Biofuels
Last updated: May 4, 2009.
Earth scientists believe the world has about
40 years
worth of oil still buried in its rocks—but they've been saying
the same thing now for at least... 40 years! Whatever the reality, one
thing is certain: with ever-growing numbers of vehicles on our streets, oil is
going to become more expensive and harder to obtain over the next few
decades. That's why many people think the future lies with alternative
fuels made from crops and waste products. Known as biofuels,
these potentially offer many advantages over petroleum. They
could help us tackle global warming
and, by reducing our dependence on oil from the Middle East, they could
help make the world a safer place. But biofuels have major drawbacks
too. Critics think their environmental benefits are overstated and
argue that, by taking land that would otherwise be used for growing food,
they could severely worsen poverty and
hunger in developing countries. Let's take a closer look at how biofuels work
and consider some of the pros and cons.
Photo: One day, every gas station could be
pumping out fuel made from plants, like this one in Santa Fe, New
Mexico, USA.
Photo by Charles Bensinger and Renewable Energy Partners of New Mexico
courtesy of US
Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
What are biofuels?
A fuel is something we burn
to release energy in a chemical reaction called combustion,
which goes like this:
Fuel + oxygen (from the air) → released
heat energy + carbon dioxide (CO2) + water (H2O)
The exact chemical reaction depends on which fuel you burn, but
broadly the same process is at work whether you burn gas in a
central-heating boiler, wood on a camp fire, gasoline in a car engine, or coal in a power plant.
Almost any organic
(carbon-based) substance can be a fuel. Our commonest fuels are such
things as coal, oil, gas, peat, and wood—all of them made from hydrocarbons (molecules built from
hydrogen and carbon atoms) and all of them
ultimately derived from living things (either dead plants or animals).
Strictly speaking, the word biofuel can mean any fuel made from living
organisms or their waste—which means most of our fuels are biofuels.
But we normally use the word "biofuels" in a much more restricted sense
to talk about liquid and gas vehicle fuels made from crops or waste
products. The best-known biofuels are ethanol
(an alcohol made from sugar beet)
and biodiesel made from vegetable oil.
Types of biofuels
Biofuels are a hot environmental topic at the moment, but they've
been around for many decades. People who work with them often talk
about first- and second-generation biofuels to distinguish between
simple, traditional biofuels that have been used for a long time and
the more complex, more advanced, and more efficient ones that are
currently in development.
First-generation biofuels
include such things as vegetable oil, biodiesel, ethanol, and methanol.
Ethanol and methanol are very strong alcohols made from sugar, wheat,
or corn in a process similar to brewing. Vegetable oil made from such
things as peanuts and soybeans can be burned directly as a fuel, or it
can be turned into biodiesel, a gasoline substitute (or additive) that
can help to reduce vehicle emissions.
Photo: Most biodiesel in the US is made from
soybeans, like these, or recycled cooking oil.
Photo by Scott Bauer courtesy of US Department of Agriculture.
Second-generation biofuels
are made by turning crops into liquid fuels using more sophisticated
chemical processes and include such things as BioHydrogen (hydrogen gas
made from crops) and mixed alcohols. They are generally more efficient
than first-generation biofuels because they release more energy per
volume, so you can further on a tank filled with them (and it also helps
if you are growing crops to make fuels, because it means you have to grow fewer plants and cultivate less land
to produce the same amount of energy).
What are the benefits of biofuels?
If you read the news, you'll have seen a great deal of coverage
about biofuels in the last few years. The basic idea is certainly very
attractive: instead of pumping oil out of the ground and shipping it
round the world, we could produce biofuels from crops and waste
instead. For a country such as the United States, which is hugely
dependent on oil from the Middle East (the world's most politically
unstable region), a plan like that has huge attractions.
There's another great benefit too. Burning fuels such as petroleum,
coal, and gas (which were made millions of years ago) releases carbon
dioxide into the air. This gas smothers Earth like a huge invisible
blanket, warms the planet—the problem we now call global warming—and is starting to
change the
climate. In theory, biofuels don't suffer from the same problem. When a
tree grows, it absorbs carbon dioxide (CO2) from the
air, and water (H2O) from the soil, and uses sunlight to
convert the carbon, hydrogen, and oxygen from these molecules into more
complex carbohydrate molecules (sugars and starches) that it stores.
