The Focus Fusion Society › Forums › Focus Fusion Cafe › Barack Obama on Energy
I agree with Frenetic that cellulosic methane has an interesting potential as a vehicle fuel; but only with the right drivetrain and the right engine. Cellulosic methane (after the CO2 is removed) can be mixed with natural gas and be delivered to fuel stations using existing pipeline infrastructure. To offset the 28 Quads of petroleum used by the US transportation fleet annually, you would need about 14 Quads of methane and a methane-fueled vehicle that was twice as efficient as the piston/crankshaft gasoline engine. Natural gas could be used as a bridge as cellulosic methane facilities were incrementally developed. Methane has one big advantage over gasoline; its autoignition temperature is 1000F versus gasoline’s 495F. A high autoignition temperature allows a higher compression ratio, which, in the Otto cycle, translates to higher efficiency. The highest compression ratio engine is a free piston engine because it has no piston rods or crankshaft. A high compression ratio, free piston motor/generator, such as Pempek’s (www.freepiston.com), can maximize methane’s efficiency potential. The free piston motor/generator recharges lithium ion batteries, as in the Chevy Volt’s drivetrain. You then get the “at the wheels” efficiency benefits of an electric car but use methane fuel to recharge while driving. In effect, you have an engine/battery combination that functions exactly like a fuel cell–except it runs on methane, not hydrogen. The drawback to methane is its energy density. A Honda Civic GX has only about half the range of the gasoline model. But if you double the “at the wheels” efficiency of the vehicle, you have a comparable range even with a less energy dense fuel. For a vehicle, you have to rethink the fuel, the drivetrain and the engine and they must all be complementary. A methane-fueled free piston electric drive vehicle has that revolutionary potential.
Sorry. The Pempek site for anyone interested is http://www.freepistonpower.com.
Just a thought about all this hype about hybrid cars.
1.) The batteries and electronics add a lot to to the cost. No all of us can afford Lexus/BMW class cars. My family has an older S-10 and a new Corolla. I couldn’t afford to buy a $40K hybrid. Are any selling for >$20k? I don’t see that happening soon.
2.) Batteries are very expensive. The Tesla electric sports car “the Tesla roadster is powered by a 1,000 pound bank of 6,831 (!) lithium ion laptop computer batteries” which gives it a range of 220 miles. At $2 per battery (I don’t know what they cost, but I’d expect this to be a low figure), the battery costs $13,600 alone, almost what I paid for my Corolla. I expect my Corolla to not require major engine work in a useful life of 10 years and about 150k miles. I would expect an “electric Corolla” to need at least half as big of battery ($6,800) and batteries don’t last forever. Consider an “electric Corolla” costing about 50% more then mine, can only go about 150 miles before stopping for a 3-4 hour re-charge (no long trips) and will
2.) Turbines. They are expensive to make and maintain. High temps= high cost alloys. High speeds (turbines, esp. small ones, operate at almost an order of magnatiude higher shaft rpms. If this high speed device fails, it is a bomb, pieces come out at increabable speeds. A car would require a balistic housing to protect operators or bystanders in case of turbine blade/bearing/shaft failures.
3.) Diesels are very well proved, and only slightly more expensive then gasoline engines. Bio-Diesel is less energy intensive to make. Currently, coal is burned for heat needed to distill ethonol, and that need for heat won’t change if cellulose is the feed stock.
4.) Bio-Diesel is less energy intensive to make then ethanol. Currently, coal is burned for the heat needed to distill ethanol, and that need for heat won’t change if cellulose is the feed stock. So for a
Rematog,
1) I agree that battery cost is a significant factor, but there are mitigating factors as well if we’re talking about a serial hybrid like the Chevy Volt.
a) In a serial hybrid you eliminate the dual drive trains and the electric drive train is much cheaper and more reliable. You eliminate water cooling, transmission (you could have 4 electric motors, one for each wheel–think about turning radius then!) and so on.
b) even if you had batteries on board for only 40-miles before the generator had to kick in, you’d eliminate a lot of gasoline: 90% of car trips are <60 miles 80% are <40 miles.
