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Hybrid Vehicles Electric Vehicles Electric Vehicle Pros & Cons
1586 messages, Last post on Oct 23, 2009 at 4:19 PM
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Replying to: prm2000 (Aug 03, 2006 4:35 pm) I'm going to dig a little deeper on this issue but I have this comment to make regarding one of their assumptions: They've comparing the emmissions from various types of power sources supplying electricity for EVs against the vehicle emmissions from an AVERAGE fleet of cars using ICEs. Is this a valid assumption to make? How likely are owners of large trucks/SUVs to move to EVs? And how likely are the owners of EVs to be migrating from current LEV and ULEV cars? I'm going to try and dig up the emissions numbers for the vehicles which are actually USED by those most likely to make the step from ICEs to pure EVs. I'll then compare THOSE emissions numbers to the emission numbers used in that analysis.
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Replying to: tpe (Aug 04, 2006 6:22 am) Again, we don't know that. The EV study reference above compared the emissions from various power plants to the emissions of AVERAGE vehicles. If one is already driving a LEV or ULEV Honda (or perhaps a hybrid like the Prius), if THOSE people make the jump to EV, what is the comparison of their current ICE emissions to that of a power plant? In all honesty: who is more likely to make the jump to a 100% EV - the current owner of a Prius or the owner of a 10-year old Chevy Malibu?
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Replying to: rorr (Aug 04, 2006 5:10 am) The 50% of electricity that is coal generated might not reduce emissions as much as people think (although it still reduces emissions), but the other 50% of generated electricity would reduce emissions dramatically. In this whole discussion I don't hear enough talk about how electric cars would dramatically reduce the amount of oil we import. At the moment the national security issue is the most important factor to me. The increased efficiency and dramatically reduced emissions are gravy. I think it is criminal that politicians help Detroit and Big Oil to suppress the electric car, and then spend many billions to fight foreign wars to stabilize the middle east oil fields.
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Replying to: prm2000 (Aug 04, 2006 6:38 am) For a very good reason, I will not contribute to such a discussion. Discussions regarding emissions comparisons and energy production can be done in a (somewhat) level-headed means. Facts and data can be presented and mulled over. Agreements can be reached (I think) without too much animosity. However, if some individuals simply feel COMPELED to drag politics into this discussion, it can ONLY end up with one side wanting to pull the ears off the folks on the other side. If your INTENT is to run me off, then by all means let's have this discussion degenerate into whining about 'Big Oil' and 'foreign wars to stabilize oil fields'.
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Replying to: rorr (Aug 04, 2006 6:37 am) Tesla Motors has an arrangement with solar installers for buyers interested in re-charging their Roadster with the sun's energy. People that can afford this car can probably also afford a PV system. That represents closing the loop.
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Replying to: tpe (Aug 04, 2006 7:48 am) My question was in regard to ALL emissions. And the data link posted by prm2000 contained info relating to both CO2 and non-CO2 emissions. Which is why I brought up the issue of LEV and ULEVs. You are correct. CO2 emissions are essentially a pure function of gas mileage rather than degree of emissions control. LEV/ULEV vehicles aren't necessarily any better at controlling CO2. To that end, I'd like to contribute the following data (from fueleconomy.gov) The Prius will generate roughly 3.4 tons of CO2 per year (15,000 miles/year). This equates to 0.45 lbs/mile of CO2 which translates to approximately 125 grams/km. The study referenced by prm2000 assumed an AVERAGE vehicle CO2 emission (composite number of cars and trucks) of roughly 250 grams/km. These numbers indicate the Prius generates 50% the GHG of the average vehicle from that study. And the study further states that electricity generated from coal powered sources would generate 55%-59% less GHG of the average vehicle. So, IF comparing a Prius to the GHG produced by a coal-fired plant for EV use, CO2 production is close to a wash. It then DOES become of interest what the OTHER non-CO2 pollutants look like. To achieve ULEV status, vehicles must emit no more than: 0.04 gm/mile (0.025 gm/km) of Total Hydrocarbons (HC) 1.7 gm/mile (1.06 gm/km) of Carbon Monoxide (CO) 0.05 gm/mile (0.031 gm/km) of Oxides of Nitrogen (NOx) The 'Average car' values used in the study for these same criteria are: 1.07 gm/km for VOC+TP (HC) 9.23 gm/km for CO 0.88 gm/km for NOx. It is further stated that a coal-fired plant would reduce these levels of non-CO2 emissions by "80-92% depending on the type of coal". Which would give the following levels of non-CO2 pollutants: 0.086 to 0.214 gm/km of HC (2x to 5x HIGHER than ULEV) 0.738 to 1.846 gm/km of CO (74% higher to 44% lower than ULEV) 0.07 to 0.176 gm/km of NOx (2x to 6x HIGHER than ULEV) Bottom line: With hybrids, it is possible to achieve roughly the same level of CO2 emissions as an equivalent EV vehicle with electricity sourced from a coal-fired (a MODERN coal-fired) power plant. Also, an EV with electricity sourced from a coal-fired plant would generate AT A MINIMUM TWICE the HC and NOx pollutants (and as much as 5x to 6x depending on the quality of the coal) compared to a current ULEV vehicle. Carbon monoxide emissions appear to be highly dependent on the type of coal used in the plant. So, if an individual lives in an area served by coal-fired plants (or if additional electrical demand would be met by a coal-fired plant), does it REALLY make more 'green' sense to go EV or conventional hybrid?
