Proven Oil Reserves, as published by the CIA Factbook, 2009

The total estimated amount of oil in an oil reservoir, including both producible and non-producible oil, is called oil in place. However, because of reservoir characteristics and limitations in petroleum extraction technologies, only a fraction of this oil can be brought to the surface, and it is only this producible fraction that is considered to be reserves. The ratio of producible oil reserves to total oil in place for a given field is often referred to as the recovery factor. Recovery factors vary greatly among oil fields. The recovery factor of any particular field may change over time based on operating history and in response to changes in technology and economics. The recovery factor may also rise over time if additional investment is made in enhanced oil recovery techniques such as gas injection, surfactants injection, water-flooding,^[1] or microbial enhanced oil recovery.

Based on data from OPEC at the beginning of 2011 the highest proved oil reserves including non-conventional oil deposits are in Venezuela (20% of global reserves), Saudi Arabia (18% of global reserves), Canada (13% of global reserves), Iran (9%).^[2]

Because the geology of the subsurface cannot be examined directly, indirect techniques must be used to estimate the size and recoverability of the resource. While new technologies have increased the accuracy of these techniques, significant uncertainties still remain. In general, most early estimates of the reserves of an oil field are conservative and tend to grow with time. This phenomenon is called reserves growth.^[3]

Many oil-producing nations do not reveal their reservoir engineering field data and instead provide unaudited claims for their oil reserves. The numbers disclosed by some national governments are suspected of being manipulated for political reasons.^[4][5]

Classifications[link]

Schematic graph illustrating petroleum volumes and probabilities. Curves represent categories of oil in assessment. There is a 95% chance (i.e., probability, F95) of at least volume V1 of economically recoverable oil, and there is a 5-percent chance (F05) of at least volume V2 of economically recoverable oil.^[6]

All reserve estimates involve uncertainty, depending on the amount of reliable geologic and engineering data available and the interpretation of those data. The relative degree of uncertainty can be expressed by dividing reserves into two principal classifications—"proven" (or "proved") and "unproven" (or "unproved").^[6] Unproven reserves can further be divided into two subcategories—"probable" and "possible"—to indicate the relative degree of uncertainty about their existence.^[6] The most commonly accepted definitions of these are based on those approved by the Society of Petroleum Engineers (SPE) and the World Petroleum Council (WPC) in 1997.^[7]

Proven reserves[link]

Proven reserves are those reserves claimed to have a reasonable certainty (normally at least 90% confidence) of being recoverable under existing economic and political conditions, with existing technology. Industry specialists refer to this as P90 (i.e., having a 90% certainty of being produced). Proven reserves are also known in the industry as 1P.^[8][9]

Proven reserves are further subdivided into "proven developed" (PD) and "proven undeveloped" (PUD).^[9][10] PD reserves are reserves that can be produced with existing wells and perforations, or from additional reservoirs where minimal additional investment (operating expense) is required.^[10] PUD reserves require additional capital investment (e.g., drilling new wells) to bring the oil to the surface.^[8][10]

Until December 2009 "1P" proven reserves were the only type the U.S. Securities and Exchange Commission allowed oil companies to report to investors. Companies listed on U.S. stock exchanges must substantiate their claims, but many governments and national oil companies do not disclose verifying data to support their claims. Since January 2010 the SEC now allows companies to also provide additional optional information declaring "2P" (both proven and probable) and "3P" (proven + probable + possible) provided the evaluation is verified by qualified third party consultants, though many companies choose to use 2P and 3P estimates only for internal purposes.

Unproven reserves[link]

An oil well in Canada, which has the world's third largest oil reserves.

