What Matters: November 2001
The Fuel Plant
By Frank Weigert '65
Heresy! Burning hydrocarbons in our cars and electric power plants need not cause a greenhouse effect. The problem only occurs because we now burn fossil fuels. The world's fuel industry is 10,000 years behind the times, mired in a hunter-gatherer mentality. We no longer get our food by hunting mammoths or picking berries. The fuel industry needs to modernize.
No idea in science is truly new. My proposal builds on some 1970s work by Nobelist Melvin Calvin1. He found an interesting shrub in the Brazilian rain forest related to the rubber tree. Instead of producing high molecular weight poly(isoprene), it produces trimers. Calvin tapped the plant to produce a latex. He then broke the emulsion, separated the organic and water layers, dried the organic layer and finally poured the liquid hydrocarbon into the fuel tank of a diesel-powered car and drove off. No refining necessary! This plant produced high-grade diesel fuel.
Calvin correctly realized there was not enough rain forest land to grow commercial quantities of this plant. Using only selective breeding, he tried to adapt the plant to grow in the desert. His efforts failed, and the project died. Calvin didn't have today's genetic engineering tools. We should use them to bring his vision to reality. I propose that a genetically engineered fuel-plant can solve our energy crisis.
Genetic engineering has made enormous strides. We can now splice genes for specific enzymes into plant genomes or mask those already there. Safety is a huge consideration when we talk about bioengineering food crops. It is less so when we burn the products. The plants should be sterile hybrids to prevent loss of control.
The plant would begin as seaweed that floats its leaves on the surface of the water for better access to sunlight and CO2. Seaweed grows small bladders filled with air to provide buoyancy. We will change these structures into fuel containers. Coconuts accumulate a fatty acid inside their nuts. Our fuel-plant will store Calvin's isoprene trimer. Its shell can be thin because it doesn't have to survive a long fall intact. Instead, it might more resemble a beachball, with a skin thick enough only to enclose its contents and discourage predators. It might grow as big as a watermelon or even a pumpkin. Through conventional breeding alone, growers already produce pumpkins weighing 1,000 pounds.
The overall plan is subject to continuous improvement. For example, the container might accumulate small amounts of toxins to discourage predators. It might have some tomato genes so it turns from green to red when it is full of fuel and ready to harvest. We might insert specific genes for the plants to grow optimally in shallow, temperate water as opposed to tropical, deep water.
The fuel-plant eliminates any greenhouse gas problem. It consumes, or fixes, atmospheric while it grows. The CO2 emitted by burning its hydrocarbon merely regenerates the CO2 it previously fixed. Over the course of a year there is no net CO2 emission. It solves the energy storage problem without batteries or dams. Hydrocarbons store integrated solar energy in a very compact and easy to use form. It puts OPEC out of business. Why pay a cartel when you can grow your own?
Parts of the energy industry would change beyond recognition. Exploration and drilling for oil would disappear as would coal mining. The tanker fleet would remain to harvest the individual fuel containers and bring them to shore. If fish stocks continue to dwindle, this fleet provides new employment for men whose life is the sea.
If a container should break or leak, the hydrocarbon is of low enough molecular weight so microorganisms could use it as food. Water pollution due to spillage would no longer be an issue. No more Torrey Canyons or Exxon Valdezes. Refineries would be much simpler with no cracking, reforming, refining, or distillation units. The entire process of readying the raw natural product for use might consist of drying the hydrocarbon and filtering any solids.
The distribution system can remain intact. It will take a generation to switch from internal combustion engines and gasoline to diesel engines and fuel-plant hydrocarbons. Alternatively, existing refineries could use the triterpene as their feedstock and continue making gasoline for existing cars. Since the fuel-plant hydrocarbon contains no sulfur or nitrogen, and has a high H/C ratio, it makes a very sweet crude.
The research to create an economically viable fuel-plant certainly involves risk. No single corporation can expect to retain all the benefits in this new field. A government project like the Human Genome effort might be the appropriate research vehicle. Sun-powered biology has to compete with physics and chemistry research, such as nuclear fission and fusion or clean coal. Political lobbying by entrenched interests should not direct long-range research away from potential gold-mines to protect previous investments. Corn-derived ethanol can never compete economically with a well-designed fuel-plant.
