Mitigation of peak oil

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Mitigation_of_peak_oil 

 

The standard Hubbert curve, plotting crude oil production of a region over time.

 

World energy consumption, 1970–2025. Source: International Energy Outlook 2004.

The mitigation of peak oil is the attempt to delay the date and minimize the social and economic effects of peak oil by reducing the consumption of and reliance on petroleum. By reducing petroleum consumption, mitigation efforts seek to favorably change the shape of the Hubbert curve, which is the graph of real oil production over time predicted by Hubbert peak theory. The peak of this curve is known as peak oil, and by changing the shape of the curve, the timing of the peak in oil production is affected. An analysis by the author of the Hirsch report showed that while the shape of the oil production curve can be affected by mitigation efforts, mitigation efforts are also affected by the shape of Hubbert curve.

For the most part, mitigation involves fuel conservation, and the use of alternative and renewable energy sources. The development of unconventional oil resources can extend the supply of petroleum, but does not reduce consumption.

Historically, world oil consumption data show that mitigation efforts during the 1973 and 1979 oil shocks lowered oil consumption, while general recessions since the 1970s have had no effect on curbing the oil consumption until 2007. In the United States, oil consumption declines in reaction to high prices.

Key questions for mitigation are the viability of methods, the roles of government and private sector and how early these solutions are implemented. The responses to such questions and steps taken towards mitigation may determine whether or not the lifestyle of a society can be maintained, and may affect the population capacity of the planet.

Alternative energy

The most effective method of mitigating peak oil is to use renewable or alternative energy sources in place of petroleum.

Nuclear power, considered by some to be a viable alternative source, can be substituted for petroleum in some cases. China is preparing for the post-peak oil future by building pebble bed reactors configured to produce hydrogen fuel from the electrolysis of water. The use of nuclear power is often a highly contentious issue because of questions of the future availability of fuel and the dangerous nature of nuclear waste. Some current research projects are focused on neutron-free fusion power, in which hydrogen and boron are heated to over 1 billion degrees, though technical and economic barriers still exist.

In its October 2009 peak oil report, the Government-supported UK Energy Research Centre warned of the risk that 'rising oil prices will encourage the rapid development of carbon-intensive alternatives which will make it difficult or impossible to prevent dangerous climate change and stated that 'early investment in low-carbon alternatives to conventional oil is of considerable importance' in avoiding this scenario.

Iceland was the first country to suggest transitioning to 100% renewable energy, using hydrogen for vehicles and its fishing fleet, in 1998, but the actual progress has been very limited.

Transportation fuel use

Because most oil is consumed for transportation most mitigation discussions revolve around transportation issues.

Fuel substitution

While there is some interchangeability, the alternative energy sources available tend to depend on whether the fuel is being used in static or mobile applications.

Biofuel

The use of biofuels, which are fuels derived from recently dead biological material, reduces dependence on petroleum and enhances energy security. Biofuels also play significant roles in the "food vs fuel" debate, mitigation of oil prices, and energy balance and efficiency. Ethanol is a biofuel produced from crops high in sugar (e.g., sugar cane, sweet sorghum) or starch, (corn/maize). Biofuels can also be produced from plants that contain high amounts of vegetable oil, such as oil palm, soybean, algae, switchgrass, or jatropha. These oils can be burned directly in certain designs of diesel engines, or they can be chemically processed to produce fuels such as biodiesel. Wood and its byproducts can also be converted into biofuels such as woodgas, methanol or ethanol fuel. It is also possible to make cellulosic ethanol from non-edible plant parts, but this can be difficult to accomplish economically. Biofuels are most commonly used in vehicles, and in heating homes, and cooking. Biofuel industries are expanding in Europe, Asia and the Americas.

Several firms have successfully created petroleum products in the lab using either solid catalysts or genetically modified microorganisms. As of July, 2008, such firms are producing petroleum products in very small quantities, but hope to increase production over the next few years.

Static installations

The substitution of oil with other fossil fuels is theoretically relatively easy when static installations are concerned, as in the case for electricity generation. Reserves of coal are substantial, and the technology to use it is well established. Increasing the use of coal, however, would lead to higher carbon emissions which is likely to be politically unacceptable in many countries due to the implications of global warming, although carbon capture and storage may provide a solution. Natural gas is another alternative, and combined cycle power generation using natural gas is the cleanest source of power available using fossil fuels, producing about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. The major difficulty in the use of natural gas is transportation and storage because of its low density. Natural gas pipelines are economical, but are impractical across oceans.

Mobile applications

Due to its high energy density and ease of handling, oil has a unique role as a transportation fuel. There are, however, a number of possible alternatives. Among the biofuels the use of bioethanol and biodiesel is already established to some extent in some countries.

The use of hydrogen fuel is another alternative under development in various countries, alongside, hydrogen vehicles though hydrogen is actually an energy storage medium, not a primary energy source, and consequently the use of a non-petroleum source would be required to extract the hydrogen for use. Though hydrogen is currently outperformed in terms of cost and efficiency by battery powered vehicles, there are applications where it would come in useful. Short haul ferries and very cold climates are two examples. Hydrogen fuel cells are about a third as efficient as batteries and double the efficiency of gasoline vehicles.

Electric vehicles powered by batteries are another alternative, and these have the advantage of having the highest well-to-wheels efficiency rate of any energy pathway and thus would allow much greater numbers of vehicles than any other methods. In addition, even if the electricity was sourced from coal-fired power plants, two advantages would remain: first it is cheaper to sequester carbon from a few thousand smokestacks than it is to retrofit hundreds of millions of vehicles, and second encouraging the use of electric vehicles allows a further pathway for scaling up of renewable energy sources.

Currently the cost of batteries capable powering electric vehicles for a 300-mile (480 km) range (comparable to the range of many gasoline vehicles) is prohibitively high, though producing batteries for plug-in hybrids with a 40-mile (64 km) range could be done with current technology and current pricing models within the reach of the average person. A plug-in hybrid with a 40-mile (64 km) range would have the advantage that it uses no gasoline or diesel at all for the first 40 miles (a distance covering 80% of all vehicle commutes).