Unproven reserves are based on geological and/or engineering data similar to that used in estimates of proven reserves, but technical, contractual, or regulatory uncertainties preclude such reserves being classified as proven.^[11] Unproven reserves may be used internally by oil companies and government agencies for future planning purposes but are not routinely compiled. They are sub-classified as probable and possible.^[11]

Probable reserves are attributed to known accumulations and claim a 50% confidence level of recovery. Industry specialists refer to them as "P50" (i.e., having a 50% certainty of being produced). These reserves are also referred to in the industry as "2P" (proven plus probable).^[8]

Possible reserves are attributed to known accumulations that have a less likely chance of being recovered than probable reserves. This term is often used for reserves which are claimed to have at least a 10% certainty of being produced ("P10"). Reasons for classifying reserves as possible include varying interpretations of geology, reserves not producible at commercial rates, uncertainty due to reserve infill (seepage from adjacent areas) and projected reserves based on future recovery methods. They are referred to in the industry as "3P" (proven plus probable plus possible).^[8]

Fraud and incompetence

In the early 1980s the Penn Square Bank of Oklahoma engaged in wide scale lending to Oil and Gas groups with reserves used as collateral for the loans. Sometimes the bank officers ignored the engineering advice about reserve size and value in order to book the loan profit. The bank resold many of the loans as 'loan participations' to larger banks like Continental Illinois, Seattle First, Michigan National, and Chase Manhattan, whose officers also sometimes ignored engineering advice. When the oil market busted, many of these loans were called, and the true nature of the reserves used as loan collateral was discovered by Federal Deposit Insurance Corporation government investigators and creditors. Penn Square went bust, and Continental Illinois was the first Too Big to Fail bailout of the modern era.^[12]

Strategic petroleum reserves[link]

Many countries maintain government-controlled oil reserves for both economic and national security reasons. According to the United States Energy Information Administration, approximately 4.1 billion barrels (650,000,000 m³) of oil are held in strategic reserves, of which 1.4 billion is government-controlled (m³=cubic meters). These reserves are generally not counted when computing a nation's oil reserves.

Resources[link]

Unconventional oil resources are greater than conventional ones.^[13]

Cumulative oil production plus remaining reserves and undiscovered resources. United States not included.

A more sophisticated system of evaluating petroleum accumulations was adopted in 2007 by the Society of Petroleum Engineers (SPE), World Petroleum Council (WPC), American Association of Petroleum Geologists (AAPG), and Society of Petroleum Evaluation Engineers (SPEE). It incorporates the 1997 definitions for reserves, but adds categories for contingent resources and prospective resources.^[6]

Contingent resources are those quantities of petroleum estimated, as of a given date, to be potentially recoverable from known accumulations, but the applied project(s) are not yet considered mature enough for commercial development due to one or more contingencies. Contingent resources may include, for example, projects for which there are currently no viable markets, or where commercial recovery is dependent on technology under development, or where evaluation of the accumulation is insufficient to clearly assess commerciality.

Prospective resources are those quantities of petroleum estimated, as of a given date, to be potentially recoverable from undiscovered accumulations by application of future development projects. Prospective resources have both an associated chance of discovery and a chance of development.

The United States Geological Survey uses the terms technically and economically recoverable resources when making its petroleum resource assessments. Technically recoverable resources represent that proportion of assessed in-place petroleum that may be recoverable using current recovery technology, without regard to cost. Economically recoverable resources are technically recoverable petroleum for which the costs of discovery, development, production, and transport, including a return to capital, can be recovered at a given market price.

"Unconventional resources" exist in petroleum accumulations that are pervasive throughout a large area. Examples include extra heavy oil, natural bitumen, and oil shale deposits. Unlike "conventional resources", in which the petroleum is recovered through wellbores and typically requires minimal processing prior to sale, unconventional resources require specialized extraction technology to produce. For example, steam and/or solvents are used to mobilize bitumen for in-situ recovery. Moreover, the extracted petroleum may require significant processing prior to sale (e.g., bitumen upgraders).^[6] The total amount of unconventional oil resources in the world considerably exceeds the amount of conventional oil reserves, but are much more difficult and expensive to develop.

Estimation techniques[link]

Example of a production decline curve for an individual well

The amount of oil in a subsurface reservoir is called oil in place (OIP).^[10] Only a fraction of this oil can be recovered from a reservoir. This fraction is called the recovery factor.^[10] The portion that can be recovered is considered to be a reserve. The portion that is not recoverable is not included unless and until methods are implemented to produce it.