Even if we ignore the greenhouse problem, society will eventually run out of cheap, minable fuels. Readers, help refine this proposal into one policy makers will implement. The long-range future of human society depends on it.
1. "The Sunny Side of the Future," CHEMTECH, June 1977, page 352
Update: September 26, 2002
In response to readers' questions, Dr. Weigert '65 has added the following FAQ and supplementary information:
Is there enough sunlight to make a dent in the world's energy needs?
More than enough. I got interested in the problem after OPEC-1. The National Academy of Sciences put out a book, Energy and the Future, by Allen Hammond, William Metz NON '91 and Thomas Maugh '65, '66 which said that in 1970 the solar influx was 50,000 times the world's energy use.
Of course, population has grown since then as has energy use per capita. The sun's output has stayed constant.
Solar energy does not have to account for 100% of our energy needs either. Even assuming a 1% conversion efficiency, we can grow enough fuel plants to make a difference on a small fraction of the ocean's surface.
Why are plants so inefficient at converting photons to organic matter?
Chlorophyll is a terrible match to the solar spectrum. It simply does not absorb most of the solar influx. Long-term research should be able to improve on it. Plants also need to attend to the business of being alive and reproducing, as well as human needs.
What if your plants get loose, like that seaweed spreading in the Mediterranean?
Use sterile hybrid technology. Liberals castigate the seed companies for selling plants which don't produce viable seed. Farmers thus have to buy new plants from the company every year. That technology works. Let's use it.
Supplementary Information:
Freeman Dyson of the Princeton Institute of Advanced Physics gave a PBS interview in which he mentioned an idea he called the gasoline plant. He proposed genetically engineering trees to produce gasoline.
Trees waste a lot of energy making wood in their struggle to get to the top of the canopy. Wood is not an ideal good fuel for a technological civilization. Gasoline is too volatile and toxic to make an ideal natural product fuel. In this one issue, Ronald Reagan was actually right. The Smoky Mountains are smoky because of air pollution from trees.
Update: September 2007
My original essay was vague about what plant species would actually do the work. I now present two starting points for research, one benthic, one pelagic. One grows invasively, the other makes lots of hydrocarbons.
Caulerpa taxifolia is the benthic (rooted) seaweed that conquered the Mediterranean. After getting loose from an aquarium outside Monaco, it grew explosively and now is a monoculture dominating the northern Mediterranean. When an infestation got loose in the Pacific Ocean off Monterrey, the U.S. government spent eight million dollars to chlorinate the ocean to eradicate it. This is a scary plant. Why is it so successful? One reason may be that it makes the toxin caulerpenyne. The structure of this material is known. The backbone is that of an isoprene trimer. Part of the biosynthesis of caulerpenyne is known. The two acetates get added last. This plant knows how to make compounds of interest as a liquid fuel, but it doesn't make a lot of them. It doesn't need to. What it makes is enough for it not only to survive but to thrive.
Botryococcus braunii is a family of pelagic (floating) algae that grow in the Indian Ocean. They all make isoprene oligomers. Different strains make them with different average molecular weights. What matters is that the dry weight of the most prolific producing strains is over 70 percent hydrocarbon. This algae truly is a fuel plant.
These hydrocarbons can be burned to either generate electricity or to power cars. They are a much cleaner fuel than coal so existing power stations could shut down much of their post-combustion gear that now scrubs pollution from the vent gases. They would not have to worry about either SO2 or ash. As a transportation fuel, the hydrocarbons could be fed into existing refineries. These could shut down much of the front end investment that removes the impurities from crude oil that damage delicate catalysts downstream. The feed would not have any ash, metals, nitrogen sulfur or phosphorus. It's a hydrocarbon! Crude oil from older fields can also contain salt water.
The hydrogen balance isn't all that bad either. C30H48 (isoprene hexamer) needs only four more hydrogen atoms to make two molecules each of octane (C8H18) and toluene (C7H8).
