For years researchers have been trying to figure out the best ways of making plants produce biofuels. But there is a funda­mental problem: photosynthesis, the process by which plants convert sunlight into stored chemical energy, is highly inefficient. Plants turn only 1 to 3 percent of sunlight into carbohydrates. That is one reason why so much land has to be devoted to growing corn for ethanol, among other bad biofuel ideas. And yet plants also have many advantages: they absorb carbon dioxide at low concen­trations directly from the atmosphere, and each plant cell can repair itself when damaged.

Scientists have begun a new effort to soup up photosynthesis and help humans make greener fuel. The U.S. Advanced Research Projects Agency for Energy, known as ARPA-e, has funded 10 such projects so far, most of which use genetic engineering to tweak a plant’s DNA-based instruction manual for growth, pigments, and the like. The largest grant—more than $6 million—has gone to the University of Florida to alter pine trees to make more turpentine, a potential fuel. Another project, led by Davis, Calif.–based Arcadia Biosciences, is aimed at inducing fast-growing grasses such as switchgrass to produce vegetable oil for the first time in history.

In the future, engineers might create a black plant that would absorb all incoming sunlight or a plant that uses different wavelengths of light to power the different steps of photo­synthesis; plants now use the same wavelengths for everything. An engineered biofuel-producing plant might even have smaller leaves, re­ducing its own energy demands for growth, or it might no longer store energy as sugar but turn it directly into a hydrocarbon molecule for human use as fuel.

The scientists in the program, dubbed PETRO, for plants engineered to replace oil, will also have to deal with the challenges of increasingly limited water supplies for crops and public skepticism of gen­etic­ally modified organ­isms. And they will face comp­etition from efforts to replace photosynthesis altogether, such as ARPA-e’s own Electrofuels program, which aims to induce microbes to make hydro­carbons, or from efforts to build artificial leaves that use the electricity from solar cells to split water into oxygen and hydro­gen for use as fuel. For plants, simply being green is no longer enough.

13 Comments

1. 1. gesimsek 02:04 PM 12/20/11

   This is the begining of the age of Sun.

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2. 2. sault in reply to gesimsek 08:16 AM 1/13/12

   Since fossil fuels are really just distilled sunlight, it always was the age of the sun. This is just cutting out the millions of years of heat and pressure required to make hydrocarbon fuels. Since solar cells are already 10x more effective than plants at converting sunlight to energy, building solar farms instead of biofuel plots will use our land much more effectively. In addition, the usage of hydrocarbon fuels usually results in %80+ of the energy in the fuel getting thrown away as waste heat, while an electric motor that throws away %10 is considered a poor performer. So powering our cars with solar electricity directly will use %2 of the land area that powering them with biofuels will. To top it all off, solar PV can be used on the exteriors of most buildings and works great in desert areas where growing crops is difficult to impossible.

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3. 3. jtdwyer 08:52 AM 1/13/12

   Agricultural production of biofuels will most likely make the amount of arable land committed to the production of each an economic consideration, eventually bringing the price of food up to the price of fuel. It will also likely increase the use of potable water used for land irrigation, increase its cost and reduce its availability.
   
   BTW, much of the water used for irrigation is non-replenished fossil water in Western aquifers. Much of the fertilizers used to increase agricultural production is derived from oil.
   
   Even the population of the U.S. is expected the Census Bureau to increase 36% by 2050, from 311 million to 423 million people. If we reduce the production of food and availability of potable water we may have increasing difficulty feeding the current U.S. population much less an additional >110 million people and much of the rest of the world.
   
   This same experiment has turned out badly in Malaysia...

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4. 4. ciendolor 02:01 PM 1/13/12

   Oddly enough, Mr Biello makes no mention of MIT's Dan Nocera or Sun Catalytix. Dan Nocera has not only a functioning photosynthetic approach, but a complete energy distribution method based on it. He clearly shows that too much of a plants captured energy goes into building lignin, which is fine for the plant, but misses our desired effect - a fuel. Therefore, any plant-based approach will of suboptimal flux conversion ratios.