Unfortunately there are currently no production models of plug-in hybrids or alternative fuel vehicles (other than flex fuel) available from big manufacturers, though both Toyota and General Motors have promised versions around 2010. Fully electric vehicles are available from Tesla Motors for their high priced sports car and also a small city vehicle from Th!nk in Norway, in limited production runs in Norway and the UK.

Alternative aviation fuel

The Airbus A380 flew on alternative fuel for the first time on 1 February 2008. Boeing also plans to use alternative fuel on the 747. Because some biofuels such as ethanol contains less energy, more "tankstops" might be necessary for such planes.

The US Air Force is currently in the process of certifying its entire fleet to run on a 50/50 blend of synthetic fuel derived from the Fischer-Tropsch process and JP-8 jet fuel.

Conservation

When alternative fuels are not available, the development of more energy efficient vehicles becomes an important mitigant. Some ways of decreasing the oil used in transportation include increasing the use of bicycles, public transport, carpooling, electric vehicles, and diesel and hybrid vehicles with higher fuel efficiency.

More comprehensive mitigations include better land use planning through smart growth to reduce the need for private transportation, increased capacity and use of mass transit, vanpooling and carpooling, bus rapid transit, telecommuting, and human-powered transport from current levels. Rationing and driving bans are also forms of reducing private transportation. The higher oil prices of 2007 and 2008 caused United States drivers to begin driving less in 2007 and to a much greater extent in the first three months of 2008.

In order to deal with potential problems from peak oil, Colin Campbell has proposed the Rimini protocol, a plan which among other things would require countries to balance oil consumption with their current production.

Unconventional oil

Unconventional oil is oil produced or extracted using techniques other than the traditional oil well method from sources such as oil sands, oil shale and the conversion of coal or natural gas to liquid hydrocarbons through processes such as Fischer-Tropsch synthesis. Currently, unconventional oil production is less efficient and has a larger environmental impact relative to conventional oil production. Compared to conventional oil, much more energy is required to extract oil from non-conventional sources, so increasing costs and carbon emissions. Technology, such as using steam injection in oil sands deposits, is being developed to increase the efficiency of unconventional oil production.

Synthetic fuel, created via coal liquefaction, requires no engine modifications for use in standard automobiles. As a byproduct of oil embargoes during Apartheid in South Africa, Sasol, using the Fischer-Tropsch process, developed relatively low-cost coal-based fuel. Currently, about 30% of South Africa's transport-fuel (mostly diesel) is produced from coal. With crude-oil prices above US$40 per barrel, this process is now cost-effective.

Masdar, an experiment in mitigation

One government which is moving forward with mitigation plans is the emirate of Abu Dhabi. The United Arab Emirates economy minister stated in 2007 that the UAE do not believe that relying on oil revenues is sustainable, and so are moving to diversify their economies. Besides allotting land for solar power plants and partnering with Massachusetts Institute of Technology to build an alternative energy research institute, a new city is being constructed 17 kilometres (11 mi) east-southeast of the city of Abu Dhabi, which will rely entirely on solar energy, with a sustainable, zero-carbon, zero-waste ecology. Known as Masdar (Arabic for source), the initiative is headed by the Abu Dhabi Future Energy Company (ADFEC) The project is estimated to take some 10 years to complete, with the first phase complete and habitable in 2009, and a goal of housing 50,000 people and 1,500 businesses. The city is intended to cover 6 square kilometres (1,500 acres), with no point further than 200 m from a solar powered personal rapid transit link, housing energy, science and technology communities, commercial areas, a university, and the headquarters of the Future Energy Company. By relying on sustainable energy sources, keeping cars out of the city, returning to older architectural conventions (such as reducing air conditioning costs with large tents and narrow spaces between buildings), using sewage to produce energy and create soil, taking advantage of all recycling opportunities (including for and from construction), and reusing gray water, Masdar is designed to be a city which will consume no oil.

Bioplastics

Another major factor in petroleum demand is the widespread use of petroleum products such as plastic. These could be partially replaced by bioplastics, which are derived from renewable plant feedstocks such as vegetable oil, corn starch, hemp plants, pea starch, or microbiota. They are used either as a direct replacement for traditional plastics or as blends with traditional plastics. The most common end use market is for packaging materials. Japan has also been a pioneer in bioplastics, incorporating them into electronics and automobiles.

US government debate over mitigation strategies

Part of the current debate revolves around energy policy, and whether to shift funding to increasing energy conservation, fuel efficiency, or other energy sources like solar, wind, and nuclear power. At congressional peak oil hearings, Rep. Tom Udall argued that while rising oil prices would encourage alternatives (both on the supply and demand side), the costs and impacts of other issues involved with petroleum based personal transportation (such as pollution, the economic effects of global warming, security threats caused by sending vast amounts of money to the Middle East, and the costs of road maintenance) should also be taken into account. "Because the price of oil is artificially low, significant private investment in alternative technologies that provide a long-term payback does not exist. Until oil and its alternatives compete in a fair market, new technologies will not thrive."

In 2005, the Congressional Budget Office suggested that, "the federal government could more effectively increase the efficiency of the nation's automotive fleet by raising gasoline taxes, imposing user fees on the purchase of low-mileage-per-gallon vehicles, or both." This would give automakers more incentive to research alternative fuel technology and increased efficiency (through lighter vehicles, better aerodynamics, and less wasted energy).

Hans-Holger Rogner, a section head at the IAEA, warned in 1997 that the level of incentive required for market driven research and development will actually rise. Because production costs are not expected to decrease and because of the continued emphasis companies give to short-term profits, "a regional breakdown for 11 world regions indicates that neither hydrocarbon resource availability nor costs are likely to become forces that automatically would help wean the global energy system from the use of fossil fuel during the next century."

The problems of privately funded research and development are not unique to peak oil mitigation. Bronwyn H. Hall, graduate economics professor at the Haas School of Business, points out that, "even if problems associated with incomplete appropriability of the returns to R&D are solved using intellectual property protection, subsidies, or tax incentives, it may still be difficult or costly to finance R&D using capital from sources external to the firm or entrepreneur. That is, there is often a wedge, sometimes large, between the rate of return required by an entrepreneur investing his own funds and that required by external investors." The severity of the problem for energy is echoed in the International Energy Agency's latest report.