The research agenda needs to determine how fast this plant grows under various environmental conditions. Mutations or genetic engineering would then continuously improve its performance. The maximum growth rate may conflict with the goal of maximum hydrocarbon concentration. Economics would determine the optimum time to harvest the crop.
I have been thinking about how DuPont management directed our R&D during the CFC replacement campaign, and I think that program can teach us about how the world should deal with the CO2 issue.
Greenhouse gas politics has much in common with the CFC ozone controversy of 20 years ago. Both started with scientists doing atmospheric modeling and predicting an adverse effect from a common human activity. The companies involved immediately went into full denial mode. They learned their tactics from the tobacco industry. Rather than spend money to address the problem, it was cheaper to confuse the issue. As long as the products were profitable, why upset the applecart. But when competition reduced CFC profit margins, the major players began to see value in the alternatives.
The atmospheric models didn't predict an ozone hole over the Antarctic every spring. A bit of reflection showed what went wrong in the modeling. The models considered only homogeneous processes. This was a heterogeneous process. Gases condensed on ice particles and reacted more rapidly there than they did in the gas phase. When Susan Solomon found the predicted anti-correlation between ozone and chlorine around the hole, even the skeptics threw in the towel. The next day DuPont went into full problem-solving mode.
A wise DuPont management gave researchers two rules to guide their activities. One dealt with product, the other with process. They are relevant to the global warming issue as well.
Product: Nothing should change for the ultimate consumer. Or, in the vernacular, Joe Sixpack should not have to buy a new car because his air conditioner's hose popped lose again. The new fluids must be drop-in replacements for the existing materials. The properties of boiling point, no flammability, and no chlorine reduced the number of possibilities to at most a pair of isomers. Considerations of toxicity and corrosion reduced the number of possibilities to one. All companies came to the same conclusion. No company would be able to tout its product as being better than the competition since everyone would be making the same materials.
Process: Use existing investment as much as possible. Here is where it gets interesting. Each company made a different CFC product mix. They had different expertise and different physical plants. Each came up with a unique way to make the replacements. Each was optimum to the specific company.
How does this apply to global warming? Let us consider electricity and transportation separately.
The consumer doesn't care how electricity is made as long as his or her gadget turns on when plugged into the wall socket. Electricity from hydro, nuclear, coal, geothermal, photovoltaics, wind, tides, or natural gas is all the same to the end user. Shut down a coal-burning plant and start up a nuke and the consumer does not have to buy a new computer. Local photovoltaic would require the consumer to buy and maintain an expensive new investment. The current payback time is quite long, well beyond the horizon of most home owners when compared with fixing up their deck.
Transportation fuels are not interchangeable. If your local filling station no longer pumps gasoline, your car becomes a lawn ornament. You can't fuel today's car with 100 percent ethanol. It would need a new engine. Jets are never going to fly on ethanol. It weighs too much for the energy it contains. You aren't going to fuel your home with ethanol instead of oil either. You'd need a new fuel tank and a new furnace and all new piping between them. Do you really want a hundred gallons of flammable ethanol in your basement? Today's infrastructure can't run on hydrogen either. America's transportation infrastructure now runs on hydrocarbons. It will continue to do so. The transportation fuel of the future will be a hydrocarbon so close to gasoline and diesel that it will serve as a drop-in replacement.
The world has a huge sunk investment in coal-burning plants to generate electricity. While wind and solar panels can and should contribute to capacity expansions, we must find greener fuels to use in the existing investment. A hydrocarbon derived from biomass makes a dandy replacement for coal. Not only does it have more energy per pound, it does not have any sulfur, mercury, metals or ash. The back-end infrastructure devoted to cleaning up the combustion gases can be shut down. Solid waste disposal becomes much easier. Electricity generation becomes greener. Sequestration becomes unnecessary.
The world's investment in petroleum refining is enormous. Fermentation of biomass to make ethanol can make absolutely no use of this equipment. Again, a plant-based hydrocarbon can use existing petroleum refining investments. The front end that treats crude oil so it won't damage sensitive downstream catalysts won't be necessary. The hydrocarbon can go directly to the acid cracking units after a superficial drying step. The output can be manipulated to give the mixture of gasoline and diesel desired by the marketplace. The asphalt industry goes out of business because there will no longer be any heavies to dispose of.
