Plug-In Hybrids

Get 100 miles per gallon (mpg) in your next car. If you are now only getting 20 mpg, getting 100 mpg would cut your gasoline bill 80%. Several future plug-in hybrid electric vehicles (PHEV) will get over 100 mpg. If you own a Toyota Prius you can buy a conversion kit today and make your car a plug-in hybrid.

PHEVs look and drive like regular hybrids. They have large hidden battery stacks that capture braking and downhill energy. Like hybrids they have computer chips that decide when to run only the electric motor, using no gas, and when to run the gasoline motor. When running the gasoline motor, extra energy is sent to the batteries. Most plug-ins can drive a number of miles only on the electric motor. A PHEV20 can run 20 miles in electric only; a PHEV40 can run 40 miles. You get the idea.

The beauty of a plug-in hybrid is that most of the time the gasoline engine is never used to recharge the batteries. The batteries are recharged by plugging the car into a standard 110 volt outlet. For example, the car could be plugged-in while in the garage each night. An added benefit of plugging-in at night is that electric rates are low because excess power is being generated in comparison to daytime peak electric demand.

80% of US daily car use is less than 50 miles. With a PHEV50, gasoline would not be used for those 80% of all daily uses. 50% of all our daily vehicle usage is less than 25 miles. PHEVs have enormous potential. Most commutes would cause zero emissions and use no fuel. You save a bundle. The country no longer needs foreign oil. Plug-in hybrids are estimated to provide these benefits over normal hybrids: 35% – 50% reduction in NOx and ROG; 45% – 65% reduction in petroleum; 30% – 45% reduction in greenhouse gases.

Toyota will build future plug-in hybrids. Toyota President Katsuaki Watanabe spoke about his dream of building a car that could cross the United States on a single tank of gasoline. My wife and I share two cars. On a given day, one of us never drives over 50 miles alone. With plug-in hybrids, one of us would travel all day on electricity from the grid that is stored in batteries. When we occasionally need range, a plug-in hybrid would automatically engage the engine if the batteries got low.
At South Coast Air Quality Management District (AQMD), Dr. Matt Miyasato reported excellent results with their early tests of four plug-in hybrids. AQMD converted four Priuses to PHEV using a kit that included Valence Lithium-ion batteries. AQMD achieved 99.9 mpg, saving a fortune in gas. When required, each Prius can still go hundreds of miles between gasoline refills.

Plug-in hybrids are also great for larger vehicles. AQMD is also testing two PHEV20 Sprinter delivery vans, one using lithium-ion batteries and one using nickel-metal hybrid batteries. AQMD has future plans for expanded use of PHEV vans, including passenger vans.

Because major auto manufacturers lost billions on electric vehicles, they are cautious about bring a PHEV to market. PHEVs require more battery power, adding cost and weight to vehicles. If customers do not bother to plug-in and recharge, actually mileage would be worse than today’s hybrids.

The nickel-metal hydride batteries in current hybrids cost thousands. Because of that cost, customers want 100,000 mile warranties. To achieve this long-life, auto makers use a narrow state of charge. Plug-ins demand more batteries that are used aggressively than in normal hybrids. This creates two problems: weight and shorter life for expensive batteries. To reduce weight and added power, PHEVs may predominately use lithium-ion batteries. Early conversion kits are unlikely to offer 100,000 mile warranties.

Writing for Green Post, Dania Ghantous raises several important points: “What about safety? What happens in a car accident? After all, there’s a lot of energy stored in lithium-ion batteries and it’s all packed in a relatively small area inside the vehicle! And what is the reliability of these batteries when subjected to extreme cycling conditions? Let’s take a closer look at some of the design criteria for a PHEV battery: 1) high storage capacity to increase range and acceleration; 2) long battery life to last more than 100,000 miles; 3) less weight to increase acceleration; 4) heat management as battery temperatures tend to increase during charging; 5) safety when in use and 6) low cost. That’s a tall order for today’s battery technology as there are serious concerns about the safety and lifetime of larger battery packs.” Full Article

