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# exhaustible and inexhaustible resources

From Wikipedia

Oil depletion

Oil depletion occurs in the second half of the production curve of an oil well, oil field, or the average of total world oil production. The Hubbert peak theory makes predictions of production rates based on prior discovery rates and anticipated production rates. Hubbert curves predict that the production curves of non-renewing resources approximate a bell curve. Thus, when the peak of production is passed, production rates enter an exponential decline.

The American Petroleum Institute estimated in 1999 the world's oil supply would be depleted between 2062 and 2094, assuming total world oil reserves at between 1.4 and 2 trillion barrels and consumption at 80 million barrels per day. In 2004, total world reserves were estimated to be 1.25 trillion barrels and daily consumption was about 85 million barrels, shifting the estimated oil depletion year to 2057. A study published in the journal Energy Policy by researchers from Oxford University, however, predicted demand would surpass supply by 2015 (unless constrained by strong recession pressures caused by reduced supply or government intervention).

The United States Energy Information Administration predicted in 2006 that world consumption of oil will increase to 98.3 million barrels per day (mbd) in 2015 and 118 mbd in 2030. With 2009 world oil consumption at 84.4 mbd, reaching the projected 2015 level of consumption would represent an average annual increase between 2009 and 2015 of 2.7% per year while EIA's own figures show declining consumption and declining supplies during the 2005-2009 period.

## Resource availability

The world's oil supply is fixed because petroleum is naturally formed far too slowly to be replaced at the rate at which it is being extracted. Over many millions of years, plankton, bacteria, and other plant and animal matter become buried in sediments on the ocean floor. When conditions are right â€“ a lack of oxygen for decomposition, and sufficient depth and temperature of burial â€“ these organic remains are converted into petroleum compounds, while the sediment accompanying them is converted into sandstone, siltstone, and other porous sedimentary rock. When capped by impermeable rocks such as shale, salt, or igneous intrusions, they form the petroleum reservoirs which are exploited today.

## Production decline models

Oil production decline occurs in a predictable manner based on geological circumstances, governmental policies, and engineering practices. The shape of the decline curve varies depending upon whether one considers a well, a field, a set of fields, or the world.

### Oil well production decline

Oil well production curves typically end in an exponential decline. At natural rates, oil well production curves appear similar to a bell curve, a phenomenon known as the Hubbert curve. The typical decline is a rapid drop in production, and eventually a leveling off to a point at which they no longer produce profitable amounts. Such wells are referred to as marginal or stripper wells.

The shape of production curve of an oil well can be affected by a number of factors:

* Well may be restricted by choice by lack of market demand or government regulation. This flattens the peak of the curve, but will not change the well's total production significantly.
* Hydraulic fracturing (fracing) or acidizing may be used to cause a sharp spike in production, and may increase the recoverable reserves of a given well.
* The field may undergo a secondary or tertiary recovery project, discussed in the next section.

### Oil field production decline

Each individual oil well is a portion of a larger fixed area oil field. As with individual wells, discovery and production amounts of oil fields generally average to a similar bell shaped production curve. Eventually, when the field is completely drilled out, a field's production goes into a sharp decline as the average production of its wells enter decline. As this decline levels off, production can continue at relatively low rates. A number of oil fields in the U.S. have been producing for over 100 years.

Oil field production curves can be modified by a number of factors:

* Production may be restricted by market conditions or government regulation.
* A secondary recovery project, such as water or gas injection, can repressurize the field and improve the production rate temporarily. However, it will not change the total production amount over the life of the field. Eventually the field will go into a steeper than normal decline.
* the field may undergo an enhanced oil recovery project, such as drilling of wells for injection of solvents, carbon dioxide, or steam. This can be very expensive but allows more oil to be coaxed out of the rock, increasing the ultimate production of the field.

