05-08-2009 - Energy

A new study shows that burning crops such as corn and switchgrass to create electricity to power electric vehicles would actually yield more transportation miles than turning those crops into ethanol.

The method would also reduce greenhouse gas emissions more than turning the crops into ethanol and using that ethanol in vehicles with internal combustion engines. The findings hold true for both corn and switchgrass as feedstocks — switchgrass being a source of cellulosic ethanol, where most of the plant is used.

The researchers found that using biomass to produce electricity for electric vehicles would produce 81 percent more transportation miles than using the same amount of crops to produce ethanol. In one example using switchgrass and a small SUV, the researchers calculated that the SUV would go 8,000 miles per acre on ethanol, but a comparable electric SUV would go 15,000 miles per acre on electricity generated by that acre of switchgrass. (View the scientists’ Ethanol vs. Electricity graphic.)

Published in the online version of Science by scientists at the University of California-Merced, Stanford University and the Carnegie Institution, the study — “Greater Transportation Energy and GHG Offsets from Bioelectricity Than Ethanol” — recommends that the crops be grown on marginal agricultural land or abandoned agricultural lands, to prevent cutting into food crops for people. Elliott Campbell of the University of California-Merced was the lead author.

Using plants to create electricity to power electric vehicles wins out because electric engines are much more efficient than internal combustion engines.

Listen to a podcast interview with Campbell here.

Written by Dan Kulpinski

6 Responses to “Crops for electricity would yield more transport miles than ethanol”

1. deborahbyrd says:

   May 9, 2009 at 7:44 am

   Dan,

   Interesting study! The energy picture is a maze of complexity at this time. But some winners are bound to emerge soon …

   Thanks for a great post,

   Deborah
2. Benjamin Napier says:

   May 9, 2009 at 10:43 am

   I would be very interested in seeing the calculations for that scenario. Did they take into consideration the fuel burned to plow, plant and harvest the biomass? To dry it? To transport it? The heat wasted in the power plant? The loss in the transformers, transmission lines and the battery chargers? The loss in the electric motors.

   The few sets of data and calculations that I have seen have left out the most important parts of this idea. There is a reason that electric cars failed almost 100 years ago. The reason: gasoline and diesel are much more efficient ways of storing, transporting and using energy than is electricity stored in batteries.

   Again, I would be very interested in seeing the calcs. Also, has anyone looked at the economic impact on rowcrop, meat and milk agriculture when the competition for land and other agricultural assets is factored in?

   100 years from now, it is likely, if our economy survives the present assaults on it, we will have a completely different way of doing things than we do now. If we allow the markets to decide, these ways will be an improvement. If we let government decide, we will likely be back in the stone age. If that is the case, most of us won’t have to worry about it. Human population will be but a fraction of what it is today amd living conditions will be primitive to say the least. I am talking Dark Ages, here.
3. Dan Kulpinski says:

   May 9, 2009 at 1:29 pm

   In this study, the scientists did a full life-cycle analysis. Follow the link and read it for yourself.

   You can also read the press release from the Carnegie Institution for Science here:
   http://www.ciw.edu/news/bioelectricity_promises_more_miles_acre_ethanol

   -dan
4. gus says:

   May 22, 2009 at 10:00 am

   DO YOU THINK THAT OIL COMPANIES WILL ALLLOW USING ELECTRIC CARS???
   WHAT WILL THEY DO WITH THEIR OIL ? DRINK IT !!!!
5. Benjamin Napier says:

   May 26, 2009 at 10:13 pm

   Gus,

   The oil companies would love us to build electric cars. It would take more natural gas and oil energy to charge the cars than we burn now. The only way around this is to build a lot of large nuclear power plants to charge the cars. Keep in mind, electric cars will feature much less range, smaller size and fewer amenties than we have become used to. Electric cars were tried over one hundred years ago and failed because it is much more efficient to carry chemical energy stored in gasoline than it is to carry electrical energy stored in batteries. There is nothing free and the laws of physics still hold sway.
6. Dan Kulpinski says:

   May 27, 2009 at 10:00 am

   Ben, you’re wrong on every count — and because you don’t cite any sources, I don’t know where you are getting your information, and thus your statement has no credibility.

   I pointed out in a comment on this post in December, http://blogs.earthsky.org/dankulpinski/2008/12/08/what-if-every-parking-space-had-a-recharger-for-electric-cars/, that electric cars use less energy and produce fewer emissions than gasoline-powered vehicles.

   A 2001 study by the Argonne National Laboratory found that plug-in hybrid electric vehicles use 41 percent less energy than cars with internal combustion engines, and create 40 percent less carbon dioxide emissions. Totally electric cars do even better.

   You can see the emissions results of the study in this powerpoint presentation by Sherry Boschert, author of ‘Plug-in Hybrids: The Cars That Will Recharge America,’ http://www.sherryboschert.com/PowerPoints/BoschertEVS23.ppt.htm

   You can also read her analysis of 49 different studies comparing the energy use and emissions of electric vehicles to gasoline vehicles here, http://www.sherryboschert.com/Downloads/Emissions.pdf

   Also, electric engines are much more efficient than gasoline engines. According to FuelEconomy.gov, only 15 percent of the energy from the fuel you put in your tank actually gets used to move the car. The rest of the energy gets lost as heat, during idel, or along the driveline. See http://www.fueleconomy.gov/FEG/atv.shtml

   In contrast, electric vehicles convert 75 percent of the chemical energy in batteries to power the wheels. See http://www.fueleconomy.gov/FEG/evtech.shtml

   So, electric vehicles outperform gasoline-powered ones in energy efficiency and emissions. And they don’t have external costs such as fighting wars to protect fuel sources.