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Replying to: rorr (Aug 04, 2006 6:58 am) Discussions regarding emissions comparisons and energy production can be done in a (somewhat) level-headed means. Facts and data can be presented and mulled over. Agreements can be reached (I think) without too much animosity. However, if some individuals simply feel COMPELED to drag politics into this discussion, it can ONLY end up with one side wanting to pull the ears off the folks on the other side. If your INTENT is to run me off, then by all means let's have this discussion degenerate into whining about 'Big Oil' and 'foreign wars to stabilize oil fields'." I'm baffled by your response. I have no intention of getting into a political debate. It is a fact that we are heavily reliant on foreign oil. It is not a political statement. It is a fact that an electric car is the most fuel flexible vehicle made. No matter what is used to generate the electricity now or in the future (NG, coal, nuclear, hydro, biomass, solar, wind, fuel cells, whatever) an electric car will use it. That is not true for an ICE vehicle. That is an enormous selling point, and it's not political. I am pretty confident that you have no clue what "side" I am on politically, so your "side" would not know who to tear the ears off of. I could care less what side you are on. It's not an issue I care about. Being reliant on unstable and relatively unfriendly countries for a vital resource puts us in a weak position. All things being equal, if we can avoid that form of reliance we would be in a stronger position which would help national security. That is hardly a partisan political statement. Discounting the real and very strong benefit of reducing oil consumption as "political", has been a very common ploy to discount BEVs. How about I make the claim that battery range and recharging time is a "political issue", and refuse to discuss it when comparing BEV and ICE? How do you think that ICE would fare based solely on performance and cost per mile comparisons? Big oil is a valid topic for discussion, but it doesn't have to be political and it also doesn't have to be here. I don't blame big oil for protecting their interests. The question is where are we going to be in the future and how do we transition from where we are now (pure petroleum) to wherever we are going to end up in 10-30-50 years. Huge companies don't go away quietly. What will their role be in the future, and what will the transition be like? It's a fair question, and it is not political.
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Replying to: rorr (Aug 04, 2006 8:48 am) How much electricity are they assuming an EV uses per mile/kilometer? For a Prius-like vehicle it should be about .25 kWh/mile. Also, not all hybrids are low polluting. A lot of times it depends on where you buy the vehicle. According to the EPA the Honda Insight is one of the most polluting vehicles outside California. http://www.epa.gov/emissweb/E-HONDA-Insight-06.htm The same is true for Toyota's Scion XA; a non-hybrid that gets excellent mileage. http://www.epa.gov/emissweb/E-TOYOTA-ScionXA-06.htm There are plenty more examples. My point is that unless you're talking GHG emissions small, fuel efficient cars aren't necessarily clean.
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Replying to: prm2000 (Aug 04, 2006 8:51 am)
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Replying to: tpe (Aug 04, 2006 11:52 am) "How much electricity are they assuming an EV uses per mile/kilometer?" I wish I could tell you. Unfortunately, I haven't taken enough time to fully digest that study (particularly the electrical production side of it). To be honest, all I did was look at their assumptions for emissions from their 'average' ICE vehicle fleet and compare those assumed emissions levels to what I know is achievable with CURRENT technology in an ICE vehicle. Just my heavy-handed approach to refuting the assertion that production of electricity for EV use was always cleaner than ICE (regardless of how advanced ICEs may be, though this was not explicitly stated). Correct, not all hybrids are low polluting. However, since the technology DOES exist (and is currently being used in California), then it follows that all fuel efficient vehicles (which are naturally lower in CO2 emissions) COULD also be lower in other emissions. So, IF we are talking about the emissions aspects of hybrids compared to EVs, then my point is that the technology is currently in place and being used on a wide-scale (I consider use in all of California wide-scale) for very clean hybrids. |
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