This process is called photosynthesis and
it's a little bit like combustion running in reverse. Through
photosynthesis, a tree uses carbon dioxide to grow. If we burn the tree
as a
fuel at the end of its life, the process of combustion releases exactly
the same amount of
carbon dioxide as the tree absorbed when it grew. So biofuels are (at
least
in theory) carbon neutral:
growing a tree (or any other plant) and then burning it as a biofuel
doesn't add any carbon dioxide to the atmosphere or make global warming
any worse.
Photo: As you read this, scientists are working hard
to develop the next generation of biofuels.
Photo by Scott Bauer courtesy of US Department of Agriculture.
What are the drawbacks of biofuels?
If it were only that simple, we'd be growing biofuels like crazy and
switching half the planet to biofuel production tomorrow.
Unfortunately, biofuels have some drastic drawbacks.
Carbon neutral?
Imagine you're a farmer. You've heard great things about biofuels
and how they can help to save the planet, so you decide to convert all
your fields to soybeans and produce biodiesel. You'll need energy to
power your tractors to plant the fields and harvest them and more
energy to ship the beans round the world. More energy will be needed to
power the chemical plants that turn the beans into biodiesel and even
more will be needed to transport the finished biodiesel to the vehicles
that use it. Using all this energy means burning fuel and releasing
carbon dioxide. You may be trying to help the planet reduce its carbon
dioxide emissions, but you're actually generating quite a lot of the
very gas you want to prevent in growing, processing, and transporting
your crops! That means biofuels are not actually carbon neutral at all.
Some studies have found that biofuels save 50-60 percent of carbon
dioxide emissions (which is a very worthwhile saving). But at least one
study has shown that the process of producing biofuels can produce more
carbon dioxide than the fuels themselves eventually save (which casts
considerable doubt on whether some biofuels are worth growing at all).
Photo: Giant farm machines use huge amounts of
energy.
These tractors and harvesters at the Beltsville Agricultural Research
Center run on a mixture of diesel and biodiesel made from soybeans.
Photo by Bob Nichols courtesy of US Department of Agriculture.
Biodiversity?
Relatively little land is needed for oil rigs and pipelines compared
to the size of the vast underground oil fields that they tap into (not
least because many oil fields are offshore). The same is not true of
biofuels: enormous amounts of land are needed to grow the crops. If you
planted up a forest on top of an old strip mine and harvested the trees
to make biofuels, there'd be a net benefit to the planet. But what if
you felled and burned a large area of rainforest to grow palm oil for
making biodiesel? Then you'd be releasing a huge amount of energy by
burning the trees, the planet would no longer benefit from the trees
growing and removing carbon dioxide, and we'd lose the forest's
wonderful biodiversity (its dense collection
of animals and plants).
You might think you were making "environmentally friendly biofuel", but
you'd be doing so much damage in the process that there could be an
overall negative impact. This problem is already occurring in
developing countries where forests are being felled (because they have
no immediate financial value) to grow lucrative crops for biofuels.
Mark Avery, conservation director of the UK charity RSPB (Royal
Society for the Protection of Birds) argues that this: "threatens to
accelerate the destruction of some of the world's most precious
habitats and wildlife. Without environmental standards, biofuels will
be little more than a green con." (Quoted in: 'Green
fuels' could be bad for the environment, Friends of the Earth,
April 10, 2007).
Fuel versus food?
There's only so much land in the world, but the number of people
each acre
has to support is increasing rapidly. As oil becomes more expensive,
so biofuels become more attractive to grow. That means farmers
may find they can earn more by growing biofuel crops than food crops,
which could lead to food shortages and increasing food prices. People
in developing countries (already with the greatest struggle for
survival)
will be hardest hit by any rise in the price of basic commodities such
as wheat. In our haste to use biofuels to tackle global warming (one of
the world's most pressing problems), it's possible we could worsen
world hunger and poverty (two of the world's other pressing problems).
(See for example: How
Biofuels Could Starve the Poor" by C. Ford Runge and Benjamin
Senauer, Foreign Affairs, May/June 2007 and
Biofuel rush harmful, Oxfam warns BBC News, October 2007.)
