Which is the most sustainable solution for Hybrid Cars ?

isn't this the wrong question? Hybrids are TRANSITIONAL, not sustainable. They're bridging the gap between electric source technology (batteries, fuel cells, etc) of the future and current capabilities. Most cars in the 50s had shorter mile range, and current cars (mostly due to larger fuel tanks, certainly not improved fuel economy) have about 300 miles. But most of us could buy a 100% electric today and it would service more than 80% of our daily needs, even if it could be only be charged to go 100 miles. Maybe the question is "Why do we need hybrids in the first place?"

the issue is that an electric car doesn't pollute when its driven, but it pollutes when its made, when the batteries need to be replaces, and when the car is finally junked. plus when its charging most of that energy comes from polluting sources... and a hybrid is the worst of gasoline and electric mixed really

agreed that an all electric car is the more efficient solution. hybrids are a band aid on the problem. According to calculations by tesla motors, their electric cars are more than 2x more efficient (kilowats per mile) than the prius or the jetta diesel. http://www.teslamotors.com/efficiency/well_to_wheel.php

but that is according to telsa, who i would say would be quite biased, in my opinion they best solution would be a hybrid of sorts, a system where a small (very small) diesel engine runs a generator that charges the batteries, but is not connected directly to the batteries. diesels can be made to operate very efficiently at a certain rpm, and can sustain those rpms with less wear then a gasoline engine. and as such the batteries would not be drained as much as a regular electric car, and therefore should last longer, cutting down on costs and waste that is until better battery systems are designed of course. another idea would be to augment the exhaust heat into a boiler/water heater, and have some sort of turbine/steam engine somewhere in the drive line to aid in power production. no need to waste the heat energy that most engines throw away

Mr. Jacob; Your opinion and suggestions are very upto mark...but in case where u wanted to interfere a small diesel engine which could be not commonly used or practically induced for regular production of battery current thru generator (although auto companies are doing lots of research of such a sort) - which is being replaced already by the technology called as regenerative braking where electric energy produced thru breaking. Perhaps this kind of practice would gain much profit in case of very populated country like India, China, etc...but needed to enhance the future auto technology especially in developing countries.

but regenerative braking can only do so much, as the car is not always braking. the systems for the generator are already produced, small diesel generators have been giving power to households and construction for years, and with a simple converter dc volts can easily be produced instead of ac. from my experience portable diesel generators are very efficient, quiet, long lasting, and use little fuel, with a few modifications automotive usage shouldn't be too difficult or costly to produce

Personally I believe ultra capacitors should be used to store the energy gained in regenerative braking in both hybrid and electric systems. Battery charge and discharge efficiencies aren't nearly upto par with capacitors, but can store more power overall. As such it makes sense, to me at least, to utilize capacitors for storing braking energy and discharging it during acceleration and utilize the batteries for storage of the greater quantity of energy needed for maintaining speed. That should, in theory, both improve battery life and improve the overall efficiency of the system. I remember reading a IEEE paper on a potential similar system, but haven't really heard much about it since. I also believe diesel is the major fuel of the future, both for the relative reliability of the engines and the flexibility of potential fuel sources. Personally in the near future I look to Loremo for producing a viable daily driver that is both efficient and practical.

Recently i have been pondering just that same question, but it raises many new ones to address, when we speak about the near future of personal transportation. I'm an all car enthusiast, who see the personal production of homemade bio-fuel, as one of the ways out of the dependency from fossil-fuel, and the day to day struggle to be on the road for pleasure, fun or necessity. It is my goal to influence car owners all over the world, to realize the possibilities of being in motion, without loosing freedom of chosen vehicle, and still considering the option to drive anywhere with an ecologic peaceful mindset. The fact that each modern household produces more than 6 tones of biowaste each year on average, has encouraged me to raise some questions regarding this huge unused resource. Each day the amount of fossil fuel spent, is in fact causing at least a part of the global warming effect. But we could do it very, very different. Any engine, especially the diesel engine where you can pour virtually anything in and get a combustion, as long as the compression is set the right way, can be converted into running on pure ethanol. So with the waste mentioned before turned into this pure-burning liquid, and produced in private households by already available mini-distilleries, there is no more need to visit the local gas station to refill the tank. It will still be a while before we can all go completely electric, and we could make good use of the fossil raw-product in many other ways, than just pouring it out into the open air. However if we wish to be as mobile and as personally comfortable in our own vehicles as we are accustomed, we’ll have to look at any possibility to keep providing the needed fuel. Recently it has been noted, that a specific kind of method for the production bio-ethanol, can be made to fit the same size as an American refrigerator, run the fermenting process on the same heating-line as the rest of any house/home with central heating, and making more than 750 liter of ethanol a year depending on the household consumption of biomass. So if any car can run on the stuff, why not face the possibility at hand and pursue the noble goal set by the author of this comment? Imagine your car… Imagine not having to bother with fuel prices, and if you can get any. Imagine being one of the real “environmentalists”. The most sustainable hybrid car would be the one, run on a small many cylindered diesel or Wankel engine concept, utilizing pure alcohol to provide the power needed to charge a battery system. From there four electric wheel mounted engines will give the whole vehicle its momentum, with the capability to function and serve as both an accelerating and decelerating/recharging entities. The hybrid car is not just a mere transition vehicle, until we get more efficient battery technology, but a necessity as an alternative form of transportation. We will need the hybrid concept to keep us ‘rolling’, and to keep us enjoying all of the freedoms we love so much. I foresee in the time soon to come, that only heavy vehicles and trucks will be hybrids and the personal transport will be electric. But it will be a while before we can settle to use the technology, for anything but transportation of goods and materials.

what about methane from the dumps? wisconsin farms and dumps are useing methane from trash and cow shit to run electric generators to power up homes. why not cars?

Honestly, there's no reason to begin investing in "future fuels" like fuel cells, electricity, or biodiesel until we deal with the problem of the incredibly low efficiencies that todays engines run at, or, for electric cars, the overwhelmingly dangerous environmental effects of the Li-ion and NiMH batteries that we use in supposedly "green" cars. I don't think it is impossible to increase the efficiency of a gas/diesel engine to something rivaling that of the power plant that produces the electricity, and this will be a much more convenient and "green" way of investing our money (to replace the terrible but hip hybrid) until we run out of oil completely and someone comes up with something decent.