Environmental Engineering Reference
In-Depth Information
In 2005 a Canadian company began producing fuel from bones,
innards, and other inedible animal parts. Although the fuel is cheaper
than crude oil, there is a strange side effect: an odor of popcorn or french
fries.
Algae
Perhaps the most exciting possibility as a feedstock for biofuel
is algae, with an oil yield of up to 50 percent.
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Algae are like
microscopic factories using photosynthesis to transform carbon dioxide
and sunlight into lipids, or oil. Some strains can double their weight
in a few hours under the right conditions. They can grow in fresh,
salty, or even contaminated water, and they do not compete with
food crops. Scientists think algae might grow fatter and faster if
they were force-fed extra carbon dioxide, which could also help
alleviate the buildup of greenhouse gases. Smokestack emissions from
power plants and other sources could be diverted directly into the
ponds, feeding the algae while keeping greenhouse gases out of the
atmosphere.
Algae have emerged as a promising feedstock for biofuels due to their
high energy content, energy yield per acre, fast growth, and ability to
grow in water of varying quality. Algae's potential, at least in theory,
is remarkable. According to the Department of Energy, it may be able
to produce more than 100 times more oil per acre than soybeans or
any other terrestrial oil-producing crop. Soybeans generate about 50
gallons of biodiesel per acre per year, but algal species can produce up
to 8,000 gallons per acre per year. Because of its high energy content,
oil from algae can be refi ned into biodiesel, green gasoline, jet fuel, or
ethanol, making it an all-purpose biofuel. And algae need only water,
sunlight, and carbon dioxide to grow. And they grow rapidly. About
100,000 strains of algae are known, and some are more effi cient pro-
ducers of biofuel than others. Some researchers estimate that algae can
compete economically with petroleum at $60 per barrel. In 2007 only
5 companies were experimenting with algae as biofuels; today there are
at least 200.
There are still biological, technological, and economic problems to be
overcome before algal biofuel can be commercially successful, but
research is intense, and breakthroughs can be expected in a few years.
At present the cost of producing biofuels from algae is exorbitant, and
beyond the technical challenges, issues such as land and water use have
to be addressed. Almost all commercial algae biomass production at
present occurs in open ponds, which take up large areas of land and are