### Multi-field production decline

Most oil is found in a small number of very large oil fields. If oil fields are discovered at a constant rate until they have all been found, the combined production of fields will yield a curve such as the one at right. Production starts off slowly, rises faster and faster, then slows down and flattens until it reaches a peak. After the production peak, production enters an exponential decline, eventually flattening out. Oil production may never actually reach zero, but eventually becomes very low. Factors which can modify this curve include:

* Inadequate demand for oil, which reduces steepness of the curve and pushes its peak into the future.
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Distributed generation

Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources.

Currently, industrial countries generate most of their electricity in large centralized facilities, such as fossil fuel (coal, gas powered) nuclear or hydropower plants. These plants have excellent economies of scale, but usually transmit electricity long distances and negatively affect the environment.

### Economies of scale

Most plants are built this way due to a number of economic, health& safety, logistical, environmental, geographical and geological factors. For example, coal power plants are built away from cities to prevent their heavy air pollution from affecting the populace. In addition, such plants are often built near collieries to minimize the cost of transporting coal. Hydroelectric plants are by their nature limited to operating at sites with sufficient water flow. Most power plants are often considered to be too far away for their waste heat to be used for heating buildings.

Low pollution is a crucial advantage of combined cycle plants that burn natural gas. The low pollution permits the plants to be near enough to a city to be used for district heating and cooling.

### Localised generation

Distributed generation is another approach. It reduces the amount of energy lost in transmitting electricity because the electricity is generated very near where it is used, perhaps even in the same building. This also reduces the size and number of power lines that must be constructed.

Typical distributed power sources in a Feed-in Tariff (FIT) scheme have low maintenance, low pollution and high efficiencies. In the past, these traits required dedicated operating engineers and large complex plants to reduce pollution. However, modern embedded systems can provide these traits with automated operation and renewables, such as sunlight, wind and geothermal. This reduces the size of power plant that can show a profit.

## Distributed energy resources

Distributed energy resource (DER) systems are small-scale power generation technologies (typically in the range of 3&nbsp;kW to 10,000&nbsp;kW) used to provide an alternative to or an enhancement of the traditional electric power system. The usual problem with distributed generators are their high costs.

One popular source is solar panels on the roofs of buildings. The production cost is $0.99 to 2.00/W (2007) plus installation and supporting equipment unless the installation is Do it yourself (DIY) bringing the cost to$5.25 to 7.50 (2010). This is comparable to coal power plant costs of $0.582 to 0.906/W (1979), adjusting for inflation. Nuclear power is higher at$2.2 to $6.00/W (2007). Some solar cells ("thin-film" type) also have waste disposal issues, since "thin-film" type solar cells often contain heavy-metal electronic wastes, such as Cadmium telluride (CdTe) and Copper indium gallium selenide (CuInGaSe), and need to be recycled. As opposed to silicon semi-conductor type solar cells which is made from quartz. The plus side is that unlike coal and nuclear, there are no fuel costs, pollution, mining safety or operating safety issues. Solar also has a low duty cycle, producing peak power at local noon each day. Average duty cycle is typically 20%. Another source is small wind turbines. These have low maintenance, and low pollution. Construction costs are higher ($0.80/W, 2007) per watt than large power plants, except in very windy areas. Wind towers and generators have substantial insurable liabilities caused by high winds, but good operating safety. In some areas of the US there may also be Property Tax costs involved with wind turbines that are not offset by incentives or accelerated depreciation.. Wind also tends to be complementary to solar; on days there is no sun there tends to be wind and vice versa. Many distributed generation sites combine wind power and solar power such as Slippery Rock University, which can be [http://view2.fatspaniel.net/FST/Portal/NorthCoastEnergySys/macoskey/HostedAdminView.html monitored online].

Distributed cogeneration sources use natural gas-fired microturbines or reciprocating engines to turn generators. The hot exhaust is then used for space or water heating, or to drive an absorptive chiller for air-conditioning. The clean fuel has only low pollution. Designs currently have uneven reliability, with some makes having excellent maintenance costs, and others being unacceptable.

### Cost factors

Cogenerators are also more expensive per watt than central generators. They find favor because most buildings already burn fuels, and the cogeneration can extract more value from the fuel.

