[RS_DEL]

Originally Posted by condor

@TSK, electricity that is generated is also extracting stored energy. Hydro, coal, nuclear - anything that you want. If we were to store the energy into these material, and then calculate the over cost, then the system/process will show by itself that it is very lossy.

The considerations that are relevant in determining possible alternatives to hydrocarbon based sources are not limited to energy efficiency ONLY. A consideration which is even more fundamental to this discussion/debate is availability.

I am not by any means a prophet of doom shouting armageddon from the roof tops. However when the global hydrocarbon supplies -those which are extractable at a reasonable cost- are looked at with respect to new consuming patterns which include BRIC demand in addition to OECD demand, the scenario starts looking bleak to put it mildly. We do not even have a full fledged economic recovery in the some of the major consuming markets and yet the prices of crude oil do not seem interested in taking a breather.

So all initiatives such as the one being discussed here and other developments whether at lab stage or undergoing field level testing need to be evaluated with an open mind keeping in view an overall perspective.

[mgh]

Consider a power station. Whatever pollution control measures need to be taken, are to be taken at one place. The power generated can be used to generate hydrogen, compressed air etc, which can be used to power vehicles that do not need any pollution control measures. Thus, you can keep pollution out of cities.
That is the main rationale. Opponents claim that you are merely moving the pollution from one place to other. However, measures to control pollution from power stations involve known technologies. Once a limit on the pollution is decided, systems can be designed to meet that goal with known technologies.As far as fuel powered vehicles are concerned, there is a never ending need to develop new technologies to meet the limits.

[tazmaan]

I had seen a doucmentry where Germany has already started converting one of their major Highway to support cars driven on compressed air. The documentary showed a couple of cars which can have similar outputs to conventional fuel engines, a compressd air tank and no need for any combustion.

The cars on test had a range of 180kms and air refill took same time as normal fuel stop (Plug system similar to CNG or similar to the way we fill air in tyres). The engine even sounds like a normal fuel engine because it has similar or same piston movements.

Off Topic
Why alternate fuels might not succeed soon:

The countries that supply fossil fuels are dependent on its income which is very huge and big enough to bribe automobile companies not to develop alternate fuel technology. Otherwise who can explain why on this earth electric cars never progressed even though batteries shrunk in size, got more efficient and cheaper, motors became more compact and powerful. GM used to lease out electric cars in 70's (or was it 80's) which was scraped over night and never started again. Billions have been spent on wars to make trillions out of crude oil trust me automobile companies come much cheaper.

[condor]

Originally Posted by RS_DEL

So all initiatives such .. and other developments .. need to be evaluated with an open mind keeping in view an overall perspective.

Definitely. We need to, and no two ways about that.

But in all other cases like petroleum, hydro, solar, wind - nature has done a lot of the work, and we are only harnessing /extracting the energy. But with compressed air tech, you want to create energy from zero. Which is why it is different & difficult.

A simple example would be with hydro power. Nature has taken the water upstream, so that it can flow down and be harnessed when it is flowing down. If nature had not done that, but instead we had to do it, then we would have to take the water up to a higher level. This needs energy. Once the water reaches up, it can then flow down - and we can extract the potential energy into other forms.

The catch is - the amount of energy that will be used to take it up will be more than what can be generated when the water flows down.

Similarly with compressed air. Compressing the air will be akin to taking the water up.

And no system is even close to 100% efficient.

[RS_DEL]

Originally Posted by condor

Definitely. We need to, and no two ways about that.

But in all other cases like petroleum, hydro, solar, wind - nature has done a Once the water reaches up, it can then flow down - and we can extract the potential energy into other forms.

T

And no system is even close to 100% efficient.

If I understand you correctly, your contention is that this alternative is not energy efficient enough.

The other side of the coin is the quantum of usable energy that can be stored in the vehicle facilitating ease of use for the user, and the cost for providing such ease of use. It is on this parameter that EVs' have not been able to make any material impact in automotive tech. The quantum of usable energy i.e. electricity that can be stored using inexpensive batteries is not adequate - atleast that is the widely held perception.

This thread , if I am not mistaken, mentions in the very begining a run cycle of 300KM for compressed air tech vehicles on each recharge/refill and a low recharge/refill cost. That to my mind makes this an alternative worth exploring.

[condor]

@RS_DEL, any system must be energy efficient.

But we never know - we could end up in a time where transportation may take precedence over the cost.

And IMO, EV's today only dont add to pollution - when seen from the car itself. But there still is pollution caused by using a EV, since there is electricity being generated. We do have threads discussing that an EV is not as efficient as it is made out to be.

Originally Posted by mgh

Consider a power station. Whatever pollution control measures need to be taken, are to be taken at one place.

That is the main rationale. Opponents claim that you are merely moving the pollution from one place to other. However, measures to control pollution from power stations involve known technologies.

No arguments against these points. While you may control pollution, there is a bigger problem:

World wide, 70% of electricity is lost due to in-efficiencies in the transmission system. So it may actually be better sense to burn the fuel locally in the car.

[RS_DEL]

Originally Posted by condor

@RS_DEL, any system must be energy efficient.

But we never know - we could end up in a time where transportation may take precedence over the cost.

