a flat topped vehicle! Imagine what that will do to aerodynamics and to the 0.32cd assumption, not to mention vehicle stability and the effect of crosswinds (its a good thing that we can't go very fast). And what does one do when the sun is not directly overhead, reducing the projected plan area, increasing the atmospheric path, increasing the angle of incidence (and hence reflection), or when the Sun is obscured?

    The bottom line is that a solar powered vehicle that even remotely approximates our present day vehicles IS NOT POSSIBLE, no matter what technological advances occur. 1.4kW/sq-M is all the Sun has to offer on a good day! For solar cars to be viable, we would need a bigger (or closer) sun, in which case gasoline would be an inconsequential concern.
  • gagricegagrice San DiegoPosts: 28,850
    The bottom line is that a solar powered vehicle that even remotely approximates our present day vehicles IS NOT POSSIBLE

    That was good information. Hopefully you would make it home before sundown in your solar car. Solar panels are useful just not for large amounts of energy in small areas. Plus their life expectancy is not long enough to pay for the energy they generate.
  • larsblarsb Posts: 8,204
    Well, to get a solar car that would replace a normal car, sure, that seems rather unlikely.

    But a solar car which could commute two people 40 miles a day? That's not impossible at all.

    Search the web for "solar car" and look at all the people making, building, and researching solar cars.

    It's not quite the "Waste of Time" a previous poster might make it out to be. :)
  • trobbtrobb Posts: 1
    OK, I am by no means an expert, but I do understand that there are more sources of natural energy than just the sun. After all, just the movement of the car is a type of energy. After considering it all, you could create a vehicle that taps into Solar Power, Wind Power, and Kinetic Energy to regain some of the power that is often lost in conversion. Consider having some port-holes near the bottom of the vehicle that allow wind caused by vehicle motion to strike a turbine to produce additional energy. It may not refuel the car, but it can certainly increase power. How about two extra wheels that lightly touch the ground below the vehicle that also have light turbines in them to recover kinetic energy from the vehicle's motion.

    These are all ideas, and by no means do I have a scientific mind to accompany them, but perhaps some of the energy converted into motion can be recovered to one degree or another.
  • Everyone has good points. Practical solutions will require out of the box thinking:

    Solar augmented Hybrid SUVs They already have large semi-flat roofs, motors, gas backup. Solar would simply augment the charging, requiring less gas over time. Vehicles don't usually travel more than 1 or 2 hours a day. They will keep charging the rest of the time, so long as they are parked in sunlight.

    Houses with solar panels could charge battery packs that are automatically swapped out when the vehicle is parked in the owners garage. Solar "roofed" parking lots could also swap out standard packs in some automated way. Maybe they'll be interchangeable with more expensive hydrogen fuel cell power packs, for those longer trips.

    Perhaps that mass of asphalt called a street could somehow end up charging interchangeable battery packs for the populous. All that surface area... hmm, maybe there's a way to turn it all into a big collector with new materials and technology.

    Solar won't do it all, but it can be a contributor. An electric motor vehicle manufacturing infrastructure is already well on its way. Hybrids and hydrogen will see to that. We might as well work all angles as a society to optimize it.

    Not magic, imagination...
  • offgridoffgrid Posts: 1

    off-grid means places or buildings or gizmos that work without mains water or power. off-grid is for those who want to unplug, relax and feel at home anywhere on the planet
  • eaaeaa Posts: 30
    Solar needs full sun at the correct angle so it's best used in a fixed location like a house.
    Solar vehicles are electric vehicles, that are charged and running from the solar panels.
    The best is a very efficient EV like the T-Zero from AC Propulsions and good solar panels at home from Sunpower at 20% efficiency. Together , but not at the same location you have a winning combination.
    Or you can suck gas thats 60% imported and making Exxon rich so they make more oil spills and kill our trade deficit and fund terrorist. It's your choice.
    I installed grid ties solar, live efficiently and ride a bicycle to work for health and the environment. I make my choices EVeryday.
This discussion has been closed.