Some larger installations utilize combined cycle generation. Usually this consists of a gas turbine whose exhaust boils water for a From Encyclopedia

Mineral Resources from the Ocean Mineral Resources from the Ocean

Oceans cover 70 percent of Earth's surface, host a vast variety of geological processes responsible for the formation and concentration of mineral resources, and are the ultimate repository of many materials eroded or dissolved from the land surface. Hence, oceans contain vast quantities of materials that presently serve as major resources for humans. Today, direct extraction of resources is limited to salt; magnesium; placer gold, tin, titanium, and diamonds; and fresh water. Ancient ocean deposits of sediments and evaporites now located on land were originally deposited under marine conditions. These deposits are being exploited on a very large scale and in preference to modern marine resources because of the easier accessibility and lower cost of terrestrial resources. Yet the increasing population and the exhaustion of readily accessible terrestrial deposits undoubtedly will lead to broader exploitation of ancient deposits and increasing extraction directly from ocean water and ocean basins . Resources presently extracted from the sea or areas that were formerly in the sea range from common construction materials to high-tech metals to water itself. Chemical analyses have demonstrated that sea water contains about 3.5 percent dissolved solids, with more than sixty chemical elements identified. The limitations on extraction of the dissolved elements as well as the extraction of solid mineral resources are nearly always economic, but may also be affected by geographic location (ownership and transport distance) and hampered by technological constraints (depth of ocean basins). The principal mineral resources presently being extracted and likely to be extracted in the near future are briefly considered here. Salt, or sodium chloride, occurs in sea water at a concentration of about 3 percent and hence constitutes more than 80 percent of the dissolved chemical elements in sea water. The quantity available in all the oceans is so enormous that it could supply all human needs for hundreds, perhaps thousands, of years. Although salt is extracted directly from the oceans in many countries by evaporating the water and leaving the residual salts, most of the nearly 200 million metric tons of salt produced annually is mined from large beds of salt. These beds, now deeply buried, were left when waters from ancient oceans evaporated in shallow seas or marginal basins, leaving residual thick beds of salt; the beds were subsequently covered and protected from solution and destruction. Like the sodium and chlorine of salt, potassium occurs in vast quantities in sea water, but its average concentration of about 1,300 parts per million (or 0.13 percent) is generally too low to permit direct economic extraction. Potassium salts, however, occur in many thick evaporite sequences along with common salt and is mined from these beds at rates of tens of millions of metric tons per year. The potassium salts were deposited when sea water had been evaporated down to about one-twentieth of its original volume. Magnesium, dissolved in sea water at a concentration of about 1,000 parts per million, is the only metal directly extracted from sea water. Presently, approximately 60 percent of the magnesium metal and many of the magnesium salts produced in the United States are extracted from sea water electrolytically. The remaining portion of the magnesium metal and salts is extracted from ancient ocean deposits where the salts precipitated during evaporation or formed during diagenesis . The principal minerals mined for this purpose are magnesite (MgCO3) and dolomite (CaMg[CO3]2). The ocean basins constitute the ultimate depositional site of sediments eroded from the land, and beaches represent the largest residual deposits of sand. Although beaches and near-shore sediments are locally extracted for use in construction, they are generally considered too valuable as recreational areas to permit removal for construction purposes. Nevertheless, older beach sand deposits are abundant on the continents, especially the coastal plains, where they are extensively mined for construction materials, glass manufacture, and preparation of silicon metal. Gravel deposits generally are more heterogeneous but occur in the same manner, and are processed extensively for building materials. Limestones (rocks composed of calcium carbonate) are forming extensively in the tropical to semitropical oceans of the world today as the result of precipitation by biological organisms ranging from mollusks to corals and plants. There is little exploitation of the modern limestones as they are forming in the oceans. However, the continents and tropical islands contain vast sequences of limestones that are extensively mined; these limestones commonly are interspersed with dolomites that formed through diagenetic alteration of limestone. Much of the limestone is used directly in cut or crushed form, but much is also calcined (cooked) to be converted into cement used for construction purposes. Gypsum (calcium sulfate hydrate) forms during evaporation of sea water and thus may occur with evaporite salts and/or with limestones. The gypsum deposits are mined and generally converted into plaster of paris and used for construction. The deep ocean floor contains extremely large quantities of nodules ranging from centimeters to decimeters in diameter (that is, from less than an inch to several inches). Although commonly called manganese nodules, they generally contain more iron than manganese, but do constitute the largest known resource of manganese. Despite the abundance and the wealth of metals contained in manganese nodules (iron, manganese, copper, cobalt, and nickel), no economic way has yet been developed to harvest these resources from the deep ocean floor. Consequently, these rich deposits remain as potential resources for the future. Terrestrial deposits of manganese are still relied on to meet human needs. Complex organic and inorganic processes constantly precipitate phosphate-rich crusts and granules in shallow marine environments. These are the analogs (comparative equivalents) of the onshore deposits being mined in several parts of the world, and represent future potential reserves if land-based deposits become exhausted. Submarine investigations of oceanic rift zones have revealed that rich deposits of zinc and copper, with associated lead, silver, and gold, are forming at the sites of hot hydrothermal emanations commonly called black smokers. These metal-rich deposits, ranging from chimneyto pancake-like, form where deeply circulating sea water has dissolved metals from the underlying rocks and issue out onto the cold seafloor along major fractures. The deposits forming today are not being mined because of their remote locations, but many analogous ancient deposits are being mined throughout the world. Placer deposits are accumulations of resistant and insoluble minerals that have been eroded from their original locations of formation and deposited along river courses or at the ocean margins. The most important of these deposits contain gold, tin, titanium, and diamonds. Today, much of the world's tin and many of the gem diamonds are recovered by dredging near-shore ocean sediments for minerals that were carried into the sea by rivers. Gold has been recovered in the past from such deposits, most notably in Nome, Alaska. Large quantities of placer titanium minerals occur in beach and near-shore sediments, but mining today is confined generally to the beaches or onshore deposits because of the higher costs and environmental constraints of marine mining. The world's oceans, with a total volume of more than 500 million cubic kilometers, hold more than 97 percent of all the water on Earth. However, the 3.5-percent salt content of this water makes it unusable for most human needs. The extraction of fresh water from ocean water has been carried out for many years, but provides only a very small portion of the water used, and remains quite expensive relative to land-based water resources. Technological advances, especially in reverse osmosis , continue to increase the efficiency of fresh-water extrac

