Chapter 4 Natural Resources. Natural resources (economically referred to as land or raw materials)...
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Transcript of Chapter 4 Natural Resources. Natural resources (economically referred to as land or raw materials)...
绿色化学电子教案
绿色化学电子教案
Chapter 4 Natural Resources Chapter 4 Natural Resources
绿色化学电子教案
绿色化学电子教案
Natural resources (economically referred to as land or
raw materials) occur naturally within environments that
exist relatively undisturbed by mankind, in a natural form.
A natural resource is often characterized by amounts of
biodiversity existent in various ecosystems. Natural
resources are derived from the environment. This is
currently restricted to the environment of Earth yet the
theoretical possibility remains of extracting them from
outside the planet, such as the asteroid belt. Many of
them are essential for our survival while others are used
for satisfying our wants. Natural resources may be further
classified in different ways.
5.1 Natural resources
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绿色化学电子教案
On the basis of origin, resources may be divided into:Considering their stage of development, natural
resources may be referred to in the following ways: Biotic - Biotic resources are obtained from the
biosphere, such as forests and their products, animals, birds and their products, fish and other marine organisms. Mineral fuels such as coal and petroleum are also included in this category because they are formed from decayed organic matter.
Abiotic - Abiotic resources include non-living things. Examples include land, water, air and ores such as gold, iron, copper, silver etc.
Classification
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绿色化学电子教案
Considering their stage of development, natural resources may be referred to in the following ways:Potential Resources - Potential resources are those that exist in a region and may be used in the future. For example, petroleum may exist in many parts of India, having sedimentary rocks but until the time it is actually drilled out and put into use, it remains a potential resource.Actual Resources are those that have been surveyed, their quantity and quality determined and are being used in present times. The development of an actual resource, such as wood processing depends upon the technology available and the cost involved. That part of the actual resource that can be developed profitably with available technology is called a reserve.
绿色化学电子教案
绿色化学电子教案
With respect to renewability, natural resources can be categorized as follows:Renewable resources are ones that can be replenished or reproduced easily. Some of them, like sunlight, air, wind, etc., are continuously available and their quantity is not affected by human consumption. Many renewable resources can be depleted by human use, but may also be replenished, thus maintaining a flow. Some of these, like agricultural crops, take a short time for renewal; others, like water, take a comparatively longer time, while still others, like forests, take even longer.Non-renewable resources are formed over very long geological periods. Minerals and fossil fuels are included in this category. Since their rate of formation is extremely slow, they cannot be replenished once they get depleted. Of these, the metallic minerals can be re-used by recycling them. But coal and petroleum cannot be recycled.
绿色化学电子教案
绿色化学电子教案
Some examples of natural resources include the following:Air, wind and atmosphere
Animals Coal, fossil fuels, rock and mineral resources
SoilsWater, oceans, lakes, groundwater and rivers
绿色化学电子教案
绿色化学电子教案
In recent years, the depletion of natural resources and attempts
to move to sustainable development has been a major focus of
development agencies. This is a particular concern in rainforest
regions, which hold most of the Earth's natural biodiversity -
irreplaceable genetic natural capital. Conservation of natural
resources is the major focus of natural capitalism,
environmentalism, the ecology movement, and green politics.
Some view this depletion as a major source of social unrest and
conflicts in developing nations.
Depletion
绿色化学电子教案
绿色化学电子教案
Mining, petroleum extraction, fishing, hunting, and forestry
are generally considered natural-resource industries.
Agriculture is considered a man-made resource. Theodore
Roosevelt, a well-known conservationist and former
United States president, was opposed to unregulated
natural resource extraction. The term is defined by the
United States Geological Survey as "The Nation's natural
resources include its minerals, energy, land, water, and
biota.
绿色化学电子教案
绿色化学电子教案
5.2 Energy resources and consumption
Despite advances in efficiency and sustainability, of all the
energy harnessed since the industrial revolution, more than
half has been consumed in the last two decades.However,
when considering this fact, it should not be overlooked that
this is primarily the result of global increases in the standard
of living and of the increase in world population, and not as a
failing of energy management as a whole.
Most of the world's energy resources are from the sun's rays
hitting earth. Some of that energy has been preserved as fossil
energy, some is directly or indirectly usable; for example, via
wind, hydro- or wave power.
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绿色化学电子教案
Fossil fuels The twentieth century saw a rapid twentyfold increase in the use of fossil fuels. Between 1980 and 2006, the worldwide annual growth rate was 2%.According to the US Energy Information Administration's 2006 estimate, the estimated 471.8 EJ total consumption in 2004 was divided as follows, with fossil fuels supplying 86% of the world's energy:
绿色化学电子教案
绿色化学电子教案
Coal fueled the industrial revolution in the 18th and 19th century.
