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Kevin
User Rank
Platinum
Re: Bigger Car Batteries Are NOT The Answer
Kevin   1/11/2012 3:08:08 PM
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Just one further comment, for completeness:

Note that in my prior comments & analysis that show that EV's do not (with today's power grid) significantly reduce energy or fossil fuel usage, I was actually being "kind" to the EV's.

I did not even  include the losses from the power plug to the wheels: charging loss, battery loss, motor controller loss, electric motor loss.  While each of these are all pretty efficient, they net about an additional ~15%-20% loss on top of the 7% electric power distribution loss, for a total of >20% losses from power plant to wheel.

This is why, after open-mindedly studying this issue extensively - I believe a more practical approach to get us off oil and fossil fuels is making car engines more efficient (via hybrid and other technologies) and creating a renewable replacement fuel for gasoline.

Although we should indeed work on improving power plant efficiencies and maximizing renewble grid power sources, it just does not seem to make economic or environmental sense to run our cars off of the grid, not to mention the big tradeoffs with EV usage profiles.

cheers,

Kevin

Kevin
User Rank
Platinum
Re: Bigger Car Batteries Are NOT The Answer
Kevin   1/4/2012 9:39:20 PM
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Charles, 

I'm convinced pure EV's currently make no sense today.  Maybe in 50+ years.  I'm a little perplexed why the government / EPA is fraudulently distorting their benefits so much.  I think that it is for these reasons: 

1.  The Power companies, Coal and NG lobbies are influential.  Wouldn't you want this huge amount of new business if you were them?  2.  We would reduce the trade imbalance because we would not be paying out as much for foreign oil.  3.  Worldwide oil supply is unstable and may be closer to running low than most people know.  4.  They think that having a zillion EV's out there can allow the "smart grid" to use those batteries for energy storage, which is necessary to make a high-percentage of the grid solar or wind powered.  I'm skeptical that this idea would work out well. 

#2 & #3 are pretty good reasons.  However, I think it would be much better to directly create a substitute fuel (biofuels / solar-synthesized fuels, possibly even liquid or gas synfuel from coal) than to tap the power grid and put up with all the trade-offs of pure EV's.  Also, as mentioned before - Natural Gas is the cleanest / most efficient power plant fossil fuel - why not just burn it directly in the vehicles?  We can cut out the "middleman" of the power plants.  CNG is rapidly becoming a world automotive fuel.

An idea for a vehicle solution would be a very efficient plug-in hybrid with a relatively small battery (~15-20 mile range), with a tri-fuel capability of gasoline, ethanol, and CNG.  There are already many bi-fuel vehicles in the world with gas-ethanol and others with gas-CNG, so this is not a big leap to 3 types.  This would allow fantastic fuel flexibility to future-proof it:

1.  electric = short trips, uses domestic coal and NG, other renewable grid sources as they grow  2. gas = legacy / available everywhere  3.  ethanol = cleaner, domestic and hopefully produced via non-corn renewable sources soon 4.  CNG = cleanest, domestic and plentiful (as long as fracking continues) also may be supplanted by biogas / syngas eventually.

Just brainstorming...

Kevin

Charles Murray
User Rank
Blogger
Re: Bigger Car Batteries Are NOT The Answer
Charles Murray   1/4/2012 8:23:36 PM
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Great info, Kevin. Obviously, there are reasons to go electric other than efficiency (the need to find an alternative to oil, for example), but this seems to shoot holes in one of the arguments for pure EVs.

Kevin
User Rank
Platinum
Re: Bigger Car Batteries Are NOT The Answer
Kevin   1/4/2012 3:27:38 PM
NO RATINGS
Charles,

I don't have a single website with that detail, but I can provide an overview that will lead to this, and also will hopefully enlighten folks to the huge distortions that are being tossed around about EV's.  In my whole (technical) life I've never seen so much distortion and misinformation than what the government is providing for EV's!

First, the PRIUS answer:  In my eyes, THERMAL EFFICIENCY is the most fair efficiency comparison:  how much heat from burning fossil fuel is converted to work.  The Prius's hybrid-optimised Atkinson-cycle engine is extremely efficient:  38% and they are working on 42-45%.  www.green.autoblog.com/2011/04/24/toyota-targets-45-thermal-efficiency-for-engines-in-next-gen-hy/

By comparison, the avg coal-powered plant is ~33% efficient and avg. natural gas powered plants are ~42%.  The latest technologies (not deployed much yet) are ~40% and 60% respectively.  Power plant efficiencies are published in a strange way - they don't talk about "efficiency", they use "heat rate".  Efficiency = 3412 / HEATRATE, where HEATRATE is in BTU/KWh.  See: www.eia.gov/cneaf/electricity/epa/epat5p3.html