There are a number of different methods of calculating oil reserves. These methods can be grouped into three general categories: "volumetric", "material balance", and "production performance". Each method has its advantages and drawbacks.^[10][11]

Volumetric method[link]

Volumetric methods attempt to determine the amount of oil in place by using the size of the reservoir as well as the physical properties of its rocks and fluids. Then a recovery factor is assumed, using assumptions from fields with similar characteristics. OIP is multiplied by the recovery factor to arrive at a reserve number. Current recovery factors for oil fields around the world typically range between 10 and 60 percent; some are over 80 percent. The wide variance is due largely to the diversity of fluid and reservoir characteristics for different deposits.^[14][15][16] The method is most useful early in the life of the reservoir, before significant production has occurred.

Materials balance method[link]

The materials balance method for an oil field uses an equation that relates the volume of oil, water and gas that has been produced from a reservoir and the change in reservoir pressure to calculate the remaining oil. It assumes that, as fluids from the reservoir are produced, there will be a change in the reservoir pressure that depends on the remaining volume of oil and gas. The method requires extensive pressure-volume-temperature analysis and an accurate pressure history of the field. It requires some production to occur (typically 5% to 10% of ultimate recovery), unless reliable pressure history can be used from a field with similar rock and fluid characteristics.^[11]

Production decline curve method[link]

The decline curve method uses production data to fit a decline curve and estimate future oil production. The three most common forms of decline curves are exponential, hyperbolic, and harmonic. It is assumed that the production will decline on a reasonably smooth curve, and so allowances must be made for wells shut in and production restrictions. The curve can be expressed mathematically or plotted on a graph to estimate future production. It has the advantage of (implicitly) including all reservoir characteristics. It requires a sufficient history to establish a statistically significant trend, ideally when production is not curtailed by regulatory or other artificial conditions.^[11]

Reserves growth[link]

Experience shows that initial estimates of the size of newly discovered oil fields are usually too low. As years pass, successive estimates of the ultimate recovery of fields tend to increase. The term reserve growth refers to the typical increases in estimated ultimate recovery that occur as oil fields are developed and produced.^[3]

Estimated reserves by country[link]

bbl = barrel of oil

Countries with largest oil reserves

Most of the world's oil reserves are in the Middle East.^[17]

OPEC countries[link]

There are doubts about the reliability of official open reserves estimates, which are not provided with any form of verification that meet external reporting standards.^[20]

Since a system of country production quotas was introduced in the 1980s, partly based on reserves levels, there have been dramatic increases in reported reserves among OPEC producers. In 1983, Kuwait increased its proven reserves from 67 Gbbl (10.7×10^⁹ m³) to 92 Gbbl (14.6×10^⁹ m³). In 1985–86, the UAE almost tripled its reserves from 33 Gbbl (5.2×10^⁹ m³) to 97 Gbbl (15.4×10^⁹ m³). Saudi Arabia raised its reported reserve number in 1988 by 50%. In 2001–02, Iran raised its proven reserves by some 30% to 130 Gbbl (21×10^⁹ m³), which advanced it to second place in reserves and ahead of Iraq. Iran denied accusations of a political motive behind the readjustment, attributing the increase instead to a combination of new discoveries and improved recovery. No details were offered of how any of the upgrades were arrived at.^[20][21]

The following table illustrates these rises.

OPEC countries

oil reserves of OPEC 1980–2005

The sudden revisions in OPEC reserves, totaling nearly 300 bn barrels, have been much debated.^[22] Some of it is defended partly by the shift in ownership of reserves away from international oil companies, some of whom were obliged to report reserves under conservative US Securities and Exchange Commission rules.^[20][23] The most prominent explanation of the revisions is prompted by a change in OPEC rules which set production quotas (partly) on reserves. In any event, the revisions in official data had little to do with the actual discovery of new reserves.^[20]

Total reserves in many OPEC countries hardly changed in the 1990s.^[20] Official reserves in Kuwait, for example, were unchanged at 96.5 Gbbl (15.34×10^⁹ m³) (including its share of the Neutral Zone) from 1991 to 2002, even though the country produced more than 8 Gbbl (1.3×10^⁹ m³) and did not make any important new discoveries during that period.^[20] The case of Saudi Arabia is also striking, with proven reserves estimated at between 260 and 264 billion barrels (4.20×10¹⁰ m³) in the past 18 years, a variation of less than 2%,^[20] while extracting approximately 60 billion barrels (9.5×10⁹ m³) during this period.