In the US, transportation by car is guided more by the government than by an invisible hand. Roads and the interstate highway system were built by local, state and federal governments and paid for by income taxes, property taxes, fuel taxes, and tolls. The Strategic Petroleum Reserve is designed to offset market imbalances. Municipal parking is frequently subsidized. Emission standards regulate pollution by cars. US fuel economy standards exist but are not high enough to have effect. There is also a gas guzzler tax of limited scope. The United States offers tax credits for certain vehicles and these frequently are hybrids or compressed natural gas cars.

In order to be profitable, many alternatives to oil require the price of oil to remain above some level. Investors in these alternatives must gamble with the limited data on oil reserves available. This imperfect information can lead to a market failure caused by a move by nature. One explanation for this is Hotelling's rule for non-renewable resources. Even with perfect information the price of oil correlates with spare capacity and spare capacity does not warn of a peak. For example, in the early 1960s (10 years before oil production peaked in the United States), there was enough spare capacity in US production that Hubbert's predicted peak of 1966-1971 was "at the very least completely unrealistic to most people," preventing the necessary steps being taken to mitigate the situation. The absence of accurate information about spare production capacity exacerbates the current situation.

Lester Brown believes this problem might be solved by the government establishing a price floor for oil. A tax shift raising gas taxes is the same idea. Opponents of such a price floor argue that the markets would distrust the government's ability to keep the policy when oil prices are low.

In 2007, a Pentagon Report, "Space-Based Solar Power: An Opportunity for Strategic Security" proposed Space-Based Solar Power as a macro solution to peak oil and fossil fuel depletion. Recently a proposal for US leadership in SBSP won the SECDEF D3 competition. Engineer Keith Henson discussed the scale in "Dollar a Gallon Gasoline". Mike Snead has recently assessed prospects for US fossil fuels and SSP in "US fossil fuel energy insecurity and space solar power". Snead and Henso recently put out a video.

Implications of an unmitigated world peak

Oil depletion scenarios

According to the Hirsch report prepared for the U.S. Department of Energy in 2005, a global decline in oil production would have serious social and economic implications without due preparation. Initially, an unmitigated peak in oil production would manifest itself as rapidly escalating prices and a worldwide energy crisis. While past oil shortages stemmed from a temporary insufficiency of supply, crossing Hubbert's Peak means that the production of oil continues to decline, so demand must be reduced to meet supply. If alternatives or conservation (orderly demand destruction) are not forthcoming, then disorderly demand destruction will occur, with the possible effect that the many products and services produced with oil become scarcer, leading to lower living standards.

• Air travel, using roughly 7% of world oil consumption, would be one of the affected services. The energy density of hydrocarbons and the power density of a jet engine are so necessary for aviation that hydrocarbon fuels are nearly impossible to replace with electricity, to an extent beyond any other common mode of transport.
• A US Army Corps of Engineers report on the military's energy options states

  The Army and the nation’s heavy use of oil and natural gas is not well coordinated with either the nation’s or the Earth’s resources and upcoming availability.

• Shipping costs

  On average, a one percent increase in fuel prices leads to a 0.4% increase in total freight rates. Using this rule of thumb, the recent doubling in oil prices has raised averaged freight rates by almost 40%.

Shipping costs are particularly relevant to a country like Japan that has greater food miles.

• Increasing cost of oil for importing countries ultimately reduces those countries' purchase of non-oil goods abroad. The Federal Reserve Bank of San Francisco discusses oil and the US balance of trade:

  Oil prices have almost quadrupled since the beginning of 2002. For an oil-importing country like the U.S., this has substantially increased the cost of petroleum imports. International trade data suggest that this increase has exacerbated the deterioration of the U.S. trade deficit, especially since the second half of 2004.

US indications of economic volatility have manifested themselves in the largest increase in inflation rates in 15 years (Sept. 2005), due mostly to higher energy costs.

• Significant oil producing countries will have a national purchasing advantage over similar countries with no oil to sell. This can result in larger militaries for oil producers or inflation of the price of whatever commodities they purchase. Saudi Arabia purchased US$40 billion worth of arms from the US between 1990 and 2000.
• The United States averaged 464 US gallons (1,760 L) of gas per person in 2004. Therefore, increased gasoline cost will likely make gas reducing alternatives increasingly necessary and common for lower income US residents.

Those who feel that much more drastic imminent social and cultural changes will occur from oil shortages are known as doomers.

Oil shale

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Oil_shale 

 

Oil shale

Sedimentary rock
Combustion of oil shale
Composition
Primary	Kerogen Quartz Feldspar Clay Carbonate Pyrite
Secondary	Uranium Iron Vanadium Nickel Molybdenum

Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced, called shale oil (not to be confused with tight oil—crude oil occurring naturally in shales). Shale oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly than the production of conventional crude oil both financially and in terms of its environmental impact. Deposits of oil shale occur around the world, including major deposits in the United States. A 2016 estimate of global deposits set the total world resources of oil shale equivalent of 6.05 trillion barrels (962 billion cubic metres) of oil in place.

Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis to yield a vapor. Upon cooling the vapor, the liquid shale oil—an unconventional oil—is separated from combustible oil-shale gas (the term shale gas can also refer to gas occurring naturally in shales). Oil shale can also be burned directly in furnaces as a low-grade fuel for power generation and district heating or used as a raw material in chemical and construction-materials processing.

Oil shale gains attention as a potential abundant source of oil whenever the price of crude oil rises. At the same time, oil-shale mining and processing raise a number of environmental concerns, such as land use, waste disposal, water use, waste-water management, greenhouse-gas emissions and air pollution. Estonia and China have well-established oil shale industries, and Brazil, Germany, and Russia also utilize oil shale.

General composition of oil shales constitutes inorganic matrix, bitumens, and kerogen. Oil shales differ from oil-bearing shales, shale deposits that contain petroleum (tight oil) that is sometimes produced from drilled wells. Examples of oil-bearing shales are the Bakken Formation, Pierre Shale, Niobrara Formation, and Eagle Ford Formation.

