Другое : Энергетические ресурсы
Энергетические ресурсы
What is energy.
Everything in the universe is either energy or matter. For us humans, energy is
the means for doing work. Picking up a book, watching TV or launching a Space
Shuttle all needs energy. Without it there would be no life, for all life uses
energy.
Energy, so far as we are concerned, comes from only two sources: the Sun and
the decay of radioactive elements inside the Earth. The Sun radiates its warmth
out to all the planets, but ours happens to be about the right distance away to
be able to support Life. In fact, Life seems to control the temperature of the
planet like a thermostat.
But
what about oil, gas or coal, which also come from inside the Earth? They were
formed because of the energy from ancient sunshine from millions of years ago
driving life on Earth. These have formed 'fossil fuels' or 'non-renewable'
energy sources.
Energy is the power that we use to do things, whether it is thinking about
building a ship or actually building it. Building it needs large amounts of
energy to power blast furnaces to make the steel, mills to roll it and
electricity to weld it to form the ship's structure. That ship, when built, has
engines, which push it through the water. Most energy is not available to us in
a usable form. We have to convert it into another form to make it work for us.
Here
are two examples:
A fast-flowing river is full of energy we
can't use. If you dam it and install turbines, you get electricity.
Coal is just black rock with one odd
property ... it burns. If you burn it, you can warm your home, cook food or
raise steam in a boiler - to make electricity.
Life
needs energy. Life's energy is self-perpetuating only so long as there is
sunshine. Plants can convert it and store it for their next generation (as in
potato tubers, groundnuts, rice or peas). Animals eat the plants or each other,
die and decompose, freeing nutrients for plants again. It is a sustainable
cycle. For hundreds of thousands of years, humans have merely been a part of
this cycle. Then we got clever and discovered that we could use energy other
than from our own muscles to do work for us.
First
we discovered that wind could drive our ships and water could power our mills.
Later, we found that coal could make heat and steam for machinery. Then came
oil and gas and nuclear power, all needed in increasingly large amounts to fuel
our endless appetite for being comfortable and doing things with as little
effort as possible. So we heat our homes, schools and workplaces in the winter.
In the richer countries, most people have a car (or several) so that they can
travel about. Transport guzzles huge amounts of energy - all so that we can
have goods and services when we want them.
Kinds of energy resources.
Almost
all of the energy we use comes from non-renewable sources.
All non-renewable
energy sources create pollution, in part due to their extraction from the crust
of our planet but mainly from their burning. Only two types exist: the fossil
fuels (coal, oil and natural gas) and nuclear fuels (uranium, plutonium and,
for the future, unusual types - isotopes - of hydrogen such as deuterium and
tritium).
Fossil fuels are
useful to us only because they liberate heat energy when we burn the carbon
they contain. "Burning" - combustion - is really oxidation; making
carbon and oxygen combine to liberate heat. Unfortunately for us, the principal
byproduct is carbon dioxide, CO2. Most scientists believe that this
is an important contributor to global warming. The heat from coal, gas and oil
we can use either directly or indirectly to raise steam in boilers and generate
electricity using steam turbines to drive generators. By contrast, properly
managed nuclear fuels liberate no pollution to the atmosphere at all. Accidents
are rare in the nuclear power industry but when they occur, their potential for
long-lasting damage is horrific. The disaster at Chernobyl on April 26, 1986
was by far the world's worst nuclear accident.
Phytoplankton
are tiny floating plants called algae. The commonest are golden or brown
colored diatoms
and din flagellates. Zooplankton are tiny animals,
which eat the phytoplankton but are themselves the main food for fish and some
whales. Oil (petroleum) and natural gas formed by complex decay processes from
microscopic life forms called phytoplankton (phyto=plant) which floated in the world's oceans
millions of years ago. Just like today's phytoplankton, they harnessed the Sun
to photosynthesis and store energy. When these myriads of tiny floating plants
died, they sank to the sea floor and became mixed with muds from distant
rivers, and were gradually buried. Over immense periods of time, the soft
sediments became ever more deeply buried and slowly hardened into rocks. Heat
from the Earth's interior and the weight of the overlying rocks gradually
changed the energy-containing substances in the accumulated plants into
hydrocarbon liquids and gases. Hydrocarbons are simple molecules made up of
carbon and hydrogen atoms joined together in chains or in rings. These
molecules, being light and mobile, migrated upwards through the rocks but
eventually became trapped beneath impermeable rock structures in the Earth's
crust. The oil and gas companies around the world know how to find these
trapped reservoirs and release their contents by drilling holes into them. As
everyone knows, crude oil and gas from these deposits form the basis for the
world's largest energy industry: oil and gas. Much oil and gas production now
comes from underneath the seabed. As the technology for extraction continues to
advance, production becomes possible from deeper and deeper waters. This means that
new oil and gas fields will continue to be found for some years yet so the
early forecasts of oil running dry have proved to be wrong. But we know that
the supplies are limited. We also know that every drop of oil we burn adds to
the monumental environment problems we already have by pumping gases like
carbon dioxide (CO2) into the
atmosphere. Many scientists worry that this continual release of CO2 is an important
cause of global warming. Coal is carbon; so is graphite (lead
pencils) and diamond (a girl's best friend as well as the hardest substance
known). Every living organism is made up of molecules based on carbon. Without
carbon, there would be no life. Coal is the most plentiful fossil fuel and,
unfortunately, the most polluting. Like oil and gas, coal started as living
plants - mostly trees - in low lying swampy areas not much above sea level,
tens or hundreds of millions of years ago. As the trees died, they did not
decompose (as they normally would, returning the carbon locked in their tissues
to the atmosphere). Because of the water logging, normal decay processes
couldn't function. So thick layers of peat built up over thousands of years.