Sadad al-Huseini, former head of exploration and production at Saudi Aramco, estimates 300 Gbbl (48×10^⁹ m³) of the world's 1,200 Gbbl (190×10^⁹ m³) of proven reserves should be recategorized as speculative resources, though he did not specify which countries had inflated their reserves.^[24] Dr. Ali Samsam Bakhtiari, a former senior expert of the National Iranian Oil Company, has estimated that Iran, Iraq, Kuwait, Saudi Arabia and the United Arab Emirates have overstated reserves by a combined 320–390bn barrels and has said, "As for Iran, the usually accepted official 132 billion barrels (2.10×10¹⁰ m³) is almost one hundred billion over any realistic assay."^[25] Petroleum Intelligence Weekly reported that official confidential Kuwaiti documents estimate reserves of Kuwait were only 48 billion barrels (7.6×10^⁹ m³), of which half were proven and half were possible. The combined value of proven and possible is half of the official public estimate of proven reserves.^[21]

In July 2011, OPEC's Annual Statistical Review showed Venezuela's reserves to be larger than Saudi Arabia's.^[26]

Prospective resources[link]

Arctic prospective resources[link]

Location of Arctic Basins assessed by the USGS

A 2008 United States Geological Survey estimates that areas north of the Arctic Circle have 90 billion barrels (1.4×10¹⁰ m³) of undiscovered, technically recoverable oil and 44 billion barrels (7.0×10⁹ m³) of natural gas liquids in 25 geologically defined areas thought to have potential for petroleum. This represented 13% of the expected undiscovered oil in the world. Of the estimated totals, more than half of the undiscovered oil resources were estimated to occur in just three geologic provinces—Arctic Alaska, the Amerasia Basin, and the East Greenland Rift Basins. More than 70% of the mean undiscovered oil resources was estimated to occur in five provinces: Arctic Alaska, Amerasia Basin, East Greenland Rift Basins, East Barents Basins, and West Greenland–East Canada. It was further estimated that approximately 84% of the oil and gas would occur offshore. The USGS did not consider economic factors such as the effects of permanent sea ice or oceanic water depth in its assessment of undiscovered oil and gas resources. This assessment was lower than a 2000 survey, which had included lands south of the Arctic Circle.^[27][28][29]

Miscellaneous prospective resources[link]

In October 2009, the USGS updated the Orinoco tar sands (Venezuela) value to 513 billion barrels (8.16×10¹⁰ m³).^[30]

The Exclusive Economic Zone is a delineated offshore area, mostly to the west and north of Cuba, which, under international agreements, is owned by Cuba. This 112,000-square-kilometer zone has been divided into 59 exploration blocks. A 2004 joint partnership between a Spanish oil company and Cuba's state oil company (CUPET) estimated Cuba's off-shore reserves to be able to produce ultimately between 4.6 and 9.3 billion barrels of crude oil.^[31]

The US Geological Survey (USGS) estimates that Cuba has resources up to 9 billion barrels (1.4×10⁹ m³) of oil. In October 2008, the Cuban government announced that it had discovered oil basins that would double its total oil resources to 20 billion barrels (3.2×10⁹ m³).^[32] Note that, consistent with the definitions of reserves and resources as given in the above sections, at this stage (June 2009), given no commercial discoveries to date, all recoverable oil estimates in the Exclusive Economic Zone (EEZ) are prospective resources estimates and not reserves estimates.