Geology

Outcrop of Ordovician oil shale (kukersite), northern Estonia

Oil shale, an organic-rich sedimentary rock, belongs to the group of sapropel fuels. It does not have a definite geological definition nor a specific chemical formula, and its seams do not always have discrete boundaries. Oil shales vary considerably in their mineral content, chemical composition, age, type of kerogen, and depositional history and not all oil shales would necessarily be classified as shales in the strict sense. According to the petrologist Adrian C. Hutton of the University of Wollongong, oil shales are not "geological nor geochemically distinctive rock but rather 'economic' term." Their common defining feature is low solubility in low-boiling organic solvents and generation of liquid organic products on thermal decomposition.

Oil shale differs from bitumen-impregnated rocks (oil sands and petroleum reservoir rocks), humic coals and carbonaceous shale. While oil sands do originate from the biodegradation of oil, heat and pressure have not (yet) transformed the kerogen in oil shale into petroleum, that means that its maturation does not exceed early mesocatagenetic.

General composition of oil shales constitutes inorganic matrix, bitumens, and kerogen. While the bitumen portion of oil shales is soluble in carbon disulfide, kerogen portion is insoluble in carbon disulfide and may contain iron, vanadium, nickel, molybdenum, and uranium. Oil shale contains a lower percentage of organic matter than coal. In commercial grades of oil shale the ratio of organic matter to mineral matter lies approximately between 0.75:5 and 1.5:5. At the same time, the organic matter in oil shale has an atomic ratio of hydrogen to carbon (H/C) approximately 1.2 to 1.8 times lower than for crude oil and about 1.5 to 3 times higher than for coals. The organic components of oil shale derive from a variety of organisms, such as the remains of algae, spores, pollen, plant cuticles and corky fragments of herbaceous and woody plants, and cellular debris from other aquatic and land plants. Some deposits contain significant fossils; Germany's Messel Pit has the status of a Unesco World Heritage Site. The mineral matter in oil shale includes various fine-grained silicates and carbonates. Inorganic matrix can contain quartz, feldspars, clays (mainly illite and chlorite), carbonates (calcite and dolomites), pyrite and some other minerals.

Geologists can classify oil shales on the basis of their composition as carbonate-rich shales, siliceous shales, or cannel shales.

Another classification, known as the van Krevelen diagram, assigns kerogen types, depending on the hydrogen, carbon, and oxygen content of oil shales' original organic matter. The most commonly used classification of oil shales, developed between 1987 and 1991 by Adrian C. Hutton, adapts petrographic terms from coal terminology. This classification designates oil shales as terrestrial, lacustrine (lake-bottom-deposited), or marine (ocean bottom-deposited), based on the environment of the initial biomass deposit. Known oil shales are predominantly aquatic (marine, lacustrine) origin. Hutton's classification scheme has proven useful in estimating the yield and composition of the extracted oil.

Resource

Fossils in Ordovician oil shale (kukersite), northern Estonia

As source rocks for most conventional oil reservoirs, oil shale deposits are found in all world oil provinces, although most of them are too deep to be exploited economically. As with all oil and gas resources, analysts distinguish between oil shale resources and oil shale reserves. "Resources" refers to all oil shale deposits, while "reserves", represents those deposits from which producers can extract oil shale economically using existing technology. Since extraction technologies develop continuously, planners can only estimate the amount of recoverable kerogen. Although resources of oil shale occur in many countries, only 33 countries possess known deposits of possible economic value. Well-explored deposits, potentially classifiable as reserves, include the Green River deposits in the western United States, the Tertiary deposits in Queensland, Australia, deposits in Sweden and Estonia, the El-Lajjun deposit in Jordan, and deposits in France, Germany, Brazil, China, southern Mongolia and Russia. These deposits have given rise to expectations of yielding at least 40 liters of shale oil per tonne of oil shale, using the Fischer Assay.

A 2016 estimate set the total world resources of oil shale equivalent to yield of 6.05 trillion barrels (962 billion cubic metres) of shale oil, with the largest resource deposits in the United States accounting more than 80% of the world total resource. For comparison, at the same time the world's proven oil reserves are estimated to be 1.6976 trillion barrels (269.90 billion cubic metres). The largest deposits in the world occur in the United States in the Green River Formation, which covers portions of Colorado, Utah, and Wyoming; about 70% of this resource lies on land owned or managed by the United States federal government. Deposits in the United States constitute more than 80% of world resources; other significant resource holders being China, Russia, and Brazil.

History

Production of oil shale in millions of metric tons, from 1880 to 2010. Source: Pierre Allix, Alan K. Burnham.

Humans have used oil shale as a fuel since prehistoric times, since it generally burns without any processing. Around 3000 BC, "rock oil" was used in Mesopotamia for road construction and making architectural adhesives. Britons of the Iron Age also used to polish it and form it into ornaments.

In the 10th century, the Arab physician Masawaih al-Mardini (Mesue the Younger) described a method of extraction of oil from "some kind of bituminous shale". The first patent for extracting oil from oil shale was British Crown Patent 330 granted in 1694 to three persons named Martin Eele, Thomas Hancock and William Portlock who had "found a way to extract and make great quantities of pitch, tarr, and oyle out of a sort of stone."

Autun oil shale mines

Modern industrial mining of oil shale began in 1837 in Autun, France, followed by exploitation in Scotland, Germany, and several other countries.

Operations during the 19th century focused on the production of kerosene, lamp oil, and paraffin; these products helped supply the growing demand for lighting that arose during the Industrial Revolution. Fuel oil, lubricating oil and grease, and ammonium sulfate were also produced. The European oil-shale industry expanded immediately before World War I due to limited access to conventional petroleum resources and to the mass production of automobiles and trucks, which accompanied an increase in gasoline consumption.

Although the Estonian and Chinese oil-shale industries continued to grow after World War II, most other countries abandoned their projects due to high processing costs and the availability of cheaper petroleum. Following the 1973 oil crisis, world production of oil shale reached a peak of 46 million tonnes in 1980 before falling to about 16 million tonnes in 2000, due to competition from cheap conventional petroleum in the 1980s.

On 2 May 1982, known in some circles as "Black Sunday", Exxon canceled its US$5 billion Colony Shale Oil Project near Parachute, Colorado because of low oil-prices and increased expenses, laying off more than 2,000 workers and leaving a trail of home-foreclosures and small-business bankruptcies. In 1986, President Ronald Reagan signed into law the Consolidated Omnibus Budget Reconciliation Act of 1985 which among other things abolished the United States' Synthetic Liquid Fuels Program.