With the advent of the automobile, airplanes and the spreading
use of electricity, oil became the dominant fuel during the
twentieth century. The growth of oil as the largest fossil fuel was
further enabled by steadily dropping prices from 1920 until 1973.
From 2003 to 2008, coal, which is one of the dirtiest sources of energy, was the fastest growing fossil fuel..
绿色化学电子教案
绿色化学电子教案
Coal is the most abundant and burned fossil fuel. This was the
fuel that launched the industrial revolution and has continued to
grow in use; China, which already has many of the world's most
polluted cities, was in 2007 building about two coal fired power
plants every week. Coal is the fastest growing fossil fuel and its
large reserves would make it a popular candidate to meet the
energy demand of the global community, short of global
warming concerns and other pollutants.
Coal
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绿色化学电子教案
According to the International Energy Agency the proven
reserves of coal are around 909 billion tonnes, which could
sustain the current production rate for 155 years, although at a
5% growth per annum this would be reduced to 45 years, or until
2051. With the Fischer-Tropsch process it is possible to make
liquid fuels such as diesel and jet fuel from coal. In the United
States, 49% of electricity generation comes from burning coal.
绿色化学电子教案
绿色化学电子教案
It is estimated that there may be 57 ZJ of oil reserves on Earth
(although estimates vary from a low of 8 ZJ, consisting of
currently proven and recoverable reserves, to a maximum of
110 ZJ) consisting of available, but not necessarily recoverable
reserves, and including optimistic estimates for unconventional
sources such as tar sands and oil shale. Current consensus
among the 18 recognized estimates of supply profiles is that the
peak of extraction will occur in 2020 at the rate of 93-million
barrels per day (mbd). Current oil consumption is at the rate of
0.18 ZJ per year (31.1 billion barrels) or 85-mbd.
Oil
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绿色化学电子教案
There is growing concern that peak oil production may be reached in the near future, resulting in severe oil price increases. A 2005 French Economics, Industry and Finance Ministry report suggested a worst-case scenario that could occur as early as 2013. There are also theories that peak of the global oil production may occur in as little as 2–3 years. The ASPO predicts peak year to be in 2010. Some other theories present the view that it has already taken place in 2005. World crude oil production (including lease condensates) according to US EIA data decreased from a peak of 73.720 mbd in 2005 to 73.437 in 2006, 72.981 in 2007, and 73.697 in 2008. According to peak oil theory, increasing production will lead to a more rapid collapse of production in the future, while decreasing production will lead to a slower decrease, as the bell-shaped curve will be spread out over more years.
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绿色化学电子教案
As of December 2009, the world had 436 reactors. Since
commercial nuclear energy began in the mid 1950s, 2008
was the first year that no new nuclear power plant was
connected to the grid, although two were connected in
2009.
Annual generation of nuclear power has been on a slight
downward trend since 2007, decreasing 1.8% in 2009 to
2558 TWh with nuclear power meeting 13–14% of the
world's electricity demand.
Nuclear power
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绿色化学电子教案
The International Atomic Energy Agency estimates the
remaining uranium resources to be equal to 2500 ZJ. This
assumes the use of breeder reactors which are able to create
more fissile material than they consume. IPCC estimated
currently proved economically recoverable uranium deposits
for once-through fuel cycles reactors to be only 2 ZJ. The
ultimately recoverable uranium is estimated to be 17 ZJ for
once-through reactors and 1000 ZJ with reprocessing and fast
breeder reactors.
Nuclear fission
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绿色化学电子教案
Resources and technology do not constrain the capacity of
nuclear power to contribute to meeting the energy demand for
the 21st century. However, political and environmental
concerns about nuclear safety and radioactive waste started to
limit the growth of this energy supply at the end of last
century, particularly due to a number of nuclear accidents.
Concerns about nuclear proliferation (especially with
plutonium produced by breeder reactors) mean that the
development of nuclear power by countries such as Iran and
Syria is being actively discouraged by the international
community.
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绿色化学电子教案
Fusion power is the process driving the sun and other stars. It generates large quantities of heat by fusing the nuclei of hydrogen or helium isotopes, which may be derived from seawater. The heat can theoretically be harnessed to generate electricity. The temperatures and pressures needed to sustain fusion make it a very difficult process to control. Fusion is theoretically able to supply vast quantities of energy, with relatively little pollution. Although both the United States and the European Union, along with other countries, are supporting fusion research (such as investing in the ITER facility), according to one report, inadequate research has stalled progress in fusion research for the past 20 years.