And IMO, EV's today only dont add to pollution - when seen from the car itself. But there still is pollution caused by using a EV, since there is electricity being generated. We do have threads discussing that an EV is not as efficient as it is made out to be.
No arguments against these points. While you may control pollution, there is a bigger problem:

World wide, 70% of electricity is lost due to in-efficiencies in the transmission system. So it may actually be better sense to burn the fuel locally in the car.

The degree of efficiency of any energy system is not absolute. The degree is assessed in relative terms.

With all due respect allow me to suggest you read up on green tech for electricity generation especially offshore wind farms . Here is a link you might find useful. Greentech generated electricity has become increasingly viable. The constraint is on the storage side- the battery tech. It is because of this constraint EVs' have not made any material impact.

How is this relevant to the TATA MDI alternative? As I mentioned earlier a run cycle of 300Km per refill/recharge and a refill/recharge cost which is indicated at 90 INR in 2007 - post #9 of this thread - makes this a desirable alternative, if the stated numbers are true ofcourse.

[condor]

@RS_DEL, again, the off-shore wind farms are still harnessing naturally available energy. It does not use generated energy to collect more energy.

Reg the cost you have quoted, we will have to wait and see how realistic was that. We both know that it is still in very early stages. I dont think they are anywhere near prototypes.

Thanks for the link. I will check it.

OT:
Nice signature !

[abybabykcc]

Originally Posted by RS_DEL

As I mentioned earlier a run cycle of 300Km per refill/recharge and a refill/recharge cost which is indicated at 90 INR in 2007 - post #9 of this thread - makes this a desirable alternative, if the stated numbers are true ofcourse.

The only way the car can run on air is if it uses sails. Then the range will be unlimited and the running cost will be 0 rupees per infinite kilometers. If the car is to run on compressed air, I don't see how you can compress enough air into a small tank that, when released, produces enough recoil or thrust to carry a car and its passengers over a range of 300 km. Also, if you are burning fuel to produce electricity to compress air to run the car, not sure how much more cost efficient it can be than burning fuel to run the car, unless, of course, a 100% of the electricity in the world is being generated by solar panels, windmills, flowing water, tides, and such, and there is zero dependence on fossil fuel to produce any electricity. Because, if the current electricity requirements are not being met by the cleaner sources and we need to burn fuel to meet the shortfall, any additional requirements will also be met by burninng fuel.

[condor]

Originally Posted by abybabykcc

The only way the car can run on air is if it uses sails. ... If the car is to run on compressed air, I don't see how you can compress enough air into a small tank that, when released, produces enough recoil or thrust to carry a car and its passengers over a range of 300 km.

That would be the conventional use of air. If that's plan, then it will not work. Let's see what the technology tries to do.

[ethan3686]

Now this is a great initiative by TATA. I Like it how they are constantly looking into new technologies.It even shows in their recent cars.Even at a low cost you do get some luxury features.Although ARIA may not have been the hit that TATA wanted it to be, it still was unique and apart from the rest when it came.
Now if tata is looking into this we can assume there will be an alternate fuel version or hybrid in coming years. Which would be great at a good priice. But then its too early to say.

[carboy]

Originally Posted by condor

World wide, 70% of electricity is lost due to in-efficiencies in the transmission system.

Do you have a cite for this. From what I have read transmission losses usually are in the range of 6-10%.

[babu.sundaram]

Originally Posted by condor

And IMO, EV's today only dont add to pollution - when seen from the car itself. But there still is pollution caused by using a EV, since there is electricity being generated.

+1 to this. To start with the poisonous batteries that need to be disposed every couple of years and the fiber body which is hard to recycle.

By Indian standards, we have energy efficiency (efficiency in converting thermal energy to electric) is ~15-20%, against a possible energy efficiency of 35%. ~50-80% of power is lost in transmission (includes wastage and power-thefts).

With all these factored, it may make sense to disperse pollution by using conventional vehicles!

[carboy]

This Tiny Pod Car Runs On Air | GizmoCrazed

5 years down the line as the first post of this thread, people are still talking about Tata's Air car.

[FlatOut]

Electric propulsion is fantastic, the problem is that storing sufficient electrical energy to power a motor vehicle for even just 200km requires a heavy battery pack. Porsche had developed a great battery car back in 1911 or so, but was forced to add an internal combustion engine to replace the electric propulsion because of its range.

Ignoring the devastating problems we are storing up for future generations if we continue to build nuclear power stations, the energy still has to come from somewhere and countries are a long way off even supplying significant amounts of renewable energy for domestic consumption, let alone for a nation's fleet of EVs.

The most efficient thing to do to beign with is to reduce vehicle mass and friction. To go and buy 10kg of shopping in a 1.5 tonne car is crazy.

If we are going to make good use of electric motors, then a tiny, lightweight petrol engine running as an on-board generator makes most sense. A couple of heavy-duty batteries can act as a small store/buffer and allow the vehicle to run without the engine at low speeds for short distances. The current proliferation of hybrids is purely for fashion and to beat taxation systems.

There is another form of efficiency which could be implemented on heavy vehicles which frequently start and stop. Replace the heavy gearbox and driveshafts with a hydraulic pump and motors, for energy regeneration use air storage tanks, which are compressed when an engine is idling or the vehicle is slowing. This is a more efficient regeneration of energy than by chemical means - and there is a limit to how quickly energy can be stored ina battery bank.