Biofuel

Biofuel is any fuel that derives from biomass - recently living organisms or their metabolic byproducts, such as manure from cows. It is a renewable energy, unlike natural resources such as petroleum, coal and nuclear fuels.

Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work.

The carbon in biofuels was recently extracted from atmospheric carbon dioxide by growing plants, so burning it does not contribute carbon dioxide to the Earth's atmosphere.

Bioenergy covers about 15% of the world's energy consumption. Sweden and Finland supply 17% and 19% respectively, of their energy needs with bioenergy. Biomass can be used both for centralized production of electricity and district heat, and for local heating.

Oxidisation of biomass does not release more CO2 than that which was absorbed by production of that same biomass. Both agricultural products specifically grown for this use and waste from industry, agriculture, forestry, and households -including straw, lumber, manure, and food leftovers-can be used for the production of bioenergy.

Classes of Biofuels

Solid

There are many forms of solid biomass that are combustible as a fuel such as:

• Wood — see wood fuel
• Dried compressed peat
• straw and other dried plants
• animal waste such as poultry droppings or cattle dung.
• husks or shells from crops such as rice, groundnut and cotton.
• bagasse

Liquid

There are also a number of liquid forms of biomass that can be used as a fuel:

• Bioalcohols — see alcohol as a fuel
• Ethanol produced from sugar cane is being used as automotive fuel in Brazil. Ethanol produced from corn is being used as a gasoline additive (oxygenator ) in the United States.
• Methanol, which is currently produced from natural gas, can also be produced from biomass — although this is not economically viable at present.
• Biologically produced oils can be used in diesel engines:
• Straight vegetable oil (SVO).
• Waste vegetable oil (WVO).
• Biodiesel obtained from transesterification of animal fats and vegetable oil.
• Oils and gases can be produced from various wastes:
• Thermal depolymerization can extract methane and oil similar to petroleum from waste.
• Methane and oils are being extracted from landfill wells and leachate in test sites.

Gaseous

• Methane produced by the nature decay of garbage or agricultural manure can be collected for use as fuel.
• Biogas
• Hydrogen can be produced by cracking any hydrocarbon fuel in a reforme or by the electrolysis of water.
• Gasification

Energy content of Biofuel

fuel type	Specific Energy Density (J/kg)	Volumetric Energy Density (J/l)
wood fuel
dried plants
animal waste
chaff
bagasse
ethanol
methanol
vegetable oil
Biodiesel
Methane
Hydrogen

Dissemination mechanisms

Biofuels have a low specific energy density compared to fossil fuels. This means that biomass energy schemes must work at a local level as their success depends on well-structured and sustainable fuel supply networks from local producers.

Small scale use of biofuels

A widespread use of biofuels is in home cooking and heating. Typical fuels for this are wood, charcoal or dried dung. The biofuel may be burned on an open fireplace or in a special stove. The efficiency of this process may vary widely from 10% for a well made fire up (even less if the fire is not made carefully) to 40% for a custom designed charcoal stove. Inefficient use of fuel may be a minor cause of deforestation (though this is negligible compared to deliberate destruction to clear land for agricultural use) but more importantly it means that more work has to be put into gathering fuel, thus the quality of cooking stoves has a direct influence on the viability of biofuels.

Unfortunately, much cooking with biofuels is done indoors, without efficient ventilation and using those fuels such as dung which cause most airborne polution. This can be a serious health hazard; 1.5 million deaths were attributed to this cause by the World Health Organisation in 2000. There are various responses to this, such as improved stoves, including those with inbuilt flues and switching to alternative fuel sources. Most of these responses have difficulties, for example flues are expensive and easily damage; alternative fuels tend to be more expensive which is difficult to implement since the people who rely on biofuels often do so precisely because they cannot afford alternatives. Organisations such as Intermediate Technology Development Group work to make improved facilities for biofuel use and better alternatives accessible to those who cannot currently get them. This work be done through designing improved ventilation, a switch to different usage of biomass such as through the creation of biogas from solid biomatter or a switch to other alternatives such as micro-hydro power.

Natural gas

Natural gas is a gas produced by the anaerobic decay of organic material. It is usually found in oil fields and natural gas fields, but is also generated in swamps and marshes (where it is called swamp gas or marsh gas), in landfill sites, and during digestion in animals.

Chemical composition and energy content

Chemical composition

The primary component of natural gas is methane (CH₄), the shortest and lightest hydrocarbon molecule. It may also contain heavier gaseous hydrocarbons such as ethane (C₂H₆), propane (C₃H₈) and butane (C₄H₁₀), as well as other gases, in varying amounts, see also natural gas condensate.

