Plug-in Hybrids Get Green Grades

Plug-in Hybrids Get Green Grades
Overall, plug-in cars are a plus for the environment, despite the fact that they would increase the demand for electricity.

By Kevin Bullis
Tuesday, July 24, 2007

Plug-in hybrids, which use electricity from the grid to replace gasoline for daily driving, would cut gas consumption and save commuters from high fuel prices. But some experts have been concerned that switching from gas to electricity, much of which is generated from fossil fuels, would actually significantly increase pollution in some parts of the country, as opposed to decreasing it.

Battery power: Plug-in hybrids, like this concept car from General Motors, could help cut both gasoline consumption and greenhouse-gas emissions.
Credit: General Motors

A study released last week by the environmental group National Resources Defense Council (NRDC) and the largely utility-funded Electric Power Research Institute shows that plug-ins, once they're on the market, will significantly cut greenhouse gases. Across the country, the vehicles will on average also decrease other pollutants, but the impact in local areas will depend on the source of electricity.

In plug-in hybrids, a large battery pack that is recharged by plugging it in stores enough energy to power a car entirely, or almost entirely, with electricity for the first 40 miles or so of driving. For longer trips, the car reverts to conventional hybrid operation, relying largely on gasoline for power but improving efficiency: by storing energy from braking in the battery and using it for acceleration, for example.

The study shows that if plug-in hybrids are adopted widely in the United States, and if measures are taken to clean up power plants, by 2050, plug-in hybrids could reduce carbon-dioxide emissions by 612 million metric tons, or roughly 5 percent of the total U.S. emissions expected in that time frame, according to Marcus Sarofim, a researcher at MIT's Joint Program for the Science and Policy of Global Change. That's a significant amount, he says, considering that transportation accounts for only about a third of the total greenhouse-gas emissions.

But if plug-in hybrids account for only a small part of the total vehicle sales in 2050 (about 20 percent, compared with 80 percent in the first scenario), and if little is done to improve pollution from power plants, the vehicles will still reduce greenhouse emissions by about 163 metric tons, according to the study.


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Open 25 Comments


Alternative sources
I really do not know whether this is practical or not at this time, but I have always thought that a car, with its large flat areas consisting of the bonnet, roof and sides, are ideal places to incorporate solar panels / cells.

These could possibly provide some amount of on-going electric power to a vehicle that has to travel more than the 40 miles stated in the article. Another advantage is that during the day, at any given time, the roof plus one side at least would get direct sunlight.

Further, with the vehicle moving at typical speeds of 40 mph plus, vents that collect on-rushing air to drive miniature wind turbines possible?

This would decrease the load on large, centralised power plants like those stated.

Anyway, talk of timelines like 2050 etc scare me in to thinking of the type of world that we will be leaving for the next generation!

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deejay
07/24/2007
Posts:23Avg Rating:

Re: Alternative sources
This is being done in competitions in Australia by one of the Universities. They already have solar powered cars which can travel long distances. The competition is a race across Australia. I think the problem currently is that the solar panels need so much surface area that there's only a driver area and it's tiny and cramped. However, this does show that the technology is already in place, and, coupled with other technologies, is viable.

http://www.unisa.edu.au/solarcar/
http://www.wsc.org.au/
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bj
07/24/2007
Posts:37Avg Rating:

Re: Alternative sources
Boeing just hit forty percent efficiency with solar panels. One would think that a literal "sun roof" would recharge a hybrid (at least partially) while the car was parked. This, of course, provided it was in the open.

Envision parking garages with solar panels for a top roof...each of which went to plugs for people to charge their cars. One solar panel roof likely wouldn't charge all the cars. But still....
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Hardheadjarh...
07/26/2007
Posts:15Avg Rating:

Re: Alternative sources
I just emailed Boeing about putting together some higher efficient cells and was told the cost currently would be prohibitive. I was trying to get 1 KW of cells into the area of a hood and top of a Saturn Station Wagon. My logic was during a 9 hour work day with 6 hours of good sun I would get 6 KWhr of energy. At 200 watts/mile that would drive the car ~ 30 miles. If the cost of cells around 30% efficient can get down to $5 per watt that makes a solar car a reality.
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Gypsy_EV
07/30/2007
Posts:15Avg Rating:


TANSTAAFL
Using "turbines over 40mph to recharge the batteries" (paraphrased) -- Good luck with that. Do that and make it work, and you've found a perpetual motion machine.