Nuclear fusion
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绿色化学电子教案
绿色化学电子教案
绿色化学电子教案
In 2008, renewable energy supplied around 19% of the
world's energy consumption. The renewables sector
has been growing significantly since the last years of
the 20th century, and in 2009 the total new investment
was estimated to have been 150 billion US dollars.
This resulted in an additional 80 GW of capacity
during the year.
Renewable energy
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绿色化学电子教案
Renewable energy sources are even larger than the traditional
fossil fuels and in theory can easily supply the world's energy
needs. 89 PW of solar power falls on the planet's surface.
While it is not possible to capture all, or even most, of this
energy, capturing less than 0.02% would be enough to meet
the current energy needs. Barriers to further solar generation
include the high price of making solar cells and reliance on
weather patterns to generate electricity.
Solar energy
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绿色化学电子教案
Current solar generation does not produce electricity at night,
which is a particular problem in high northern and southern
latitude countries; energy demand is highest in winter, while
availability of solar energy is lowest. This could be overcome
by buying power from countries closer to the equator during
winter months, and may also be addressed with technological
developments like Infrared Solar Panel systems which can
capture energy in cloudy conditions and even at night.
Globally, solar generation is the fastest growing source of
energy, seeing an annual average growth of 35% over the past
few years. Japan, Europe, China, U.S. and India are the major
growing investors in solar energy.
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绿色化学电子教案
The available wind energy estimates range from 300 TW to
870 TW. Using the lower estimate, just 5% of the available
wind energy would supply the current worldwide energy needs.
Most of this wind energy is available over the open ocean. The
oceans cover 71% of the planet and wind tends to blow more
strongly over open water because there are fewer obstructions.
Wind power
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绿色化学电子教案
At the end of 2005, 0.3 GW of electricity was produced by tidal power. Due to the tidal forces created by the Moon (68%) and the Sun (32%), and the Earth's relative rotation with respect to Moon and Sun, there are fluctuating tides. These tidal fluctuations result in dissipation at an average rate of about 3.7 TW.
Another physical limitation is the energy available in the tidal fluctuations of the oceans, which is about 0.6 EJ. Therefore, this limits the available tidal energy to around 0.8 TW (20% of the dissipation rate) in order not to disturb the tidal dynamics too much. Waves are derived from wind, which is in turn derived from solar energy, and at each conversion there is a drop of about two orders of magnitude in available energy. The total power of waves that wash against our shores add up to 3 TW.
Wave and tidal power
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绿色化学电子教案
Waves are derived from wind,
which is in turn derived from
solar energy, and at each
conversion there is a drop of
about two orders of magnitude in
available energy. The total power
of waves that wash against our
shores add up to 3 TW.
绿色化学电子教案
绿色化学电子教案
Worldwide hydroelectricity installed capacity reached 816 GW in 2005, consisting of 750 GW of large plants, and 66 GW of small hydro installations. Large hydro capacity totaling 10.9 GW was added by China, Brazil, and India during the year, but there was a much faster growth (8%) small hydro, with 5 GW added, mostly in China where some 58% of the world's small hydro plants are now located. China is the largest hydropower producer in the world, and continues to add capacity. In the Western world, although Canada is the largest producer of hydroelectricity in the world, the construction of large hydro plants has stagnated due to environmental concerns. The trend in both Canada and the United States has been to micro hydro because it has negligible environmental impacts and opens up many more locations for power generation.
Hydropower
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绿色化学电子教案
Until the beginning of the nineteenth century biomass was the predominant fuel, today it has only a small share of the overall energy supply. Electricity produced from biomass sources was estimated at 44 GW for 2005. Biomass electricity generation increased by over 100% in Germany, Hungary, the Netherlands, Poland, and Spain. A further 220 GW was used for heating (in 2004), bringing the total energy consumed from biomass to around 264 GW. The use of biomass fires for cooking is excluded. World production of bioethanol increased by 8% in 2005 to reach 33 billion litres (8.72 billion US gallons), with most of the increase in the United States, bringing it level to the levels of consumption in Brazil. Biodiesel increased by 85% to 3.9 billion litres (1.03 billion US gallons), making it the fastest growing renewable energy source in 2005. Over 50% is produced in Germany.
Biomass and biofuels
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绿色化学电子教案
Geothermal energy is used commercially in over 70
countries.In the year 2004, 200 PJ (57 TWh) of electricity
was generated from geothermal resources, and an additional
270 PJ of geothermal energy was used directly, mostly for
space heating. In 2007, the world had a global capacity for
10 GW of electricity generation and an additional 28 GW of
direct heating, including extraction by geothermal heat
pumps. Heat pumps are small and widely distributed, so
estimates of their total capacity are uncertain and range up to
100 GW.
Geothermal