Hydrogen sulfide (H₂S see acid gas) and mercury (Hg) are common contaminants, which must be removed prior to most uses.

Energy content

Combustion of one hundred cubic feet (1 ccf) of commercial quality natural gas typically yields approximately 1 therm (100,000 British thermal units, 30 kWh). One cubic meter yields 38 MJ (10.6 kWh).

Storage and transport

The major difficulty in the use of natural gas is transportation. Natural gas pipelines are economical, but are impractical across oceans. Many existing pipelines in North America are close to reaching their capacity prompting some politicians in colder climates to speak publicly of potential shortages. Liquefied natural gas (LNG) tankers are also used, but have higher cost and safety problems. In many cases, as with oil fields in Saudi Arabia, the natural gas which is recovered in the course of recovering petroleum cannot be profitably sold, and is simply burned at the oil field (known as flaring ). This wasteful practice is now illegal in many countries, especially since it adds greenhouse gas pollution to the atmosphere, and since a profitable method may be found in the future. The gas is instead re-injected back into the ground for possible later recovery, and to assist oil pumping by keeping underground pressures higher.

Natural gas is often stored as Compressed Natural Gas or CNG.

Natural gas crisis

Many politicians and prominent figures in North America have spoken publicly about a possible natural gas crisis . This list includes former Secretary of Energy Spencer Abraham, Chairman of the Federal Reserve Alan Greenspan, Ontario Minister of Energy Dwight Duncan.

The natural gas crisis is typically described by the increasing price of natural gas in the U.S. over the last few years due to the decline in indigenous supply and the increase in demand for electricity generation. The price has become so high that many industrial users, mainly in the petrochemical industry, have closed their plants causing loss of jobs. Alan Greenspan has suggested that a solution to the natural gas crisis is the importation of liquified natural gas, or LNG.

Uses

Power generation

Natural gas is important as a major source for electricity generation through the use of gas turbines and steam turbines. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Environmentally, natural gas burns cleaner than other fossil fuels, such as oil and coal, and produces less greenhouse gases. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. Combined cycle power generation using natural gas is thus the cleanest source of power available using fossil fuels, and this technology is widely used wherever gas can be obtained at a reasonable cost. Fuel cell technology may eventually provide cleaner options for converting natural gas into electricity, but as yet it is not price-competitive.

Natural gas vehicles

Compressed natural gas (and LPG) is used as a clean alternative to other automobile fuels. As of 2003, the countries with the largest number of natural gas vehicles were Argentina, Brazil, Pakistan, Italy, and India.

Domestic use

Natural gas is supplied to homes where it is used for such purposes as cooking and heating CNG is used in rural homes without connections to piped-in public utility services, or with portable grills.

Fertilizer

Natural gas is a major feedstock for the production of ammonia, via the Haber process, for use in fertilizer production.

Sources

Natural gas is commercially produced from oil fields and natural gas fields.

Possible future sources

One experimental idea is to use the methane gas that is naturally produced from landfills to supply power to cities. Tests have shown that methane gas could be a financially sustainable power source.

There are plans in Ontario to capture the methane gasses rising from the manure of cattle caged in a factory farm and to use that gas to provide power to a small town.

There is also the possibility that with the source separation of organic materials from the waste stream that by using an anerobic digester, the methane can be used to produce useable energy. This can be improved by adding other organic material (plants as well as slaughter house waste) to the digester.

Safety

In any form, a strong bad scent (such as ethanethiol) is deliberately added to the otherwise colorless and odorless gas, so that leaks can be detected by the smell before an explosion occurs. In mines, sensors are used and mining apparatus has been specifically developed to avoid ignition sources (e.g. the Davy lamp). Adding scent to natural gas began after the 1937 New London School explosion. The buildup of gas in the school went unnoticed, and killed three hundred students and faculty when it ignited.

Explosions caused by natural gas leaks occur a few times each year. Individual homes and small businesses are most frequently affected when an internal leak builds up gas inside the structure. Frequently, the blast will be enough to significantly damage a building but leave it standing. In these cases, the people inside tend to have minor to moderate injuries. Occasionally, the gas can collect in high enough quantities to cause a deadly explosion, disintegrating one or more buildings in the process. The gas usually dissipates readily outdoors, but can sometimes collect in dangerous quantities if weather conditions are right. Considering the tens of millions of structures that use the fuel, the risks of using natural gas are very low.

Natural gas is non-toxic, though some gas fields yield 'acid gas' or 'sour gas' containing hydrogen sulfide. This untreated gas is toxic.

Extraction of natural gas (or oil) leads to decrease in pressure in the reservoir. This in turn may lead to subsidence at ground level. Subsidence may affect ecosystems, waterways, sewer and water supply systems, foundations etc.

