probably have heard about ethanol and biodiesel, liquid fuels made from plants
rather than petroleum. They use a renewable resource, and burning them doesn't
contribute to global warming. But can you make gasoline directly from plants?
As we hear from VOA's Art Chimes, scientists are learning how to do just that.
promising research programs suggest several ways to get gasoline out of plant
material, according to William Schultz, with the National Science Foundation
and the University of Michigan.
we are going to do is change a biofuel, such as poplar, switchgrass, corn
stover (which is just the part of the corn we don't normally eat) and others,
and by one of three processes – gasification, pyrolysis, or deconstruction –
produce precursors to green gasoline."
"precursors" are chemical molecules similar to what is found in crude
oil, molecules that can be refined to produce gasoline.
mentioned that there are at least three different ways to get from plants to
gasoline. Gasification is the oldest, and has been used to convert coal to
gasoline, but it is expensive and not very efficient.
uses heat and chemical catalysts to promote the conversion of plants to
gasoline. It is efficient and can even use waste paper as its raw material, but
so far can only produce some components of gas.
third process uses sugars, which can be easily derived from plants. It is being
developed at a company called Virent Energy Systems. Company founder Randy
Cortright says their process produces gasoline that's actually better than what
you can buy at a service station.
did an analysis of this, of our green gasoline versus just standard unleaded
gasoline we got at the gasoline station across the street. We have the same
components in there. In fact, it's actually got a higher octane and some
preferable blending component that you can utilize."
says Virent's plant-based process can also produce chemicals that can be used
to make plastics and pharmaceuticals, just like petroleum. It can also produce
jet fuel, noting that ethanol is a poor choice for aviation fuel since a liter
of ethanol packs less energy than a liter of gas.
don't have the energy content there," Cortwright explained. "While
you can burn ethanol in your automobile, you would not take ethanol and put it
on an airplane because it has a lower energy content. And ideal fuel right now
is a hydrocarbon fuel, and what we're looking at is, the hydrocarbon doesn't
have to come from petroleum. It can come from biomass, and that's what we're
doing with our process."
its briefing on green gasoline, the National Science Foundation decorated a
meeting room with some of the plants that might fuel the 21st century energy
you look at some of these plants around here, what we're trying to do is take
the non-edible portion of the plants," said University of Massachusetts
chemical engineering professor George Huber. "This is the fastest
[growing] and most abundant form of plant material, and produce green gasoline,
green diesel, and green jet fuel.
pointed out that it's not enough just to turn plant biomass into gasoline, you
have to do it efficiently and economically to compete with petroleum.
a fuel – it's a commodity. You have to have a very highly optimized and
integrated process to make a profit. You're competing against petroleum oil
that's been around for over 100 years, and the petroleum industry has developed
and they've learned how to economically refine crude oil. Now we need to learn
how to economically refine biomass resources."
said one factor favoring biomass-based gasoline is that the chemical production
process should be quicker than the biological process used to make ethanol from
similar raw materials.
gasoline made from crude oil, burning green gasoline produces carbon dioxide, a
greenhouse gas. But there's virtually no net impact on climate because the CO2
released comes from CO2 absorbed from the atmosphere when the plant was
green gasoline is still in the research stage, William Schultz of the National
Science Foundation pointed out that it is building on technologies that have
been around for a long time.
of the processes that we're considering have been around for a century. I guess
it just hadn't been thought that we could do the same things with switchgrass
as has been done with coal 50-100 years ago. Making it into liquid fuels is
more of a challenging process, and I think we're really close, and I think that
everyone who is involved in this sees how close we are. So it's not a
technology that's 20 years away. I think we think it's 5-10 years away."
one more thing: Schultz points out that while the chemical process for making
green gasoline still has a long way to go, so does the breeding of plants
specifically designed to be turned into fuel. Breeding has improved wheat,
corn, and other crops over thousands of years. Improvements can also be
expected in the undomesticated plants that would go into biofuels.
industrial facilities may one day be making gasoline, jet fuel, and maybe even
plastics and medicines from plants. And smaller facilities might end up right
where biomass is grown.
a farm that produces primarily food crops, just its waste product might be
enough to produce more energy than they need. Perhaps you could do enough
energy from the waste products from the food production that you could make a
farm energy-self sufficient, even if it's not a biofeedstock energy
producer," added William Schultz of the National Science Foundation, which
is funding research on green gasoline.