TANSTAAFL == There Ain't No Such Thing As A Free Lunch
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jesup
07/24/2007
Posts:8Avg Rating:


Re: Alternative sources
For southern regions of the US and other sunny climes, solar panels on PHEVs are eminently practical now and could displaced a portion of the battery pack while lessening GHGs vehicle weight and costs, especially if the panels were eligible for solar subsidies.

PHEV batteries have an installed cost about $1K per kWh with perhaps an 8-year warranty and store off-peak electricity which costs 6 – 10 ¢ per kWh. Thin film solar cells have an installed cost of $6K per peak kilowatt (kWp) with a 20-year warranty and, for cities in the lower tier of states, provide a daily average of 5 kWh per kWp at 0 ¢ per kWh. (ref. http://www.solarpanelsplus.com/solar-insolation-levels/ )

The kicker is variability of solar radiation, daily and seasonally. Other issue is that the horizontal area on a medium sized car is limited - about 3 sq. meters and thin film solar cells have an efficiency of about 10% (less for a-Si; more for CIGS and CdTe). So, this means that only 300 watts of peak power, or an average of 1.5 kWh daily, is available using thin film cells. Crystalline silicon solar panels have an efficiency of about 20% but their integration into the car's skin would be more difficult than with flexible thin film panels.
(1.5 kWh would translate to about 4 or 5 miles of travel.)
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pmcha5e
07/24/2007
Posts:1

Re: Alternative sources
We must be practical. Who would buy a car that would lose its charge if parked in a garage, or in the shade?
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lambdafunds
07/25/2007
Posts:9Avg Rating:


Re: Alternative sources
"Further, with the vehicle moving at typical speeds of 40 mph plus, vents that collect on-rushing air to drive miniature wind turbines possible?"

I believe that you have just suggested a perpetual motion machine. :-D
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JRT
07/14/2008
Posts:4

Couple with wind power
This makes alot of sense to me. There is huge untapped potential in wind energy. Germany, Spain, Denmark, Scotland are way ahead of us (see the sponsor adds for Tech Review from Spain Technology for good links. With their wind at bay, I am baffled why Europe has not led the charge on plug-in cars (no pun intended !) Seriously, look at how wind energy stocks have soared with wind production increasing 20-30 % a year in W. Europe with the U.S. not far behind and China making major commitments. All of the technology for both electricity production and plug-in cars is in place. With no emmissions this is clearly a win-win for everyone, with money to be made from improvement in transferring the energy and developing/manufacturing components, for which there is a shortage right now. Energy from tides, waves and solar are not far behind. Burning things like ethanol is a waste of farmland, causes emmissions, uses water, is fraught with waste issues, and is increasing the price of food. I want to know why the U.S. is not spear-heading both plug-in vehicles and wind production simultaneously. There's an open invite here to make some serious dollars. HS
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hansy
07/24/2007
Posts:2Avg Rating:

Re: Couple with wind power
I see what youre saying & agree. I think one of the major problems with power in the USA, as well as most places, is that it is produced in one place & consumed in another, and it is wasteful & expensive to keep moving it back and forth between places. If we can produce it & consume it in the same place (as close as possible) we are way ahead of where we are today. Now, thinking on those lines, if we can have small wind turbines on the roofs of people's houses that plug-in to their panel to power the house or alternatively power the car plugged-in in the garage, to charge it at night (when consumption by the house might be lower) then we would really have something. I am the (somewhat smug) new owner of a Prius & it has changed my life in three weeks. I already drive slower (yes, grandpa was right, it only changes a couple minutes of arrival time, at most) is safer, and uses far less energy then jamming it at every light & passing every car you can & all that nonsense. Combined with the nearly 50 mpg I get (not quite but almost) I really want to get it over 50 a regular basis to really feel great. If the car could be plugged-in as night, I'm thinking we would be there easily. Please some one more brilliant than I do this for us. I will buy it. Thanks. Peace. Jason Sjobeck
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Sjobeck
07/30/2007
Posts:17Avg Rating:


Re: Couple with wind power
I could not agree more with your comments. Electric Cars are the future if we want a sustainable way of living. It means energy independence, better on the environment, and less costs to fill-up than petro/oil. Don't even get me started on biofuels. They are a joke when comapred to electric cars with electricity from a clean energy source. We can always build another wind plant or solar plant, but oil resources are finite and from many countries that we should not be sending our money too.