See also[link]

Energy portal

• Decline curve analysis
• Global strategic petroleum reserves
• Oil exploration
• Peak oil
• Petroleum Industry
• Strategic Petroleum Reserve

Energy and resources:

• Energy security
• World energy resources and consumption
• List of countries by natural gas proven reserves

References[link]

• http://www.opec.org/opec_web/en/data_graphs/330.htm

External links[link]

• OPEC Annual Statistical Bulletin
• Energy Supply page on the Global Education Project web site, including many charts and graphs on the world's energy supply and use
• Oil reserves (most recent) by country

v t e Peak oil Core issues Peak oil Mitigation of peak oil Predicting the timing of peak oil Hubbert peak theory Olduvai theory Results/responses Hirsch report Rimini protocol Price of petroleum 2000s energy crisis Energy crisis Export Land Model Food vs. fuel Oil reserves Pickens Plan Simple living Swing producer Transition Towns People Albert Bartlett Colin J. Campbell David Goodstein John Michael Greer Richard Heinberg M. King Hubbert James Kunstler Jeremy Leggett Dale Allen Pfeiffer Richard Rainwater Matthew Simmons Richard C. Duncan Kenneth S. Deffeyes Books The End of Oil The Long Emergency Out of Gas The Party's Over Power Down Beyond Oil Films A Crude Awakening Collapse The End of Suburbia Oil Factor PetroApocalypse Now? How Cuba Survived Peak Oil What a Way to Go Gashole Organizations ASPO The Oil Drum Energy Watch Group ODAC OPEC OAPEC IEA Post Carbon Institute Other "peaks" Peak car Peak coal Peak copper Peak phosphorus Peak gas Peak uranium Peak water Peak wheat Peak wood

Richard in his garden ca. 2011
Born	1950
Occupation	Writer, educator, environmentalist
Language	English
Nationality	USA
Ethnicity	USA
Genres	non-fiction
Subjects	peak oil, resource depletion, sustainability
Notable work(s)	The Party's Over: Oil, War, and the Fate of Industrial Societies
Spouse(s)	Janet Barocco
richardheinberg.com

Richard Heinberg is an American journalist and educator who has written extensively on energy, economic, and ecological issues, including oil depletion. He is the author of ten books. He serves as the senior fellow at the Post Carbon Institute.

Career[link]

Heinberg, after two years in college and a period of personal study, became personal assistant to Immanuel Velikovsky in November 1979 and after Velikovsky's death assisted Mrs. Velikovsky editing manuscripts.^[1][2] He published his first book in 1989, Memories and Visions of Paradise: Exploring the Universal Myth of a Lost Golden Age,^[3] which was the result of ten years of study of world mythology. An expanded second edition was published in 1995.^[4] He began publishing his alternative newsletter, the MuseLetter, in 1992. His next book was published in 1993: Celebrate the Solstice: Honoring the Earth's Seasonal Rhythms through Festival and Ceremony.^[5]

In June 1995, speaking to the International Society for the Comparative Study of Civilizations in Dayton, Ohio, Heinberg provided "A Primitivist Critique of Civilization"^[6] and discussed the ways in which "We are, it would seem, killing the planet."

His books from the later 1990s address the relationships between humanity and the natural world. In 1998 he began teaching at New College of California.^{[citation needed]} in the "Culture, Ecology and Sustainable Community" program, which he helped design. He remained a member of the Core Faculty until 2007, when the College closed its doors.

In 2003, Heinberg published The Party's Over: Oil, War, and the Fate of Industrial Societies, one of the first full-length analyses on the issue of peak oil.

In 2004, Heinberg provided the closing address for the First US Conference on Peak Oil and Community Solutions. His title was "Beyond the Peak."

In February 2007 Heinberg addressed the Committee on International Trade of the European Parliament and served as an advisor to the National Petroleum Council in its report to the U.S. Secretary of Energy on Peak Oil. In October 2007 he addressed members of the New Zealand Parliament. In 2008 he was a Mayor’s appointed member of the Oil Independent Oakland 2020 Task Force (Oakland, California),^[7] which was convened to chart a path for the city to dramatically reduce its petroleum dependence.

Heinberg is now the Senior Fellow of the Post Carbon Institute in Santa Rosa, California. He lives in Santa Rosa, California. He is also a violinist, illustrator and book designer. He is married to Janet Barocco.