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5. 5. Evelayo 11:23 PM 1/13/12

   sault, yours is a very good idea, much better than the use of biofuels derived from crops, which are needed to feed a growing human population (which we should strive to reduce by peaceful means). However, an always neglected idea is to convert garbage into fuel using pyrolysis; although pyrolisis is currently somewhat expensive, costs can be reduced by future breakthroughs. Another neglected similar idea is to burn garbage directly and use the electricity to replace the burning of coal, thus saving resources and avoiding the radioactive ash residue of burning coal; this form of electricity generation is cheap and it can also be used to synthetically produce biofuels without needing plant crops. Garbage is a limitless fuel source, that when used alongside good recycling programs, has great potential to provide cheap energy independence, which is greener than coal or other fossil fuels. I personally believe that the future for vehicles lies in electric and hybrid power rather than liquid fuels as battery technology is improving and there are many companies working on battery efficiency and long life.
   

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6. 6. gunt in reply to Evelayo 12:14 PM 1/14/12

   I am also for turning our garbage into electricity.
   But – let's do a little math.
   
   The US electricity consumption per year is about 4 400 Tera watthours (Twh).
   These are 4.4 Tera kwh
   
   You need about 1.5 kg of garbage to extract 1 kwh.
   So , to generate these 4.4 Tera kwh you would need about 6.5 Tera kg garbage.
   These are 6,5 Giga tons of garbage per year.
   
   Now, let's look into the garbage situation :
   The overall amount of garbage per year in the US is about 200 Million tons
   This is 0.2 Gigatons.
   
   So , assuming that all the garbage can be converted into fuel (electricity) (which is very unlikely) you end up with 0,2 / 6,5 = 3% of the US electricity demand.
   
   So, yes, I am also for avoidance and utilization of garbage.
   But - unfortunately - this cannot solve our energy demands
   

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7. 7. Carlyle 06:44 PM 1/14/12

   This is another example of the total disconnect between reality & adolescent dreaming but be sure the poor old taxpayer will have to come up with more millions if not billions before this fantasy dies. People will die too as land water is diverted from food production. It is already happening, despite the appalling results, as is the case with all the other alternative systems.
   To spend billions on intermittent energy sources with no cost effective method of massive energy storage or even the prospect of such a system is in my opinion a crime against humanity. I know battery storage in hundreds of millions of cars has been suggested but that is as irrational as all the other schemes. Only nuclear can fill the bill & wean us off carbon fuel for power generation.
   Meanwhile, holding out alternative energy as a prospect continues the unnecessary waste of fossil fuels. Who is holding their hand up to claim responsibility for this continuing waste? All those who rest their case on belief instead of cold, sometimes unpalatable truth are responsible.
   

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8. 8. Carlyle in reply to Carlyle 09:01 PM 1/14/12

   By the way, by increasing the Co2 in a contained environment, the efficiency of sunlight to carbohydrates can be raised from 3% to as high as 7%.
   That is nature taking advantage of a resource & it is occurring naturally, confounding the alarmists once again.
   

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9. 9. sault in reply to Carlyle 02:27 AM 1/15/12

   "I know battery storage in hundreds of millions of cars has been suggested but that is as irrational as all the other schemes."
   
   Or, to put it another way, "I know that there's a giant hole in my argument, but I'll just dismiss it out of hand with no proof along with every other objection to my preferred solution."

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10. 10. sault in reply to Carlyle 02:31 AM 1/15/12

    "All those who rest their case on belief instead of cold, sometimes unpalatable truth are responsible."
    
    Almost had a hernia laughing at this one! Do you honestly think you incorporate the "cold, sometimes unpalatable truth" when you type your fact-free rants out on these boards? How come You NEVER present this "cold, sometimes unpalatable truth" but just assert you're right?

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11. 11. Carlyle in reply to sault 05:48 AM 1/15/12

    Your earlier suggestion of using electric car batteries for grid backup storage was demolished in an earlier forum. Do we need to visit it again?

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12. 12. eco-steve 10:42 AM 1/15/12

    There is plenty of grease being carried around by obese americans. And plenty is being revovered by plastic surgeons using liposuccion. Who says the US lacks ideas and ressources?

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13. 13. adamsunny 07:03 PM 2/16/12

    There already are several species of plants with black leaves. One of them, black pearl pepper, is a common ornamental.

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