So...you can see that the Prius is already MORE efficient than the avg coal plant (48% share of grid power) and just a little less than the avg NG plant (~18% of grid).  It doesn't make much difference, but in case you were wondering, the avg transmission loss for power is ~7%.  Technically, the plant efficiencies should be derated by a factor of 0.93 to account for distribution.  www.renewableenergyworld.com/rea/news/article/2007/07/energy-efficiency-in-the-power-grid-49238

A wonderfully data rich chart is provided by Lawrence Livermore Labs that shows an intuitive view of US Energy sources, efficiency, usage, etc.  www.llnl.gov/news/newsreleases/2010/images/energy-flow-annotated.pdf

Now....a fair statement is "what if all power came from renewable sources?".  That would be wonderful...but we are very far from this today.  So...if you are driving your EV in Seattle where 90% of your power is from hydro - this is wonderful!  If you charge your EV from your own solar panels - great!  My comments are based on USA avg, which of course is most relevant to "mass market cars". 

So, to be most complete - if one takes the LL Labs chart and does some creative calculations, subtracting out the "zero fossil fuel sources" (Solar, Nuke, Hydro, Wind, Geothermal), and setting them to be "100% efficient", and then see how much fraction of fossil fuel heat (Coal + NG) would be used to charge the average EV,  the net "efficiency of fossil fuel usage" (too involved to show math) would be ~38%.  Good...but only about the SAME as a PRIUS!!!

So...when you hear of the 99 MPGe of the Nissan LEAF - you should DIVIDE by a factor of ~2.6 to 3.0 to get a truly fair equivalent fossil fuel usage using USA avg data.   This is 33 - 38 MPG equiv.  So, you see....EV's do not really make any difference in fossil fuel usage vs. an efficient conventional car (many are 40 MPG now)...and the PRIUS (at ~50MPG+) actually burns LESS fossil fuel per mile than a LEAF!!!  The main thing you can say for EV's is that they are converting the use of OIL to COAL + NATURAL GAS, at about the same net energy efficiency.  Oil is politically more problematic....Coal is much dirtier (but people are working on cleaning it up some).  Natural Gas is the most efficient and cleanest mid-term solution...but eventually all fossil fuels will go away. 

www.forbes.com/sites/warrenmeyer/2010/11/24/the-epas-electric-vehicle-mileage-fraud/

Sorry if this is verbose, but it is not a simple subject and is clouded with many layers of information (and mis-information).   As the grid is increasingly fed with renewable sources, the favor will swing more towards EV's....but that will sadly take many decades at best.  In the mean time - I think our $$$ is better spent on more efficient vehicles, alternate fuels, and greening the grid - and EV's are a huge distraction in this endeavor, and do little to advance us in this direction.

cheers,

Kevin

Charles Murray
User Rank
Blogger
Re: Bigger Car Batteries Are NOT The Answer
Charles Murray   1/3/2012 10:01:00 PM
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Great points, Kevin. Could you lead us to a website that compares Prius fossil fuel usage to coal burning?

Kevin
User Rank
Platinum
Bigger Car Batteries Are NOT The Answer
Kevin   1/3/2012 7:42:17 PM
NO RATINGS
The Prius plug-in hybrid seems to be nearly a "perfect" balance for a practical commuter car, building on the very good existing Prius.  Of course...Toyota was the first to commercialize a mass-market hybrid, and has sold many more than anyone, so you expect them to "get it right".  For short trips, it has all the advantages of a pure EV, but can do long trips too and be extremely efficient on gas.  Zero recharge time or range worries.  Decent cost vs. large-battery EV's.  Nearly perfect balance, IMO (at least for the state of today's technologies). 

The VOLT is not far off this mark too...but is a bit on the spendy side IMO, and its MPG while burning gas is not great.  Chevy should make the battery SMALLER, reduce weight, reduce cost and make the gas engine more efficient (or go turbo-diesel)....to catch up with what the Prius has already done.

A relevant question for bigger batteries in EV's is "what is big enough" ?  Of course, there is no perfect answer, but the analogy of "what is enough horsepower?" is similar.  When I'm buying a car, I want enough horsepower to meet my driving style needs, for minimum cost.  My mid-life-crisis neighbor wants a Corvette ZR1, while I'm happy with a turbo 1.8 liter VW....but my neighbor will pay dearly for his choice (environmental travesty aside).  Sure, from a strictly performance measure - "bigger is better"....but practicality and prudence beg to differ for most people.

Regarding pure EV's....IMO, sadly, they are a fad that will die as soon as the government stops the incentives to buy them.  They are a niche product at best, too expensive, too many trade-offs..and I think there are much better ways long-term to get off of oil (and ultimately all fossil fuels, which EV's don't help much with today anyway).  I have researched the details - and it is a fact that today's Prius burns LESS fossil fuel (as oil) than the equivalent amount of COAL that would be burned to power an EV the same distance (in most states).  Biofuels / Solar synthesized fuels and possibly even hydrogen (I add with reservations) make much better long-term automotive fuels than electrons out of batteries.  Note that I'm PRO-Solar, PRO-Wind Power, PRO-alternative energy, PRO-smart grid...but I just don't see how EV's are a practical mass-market solution to transportation no matter how much the zealots hope it to be true.