Not everyone agrees with this assessment. Some think growing biofuel
crops could be a lifesaver for farmers in both developed and developing
countries. According to a 2007
study by the Organisation for Economic Development (OECD),
US ethanol production for biodiesel will double by 2016,
while biofuel production in Brazil is forecast to increase by about 150
percent in the same period. Rising prices could be good for farmers.
Photo: Do we really have to choose been food and fuel? Photo by Scott Bauer courtesy of US Department of Agriculture/Agricultural Research Service (USDA/ARS).
There could be benefits for developing countries too. According to
Peter Kendall, president of Britain's National Farmers Union: "What has
been holding back agriculture in the developing world is not a shortage
of land, but the rock-bottom prices caused by the fact that world
markets have been swamped by surplus grain, from both the EU and US. If
the demand for biofuels helps to change that, directly by lifting
prices and indirectly by mopping up the surpluses, then it will give
Third World farming the biggest single boost it has ever had. That, in
turn, will do more to alleviate starvation in Africa and elsewhere than
all the food aid programmes put together." (Quoted in: Biofuels 'will
not lead to hunger', BBC News Viewpoint, October
5, 2006).
Power to the people?
In theory, biofuels give local communities the power to grow their
own fuel and lead self-sufficient, sustainable lives with little impact
on the planet. There's nothing to stop anyone making their own
biofuels by growing "energy crops" on their own land or producing their
own biodiesel from waste
products. Indeed, When Rudolph Diesel (1858–1913) invented his
diesel engine in the 1890s, he envisaged people doing just this: his vision
was one of local communities growing crops to run their engines and
making themselves entirely self-sufficient in energy in the process.
Ironically, Diesel's community-spirited ideas were quickly lost and
forgotten. Today, hardly anyone makes their own fuel; virtually all
diesel engines run on petroleum pumped from the ground by multinational
oil companies in a centralized, globalized market. Just as huge
multinationals dominate oil production,
so they are already dominating the production of biofuels. Far from
taking control of their own future, local communities in such places as
Kalimantan, Indonesia have been forced from their land so that large
companies can fell their forests, strip the land, and grow palm oil for
making biodiesel. (See, for example: "Losing
land to palm oil in Kalimantan", BBC News, August 3, 2007).
Venture capital firms, genetic engineering corporations, oil firms,
and car firms have already moved in on what they see as the next hugely
lucrative business opportunity. Some would see that as a good thing.
The world has a huge investment in burning oil and it will take a
herculean effort (and massive investment) to switch people over to more
environmentally friendly
forms of power. But, on the other hand, are we simply switching
all the problems of an oil-dependent economy for a different
set of problems with biofuels?
Photo: Power to the people: This truck driver
is helping save the planet by filling up with 95% ethanol, a fuel made
from corn. It's just the same as filling up with ordinary diesel or
gasoline, but the truck's engine has been specially modified.
Photo by Warren Gretz courtesy of US Department of
Energy/National Renewable Energy Laboratory (DOE/NREL).
Biofuels: good or bad?
On balance, then, the case for biofuels isn't nearly so clear cut as
it seems. If they're produced in a responsible way, biofuels could help
us cut carbon dioxide emissions and tackle global warming. But in the
dash for profit, there's a risk they could lead to greater emissions
and significant loss of biodiversity and exacerbate
problems such as poverty and hunger in developing nations. With limited
world resources and a growing global population, perhaps it makes more
sense to try to cut the energy we use and
reduce our dependence on cars
than simply to substitute biofuels for
oil and carry on as we are. Scientists are urging us to act quickly to
reduce the impacts of global warming, but it might
pay us to take a bit more time with biofuels and act more wisely. In
our haste
to protect the planet, we have to be absolutely certain we're not
helping to destroy it.
Further reading
Books you can read
Websites
The looming oil crisis
Biofuels: general information
- Biomass:
An introduction to biomass and biofuels from the US National Renewable
Energy Laboratory, including details of the latest research.
- Biofuel
review: All the latest news from the biofuels industry.
- How to run your car on chip oil: BBC News, 17 October 2007.
Biofuels: more critical pieces