It's too bad the U.S. didn't pour more resources into battery technology (companies like A123)and wind and solar earlier. We could have taken the $500 Billion spent on Iraq to secure oil and built some renewable energy plants instead, which would make alot more sense. Hopefully our Congress will do what's right here rather than what the special interests want, and we'll be charging in our cars from cleaner, more sustainable energy sources in the future.
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kdigiovi
07/30/2007
Posts:1

Power distribution
If they're not careful, this could require huge new power-distribution powerlines, cutting huge swaths through formerly forested/protected areas (and the Federal government is trying to take control of this away from the states).

You'd want the power stations near the use, but most of those areas are both a) expensive, and b) unlikely to be easy to site in due to NIMBY (Not In My Back Yard - see the Cape wind power fiasco). And then there's the environmental damage of mining all that additional coal (see West Virgina), and acid rain issues (especially if the new plants aren't cleaner, though perhaps using the existing pollution-trading methods may help).
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jesup
07/24/2007
Posts:8Avg Rating:

Re: Power distribution
If that was necessary it certainly reduces the appeal this technology
has to me but one would hope that - especially with batteries improving - plug-in are mostly plugged in during the night when the demand for electric power is lower anyway.

Christoph
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cwl
07/24/2007
Posts:2

Gasoline vs Electricity
The standard wisdom is to get rid of any use of gasoline, but when you compare the amound of CO2 produced by a coal fired plant to that of a Prius, the Prius is actually cleaner at 50 mpg. If you add in replacing the gas engine with the high compression engine, you could get up to 200 mpg. Add in ultra high capacitors and that 200 mpg could reach 800 mpg. At some point in there, the Prius starts becoming cleaner then a natural gas plant. Change the batteries to lithium ions that can recharge in 6 minutes, and gas mileage improves again. While I seriously doubt we will see 800 mpg cars, it does seem that 400 mgp is quite possible, and that trying to make 50 yr policy decisions at the start of a new technology may not be the smartest move.
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tsaidak
07/24/2007
Posts:13Avg Rating:

Re: Gasoline vs Electricity
I'll take the full-electric approach over hybrid technologies. Primarily because they're perfectly clean, and because I am told we are more effective in controlling emissions and implementing other efficiencies at the central power-generation facilities than in millions of individual owner-maintained automobiles.

One entry into that market already on the road is the Tesla. The design is poised to take ready advantage of any progress in electrical storage media, but in the meantime it's a sharp, fast, uncompromising design and free of emissions.

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burnside
07/24/2007
Posts:7Avg Rating:

Re: Gasoline vs Electricity
The problem with electric vehicles is - what happens if you need to go one kilometer farther than the max range on a charge? With a hybrid vehicle you not only have a range of about 500 miles per tank, but the time to refill is 3-5 minutes. Typical electric vehicles have a range of less than 200 miles, and it takes hours to recharge.

Thus you force people into a two-vehicle strategy - one for short trips, another for long.
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cullen
07/25/2007
Posts:3
Re: Gasoline vs Electricity
Most trips are not that long. True, the pure electric does not make the perfect cross-country vehicle, but by far most people never leave a small radius of geography. And ... let us start some where, yes, get some momentum, experience, shared knowledge, popularity, design, support, funding, science, innovation, and then conquer that problem for the long-term.

It is no surprise that the short-term mentality of US auto makers (who ought to be ashamed of themselves on so many levels, not just this issue) are no where on this one. (We need all the fat white 58 year old men holding out for retirement in Detroit to just get out of the way & let this generation who is raring & ready to do this thing get on with it)

I drive around Oregon & am stunned how many hybrids there are ... let us take this to the next level.

Thanks.