Question:We consider Air, sunlight, water etc as a renewable natural resource. But with the increasing scarcity of water especially Drinking Water, do you still think Fresh Water as a non-exhaustible natural resource?

Answers:Here is Michigan it is nearly inexhaustible. Four Great Lakes, 11000+ inland lakes (35000+ bodies of water), many rivers and streams. That said, most of the world has a short supply of water.

Question:does anybody know the characteristics of economic resources 4 a yr 9 assignment?

Answers:they are exhaustable or diminishable, rivalry in consumption, they entail opportunity costs, scarse therefore you cant get them free and not everyhere.

Question:i do intense workouts in karate everyday like sparring but i get exausted 30 sec. in, how can i naturally get more energy other than supplements and carbs.

Answers:My son's keigen get's exhausted after 30 secs of sparring or doing kata's and he's as fit as anything!!!!!! Karate takes a lot of energy and skill anyway, but the best thing is to control your breathing.

Question:I need a two page essay on explaining why air isn't a renewable resource. So, i need a lot of RELIABLE info . thanks!!!

Answers:Air is a combination of several different gasses including nitrogen, oxygen, carbon dioxide, and water vapor...it is difficult to extract the gasses...air doesn't burn either...the oxygen in the air supplies the fuel for combustion, but when the oxygen is exhausted the fire goes out. However, when air moves to become wind it then becomes a renewable resource.