ACEEE Releases Report on Plug-in Hybrids; Finds Benefits, But Issues
25 September 2006
|CO2 emissions associated with all electric use of a PHEV varies significantly with the regional power-generation mix—and, in some regions, also over time. Total US is the dashed red line. Click to enlarge.|
Plug-in hybrid vehicles could contribute greatly to reducing automobile oil consumption and emissions, but reaching those goals requires major progress in key areas such as improving battery technology and cleaner power generation, according to a new report by the American Council for an Energy-Efficient Economy (ACEEE).
The consumption- and emissions-related benefits of plug-ins will vary substantially based on the method of power generation for the local grid, the vehicle’s electric-only range, operational strategy, and drive cycle characteristics, the authors argue.
The report finds that greenhouse gas emissions reductions associated with a plug-in powered by today’s electric grid would be about 15% on average across the nation, ranging from 32% using California electricity to zero using Upper Midwest electricity.
Although reduction of fuel consumption with plug-ins could be quite large, according to the report, the authors suggest that plug-ins with modest electric-only range will appear first because of the steep increase in battery size and cost linked to increased fuel savings.
Furthermore, the authors are not optimistic about the full-electric scenario for PHEVs in the short term (that the hybrid operates as a full-electric vehicle up to the state of charge determined by its operating strategy, then switching to a conventional hybrid mode).
Achieving adequate battery lifetimes and minimizing battery costs will require a vehicle control logic that turns on the internal combustion engine when extra power is needed, even within the electric-only range of the vehicle—James Kliesch, co-author
The ACEEE report estimates fuel savings relative to today’s hybrids of 30% for a plug-in with a 20-mile electric-only range and 50% for a 40-mile range.
With high volumes and a drop in nickel prices, the cost of the nickel-metal hydride batteries used in hybrids at present could fall quite dramatically. To reach an appropriate balance of size, weight, and power for a long-range plug-in, however, researchers’ bets are on lithium-ion batteries, which still need technological breakthroughs to reach commercial production for plug-in applications. Projections of long-term costs for plug-in batteries imply that the incremental cost of a plug-in could match that of a hybrid today.
The report concludes that plug-ins are likely to emerge through gradual increases in the electric-only range of hybrids and can therefore be regarded as one of several elements in the evolution of the hybrid, albeit one with enormous potential to lessen the vehicles’ environmental impact.
The authors caution that work on plug-in development should not divert attention from readily available measures to lessen the oil dependence and greenhouse gas emissions of the transportation sector.
Plug-ins represent a major step toward the electrification of the transportation sector, a transition that has tremendous potential to help solve some big problems. But realizing this potential means maintaining an all-out effort on advanced batteries, cleaning up electric power generators, and adopting policies that drive efficiency technologies by requiring a sustained ramp-up of average fuel economy.—Therese Langer, co-author
ECAR East Central Area Reliability Coordination Agreement
ERCOT Electric Reliability Council of Texas
MAAC Mid-Atlantic Area Council
MAIN Mid-America Interconnected Network
MAPP Mid-Continent Area Power Council
NPCC-NY Northeast Power Coordinating Council/New York
NPCC-NE Northeast Power Coordinating Council/New England
FRCC Florida Reliability Coordinating Council
SERC Southeastern Electric Reliability Council
SPP Southwest Power Pool
WECC-NW Western Electricity Coordinating Council/Northwest Power Pool Area
WECC-RM+ Western Electricity Coordinating Council/Rocky Mountain Power Area and Arizona-New Mexico-Southern Nevada Power Area
WECC-CA Western Electricity Coordinating Council/California
US United States
Posted by: stomv | 25 September 2006 at 04:34 AM
Excellent, balanced report on the issue.
Posted by: jw | 25 September 2006 at 08:05 AM
I don't have a login to download the PDF, but does anyone have the full report PDF and know if they calculated it correctly by time of day? Just knowing how much power comes from what CO2 sources in each region isn't enough information. You need to know how much power is coming from what sources AT NIGHT and if those sources were going to continue to run or not. For example, if you're in a region where, say, 33% comes from nuclear and 67% comes from coal, chances are at night time you're getting 100% from nuclear since coal plants can be fired up and shut down depending on load.
Posted by: Sid Hoffman | 25 September 2006 at 08:43 AM
>I don't have a login to download the PDF, but does anyone have the full report PDF and know if they calculated it correctly by time of day? Just knowing how much power comes from what CO2 sources in each region isn't enough information. You need to know how much power is coming from what sources AT NIGHT and if those sources were going to continue to run or not. For example, if you're in a region where, say, 33% comes from nuclear and 67% comes from coal, chances are at night time you're getting 100% from nuclear since coal plants can be fired up and shut down depending on load.>
Hi Sid Hoffman,
there are good news for Plugin or EV owwers who are now entering the heating period in the northern hemisphere. Usually here in Germany you have a natural gas or oil heating system which is only heating.