The global oil-shale industry began to revive at the beginning of the 21st century. In 2003, an oil-shale development program restarted in the United States. Authorities introduced a commercial leasing program permitting the extraction of oil shale and oil sands on federal lands in 2005, in accordance with the Energy Policy Act of 2005.

Industry

Shell's experimental in-situ oil-shale facility, Piceance Basin, Colorado, USA

As of 2008, industry uses oil shale in Brazil, China, Estonia and to some extent in Germany, and Russia. Several additional countries started assessing their reserves or had built experimental production plants, while others had phased out their oil shale industry. Oil shale serves for oil production in Estonia, Brazil, and China; for power generation in Estonia, China, and Germany; for cement production in Estonia, Germany, and China; and for use in chemical industries in China, Estonia, and Russia.

As of 2009, 80% of oil shale used globally is extracted in Estonia, mainly due to the Oil-shale-fired power plants. Oil-shale-fired power plants occur in Estonia, which has an installed capacity of 2,967 megawatts (MW), China (12 MW), and Germany (9.9 MW). Israel, Romania and Russia have in the past run power plants fired by oil shale, but have shut them down or switched to other fuel sources such as natural gas. Jordan and Egypt plan to construct power plants fired by oil shale, while Canada and Turkey plan to burn oil shale along with coal for power generation. Oil shale serves as the main fuel for power generation only in Estonia, where 90.3% of country's electrical generation in 2016 was produced from oil shale.

According to the World Energy Council, in 2008 the total production of shale oil from oil shale was 930,000 tonnes, equal to 17,700 barrels per day (2,810 m³/d), of which China produced 375,000 tonnes, Estonia 355,000 tonnes, and Brazil 200,000 tonnes. In comparison, production of the conventional oil and natural gas liquids in 2008 amounted 3.95 billion tonnes or 82.1 million barrels per day (13.1×10⁶ m³/d).

Extraction and processing

Overview of shale oil extraction.

 

Mining of oil shale. VKG Ojamaa.

Most exploitation of oil shale involves mining followed by shipping elsewhere, after which one can burn the shale directly to generate electricity, or undertake further processing. The most common methods of surface mining involve open pit mining and strip mining. These procedures remove most of the overlying material to expose the deposits of oil shale, and become practical when the deposits occur near the surface. Underground mining of oil shale, which removes less of the overlying material, employs the room-and-pillar method.

The extraction of the useful components of oil shale usually takes place above ground (ex-situ processing), although several newer technologies perform this underground (on-site or in-situ processing). In either case, the chemical process of pyrolysis converts the kerogen in the oil shale to shale oil (synthetic crude oil) and oil shale gas. Most conversion technologies involve heating shale in the absence of oxygen to a temperature at which kerogen decomposes (pyrolyses) into gas, condensable oil, and a solid residue. This usually takes place between 450 °C (842 °F) and 500 °C (932 °F). The process of decomposition begins at relatively low temperatures (300 °C or 572 °F), but proceeds more rapidly and more completely at higher temperatures.

In-situ processing involves heating the oil shale underground. Such technologies can potentially extract more oil from a given area of land than ex-situ processes, since they can access the material at greater depths than surface mines can. Several companies have patented methods for in-situ retorting. However, most of these methods remain in the experimental phase. One can distinguish true in-situ processes (TIS) and modified in-situ processes (MIS). True in-situ processes do not involve mining the oil shale. Modified in-situ processes involve removing part of the oil shale and bringing it to the surface for modified in-situ retorting in order to create permeability for gas flow in a rubble chimney. Explosives rubblize the oil-shale deposit.

Hundreds of patents for oil shale retorting technologies exist; however, only a few dozen have undergone testing. By 2006, only four technologies remained in commercial use: Kiviter, Galoter, Fushun, and Petrosix.

Applications and products

Industry can use oil shale as a fuel for thermal power-plants, burning it (like coal) to drive steam turbines; some of these plants employ the resulting heat for district heating of homes and businesses. In addition to its use as a fuel, oil shale may also serve in the production of specialty carbon fibers, adsorbent carbons, carbon black, phenols, resins, glues, tanning agents, mastic, road bitumen, cement, bricks, construction and decorative blocks, soil-additives, fertilizers, rock-wool insulation, glass, and pharmaceutical products. However, oil shale use for production of these items remains small or only in its experimental stages. Some oil shales yield sulfur, ammonia, alumina, soda ash, uranium, and nahcolite as shale-oil extraction byproducts. Between 1946 and 1952, a marine type of Dictyonema shale served for uranium production in Sillamäe, Estonia, and between 1950 and 1989 Sweden used alum shale for the same purposes. Oil shale gas has served as a substitute for natural gas, but as of 2009, producing oil shale gas as a natural-gas substitute remained economically infeasible.

The shale oil derived from oil shale does not directly substitute for crude oil in all applications. It may contain higher concentrations of olefins, oxygen, and nitrogen than conventional crude oil. Some shale oils may have higher sulfur or arsenic content. By comparison with West Texas Intermediate, the benchmark standard for crude oil in the futures-contract market, the Green River shale oil sulfur content ranges from near 0% to 4.9% (in average 0.76%), where West Texas Intermediate's sulfur content has a maximum of 0.42%. The sulfur content in shale oil from Jordan's oil shales may rise even up to 9.5%. The arsenic content, for example, becomes an issue for Green River formation oil shale. The higher concentrations of these materials means that the oil must undergo considerable upgrading (hydrotreating) before serving as oil-refinery feedstock. Above-ground retorting processes tended to yield a lower API gravity shale oil than the in situ processes. Shale oil serves best for producing middle-distillates such as kerosene, jet fuel, and diesel fuel. Worldwide demand for these middle distillates, particularly for diesel fuels, increased rapidly in the 1990s and 2000s. However, appropriate refining processes equivalent to hydrocracking can transform shale oil into a lighter-range hydrocarbon (gasoline).