Jerry dycus
User Rank
Gold
Re: Battery Cost vs Price
Jerry dycus   9/7/2011 8:36:16 PM
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Mike you have some facts wrong. The Volt has a 16kwhr battery pack, not 40, but only uses about 12kwhrs to give it long life.

Next while I disagree a Cruze is similar, your calcs on it's fuel costs are way off. Since now gas costs about $3.60/gal so minimum $.10/mile. YMMV.  But over those yrs to get 300k gas prices will at least triple while a 2kw PV panel set can charge the Volt for 30 yrs. I get panels for $1/wt retail now at many places and first quality for under $1.50/wt.  So for grins let's call it $5k for E fuel.

But the Cruze will average about $6/gal at least so $.20/mile x's 300k equals $60k in fuel costs.  So if one uses something close to real numbers, the Volt smokes the Cruze by being 50% or more cheaper.

More reasonable would be over 100k miles though but even there the Volt still wins and the Leaf kicks posteriors on lifetime costs.

And you compare the Volt, Leaf with economy cars when they should be compared to other high tech cars like they are, with BMW's, Audi's etc which in many cases cost more.

Clarifying on the coming battery glut I don't mean a lot of EV's won't get built causing it but the industry capacity is way more than even very fast EV production ramp up can absorb.  Don't forget in a couple yrs both Ford and GM will be making their own batteries they have stated several times, leaving LG, A123 out in the cold too.

In lithium battery's case, a glut will lead to batteries becoming a commodity, thus low cost will be magnified.

The numbers of EV's that get built depends mostly on the price of gas. I expect 50k next yr and doubling every yr for a while until they make up about 50% of the transport vehicles.

 And oil over the next 5 yrs will likely hit $10/gal as another 3 billion new people want their share of the world's oil.

For those of you bad mouthing lead batteries all mine use them and my costs are just $.01/mile for them.  With electric fuel and battery cost just $.015/mile.  I just shake my head at people paying $40-80/tank for gas while I don't ntice the electric cost on my $35/mo electric bill. 

Wesley
User Rank
Iron
the electric part of Hybrid
Wesley   8/29/2011 11:23:11 AM
NO RATINGS
The hybrid is not an electric vehicle but rather an optomized IC vehicle (when used as a Prias in the gas only mode).

Acceleration eats gas or drains batteries or both. Cruise power is greatly below peak needed for acceleration. Beaking - stopping or slowing is an available energy source and the hybrid transfers slowing or stopping energy and stores it for use on the next acceleration. 

The hybrid IC engine can be sized smaller than desired by using electric in parallel to accomodate peak loads. 

Oversizing the battery for a given system reduces gas millage. Once the battery is fully charged, there is no place to further store regeneration. Driving carefully can also reduce millage.

A driving cycle should never deplete or fully charge the battery - Its capacity is there only to even out the peak and minimum loads of the IC engine.

The Prias is what a gas vehicle should be.

Electric is a good idea when our expectation of a car is greatly reduced. Millage, speed, size, weight and cost are impacted. It is in a nitch market by design.

jmiller
User Rank
Platinum
Rechargeable battery available at the Gas Station.
jmiller   8/28/2011 6:12:35 PM
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Wouldn't it be cool to be able to pull into the gas station and replace the existing battery with a fully charged replacement at the gas station.  Leaving your battery there to be charged for the next consumer.  I think in order to get past this range vs. economically feasible battery issue I think we will have to come to that kind of situation.  And that will have to be driven by governement subsidies and such.  However, as we talk about governement subsidies, we see how the market is reacting to the current government subsidizing of ethenol.

Quite often we as a society do not want our tax dollars to support unprofitable renewable resources, and yet, we won't pay extra for the technology and in the end we are not supporting and are voting with our dollars, that we don't want this type of renewable technology.

Larry4pyro
User Rank
Iron
Re: Big batteries, big costs
Larry4pyro   8/26/2011 3:29:19 PM
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Another factor in the determination of an ideal battery size is the infrastructure required to recharge it.  If done at home, most users would not want to wait more than 10 hours before using the car again.  This means the battery size cannot be larger than what a typical residential wiring system could deliver in that amount of time.  If the battery is intended to be quickly charged at a commercial charge stations, much like today's gas station.  Then that charger must be capable of deliver the necessary in only 5 or 10 minutes, otherwise the wait becomes too long for most ordinary people.  This means the commercial charging station has to operate at extreme voltage and current, which introduces safety issues that have to be addressed.  All of this adds complexity and cost which would have to be considered when determining the ideal battery size.

In my opinion I believe GM has struck a good balance in sizing the battery for the Volt.  It has sufficient range for about 80% of most drives and yet can be recharged from ordinary 120 volt outlets.

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