Plug-in hybrids do have a big future. The plug-in hybrid design could work with any fuel including ethanol, biodiesel and hydrogen. A PHEV running on E85 ethanol would potential only use one gallon of gasoline every 500 miles, with the rest of the mileage being fueled by electricity and plant-fuel. Such PHEVs would make us free of oil dependency and national security problems that result from sending billions to the wrong countries. The plug-in hybrid design could work with any fuel including ethanol, biodiesel and hydrogen. The large public transit operator AC Transit has three plug-in hybrid hydrogen buses. The plug-in design allows AC Transit to save millions with smaller hydrogen fuel cells than in the plug-in design were not used.

John Addison publishes the California Hydrogen Report (www.cah2report.com). His firm, Optimark Inc. conducts market intelligence and market development for cleantech and information technology corporations.

http://www.calcars.org/audio-video/wnbc-calcars-15aug05.html

http://www.aqmd.gov/tao/ConferencesWorkshops/techforum.htm

9 replies
  1. Anonymous
    Anonymous says:

    Sounds quite optimistic, but PHEVs are not the panacea that will make it so that "Most commutes would cause zero emissions and use no fuel." This claim is certainly false because PHEVs simply move the emissions elsewhere: the energy from plugging-in originated at a emitting power plant down the road. Moreover, examining these sources reveals that it's environmentally ambiguous at best because the majority of power plants are coal-fired, which is the top carbon dioxide emitter per unit electricity (by a large margin). These negative aspects must be taken into account into cost-benefit analyses.

  2. James Fraser
    James Fraser says:

    Anonymous has to soften his comments in that we are undergoing a transition in use of fuels. We cannot get zero emissions from plug-ins today, but they do reduce emissions due to the fact than power plants (even coal) produce less emissions per unit of power than vehicles because they operate at 35+% efficiency vs ~15% for gasoline ICEs. Moreover as we progress through the transition (taking at least 30 years)that will occur due to increasing costs of oil, If all vehicles (not really probable)were plug-ins we could produce enough biofuels to power them and reduce the emissions from the ICE part of a plug-in to zero. It is likely that a good portion of our light vehicle fleet will eventually become BEV’s (battery electric vehicles) reducing the liquid fuel requirement even more. Two additional events are likely by that time 1) A greater % of our electricity will be generated by that time, further reducing emissions 2) CO2 emissions from coal fired plants will have to be reduced to prevent global warming through carbon capture and control technologies.Because an existing infrastructure exists that can take advantage of off peak power for some time, large amounts of money do not have to be spent for an infrastructure to distribute electricity, compared to a completely new infrastructure that would be required for hydrogen if we were to follow that route.This Energy Revolution is going to take a long time and require a lot of patience with little instant gratification.

  3. James Fraser
    James Fraser says:

    Anonymous has to soften his comments in that we are undergoing a transition in use of fuels. We cannot get zero emissions from plug-ins today, but they do reduce emissions due to the fact than power plants (even coal) produce less emissions per unit of power than vehicles because they operate at 35+% efficiency vs ~15% for gasoline ICEs. Moreover as we progress through the transition (taking at least 30 years)that will occur due to increasing costs of oil, If all vehicles (not really probable)were plug-ins we could produce enough biofuels to power them and reduce the emissions from the ICE part of a plug-in to zero. It is likely that a good portion of our light vehicle fleet will eventually become BEV's (battery electric vehicles) reducing the liquid fuel requirement even more. Two additional events are likely by that time 1) A greater % of our electricity will be generated by that time, further reducing emissions 2) CO2 emissions from coal fired plants will have to be reduced to prevent global warming through carbon capture and control technologies.Because an existing infrastructure exists that can take advantage of off peak power for some time, large amounts of money do not have to be spent for an infrastructure to distribute electricity, compared to a completely new infrastructure that would be required for hydrogen if we were to follow that route.This Energy Revolution is going to take a long time and require a lot of patience with little instant gratification.