Economics

The amount of economically recoverable oil shale is unknown. The various attempts to develop oil shale deposits have succeeded only when the cost of shale-oil production in a given region comes in below the price of crude oil or its other substitutes. According to a survey conducted by the RAND Corporation, the cost of producing a barrel of oil at a surface retorting complex in the United States (comprising a mine, retorting plant, upgrading plant, supporting utilities, and spent shale reclamation), would range between US$70–95 ($440–600/m³, adjusted to 2005 values). This estimate considers varying levels of kerogen quality and extraction efficiency. In order to run a profitable operation, the price of crude oil would need to remain above these levels. The analysis also discusses the expectation that processing costs would drop after the establishment of the complex. The hypothetical unit would see a cost reduction of 35–70% after producing its first 500 million barrels (79 million cubic metres). Assuming an increase in output of 25 thousand barrels per day (4.0×10³ m³/d) during each year after the start of commercial production, RAND predicts the costs would decline to $35–48 per barrel ($220–300/m³) within 12 years. After achieving the milestone of 1 billion barrels (160 million cubic metres), its costs would decline further to $30–40 per barrel ($190–250/m³). Some commentators compare the proposed American oil-shale industry to the Athabasca oil-sands industry (the latter enterprise generated over 1 million barrels (160,000 cubic metres) of oil per day in late 2007), stating that "the first-generation facility is the hardest, both technically and economically".

In 2005, Royal Dutch Shell announced that its in-situ process could become competitive for oil prices over $30 per barrel ($190/m³). A 2004 report by the United States Department of Energy stated that both the Shell technology and technology used in the Stuart Oil Shale Project could be competitive at prices above $25 per barrel, and that the Viru Keemia Grupp expected full-scale production to be economical at prices above $18 per barrel ($130/m³).

To increase efficiency when retorting oil shale, researchers have proposed and tested several co-pyrolysis processes.

A 1972 publication in the journal Pétrole Informations (ISSN 0755-561X) compared shale-based oil production unfavorably with coal liquefaction. The article portrayed coal liquefaction as less expensive, generating more oil, and creating fewer environmental impacts than extraction from oil shale. It cited a conversion ratio of 650 liters (170 U.S. gal; 140 imp gal) of oil per one ton of coal, as against 150 liters (40 U.S. gal; 33 imp gal) of shale oil per one ton of oil shale.

A critical measure of the viability of oil shale as an energy source lies in the ratio of the energy produced by the shale to the energy used in its mining and processing, a ratio known as "Energy Returned on Energy Invested" (EROEI). A 1984 study estimated the EROEI of the various known oil-shale deposits as varying between 0.7–13.3 although known oil-shale extraction development projects assert an EROEI between 3 and 10. According to the World Energy Outlook 2010, the EROEI of ex-situ processing is typically 4 to 5 while of in-situ processing it may be even as low as 2. However, according to the IEA most of used energy can be provided by burning the spent shale or oil-shale gas.

The water needed in the oil shale retorting process offers an additional economic consideration: this may pose a problem in areas with water scarcity.

Environmental considerations

Main article: Environmental impact of the oil shale industry

Mining oil shale involves a number of environmental impacts, more pronounced in surface mining than in underground mining. These include acid drainage induced by the sudden rapid exposure and subsequent oxidation of formerly buried materials, the introduction of metals including mercury into surface-water and groundwater, increased erosion, sulfur-gas emissions, and air pollution caused by the production of particulates during processing, transport, and support activities. In 2002, about 97% of air pollution, 86% of total waste and 23% of water pollution in Estonia came from the power industry, which uses oil shale as the main resource for its power production.

Oil-shale extraction can damage the biological and recreational value of land and the ecosystem in the mining area. Combustion and thermal processing generate waste material. In addition, the atmospheric emissions from oil shale processing and combustion include carbon dioxide, a greenhouse gas. Environmentalists oppose production and usage of oil shale, as it creates even more greenhouse gases than conventional fossil fuels. Experimental in situ conversion processes and carbon capture and storage technologies may reduce some of these concerns in the future, but at the same time they may cause other problems, including groundwater pollution. Among the water contaminants commonly associated with oil shale processing are oxygen and nitrogen heterocyclic hydrocarbons. Commonly detected examples include quinoline derivatives, pyridine, and various alkyl homologues of pyridine (picoline, lutidine).

Water concerns are sensitive issues in arid regions, such as the western US and Israel's Negev Desert, where plans exist to expand oil-shale extraction despite a water shortage. Depending on technology, above-ground retorting uses between one and five barrels of water per barrel of produced shale-oil. A 2008 programmatic environmental impact statement issued by the US Bureau of Land Management stated that surface mining and retort operations produce 2 to 10 U.S. gallons (7.6 to 37.9 l; 1.7 to 8.3 imp gal) of waste water per 1 short ton (0.91 t) of processed oil shale. In situ processing, according to one estimate, uses about one-tenth as much water.

Environmental activists, including members of Greenpeace, have organized strong protests against the oil shale industry. In one result, Queensland Energy Resources put the proposed Stuart Oil Shale Project in Australia on hold in 2004.

Extraterrestrial oil shale

Some comets contain "massive amounts of an organic material almost identical to high grade oil shale," the equivalent of cubic kilometers of such mixed with other material; for instance, corresponding hydrocarbons were detected in a probe fly-by through the tail of Comet Halley during 1986.

Epoch (astronomy)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Epoch_(astronomy) 

In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit.

The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the positions and velocities of astronomical objects in the sky at a given time or times.

Astronomical quantities can be specified in any of several ways, for example, as a polynomial function of the time-interval, with an epoch as a temporal point of origin (this is a common current way of using an epoch). Alternatively, the time-varying astronomical quantity can be expressed as a constant, equal to the measure that it had at the epoch, leaving its variation over time to be specified in some other way—for example, by a table, as was common during the 17th and 18th centuries.

The word epoch was often used in a different way in older astronomical literature, e.g. during the 18th century, in connection with astronomical tables. At that time, it was customary to denote as "epochs", not the standard date and time of origin for time-varying astronomical quantities, but rather the values at that date and time of those time-varying quantities themselves. In accordance with that alternative historical usage, an expression such as 'correcting the epochs' would refer to the adjustment, usually by a small amount, of the values of the tabulated astronomical quantities applicable to a fixed standard date and time of reference (and not, as might be expected from current usage, to a change from one date and time of reference to a different date and time).