These then became covered in sands or muds as the land subsided. As more
material accumulated above the peat, the water was squeezed out leaving just
carbon-rich plant remains. After millions of years, this slowly changed -
metamorphosis - (like the oil and gas from the plankton) into coal.
Nuclear power
taps the ultimate source of energy, which powers the universe, and its myriads
of stars like our Sun. It exploits the famous E=mc2 [e1] equation, which shows
that matter, can change into energy. Nuclear engineers deliberately arrange to
"split" certain atoms - this is called nuclear fission. When this
happens, some matter gets destroyed - liberating huge amounts of energy. This
energy mostly ends up as heat from which you can make steam to drive turbines
and generators, and make electricity in power stations. In the Sun, atoms of
hydrogen fuse to create helium and liberate the seemingly endless stream of
energy we call sunlight. Without this solar fusion reactor 150 million
kilometers away, our home planet would be a frigid lifeless world. Scientists
hope to reproduce this fusion reaction in a controlled way to yield almost
unlimited energy supplies with far fewer radioactive waste problems. So far,
they've only managed the uncontrolled reactions ... hydrogen bombs. The discovery of
nuclear reactions is a wonderful example of the neutrality or indifference of
science. Like so many other discoveries, humans for good or for ill could
exploit nuclear reactions. The pressures of war caused the ill to be developed
first but out of that development came an industry, which now provides 22% of
electricity supply in the OECD countries. In France, it provides 73%; in the UK
23% and 17% in the USA. And whilst it's true that the two nuclear bombs used in
anger on Japan killed and maimed hundreds of thousands, they have some way to
go to catch up with the hundreds of millions of people who've lost their lives
because of ordinary bombs, high-explosive shells, bullets and mines. Many claim
that the very existence of nuclear weapons has prevented major conflict since
World War 2. But what really scares people - and rightly so - is that modern
nuclear weapons could destroy the entire planet ... if they're ever used in
anger again. So now, there are forces -like the World Court Project - afoot to
make their possession and use illegal throughout the world. On the other hand,
many countries view with disgust the idea that the nuclear "haves"
should keep their weapons whilst making sure that the "have nots"
don't get any; a kind of nuclear imperialism. This is a good reason for making
all such weapons illegal. Otherwise, proliferation is a worry, particularly
since the break-up of the Soviet Union, which has inadvertently made weapons-grade
materials available on the international black market. Sooner or later,
extremists will accumulate enough of this to build a crude device, which could
easily be carried by a vehicle, driven into a major city and detonated. The
prospects are frightening. As in any industry, accidents happen. Serious
accidents can mean the spreading of dangerous radioactivity into the
environment. Several serious accidents have occurred, as everyone knows.
Several other less well-known accidents associated with the race to build
nuclear weapons occurred in the former Soviet Union, causing the contamination
of hundreds of square kilometers of land. Renewable sources - Renewable energy
sources have long been energy's Cinderella. Today, wind power is finally coming
into its own. Denmark, already employing 12,000 people in its wind industry,
intends wind power to produce half its total electricity needs by 2030. Several
major wave power projects are now underway and solar energy is booming in
Germany, the western USA and, in a smaller way, in remoter parts of the South.
Equally important in cold climates is the design of buildings to capture
'passive' energy and retain it through insulation. Other minor renewables
include geothermal power in volcanically active countries like Iceland, while
tidal barrages remain a possibility in the UK and eastern Canada.
People
use some kinds of renewable sources.
At
first, it is wind energy. We have been harnessing the wind's energy for
hundreds of years. From old Holland to farms in the United States, windmills
have been used for pumping water or grinding grain. Today, the windmill's
modern equivalent – a wind turbine – can use the wind's energy to generate
electricity. Wind turbines, like windmills, are mounted on a tower to capture
the most energy. At 100 feet (30 meters) or more aboveground, they can take
advantage of the faster and less turbulent wind. Turbines catch the wind's
energy with their propeller-like blades. Usually, two or three blades are
mounted on a shaft to form a rotor. A blade acts much like an airplane wing.
When the wind blows, a pocket of low-pressure air forms on the downwind side of
the blade. The low-pressure air pocket then pulls the blade toward it, causing
the rotor to turn. This is called lift. The force of the lift is actually much
stronger than the wind's force against the front side of the blade, which is
called drag. The combination of lift and drag causes the rotor to spin like a
propeller, and the turning shaft spins a generator to make electricity. Wind
turbines can be used as stand-alone applications, or they can be connected to a
utility power grid or even combined with a photovoltaic (solar cell) system.
Stand-alone wind turbines are typically used for water pumping or
communications. However, homeowners or farmers in windy areas can also use wind
turbines as a way to cut their electric bills. For utility-scale sources of
wind energy, a large number of wind turbines are usually built close together
to form a wind plant. Several electricity providers today use wind plants to
supply power to their customers.
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