Engineering Mobile Electric Power Systems (Part 1)

It has always intrigued me, the concept of electrically driven automobiles, but the ever present question that nags me is "How does one replenish the energy expended during operation of the vehicle." This will necessitate the development and deployment of a completely new system of "charging stations" for lack of a better term. Will there be "battery depots" where one drives in when his power is low, and exchanges his low battery for a re-charged one for a fee? It's not as simple as driving into a "filling station" and inserting your card, filling your tank in 3 minutes, and you are on your way again. It seems to me that the concept is sound, but the implementation is in need of further investigation, which, of course, is the subject of the discussion. The relative cost of the battery used, the cost of developing a replenishment system and the safety concerns are all things that must be weighed and ultimately conquered in order to make the plan work. I, for one, am optimistic about the prospect that someone will develope a technology to alleviate the stress on the fossil fuel based transportation system in which we find ourselves now, but at my age, I doubt if I will have the opportunity to avail myself of the experience.

What you are envisioning is a future were vehicles would be 100% electricity powered. That may eventually happen, but what will probably happen first is a transition away from 100% fossil fuel based transportation. That trend has already started in a small way with hybrid vehicles.

These HEV's still get 100% of the *average* motive power from fuel. Now if we grow the electric components in the HEV, we could conceivably transition it towards more electrive drive. The first few miles could be electric dominant, then the vehicle would transition back to the normal HEV mode. This would allow the user to drive "normally", but would help reduce fuel consumption if you recharge your battery each night.

You are correct, going 100% electric with "battery refueling" is very problematic, especially considering that refueling with gasoline today is equivalent to a 7 MegaWatt feed. Fuel cell systems with hydrogen or other refueling would make more sense. But in general, we will transition away from 100% fossil fuel based transportation and enter a new world of various fuel and electric hybrid options.

HLNW

The important thing to remember is that without the commitment GE has made to electric traction over a long period we would be a lot worse off than we are presently. GE's motorised wheel has successfully powered off highway vehicles since 1964. Since the adoption of AC drive systems developed by GE, ABB, Komatsu and others everybody, including Caterpillar, have finally realised that electric traction is the only real alternative.

Another related item I've been interested in, this time from ABB, is the storage of regenerated energy from train retard effort at fixed sites rather than on the loco. Obviously this is only applicable to Electric Overhead Traction systems such as in QLD, Australia and Europe. Electric freight locos burn off their retard energy in the same manner as diesel electric locos. In places where there is duplicated track or even where there is any slope stored energy from retard effort can be applied to trains which need to climb the slope. Why it is especially useful is transportation of minerals to port is generally a downhill haul. In QLD the fixed technology is completely applicable making the weight of batteries irrelevant, due to the extensive overhead traction system. In WA travelling battery packs (part 2) are fully applicable. For instance GE's large customer BHP Iron Ore hauls the product 426km down hill from Newman to Port Hedland falling 1100 metres on the way. The only obstacle in the way is a short uphill pinch at the Chitchester Range. BHP use 6000hp GE AC (diesel electric) locos for this job and the peak power is needed for the Chitchesters. Stored energy has a big potential to reduce installed power. Currently it takes more diesel to take empty trains to Newman than loaded trains to Port Hedland.

I agree with your comments and I am aware of the traction advantage, etc. of using electric powered transportation. However, I am still not convinced that there is an easy or cost-effective way to replenish the energy that is required to, in effect, replace the existing system of cars, trucks and other mobile devices. This will require an enormous amount of re-designing of the current technology and the current supply system.

As I first observed, it is not feasible to simply have a "cache" of storage batteries that can be interchanged from vehicle to vehicle as the need arises. Probably the biggest roadblock is the relatively short distance that one can get from any currently available storage battery. Longer range batteries are probably capable of being manufactured but not at a price that would make them commrcially successful. Solar panels mounted atop the vehicle might be an explorable alternate, but, as with the storage battery dilemma, these are not yet refined to satisfy a commercial application requiring the amount of energy this application would require.

No disagreement regarding recharge issues. This is why rail and off road applications are looming large in the sights of the companies who are actually doing something, rather than talk.

Liquid fuels or even solid fuels of specialised types will be hard to beat. Simply put refuelability is the key ingredient. Energy storage technology is the stumbling block to virtually all progress toward real efficiency and energy independance. So the good news in all of this is, GE and ABB don't like running up dry gullies, results will come from this work.

GM seem fixated on Hydrogen which has even more problems than batteries in terms of recharge infrastructure. Effective energy storage is the key to commercialisation of fuel cells too.

In the short term ,the ability to use much smaller ICEs running at the most efficient point on their operating curve, while still delivering equivalent or improved power and torque can make an order of magnitude difference to fuel useage.

Power systems alone are not going to get us where we need to go, material sciences too need to play a major role, and not merely in weight saving, which of itself is of more benefit than most realise, but in reducing other energy losses without tipping the weight balance the other direction.

Be it vehicles or buildings a large amount of energy is expended making the internal climate habitable. Looking at vehicles, between heating and cooling (even if it is just opening the windows) the amount of unrecoverable energy expended makes the EV a marginal proposition using today's materials and methods.

It is all very perplexing when we consider that the world has been under the "spell" of oil for too long now. It wasn't so long ago that I remember oil being at $26 (US) per barrel and the oil producers here in the US were saying that at that price, it wasn't economically feasible to remove it from the ground. Now, when the price is over four times that amount, they still are leaving it in the ground. Why? My own thoughts are that they are waiting until the rest of the world has depleted their supplies and they will then have a monopoly on the commodity. That topic alone would make good fodder for another discussion.

Renewable fuels, such as ethenol from corn, are reasonably plentiful, but the costs are still not going to be as commercially economical as has been perported. There are hidden costs, for instance, with corn when you consider the strain corn usage exerts on the food supply. Corn is a very large staple in many countries.

Further, I believe it is Norway, who uses hydrogen nearly exclusively for powering their internal combustion engines. Hydrogen, admittedly, is plentiful, but it is also very dangerous. I am not convinced that it is a viable alternative either.

I get depressed reading my own comments in this forum, because I sound so negative. However, I did say in my first reply, and I still stand by that "I, for one, am optimistic..." I won't give up hope for the future. Someone will come forward and start the "energy revolution" that will keep us warm and mobile. Where are you?

I agree with the thread; fossil fuels are a great way to quickly fill a mobile platform with energy. And, yes we have been captivated to this form of energy for a century now... but times are changing and more sources of energy will start competing and displacing oil/gas/diesel.

Norway does not power much of it's fleet with Hydrogen. Iceland and Norway do have a few H2 demonstration sites, but they are still gasoline/diesel dominant.

Bio-fuels such as Ethenol will also play a role, but these may be regionally important, not globally... like Brazil's abaility to creat Ethenol is much better than most contries, so they are taking advantage of it.

The engergy revolution is happening right now.. restarted about 5 years ago in earnest, and is catching steam, unlike the energy crunch of the 70's which gave way to the relative prosperity of the 80's, we are now in a race to diversify our fuels, electrify our equipment, and make our environmental impact lighter.

Herman