[Wildwell]

A staggering 98 tons of prehistoric, buried plant material – that's 196,000 pounds – is required to produce each gallon of gasoline we burn in our cars, SUVs, trucks and other vehicles, according to a study conducted at the University of Utah.

"Can you imagine loading 40 acres worth of wheat – stalks, roots and all – into the tank of your car or SUV every 20 miles?" asks ecologist Jeff Dukes, whose study will be published in the November issue of the journal Climatic Change.

But that's how much ancient plant matter had to be buried millions of years ago and converted by pressure, heat and time into oil to produce one gallon of gas, Dukes concluded.

Dukes also calculated that the amount of fossil fuel burned in a single year – 1997 was used in the study – totals 97 million billion pounds of carbon, which is equivalent to more than 400 times "all the plant matter that grows in the world in a year," including vast amounts of microscopic plant life in the oceans.

"Every day, people are using the fossil fuel equivalent of all the plant matter that grows on land and in the oceans over the course of a whole year," he adds.

In another calcultation, Dukes determined that "the amount of plants that went into the fossil fuels we burned since the Industrial Revolution began [in 1751] is equal to all the plants grown on Earth over 13,300 years."

Dukes calculated ancient plant matter needed for a gallon of gasoline in metric units:

* One gallon of oil weighs 3.26 kilograms. A gallon of oil produces up to 0.67 gallons of gasoline. So 3.26 kilograms for a gallon of oil divided by 0.67 gallons means that at least 4.87 kilograms of oil are needed to make a gallon of gasoline.

* Oil is 85 percent carbon, so 0.85 times 4.87 kilograms equals 4.14 kilograms of carbon in the oil used to make a gallon of gasoline.

* Since only about one-10,750th of the original carbon in ancient plant material actually ends up as oil, multiply 4.14 kilograms by 10,750 to get roughly 44,500 kilograms of carbon in ancient plant matter to make a gallon of gas.

* About half of plant matter is carbon, so double the 44,500 kilograms to get 89,000 kilograms – or 89 metric tons – of ancient plant matter to make a gallon of gas. In U.S. units, that is equal to a bit more than 196,000 pounds or 98 tons.

Dukes made similar calculations for oil, natural gas and coal to determine that it took 44 million billion kilograms (97 million billion pounds) of carbon in ancient plant matter to produce all the fossil fuel used in 1997. That includes 29 million billion kilograms of prehistoric plants to produce a year's worth of oil (including gasoline), almost 15 million billion kilograms of buried plant matter to make all the natural gas used in 1997, and 27,000 billion kilograms of dead plants to produce all the coal used in the same year.

"It took an incredible amount of plant matter to generate the fossil fuels we are using today," says Dukes. "The new contribution of this research is to enable us to picture just how inefficient and unsustainable fossil fuels are – inefficient in terms of the conversion of the original solar energy to fossil fuels. Fortunately, it is much more efficient to use modern energy sources like wind and solar. As the reasons keep piling up to switch away from fossil fuels, it is important that we develop these modern power sources as quickly as possible."

http://www.eurekalert.org/pub_releases/ ... 102603.php

In short, that's 1470 tonnes of ancient plants to full up a car gas tank or 600 acres.

An incredible 5,272,400 tons of ancient plants or 2,512,000 acres of ancient plant life to fill a Jumbo jet.

[DarkDawg]

"It took an incredible amount of plant matter to generate the fossil fuels we are using today," says Dukes.

You know, all you negative people are really starting to bring me down. Why do you need to look at it from the "glass is half empty" viewpoint?

The good news is that oil IS renewable. Yippeeeeee!!!!!!!

[rogerhb]

A staggering 98 tons of prehistoric, buried plant material – that's 196,000 pounds – is required to produce each gallon of gasoline we burn in our cars, SUVs, trucks and other vehicles, according to a study conducted at the University of Utah.

Hey, dude, just shut up and fill the tank, I haven't got all day!

[Wildwell]

I see everyone missed it, a little futher down:

What about modern plant biomass?

Unlike the inefficiency of converting ancient plants to oil, natural gas and coal, modern plant "biomass" can provide energy more efficiently, either by burning it or converting into fuels like ethanol. So Dukes analyzed how much modern plant matter it would take to replace society's current consumption of fossil fuels.

He began with a United Nations estimate that the total energy content of all coal, oil and natural gas used worldwide in 1997 equaled 315,271 million billion joules (a unit of energy). He divided that by the typical value of heat produced when wood is burned: 20,000 joules per gram of dry wood. The result is that fossil fuel consumption in 1997 equaled the energy in 15.8 trillion kilograms of wood. Dukes multiplied that by 45 percent – the proportion of carbon in plant material – to calculate that fossil fuel consumption in 1997 equaled the energy in 7.1 trillion kilograms of carbon in plant matter.

Studies have estimated that all land plants today contain 56.4 trillion kilograms of carbon, but only 56 percent of that is above ground and could be harvested. So excluding roots, land plants thus contain 56 percent times 56.4, or 31.6 trillion kilograms of carbon.

Dukes then divided the 1997 fossil fuel use equivalent of 7.1 trillion kilograms of carbon in plant matter by 31.6 trillion kilograms now available in plants. He found we would need to harvest 22 percent of all land plants just to equal the fossil fuel energy used in 1997 – about a 50 percent increase over the amount of plants now removed or paved over each year.

"Relying totally on biomass for our power – using crop residues and quick-growing forests as fuel sources – would force us to dedicate a huge part of the landscape to growing these fuels," Dukes says. "It would have major environmental consequences. We would have to choose between our rain forests and our vehicles and appliances. Biomass burning can be part of the solution if we use agricultural wastes, but other technologies have to be a major part of the solution as well – things like wind and solar power."

[rogerhb]

I see everyone missed it, a little futher down:

What about modern plant biomass?

George Monbiot warns us of using biomass for fuel for cars because of sacrificing food production for fuel production, especially in a free market if the fuel is worth more than the food.

[Battle_Scarred_Galactico]

Very interesting, and I'm sure 100% accurate.

The part I have a problem with is his glossing over of the consequenses of "switching"(read: being forced) to wind and solar.