Future of Oil

Future of oil

The Hubbert peak theory, also known as peak oil, is a controversial theory concerning the long-term rate of conventional oil and other fossil fuel production and depletion. It assumes that oil reserves are not replenished, and predicts that future world oil production must inevitably reach a peak and then decline as these reserves are exhausted. Much of the controversy is over whether past production or discovery data can be used to predict a future peak. Based on available production data, proponents have previously (and incorrectly) predicted the peak years to be 1989, 1995, or 1995-2000. A new prediction by Goldman Sachs picks 2007 for oil and some time later for natural gas.

Classification

The oil industry classifies "crude" by the location of its origin (e.g., "West Texas Intermediate, WTI" or "Brent") and often by its relative weight or viscosity ("light", "intermediate" or "heavy"); refiners may also refer to it as "sweet", which means it contains relatively little sulfur, or as "sour", which means it contains substantial amounts of sulfur and requires more refining in order to meet current product specifications.

The world reference barrels are:

• Brent Blend, comprising 15 oils from fields in the Brent and Ninian systems in the East Shetland Basin of the North Sea. The oil is landed at Sullom Voe terminal in the Shetlands. Oil production from Europe, Africa and Middle Eastern oil flowing West tends to be priced off the price of this oil, which forms a benchmark.
• West Texas Intermediate (WTI) for North American oil.
• Dubai used as benchmark for the Asia-Pacific region for Middle East Oil
• Tapis (from Malaysia, used as a reference for light Far East oil)
• Minas (from Indonesia, used as a reference for heavy Far East oil)
• The OPEC Basket consisting of
• Arab Light Saudi Arabia
• Bonny Light Nigeria
• Fateh Dubai
• Isthmus Mexico (non-OPEC)
• Minas Indonesia
• Saharan Blend Algeria
• Tia Juana Light Venezuela

OPEC attempts to keep the price of the Opec Basket between upper and lower limits, by increasing and decreasing production. This makes the measure important for market analysts. The OPEC Basket, including a mix of light and heavy crudes, is heavier than both Brent and WTI.

Pricing

In modern western economies, both the primary source of energy and the primary form of stored and transported energy is hydrocarbon fossil fuels. Because pumping the hydrocarbons out of the ground is currently inexpensive (about one U.S. dollar per barrel in Saudi Arabia in 2004), the price of energy comes from the costs of refining and distribution, and from taxation and profits by the various governments and companies in the custody chain between producer and consumer. The price of crude delivered to a refinery in the U.S. is about $50 a barrel in late 2004.

The price of oil fluctuates quite widely in response to crises or recessions in major economies, because any economic downturn reduces the demand for oil. On the supply side the OPEC cartel uses its influence to stabilise or raise oil prices. During 2004, the OPEC official price range for its crude oil is US $22 to US $28 per barrel.

A recent low point was reached in January 1999, after increased oil production from Iraq coincided with the Asian financial crisis, which reduced demand. The prices then rapidly increased, more than doubling by September 2000, then fell until the end of 2001 before steadily increasing, reaching US $40 to US $50 per barrel by September 2004 (see Oil price increases of 2004). In October 2004, light crude futures on the NYMEX for November delivery exceeded US $53 per barrel and for December delivery exceeded US $55 per barrel.

The New York Mercantile Exchange (NYMEX) trades crude oil (including futures contracts) and provides the basis of US crude oil pricing via WTI (West Texas Intermediate). Other exchanges also trade crude oil futures, eg the International Petroleum Exchange (IPE) in London trades contracts in Brent crude. Wet oil is normally bought and sold via bilateral deals between companies, typically with reference to a marker crude oil grade that is typically quoted via the pricing agency Platts , for example in Europe a particular grade of oil, say Fulmar, might be sold at a price of "Brent plus US$0.25/barrel".

Top petroleum producing countries

(Ordered by amount produced in 2003):

• Saudi Arabia (OPEC)
• United States
• Russia
• Iran (OPEC)
• Mexico
• China
• Norway
• Canada
• United Arab Emirates (U.A.E) (OPEC)
• Venezuela (OPEC)
• United Kingdom (U.K)
• Kuwait (OPEC)
• Nigeria (OPEC)

(Ordered by amount exported in 2003):

• Saudi Arabia (OPEC)
• Russia
• Norway
• Iran (OPEC)
• United Arab Emirates (U.A.E) (OPEC)
• Venezuela (OPEC)
• Kuwait (OPEC)
• Nigeria (OPEC)
• Mexico
• Algeria (OPEC)
• Libya (OPEC)

Note that the USA consumes almost all of its own production.

Source: Energy Statistics from the U.S. Government