  4. James Fraser
    James Fraser says:

    Anonymous has to soften his comments in that we are undergoing a transition in use of fuels. We cannot get zero emissions from plug-ins today, but they do reduce emissions due to the fact than power plants (even coal) produce less emissions per unit of power than vehicles because they operate at 35+% efficiency vs ~15% for gasoline ICEs. Moreover as we progress through the transition (taking at least 30 years)that will occur due to increasing costs of oil, If all vehicles (not really probable)were plug-ins we could produce enough biofuels to power them and reduce the emissions from the ICE part of a plug-in to zero. It is likely that a good portion of our light vehicle fleet will eventually become BEV’s (battery electric vehicles) reducing the liquid fuel requirement even more. Two additional events are likely by that time 1) A greater % of our electricity will be generated by that time, further reducing emissions 2) CO2 emissions from coal fired plants will have to be reduced to prevent global warming through carbon capture and control technologies.Because an existing infrastructure exists that can take advantage of off peak power for some time, large amounts of money do not have to be spent for an infrastructure to distribute electricity, compared to a completely new infrastructure that would be required for hydrogen if we were to follow that route.This Energy Revolution is going to take a long time and require a lot of patience with little instant gratification.

  5. Anonymous
    Anonymous says:

    James,Your analysis is not comparing the input/output effects on an apples-to-apples basis:1. Your assertion that ICEs are 15% efficient is not correct if we are measuring the energy generated; it's more on the order of 20-25% (most physics and environmental science texts cite this). Encyclopedia citation enclosed for reference here.The 15% power is what actually goes to the wheels, after driveshaft and other mechanical losses (~5-10%), but this will happen with PHEVs as well, so the correct figure to be used at the engine is 20-25%2. Your cited reference of 35%+ efficiency is in terms of thermal efficiency, i.e., including steam production, which is actually a large component of the heat energy. When the turbine powers the generator to make electricity, more heat is lost in the process. This means that the electricity efficiency (we care about electric efficiency because you can't charge your hybrid with steam) is lower than that figure.3. You also did not account for transmission losses, which were on the order of 7.2%+ (at least), which will bring your electric efficiency figure down further.Now we're on the same page comparing the input of electricity at the point the energy enters the vehicle: ICE at around 20-25% and <28% for power plant (still need to subtract steam to elec conversion, which varies greatly and depends on equipment). This is the energy efficiency.However, coal-fired electricity produces <a HREF="http://www.eia.doe.gov/cneaf/electricity/page/co2_report/co2report.html&quot; rel="nofollow"> a lot more CO2 per unit electricity. This means that coal-fired electricity that supplies PHEVs most likely will not emit fewer emissions. Moreover, SOx, NOx, particulate matter is generated at a far greater amount per unit electricity for coal. If you are interested in the environment, this is a serious consideration.Note: I never advocated for a hydrogen infrastructure. The point I am making is that PHEVs greatly complicate the inherent beauty of normal hybrids–recovering previously "lost" energy from braking/etc. You've now introduced an energy source under the guise of being low or zero emissions when that claim is patently false.I agree that the long-term prospect for this might be different, should carbon recapture technologies be invented, but that's a big if. The hype surrounding these vehicles is sold in an intellectually dishonest manner, which I find to be problematic. Thus, until these posts reflect the truth, these comments are more than merited.Environmental scientists and economists who are analyzing global warming worry greatly for when petroleum resources become economically inviable and we switch over to coal. The academic literature calls to attention the detrimental effects of exacerbating global climate change if coal is to become an even larger fuel source (because it is so incredibly carbon intensive). There's no free lunch for electrical generation, except perhaps for wind (even it also has its caveats). We have to choose between lesser evils and the PHEV conversion losses are always underemphasized.

Leave a Reply

Want to join the discussion?
Feel free to contribute!