Epoch versus equinox

Astronomical data are often specified not only in their relation to an epoch or date of reference but also in their relations to other conditions of reference, such as coordinate systems specified by "equinox", or "equinox and equator", or "equinox and ecliptic" – when these are needed for fully specifying astronomical data of the considered type.

Date-references for coordinate systems

When the data are dependent for their values on a particular coordinate system, the date of that coordinate system needs to be specified directly or indirectly.

Celestial coordinate systems most commonly used in astronomy are equatorial coordinates and ecliptic coordinates. These are defined relative to the (moving) vernal equinox position, which itself is determined by the orientations of the Earth's rotation axis and orbit around the Sun. Their orientations vary (though slowly, e.g. due to precession), and there is an infinity of such coordinate systems possible. Thus the coordinate systems most used in astronomy need their own date-reference because the coordinate systems of that type are themselves in motion, e.g. by the precession of the equinoxes, nowadays often resolved into precessional components, separate precessions of the equator and of the ecliptic.

The epoch of the coordinate system need not be the same, and often in practice is not the same, as the epoch for the data themselves.

The difference between reference to an epoch alone, and a reference to a certain equinox with equator or ecliptic, is therefore that the reference to the epoch contributes to specifying the date of the values of astronomical variables themselves; while the reference to an equinox along with equator/ecliptic, of a certain date, addresses the identification of, or changes in, the coordinate system in terms of which those astronomical variables are expressed. (Sometimes the word 'equinox' may be used alone, e.g. where it is obvious from the context to users of the data in which form the considered astronomical variables are expressed, in equatorial form or ecliptic form.)

The equinox with equator/ecliptic of a given date defines which coordinate system is used. Most standard coordinates in use today refer to 2000 TT (i.e. to 12h on the Terrestrial Time scale on January 1, 2000), which occurred about 64 seconds sooner than noon UT1 on the same date (see ΔT). Before about 1984, coordinate systems dated to 1950 or 1900 were commonly used.

There is a special meaning of the expression "equinox (and ecliptic/equator) of date". When coordinates are expressed as polynomials in time relative to a reference frame defined in this way, that means the values obtained for the coordinates in respect of any interval t after the stated epoch, are in terms of the coordinate system of the same date as the obtained values themselves, i.e. the date of the coordinate system is equal to (epoch + t).

It can be seen that the date of the coordinate system need not be the same as the epoch of the astronomical quantities themselves. But in that case (apart from the "equinox of date" case described above), two dates will be associated with the data: one date is the epoch for the time-dependent expressions giving the values, and the other date is that of the coordinate system in which the values are expressed.

For example, orbital elements, especially osculating elements for minor planets, are routinely given with reference to two dates: first, relative to a recent epoch for all of the elements: but some of the data are dependent on a chosen coordinate system, and then it is usual to specify the coordinate system of a standard epoch which often is not the same as the epoch of the data. An example is as follows: For minor planet (5145) Pholus, orbital elements have been given including the following data:

Epoch 2010 Jan. 4.0 TT . . . = JDT 2455200.5
M 72.00071 . . . . . . . .(2000.0)
n. 0.01076162 .. . . . Peri . 354.75938
a 20.3181594 . . . . . Node . 119.42656
e. 0.5715321 . . . . . Incl .. 24.66109

where the epoch is expressed in terms of Terrestrial Time, with an equivalent Julian date. Four of the elements are independent of any particular coordinate system: M is mean anomaly (deg), n: mean daily motion (deg/d), a: size of semi-major axis (AU), e: eccentricity (dimensionless). But the argument of perihelion, longitude of the ascending node and the inclination are all coordinate-dependent, and are specified relative to the reference frame of the equinox and ecliptic of another date "2000.0", otherwise known as J2000, i.e. January 1.5, 2000 (12h on January 1) or JD 2451545.0.

Epochs and periods of validity

In the particular set of coordinates exampled above, much of the elements has been omitted as unknown or undetermined; for example, the element n allows an approximate time-dependence of the element M to be calculated, but the other elements and n itself are treated as constant, which represents a temporary approximation.

Thus a particular coordinate system (equinox and equator/ecliptic of a particular date, such as J2000.0) could be used forever, but a set of osculating elements for a particular epoch may only be (approximately) valid for a rather limited time, because osculating elements such as those exampled above do not show the effect of future perturbations which will change the values of the elements.

Nevertheless, the period of validity is a different matter in principle and not the result of the use of an epoch to express the data. In other cases, e.g. the case of a complete analytical theory of the motion of some astronomical body, all of the elements will usually be given in the form of polynomials in interval of time from the epoch, and they will also be accompanied by trigonometrical terms of periodical perturbations specified appropriately. In that case, their period of validity may stretch over several centuries or even millennia on either side of the stated epoch.

Some data and some epochs have a long period of use for other reasons. For example, the boundaries of the IAU constellations are specified relative to an equinox from near the beginning of the year 1875. This is a matter of convention, but the convention is defined in terms of the equator and ecliptic as they were in 1875. To find out in which constellation a particular comet stands today, the current position of that comet must be expressed in the coordinate system of 1875 (equinox/equator of 1875). Thus that coordinate system can still be used today, even though most comet predictions made originally for 1875 (epoch = 1875) would no longer, because of the lack of information about their time-dependence and perturbations, be useful today.

Changing the standard equinox and epoch

To calculate the visibility of a celestial object for an observer at a specific time and place on the Earth, the coordinates of the object are needed relative to a coordinate system of current date. If coordinates relative to some other date are used, then that will cause errors in the results. The magnitude of those errors increases with the time difference between the date and time of observation and the date of the coordinate system used, because of the precession of the equinoxes. If the time difference is small, then fairly easy and small corrections for the precession may well suffice. If the time difference gets large, then fuller and more accurate corrections must be applied. For this reason, a star position read from a star atlas or catalog based on a sufficiently old equinox and equator cannot be used without corrections if reasonable accuracy is required.

Additionally, stars move relative to each other through space. Apparent motion across the sky relative to other stars is called proper motion. Most stars have very small proper motions, but a few have proper motions that accumulate to noticeable distances after a few tens of years. So, some stellar positions read from a star atlas or catalog for a sufficiently old epoch require proper motion corrections as well, for reasonable accuracy.