Heinberg has proposed an international protocol to peak oil management with the aim of reducing the impact of the arrival of the peak.^[8] The adoption of the Protocol would mean that oil-importing nations should deal to reduce their importations in an annual percentage, while exporting countries should deal to reduce their exportations in the same percentage. The Uppsala Protocol^[9] has been focused in a similar direction.

Heinberg is the editor of MuseLetter,^[10] which has been included in Utne Magazine’s annual list of Best Alternative Newsletters. He has appeared in the documentaries The End of Suburbia, The 11th Hour, Crude Impact, Oil, Smoke & Mirrors, Chasing God, What a Way to Go: Life at the End of Empire, The Great Squeeze, The Power of Community: How Cuba Survived Peak Oil, A Farm for the Future and Ripe For Change.

Publications[link]

• Memories and Visions of Paradise: Exploring the Universal Myth of a Lost Golden Age (1989; revised edition, 1995; British edition, 1990; Portuguese edition, 1991)
• Celebrate the Solstice: Honoring the Earth’s Seasonal Rhythms through Festival and Ceremony (1993; Italian edition, 2002; Portuguese edition, 2002)
• A New Covenant with Nature: Notes on the End of Civilization and the Renewal of Culture (1996; Portuguese edition, 1998) ISBN 978-0-8356-0746-9
• Cloning the Buddha: The Moral Impact of Biotechnology (1999; Indian edition, 2001; Japanese edition, 2001; Chinese edition, 2001)
• The Party's Over: Oil, War, and the Fate of Industrial Societies (2003; British, Italian, German, Spanish, and Arabic editions, 2004–2005; revised North American edition, 2005; Spanish edition, 2007; French edition, 2008)
• Powerdown: Options and Actions for a Post-Carbon World (ISBN 9780865715103) (2004; British edition 2005)
• The Oil Depletion Protocol: A Plan to Avert Oil Wars, Terrorism and Economic Collapse (2006, ISBN 978-0-86571-563-9),
• Peak Everything: Waking Up to the Century of Declines (2007, ISBN 978-0-86571-598-1).
• Blackout: Coal, Climate, and the Last Energy Crisis (June, 2009). (ISBN 9780865716568)
• The Post Carbon Reader: Managing the 21st Century’s Sustainability Crises, edited by Richard Heinberg & Daniel Lerch (2010) ISBN 978-0-9709500-6-2
• The End of Growth, (September 2011) ISBN 978-0-86571-695-7

See also[link]

• Oil depletion
• Peak oil
• Petrodollar warfare

References[link]

External links[link]

Wikisource has original works written by or about: Richard Heinberg

• Post Carbon Institute
• Heinberg's personal website
• 2008 interview on Global Public Media Heinberg on Post Carbon Institute's Green New Deal
• OneWorldTV video interview with Richard Heinberg
• Interview: (October 21, 2006) The Oil Depletion Protocol
• Interview, July 2006
• Oil, Smoke & Mirrors Contains interviews with Heinberg discussing peak oil.
• Critique of Civilization Paper presented at the 24th annual meeting of the International Society for the Comparative Study of Civilizations, June 15, 1995.
• Peak Everything lecture on YouTube
• BLIND SPOT Documentary, Official Website.
• The End of Growth: Heinberg on the Keiser Report 2011 interview with Richard Heinberg

v t e Peak oil Core issues Peak oil Mitigation of peak oil Predicting the timing of peak oil Hubbert peak theory Olduvai theory Results/responses Hirsch report Rimini protocol Price of petroleum 2000s energy crisis Energy crisis Export Land Model Food vs. fuel Oil reserves Pickens Plan Simple living Swing producer Transition Towns People Albert Bartlett Colin J. Campbell David Goodstein John Michael Greer Richard Heinberg M. King Hubbert James Kunstler Jeremy Leggett Dale Allen Pfeiffer Richard Rainwater Matthew Simmons Richard C. Duncan Kenneth S. Deffeyes Books The End of Oil The Long Emergency Out of Gas The Party's Over Power Down Beyond Oil Films A Crude Awakening Collapse The End of Suburbia Oil Factor PetroApocalypse Now? How Cuba Survived Peak Oil What a Way to Go Gashole Organizations ASPO The Oil Drum Energy Watch Group ODAC OPEC OAPEC IEA Post Carbon Institute Other "peaks" Peak car Peak coal Peak copper Peak phosphorus Peak gas Peak uranium Peak water Peak wheat Peak wood