Genetic engineering is an infant field. What we can do today will seem trivial to society fifty years from now if we devote some investment to modifying algae to grow fuel rather than to sequencing animals from aardvarks to zebras.
The United States is dividing into two camps as opposed to each other as Christianity and Islam but over the issue of global warming. Most scientists agree it is a problem. Many despair over finding any solution. A book presenting this point of view is Suicidal Planet by Mayer Hillman et. al. At the other extreme is the book The Politically Incorrect Guide to Global Warming by Christopher Horner, which rehashes every negative opinion that has ever been presented. A good recent article, though a bit on the pessimistic side, is by Nate Lewis, a Caltech chemistry professor. In my opinion he is a bit too polite in his criticism of the nuclear and coal industries. It is available as a PDF online. I highly recommend it. Scientists who pontificate on the issue need to be aware of the opposition lest they become parodies subject to ridicule by the economic right.
Capitalism is the cause of this problem. Its values should not be a major factor in determining a solution. Capitalism is about a deal between a buyer and a seller. It has no mechanism to deal with the concept of harm to uninvolved third parties. This is most easily seen in the issue of pollution. Consider a company with a barrel of highly toxic waste. The EPA specifies an expensive disposal process. The CEO sees this expense as coming right out of his bonus. Dumping it on some back road is much cheaper. The customer doesn't care, as long as the manufacturer allocates some of the savings to lowering the price. Who cares if some yokels die of heavy metal poisoning! They play no role in the capitalist model. When the United States decided to abolish slavery, Abraham Lincoln did not establish a cap and trade policy for slaves. He abolished the practice. He did not even compensate slave owners for the property he freed. Of course it took a long, bloody war to do this. Hopefully solving the global warming problem will not require such drastic action, but it might.
It might be easier to ban activities which are not yet a major issue, but might be in the future. Let's ban mining of oil shale and tar sands now, rather than wait for an industry to develop using these high carbon fuels. Put coal mine owners on notice that there will be no new ones. Ask mine owners to either put out the fire burning under Centralia, PA, or at least make use of the heat it is now producing. Do not allow new oil well drilling in pristine sites.
Once industry can't invest in conventional activities, it will use existing cash flow to try to stay in business in unconventional ways, or return it to shareholders for them to do so.
Update: September 2009
Fertilization. The ocean is a desert, but it doesn't lack for water. The limiting reagent is reduced iron. An attempt to fertilize the ocean with Sahara Desert sand produced only a brief algae bloom.1 Even if it had worked, this approach is not sustainable.
Nature gives us a sustainable alternative. Ocean upwellings bring deep-sea nutrients to the surface, producing transient algae blooms. Unfortunately, the most responsive algae species may not be useful for fuel production and some are toxic if ingested.2 Oil companies routinely pump up oil and gas from miles UNDER the surface of the ocean. Why not dredge surface muck to provide the fertilizer.3 The energy might be come from surface photovoltaics, wind or ocean currents.
Notes
1 http://www.csa.com/discoveryguides/oceangard/overview.php
2 http://www.whoi.edu/redtide/
3 http://www.windows.ucar.edu/tour/link=/earth/Water/ocean_upwelling.html
About the Author
Frank Weigert '65 grew up in Chicago and Philipsburg, Pennsylvania. He earned a bachelor's degree in chemistry from MIT in 1965 and went on to Caltech, where he earned a PhD in 1968 studying Carbon-13 nuclear magnetic resonance. He joined the Central Research Department at Dupont in 1968 where he worked on catalysis, photo-imaging, and fluorine chemistry over a 26-year career with the company. He retired in 1994 after contributing to 33 patents and 64 publications.
What Matters is a guest opinion column written by a different MIT alumnus or alumna. The views expressed are entirely those of the author and do not necessarily represent the views of the Alumni Association or MIT. Interested in writing a column? Email whatmatters@mit.edu.