2) Batteries are expensive, but the Tesla example isn’t the operative one. They weren’t going for affordability. Think about the Chevy Volt-class vehicle. You add 40 miles-worth of expensive batteries (much less than the Tesla Roadster), but you eliminate much of what went to support a gasoline engine and its drive train. You still have a gas/diesel/ethanol/other generator, but it is much simple, running only at its optimal rpm for electricity conversion.
You’re also not figuring in maintenance and operating cost differences. Maintaining an electric motor and batteries and paying for charging them and paying for the maintenance and fuel for a small, range-extending generator will be much cheaper than the maintenance and fuel for today’s gasoline drive train–even factoring in battery replacement.
3) How many people die each year from pollution caused by burning gasoline (even leaving aside global warming)? If the true cost of gas were reflected in its price we’d have had $4 gas long ago.
4) I agree that diesels can be an attractive option for “range extension” but shouldn’t be the “go to” fuel because of the particulate matter they emit. Diesels are dirty. If cellulosic ethanol becomes viable then other parts of a plant could be burned to provide the heat. Most of the mass in plant biomass is cellulose and lignin. The lignin could be burned to provide the heat to distill the ethanol produced from the cellulose.
5) Steam is a longshot IMHO.
Yes, hybrids are new and there are issues that need resolution, but I think the major auto manufacturers aren’t like the “anti-nuke” activists of the 70s. IMHO serial hybrids offer a simple design that avoids the compromises implicit in your post. Most trips can be electric-only, eliminating pollution and cost for most trips for most people, but still provide range and refueling options for longer trips. They’ll be cheaper to maintain and operate and more reliable. I would expect them to last at least as long as today’s gasoline cars, given the smaller number of moving parts, etc.
Hybrids are still less attractive then all electric for automobiles, if the charging time and battery cost/life issues can be overcome.
I’ve found nothing regarding possible cost for the EEStor capacitor system.
Regarding charging the EEStor capacitor system, from my fast net search, I’ve seen about 3kv as an operating voltage. 3160V is a very common standard industrial voltage. So if a charging station is tied to existing tranmission lines, then xforms the power to 3160V, the hardward (xformers, disconnect switches, cables, plugs, etc.) are all off the shelf comercial items.
As I would envision use of my “EEStor Corolla”, I’d plug in 208V/110V at home/work, etc to charge using the onboard xformer to boost volatge to the storage level. This would take hours to charge (overnight normally).
But, when driving cross country, would pull into a charging station, plug in a heavy cable to the cars fast charge fitting, and swipe my credit card. About 5-10 minutes later (and it take that long to get kids in/out of bathroom, lol) the EEStor capacitor would be fully charged for the next 3 hour leg.
I could live with that…
Rematog wrote: Hybrids are still less attractive then all electric for automobiles, if the charging time and battery cost/life issues can be overcome.
Agreed. Of course if we could solve the problems with a technology then it is, by definition, more attractive. 🙂 If EEStor comes through (they keep pushing back their time frames for commercialization) then that could solve a lot of problems. Until then, a serial hybrid would be a big improvement even using currently available technology. It’s essentially an all-electric vehicle with an on-board generator. If electric storage tech improves and commercial charging is as broadly available as gas is today then the generator won’t be needed.
Lol, yes, if problems are overcome, a tech is more attractive.
Your post refers to hybrids with significant battery only range and grid recharging. I concede that a vehicle with those charateristics would reduce automotive emissions. But to my knowledge, the current crop of hybrids do not have either of those charateristics.
Also, why not use a high efficiency diesel in a hybrid? It would then be also capable of using bio-diesel fuels.
But, I still contend that the cost of the current hybrids puts them out of the range of much of the market. Yes, having an all electric drive with in wheel motors has advantages, but is cost one of those advantages?
If a hybrid had enough batteries to have reasonable all electric range, say 60 miles, it would have a battery of considerable size, and hence, cost.
I know I being redundant, but cost is a very important factor if these vehicles are to make a real change in oil consumption. I personally would rather buy a $20K all electric Corolla and a $20K turbo-diesel Corolla getting 50 mpg, rather than a single, $40K hybrid. But even then, I have to be convinced that the life cycle cost of the all electric had at least cost parity, including battery replacement, over the turbo-diesel, before I’d buy one.