The Edge
Background information
Birth name	David Howell Evans
Born	(1961-08-08) 8 August 1961 (age 50) Barking, Essex, England, United Kingdom
Origin	County Dublin, Ireland
Genres	Rock, post-punk, alternative rock
Occupations	Musician, songwriter, activist
Instruments	Guitar, vocals, keyboards, piano, bass guitar
Years active	1976–present
Labels	Island, Mercury
Associated acts	U2, Passengers
Website	www.u2.com
Notable instruments
Gibson Explorer Fender Stratocaster Gibson Les Paul Fender Telecaster Gretsch Country Gentleman Gretsch White Falcon Rickenbacker 330/12

David Howell Evans (born 8 August 1961), more widely known by his stage name The Edge (or just Edge),^[1] is a musician best known as the guitarist, backing vocalist, and keyboardist of the Irish rock band U2. A member of the group since its inception, he has recorded 12 studio albums with the band and has released one solo record. As a guitarist, The Edge has crafted a minimalistic and textural style of playing. His use of a rhythmic delay effect yields a distinctive ambient, chiming sound that has become a signature of U2's music.

The Edge was born in England to a Welsh family, but was raised in Ireland after moving there as an infant. In 1976, at Mount Temple Comprehensive School, he formed U2 with his fellow students and his older brother Dik. Inspired by the ethos of punk rock and its basic arrangements, the group began to write its own material. They eventually became one of the most popular acts in popular music, with successful albums such as 1987's The Joshua Tree and 1991's Achtung Baby. Over the years, The Edge has experimented with various guitar effects and introduced influences from several genres of music into his own style, including American roots music, industrial music, and alternative rock. With U2, The Edge has also played keyboards, co-produced their 1993 record Zooropa, and occasionally contributed lyrics. The Edge met his second and current wife, Morleigh Steinberg, through her collaborations with the band.

As a member of U2 and as an individual, The Edge has campaigned for human rights and philanthropic causes. He co-founded Music Rising, a charity to support musicians affected by Hurricane Katrina. He has collaborated with U2 bandmate Bono on several projects, including songs for Roy Orbison and Tina Turner, and the soundtracks to the musical Spider-Man: Turn Off the Dark and the Royal Shakespeare Company's London stage adaptation of A Clockwork Orange. In 2011, Rolling Stone magazine placed him at number 38 on its list of "The 100 Greatest Guitarists of All Time".

Personal life[link]

The Edge at a U2 concert in Anaheim (2005)

David Howell Evans was born at the Barking Maternity Hospital,^[2] Essex, England to Welsh parents Garvin and Gwenda Evans.^[1] When he was one, his family moved to County Dublin, Ireland where he attended St Andrew's National School. He received piano and guitar lessons and often performed with his brother Dik Evans before they both answered an advertisement posted by Larry Mullen, Jr. at their school, Mount Temple Comprehensive School, seeking musicians to form a band.^[3] The band accepted both of them. This band went through several incarnations before emerging as U2 in March 1978 (Dik Evans left the band just before the name change).^[3] U2 began performing in various venues in Ireland and eventually began developing a following. Their debut album, Boy, was released in 1980.