Jason Sjobeck
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Sjobeck
07/30/2007
Posts:17Avg Rating:

Re: Gasoline vs Electricity
I can only speak to my own experience. While I freely admit that most days my trips are not that long, I do make trips of 500 miles or more. A current generation pure-play electric vehicle simply doesn't work in those situations. I am then forced into the choice of either owning another gasoline vehicle for those situations or renting. Hybrid vehicles - particularly in my area - are pretty decent choices (which I've owned for 4 years now).
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cullen
07/30/2007
Posts:3

Re: Gasoline vs Electricity
I can almost see getting close to 200 mpg but 400, no way. The body is not streamlined enough and it is too heave, too much friction in its current configuration. It would need to be lighter and completely electric drive, no friction breaks and lower drag bearings. Granted some world champion cars get over 4000 mpg but they are a one passenger vehicle with rock hard tires. I still like an all electric and work on charging it with wind or solar. If the Ultra capacitor did come to pass all the better for the EV.
Either way it would be a huge improvement to current choices.
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Gypsy_EV
07/31/2007
Posts:15Avg Rating:


Here's what I don't understand...
I'm not an auto engineer by any stretch. Just a software engineer who finds the topic interesting. However, I've always wondered why I've never seen a series hybrid built with a small engine highly tuned for efficiency paired with a medium size battery pack. The engine, I would think, would need to generate just enough power to cruise the car along at 80mph on the interstate and the battery pack would only need to hold enough juice to buffer the engine from the powertrain (probably less than 50% the normal size). I think that setup (in a Toyota Camry for example) would get in excess of 60mph and would meet the driving habits of over 99.9% of the population. So, what am I not understanding?
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RichardL
07/24/2007
Posts:3Avg Rating:

Re: Here's what I don't understand...
you are largely correct.....altho' what you would really want to use is a gas turbine which is very efficient but can really only be run at two speeds, on full or off....you can turn it off when it reaches 80% or so that breaking energy isnt wasted...the battery pack might have to be bigger than you think tho. Still, this is by far the most inherently efficient setup we can easily create w/ current tech. It is a wonder to me why it hasn't been done myself. The only thing i can think of is that there might be problems handling the precession or the turbine, but that doesn't seem too difficult to handle.....modern chainsaws have systems to dampen the effects of precession [really the effects of angular momentum in a precessing system].
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cripdyke
07/24/2007
Posts:17Avg Rating:


Re: Here's what I don't understand...
Your analysis is correct as far as it goes.

If you have a small Otto or Diesel engine, a large electric motor, and a battery that can run it for a short time, there is a rather large problem: how do you charge the battery?

The answer is that you are going to need some sort of an auxiliary power unit to supply either mechanical or electrical power to charge the battery and to help run the vehicle when the battery has been depleted.
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JRT
07/14/2008
Posts:4

>>> a SIMPLE solution for ELECTRIC CARS >>>
.

in my latest article ("Cellphone Battery Electric Cars") you can find a SIMPLE solution to the main problem of all Electric Cars: the (still) low autonomy

http://www.gaetanomarano.it/articles/033cellphoneCAR.html

.
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Gaetano Mara...
07/24/2007
Posts:102Avg Rating:


Lifestyle vs mpg
More important impact can be made by lifestyle choice. Live close to town, ride a bike, walk, buy local. So many get hyped up about mpg that they forget what makes the most impact.

While I do think the electric car technology is cool and important, you can make an impact today without waiting for the next generation of plug ins.

How about a solar array on the garage roof to charge the car while parked? That would be my dream.

But I would still ride a bike.....

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sroszko
07/24/2007
Posts:1
Re: Lifestyle vs mpg
I think you're entirely right. But perhaps it is also important to consider what the majority of people are likely actually to do as opposed to what they should be doing.

That Calif. car builder I mentioned above (no, I'm not an investor) makes essentially a duplicate of a production Lotus Exige. The gas-fired variety gets 23 city/29 hwy while its electric twin will travel considerably more than 200mi on a four-dollar charge. At current prices that's easily in excess of 100mpg, so you see the implications.

Incidentally, one of my old college chums installed a 24kw solar array at his home in FL. He likes the power bills much better now - I think it's only a connection charge. He's feeding excess power INTO the grid during the day, draws what he needs at night, the net is just about zero.