Tuesday, January 30, 2007

Is Corn the Best Biofuel?

If we grow corn for ethanol production, it's good for energy independence and the environment, right? Well, maybe. An article in Business Week with the headline, "Food vs. Fuel," points out some of the shortcomings of corn as a source of ethanol:
Corn is just the first step. It's a lousy raw material for fuel because producing 10 gallons of ethanol consumes the energy equivalent of about 7 gallons of gasoline, and greenhouse gas reductions are minuscule. That's why the key will be changing to more environmentally friendly sources, such as agricultural waste, trees, or new crops.
...
One of the best candidates: perennial prairie grasses. Their deep roots store carbon captured from the air, improve soils, and require little water. Companies are now trying to breed the most productive varieties.
So other crops may be more appropriate, but they need more R&D.
I don't want to downplay the promise of biofuels, but the details of how to make it all work seem to get more and more complicated as we take a closer look. Increased use of biofuels affects food supplies, water supplies, carbon emissions and carbon capture by plants. I'd say we all have some homework to do.

4 Comments:

Anonymous jason said...

I thought I heard the President say that the smart scientists (real smart) at DuPont grew a watermellon that was filled with light sweet crude?

9:02 PM, January 30, 2007  
Anonymous Semper said...

Here are some estimated ethanol yields by the gallon for different plants per acre of land:

Corn Grain = 354 gallons per acre (one of the world’s life sustaining food crops)

Sugar Cane = 662 gallons per acre (from South America, imported with a 100% duty)

Switch Grass = 1000 gallons per acre ( there is no reason to oppose this crop)

Hemp = 1000 gallons per acre (no need for chemicals or irrigation and can be cultivated 3-4 times a year)

Here are some estimated energy outputs:

Plant
Energy Output (kJ/kg)

Corn
16510

Grains, Cereals
17610

Rape
20170

Wood
18660

Hemp
16450

Corn, grain and cerals would leave less food supply and feed for cattle etc.

Wood from trees takes time to reproduce.

Rapeseed due to the costs of growing, crushing, and refining rapeseed biodiesel, rapeseed derived biodiesel cost more to produce than standard diesel fuel. Also linked to adverse effects in asthma and hay fever sufferers.

Its estimated that methane and methanol production alone from hemp grown as biomass could replace 90% of the world's energy needs. For millennia the hemp plant has been cultivated for its strong, durable fibre. It is used for twine, yarn, rope, cable, and string, for artificial sponges, and for coarse fabrics such as sacking and canvas. Around the world it is used to make a fabric similar to linen. The plant is also grown for its seed--used in hempseed oil, paints, soaps, varnishes, and bird feed--and for medicine.

7:03 PM, September 27, 2007  
Blogger Ben said...

Semp: where did you get the estimations for the crops including hemp? (I haven't seen a hemp estimation before.)

I'd love to see hemp being made into biofuel, but I suspect the sugar/corn lobbies are too strong for that. Not to mention the DEA (they keep raiding native american tribes that grow hemp to sell...) Though if memory serves a western state (Colorado maybe?) is suing the federal govt for the right to grow hemp. So there's hope. Just not much :(

9:28 PM, November 01, 2007  
Anonymous Ron said...

I am all for biofuels and I think they have a great future. But they are in part causing our global food crisis. We need to:
1. Pull back some subsidies for corn based biofuels soon.
2. Put more money into biofuels that will not affect food markets - i.e. that can be produced in non food-competitive avenues.
3. Look at bioengineering to increase energy efficiency of some sources.

4:21 PM, April 24, 2008  

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