In 1981, leading up to the October tour, Evans came very close to leaving U2 for religious reasons, but he decided to stay.^[3] During this period, he became involved with a group called Shalom Tigers, in which bandmates Bono and Larry Mullen Jr. were also involved.^[4] Shortly after deciding to remain with the band, he wrote a piece of music that later became "Sunday Bloody Sunday".^[3] The Edge married his high school girlfriend Aislinn O'Sullivan on 12 July 1983.^[5] The couple had three daughters together: Hollie in 1984, Arran in 1985 and Blue Angel in 1989.^[4] The couple separated in 1990, but were unable to get officially divorced because of Irish laws regarding marriage annulment; divorce was legalised in 1995 and the couple were legally divorced in 1996.^[4]

In 1993, The Edge began dating Morleigh Steinberg, a professional dancer and choreographer employed by the band as a belly dancer during the Zoo TV Tour. They had a daughter, Sian (born 1997), and a son, Levi (born 25 October 1999),^[4] before marrying on 22 June 2002.^[4] He appeared in the 2009 music documentary film It Might Get Loud.^[6] The Edge has been criticized for his efforts to build five luxury mansions on a 156 acre plot of land in Malibu, California.^[7] The California Coastal Commission voted 8-4 against the plans, with the project described by the commission's executive director, Peter Douglas, as "In 38 years...one of the three worst projects that I've seen in terms of environmental devastation...It's a contradiction in terms – you can't be serious about being an environmentalist and pick this location."^[7] The Santa Monica Mountains Conservancy agreed to remain neutral on the issue following a $1 million donation from The Edge and a commitment from The Edge to designate 100 acres of the land as open space for public footpaths.^[7]

Music style[link]

Guitar playing[link]

As a guitar player, The Edge has a sound typified by a low-key playing style, a chiming, shimmering sound (thanks in part to the sound of VOX AC-30s) that he achieves with extensive use of delay effects and reverb. The feedback delay is often set to a dotted eighth note (3/16 of a measure), and the feedback gain is adjusted until a note played repeats two or three times.^{[citation needed]}

On 1987's The Joshua Tree, The Edge often contributes just a few simple lead lines given depth and richness by an ever-present delay. For example, the introduction to "Where the Streets Have No Name" is simply a repeated six-note arpeggio, broadened by a modulated delay effect. The Edge has said that he views musical notes as "expensive", in that he prefers to play as few notes as possible. He said in 1982 of his style,

"I like a nice ringing sound on guitar, and most of my chords I find two strings and make them ring the same note, so it's almost like a 12-string sound. So for E I might play a B, E, E and B and make it ring. It works very well with the Gibson Explorer. It's funny because the bass end of the Explorer was so awful that I used to stay away from the low strings, and a lot of the chords I played were very trebly, on the first four, or even three strings. I discovered that through using this one area of the fretboard I was developing a very stylized way of doing something that someone else would play in a normal way."^[9]

Many different influences have shaped The Edge's guitar technique.^{[citation needed]} His first guitar was an old acoustic guitar that his mother bought him at a local flea market for only a few pounds; he was nine at the time. He and his brother Dik Evans both experimented with this instrument.^[9] He said in 1982 of this early experimentation, "I suppose the first link in the chain was a visit to the local jumble sale where I purchased a guitar for a pound. That was my first instrument. It was an acoustic guitar and me and my elder brother Dik both played it, plonking away, all very rudimentary stuff, open chords and all that."^[9] The Edge has stated that many of his guitar parts are based around guitar effects. This is especially true from the Achtung Baby era onwards, although much of the band's 1980s material made heavy use of echos.

Vocals[link]

The Edge in June 2005

The Edge also supplies the backing vocals for U2. U2's 1983 live album and video release, Under a Blood Red Sky and Live at Red Rocks: Under a Blood Red Sky are good reference points for his singing (as are the live DVDs from the Elevation Tour, U2 Go Home: Live from Slane Castle and Elevation 2001: Live from Boston). For example, he sings the chorus to "Sunday Bloody Sunday" (Bono harmonizes on the final 'Sunday'). U2 used this tradeoff technique later in "Bullet the Blue Sky" as well. His backing vocals are sometimes in the form of a repeated cry; examples of songs that use this approach include "Beautiful Day", "New Year's Day" and "Stay (Faraway, So Close!)". Another technique he uses in his backing vocals is the falsetto, in songs such as "Stuck in a Moment You Can't Get Out Of", "Sometimes You Can't Make It on Your Own", "A Man and a Woman", "The Wanderer", live versions of "The Fly", and "Window in the Skies".