Due to precession and proper motion, star data become less useful as the age of the observations and their epoch, and the equinox and equator to which they are referred, get older. After a while, it is easier or better to switch to newer data, generally referred to a newer epoch and equinox/equator, than to keep applying corrections to the older data.

Specifying an epoch or equinox

Epochs and equinoxes are moments in time, so they can be specified in the same way as moments that indicate things other than epochs and equinoxes. The following standard ways of specifying epochs and equinoxes seem most popular:

• Julian days, e.g., JD 2433282.4235 for January 0.9235, 1950 TT
• Besselian years (see below), e.g., 1950.0 or B1950.0 for January 0.9235, 1950 TT
• Julian years, e.g., J2000.0 for January 1.5, 2000, TT

All three of these are expressed in TT = Terrestrial Time.

Besselian years, used mostly for star positions, can be encountered in older catalogs but are now becoming obsolete. The Hipparcos catalog summary, for example, defines the "catalog epoch" as J1991.25 (8.75 Julian years before January 1.5, 2000, TT, e.g., April 2.5625, 1991 TT).

Besselian years

A Besselian year is named after the German mathematician and astronomer Friedrich Bessel (1784–1846). Meeus defines the beginning of a Besselian year to be the moment at which the mean longitude of the Sun, including the effect of aberration and measured from the mean equinox of the date, is exactly 280 degrees. This moment falls near the beginning of the corresponding Gregorian year. The definition depended on a particular theory of the orbit of the Earth around the Sun, that of Newcomb (1895), which is now obsolete; for that reason among others, the use of Besselian years has also become or is becoming obsolete.

Lieske says that a "Besselian epoch" can be calculated from the Julian date according to

B = 1900.0 + (Julian date − 2415020.31352) / 365.242198781

Lieske's definition is not exactly consistent with the earlier definition in terms of the mean longitude of the Sun. When using Besselian years, specify which definition is being used.

To distinguish between calendar years and Besselian years, it became customary to add ".0" to the Besselian years. Since the switch to Julian years in the mid-1980s, it has become customary to prefix "B" to Besselian years. So, "1950" is the calendar year 1950, and "1950.0" = "B1950.0" is the beginning of Besselian year 1950.

• The IAU constellation boundaries are defined in the equatorial coordinate system relative to the equinox of B1875.0.
• The Henry Draper Catalog uses the equinox B1900.0.
• The classical star atlas Tabulae Caelestes used B1925.0 as its equinox.

According to Meeus, and also according to the formula given above,

• B1900.0 = JDE 2415020.3135 = 1900 January 0.8135 TT
• B1950.0 = JDE 2433282.4235 = 1950 January 0.9235 TT

Julian Dates and J2000

A Julian year is an interval with the length of a mean year in the Julian calendar, i.e. 365.25 days. This interval measure does not itself define any epoch: the Gregorian calendar is in general use for dating. But, standard conventional epochs which are not Besselian epochs have been often designated nowadays with a prefix "J", and the calendar date to which they refer is widely known, although not always the same date in the year: thus "J2000" refers to the instant of 12 noon (midday) on January 1, 2000, and J1900 refers to the instant of 12 noon on January 0, 1900, equal to December 31, 1899. It is also usual now to specify on what time scale the time of day is expressed in that epoch-designation, e.g. often Terrestrial Time.

In addition, an epoch optionally prefixed by "J" and designated as a year with decimals (2000 + x), where x is either positive or negative and is quoted to 1 or 2 decimal places, has come to mean a date that is an interval of x Julian years of 365.25 days away from the epoch J2000 = JD 2451545.0 (TT), still corresponding (in spite of the use of the prefix "J" or word "Julian") to the Gregorian calendar date of January 1, 2000, at 12h TT (about 64 seconds before noon UTC on the same calendar day).) Like the Besselian epoch, an arbitrary Julian epoch is therefore related to the Julian date by

J = 2000 + (Julian date − 2451545.0) ÷ 365.25

The IAU decided at their General Assembly of 1976 that the new standard equinox of J2000.0 should be used starting in 1984. Before that, the equinox of B1950.0 seems to have been the standard.

Different astronomers or groups of astronomers used to define individually, but today standard epochs are generally defined by international agreement through the IAU, so astronomers worldwide can collaborate more effectively. It is inefficient and error-prone if data or observations of one group have to be translated in non-standard ways so that other groups could compare the data with information from other sources. An example of how this works: if a star's position is measured by someone today, they then use a standard transformation to obtain the position expressed in terms of the standard reference frame of J2000, and it is often then this J2000 position which is shared with others.

On the other hand, there has also been an astronomical tradition of retaining observations in just the form in which they were made, so that others can later correct the reductions to standard if that proves desirable, as has sometimes occurred.

The currently-used standard epoch "J2000" is defined by international agreement to be equivalent to:

1. The Gregorian date January 1, 2000, at 12:00 TT (Terrestrial Time).
2. The Julian date 2451545.0 TT (Terrestrial Time).
3. January 1, 2000, 11:59:27.816 TAI (International Atomic Time).
4. January 1, 2000, 11:58:55.816 UTC (Coordinated Universal Time).

Epoch of the day

Over shorter timescales, there are a variety of practices for defining when each day begins. In ordinary usage, the civil day is reckoned by the midnight epoch, that is, the civil day begins at midnight. But in older astronomical usage, it was usual, until January 1, 1925, to reckon by a noon epoch, 12 hours after the start of the civil day of the same denomination, so that the day began when the mean sun crossed the meridian at noon. This is still reflected in the definition of J2000, which started at noon, Terrestrial Time.

In traditional cultures and in antiquity other epochs were used. In ancient Egypt, days were reckoned from sunrise to sunrise, following a morning epoch. This may be related to the fact that the Egyptians regulated their year by the heliacal rising of the star Sirius, a phenomenon which occurs in the morning just before dawn.

In some cultures following a lunar or lunisolar calendar, in which the beginning of the month is determined by the appearance of the New Moon in the evening, the beginning of the day was reckoned from sunset to sunset, following an evening epoch, e.g. the Jewish and Islamic calendars and in Medieval Western Europe in reckoning the dates of religious festivals, while in others a morning epoch was followed, e.g. the Hindu and Buddhist calendars.