On the other side you have a gas powered car which has losses from 80-60%.
If you drive by electricity you can put a motor with generator in your house, generate electricity and simultaneously heating your house.
I do so with this engine:
CU to down under
Posted by: German | 25 September 2006 at 09:53 AM
Sid, footnote 8, page 5
"The mixes of fuels used by power plants, and thus their emission profiles, vary by time of day. Overnight power, for example is typically generated using base load sources with low marginal costs, such as coal and nuclear power,"
Certainly assumptions are made- we would like to think that the power grid will get greener.
I'm looking forward to recharging my PHEV with my PV by 2010!
Posted by: fyi CO2 | 25 September 2006 at 10:44 AM
The CO2 profiles will vary due to energy sources used to produce electricity. WECC-CA, WECC-NW, and NPCC-NY rely on nuclear and Hyroelectric power more than the others. WECC-CA also has large scale solar electric power generation as a future possibility, as does WECC-RM+.
Posted by: allen Z | 25 September 2006 at 10:52 AM
SOFCs could use NG, charge your car and heat your home at the same time, over night. Cogeneration is a good way to get more out of fuel.
Posted by: SJC | 25 September 2006 at 10:57 AM
It sounds like they're saying that he GHG emissions would be 15% over a regular hybrid (rather than only 15% over an ICE).
That is a key point, because the GHG emissions of a standard hybrid over a ICE car are already pretty substantial.
And 15% is nothing to shake a stick at.
Additionally, it is a lot easier to capture CO2 from a central coal station than from individual ICEs.
I think that the tone of the reporting here has been inadvertently negative.
Posted by: BBM | 25 September 2006 at 12:19 PM
fyi CO2, do you work at night?
Posted by: Patrick | 25 September 2006 at 12:29 PM
Certainly far fewer issues and costs to bring PHEV to market than hydrogen, either combustion or fuel cell. Not that they can't be combined, but based on the comparative flow of dollars, you have to wonder what would yield faster and more effective results, given comparable research funding.
Posted by: Erick | 25 September 2006 at 02:20 PM
Why stop with gas-electric plug-ins? What about biodiesel-electric, alcohol-electric (ethanol, butanol, etc.), biomethane-electric, and hydrogen-electric? Or flex-fuel electric hybrids that run on electricity combined with CNG, alcohol, and hydrogen? Consider as many possibilities as we can.
Posted by: Mark R. W. Jr. | 25 September 2006 at 03:32 PM
BBM, I don't work too much, but during the day, PV modules charge the battery, and then the battery supplies power to the load as needed.
Posted by: FYI co2 | 25 September 2006 at 04:22 PM
You are reading incorrectly. I (Patrick) posed the question to you.
If you have PV at home and you drive to work the PV will not be charging your vehicle batteries...and then you have to install another set of batteries at home to store energy. I think it would be more advantageous to install PV sized to provide the power normally used by your house during the day and then just feed off the grid for nighttime for your vehicle. PV array on your vehicle won't provide much energy (not for the wear and tear caused by driving, especially in a dry sunny area where the PVs will output more power since they will be forced to cope with more dust at speed when you drive).
Now if only we had a cost effective and quick method to reform biomass into fuel on board the vehicle...eat your lunch and toss the scraps into your on board trash reformer (okay, I've watched Back to the Future too many times).
Posted by: Patrick | 25 September 2006 at 04:33 PM
Both Toyota and Honda have extensive developments of energy-efficient homes with in-home electricity/heat generation. Directly connected to the engine heat pump, especially with geo heat exchange loop, could produce both AC and heat about 4 times more then they consume (4kW*h heat equivalent per 1kW*h energy consumed). Quite and clean NG engine with sophisticated control and integrated battery is the key.
Posted by: Andrey | 25 September 2006 at 09:42 PM
I know Patrick, I know and I`m waiting desperately for the Honda 1kw/el engine. But who are the first where Honda is exporting it? The US! :-( If that continues i`ll want to have a greencard!
Posted by: German | 25 September 2006 at 11:14 PM
Patrick, sorry for the post confusion.
Yes, in essence we sell the PV to the grid during the day and use less than we sold the grid for the car/house overnight.
Posted by: fyi CO2 | 26 September 2006 at 07:13 AM