development is the ongoing effort
to provide sustainable energy resources through knowledge, skills, and
constructions. When harnessing energy from primary energy sources and
converting them into more convenient secondary energy forms, such as electrical
energy and cleaner fuel, both emissions (reducing pollution) and
quality (more efficient use) are important.
power: worldwide installed capacity and prediction 1997-2010
on external energy sources
advanced societies have become increasingly vulnerable in their dependence
on external energy sources for transportation, the production of many
manufactured goods, and the delivery of energy services. This energy
allows people, in general, to live under otherwise unfavorable climatic
conditions through the use of heating, ventilation, and/or air
conditioning. Level of dependence of human societies on external energy
sources differs, as does the climate,
traffic congestion, pollution,
production, and greenhouse
gas emissions of each society.
levels of human comfort generally induce increased dependence on external
energy sources. Conversely, comfort can also be realized with lowered
energy consumption by the application of energy efficiency and
conservation approaches. Wise energy use therefore embodies the idea of
balancing human comfort with reasonable energy
consumption levels by researching and implementing effective and
sustainable energy harvesting and utilization measures.
an example of external energy dependence, U.S. President George W. Bush
has stated that "America is addicted to oil, which is often imported
from unstable parts of the world." Another example is the growing
reliance on energy supplies to Europe from Russia.
to energy development
of any given energy source in human societies encounters limits to
quantitative expansion. At the beginning of the 21st century some issues
have achieved global dimension. Principal fossil energy sources, such as oil
and natural gas are approaching production declines that may occur within
the span of a generation. Closely linked to energy development are
concerns about the environmental effects of energy use, such as climate
changes. Energy development issues are part of the much debated
sustainable development problem.
sources are substances or processes with concentrations of energy at a
high enough potential to be feasibly encouraged to convert to lower energy
forms under human control for human benefit. Except for nuclear
fuels, tidal energy and geothermal energy, all terrestrial energy
sources are from current solar insolation or from fossil remains of plant
and animal life that relied directly and indirectly upon sunlight,
respectively. And ultimately, solar
energy itself is the result of the Sun's
nuclear fusion. Geothermal power is the result of the accumulation of
radioactive materials during the formation of Earth that was the byproduct
of a previous supernova event.
fuels, in terms of energy, involve the burning of coal
or hydrocarbon fuels, which are the remains of the decomposition of plants
and animals. Steam power plant combustion heats water to create steam,
which turns a turbine,
which, in turn, generates electricity, waste heat, and pollution.
There are three main types of fossil fuels: coal, petroleum, and natural
it is based on the simple process of combustion, the burning of fossil
fuels can generate large amounts of electricity with a small amount of
fuel. Gas-fired power plants are more efficient than coal fired power
fuels such as coal are readily available and are currently plentiful.
Excluding external costs, coal is less expensive than most other
sources of energy because there are large deposits of coal in the
technology already exists for the use of fossil fuels, though oil and
natural gas are approaching peak production and will require a
transition to other fuels and/or other measures.
used fossil fuels in liquid form such as light crude oil, gasoline,
and liquefied propane gas are easy to distribute.
combustion of fossil fuels leads to the release of pollution into the
atmosphere. A typical coal plant produces:
tons of carbon dioxide (CO2), the primary human cause of global
tons of sulfur dioxide (SO2), the leading cause of acid rain
tons of small airborne particles, which result in chronic
bronchitis, aggravated asthma, and premature death, in addition to
tons of nitrogen oxides (NOx), leading to formation of ozone
(smog) which inflames the lungs, burning lung tissue making people
more susceptible to respiratory illness.
tons of carbon monoxide (CO), resulting in headaches and
additional stress on people with heart disease.
tons of hydrocarbons, volatile organic compounds (VOC), which form
pounds of mercury, where just 1/70th of a teaspoon deposited on a
25-acre lake can make the fish unsafe to eat.
pounds of arsenic, which will cause cancer in one out of 100
people who drink water containing 50 parts per billion.
pounds of lead, 4 pounds of cadmium, other toxic heavy metals, and
trace amounts of uranium.
on fossil fuels from volatile regions or countries creates energy
security risks for dependent countries. Oil dependence in particular
has lead to monopolization, war, and socio-political instability.
are considered non-renewable resources, which will eventually decline
in production and become exhausted, with dire consequences to
societies that remain highly dependent on them. Fossil fuels are
actually slowly forming continuously, but we are using them up at a
rate approximately 100,000 times faster than they are formed.
fossil fuels is becoming more difficult as we consume the most
accessible fuel deposits. Extraction of fossil fuels is becoming more
expensive and more dangerous as mines get deeper and oil
rigs go further out to sea.
of fossil fuels can result in extensive environmental degradation,
such as the strip mining and mountaintop removal of coal.
drilling and transportation of petroleum can result in accidents that
result in the despoilation of hundreds of kilometers of beaches and
the death or elimination of many forms of wildlife in the area.
storage of these fuels can result in accidents with explosions and
poisoning of the atmosphere and groundwater.
hydro energy, the gravitational descent of a river is compressed from a
long run to a single location with a dam or a flume. This creates a
location where concentrated pressure and flow can be used to turn turbines
wheels, which drive a mechanical mill or an electric generator. An
electric generator, when there is excess energy available, can be run
backwards as a motor to pump water back up for later use.
power stations can promptly increase to full capacity, unlike other
types of power stations. This is because water can be accumulated
above the dam and released to coincide with peaks in demand.
can be generated constantly, because there are no outside forces,
which affect the availability of water. This is in contrast to wind,
solar or tidal power, all of which are far less reliable.
power produces no waste or pollution.
is a renewable resource; oil, natural gas, and coal reserves will be
depleted over time.
secures a country's access to energy supplies.
construction of a dam can have a serious environmental impact on the
surrounding areas. The amount and the quality of water
downstream can be affected, which affects plant life both aquatic, and
land-based. Because a river valley is being flooded, the delicate
local habitat of many species are destroyed, while people living
nearby may have to relocate their homes.
can only be used in areas where there is a sufficient supply of water.
submerges large forests (if they have not been harvested). If such
vegetation decayed, it could release methane, a greenhouse gas.
can contain huge amounts of water. As with every energy storage
system, failure of containment can lead to catastrophic results, i.e.
power stations work similar to fossil fuel power plants, except for the
fact that the heat is produced by the reaction of uranium inside a nuclear
reactor. The reactor uses uranium rods, the atoms of which are split in
the process of fission, releasing a large amount of energy. The process
continues as a chain reaction with other nuclei takes place. The heat
released heats water to create steam, which spins a turbine, producing
cost of making nuclear power, with current legislation, is about the
same as making coal power, which is considered very inexpensive (see
Economics of new nuclear power plants). If a carbon tax is applied,
nuclear does not have to pay anything.
operation of an uncontained nuclear reactor near human settlements can
be catastrophic, as shown by the Chernobyl disaster in the Ukraine
(former USSR), where large areas of land were affected by radioactive
produced from nuclear fission of uranium is both poisonous and highly
radioactive, requiring maintenance and monitoring at the storage
sites. Moreover, the long-term disposal of the long-lived nuclear
waste causes serious problems, since (unless the spent fuel is
reprocessed) it takes from one to three thousand years for the spent
fuel to come back to the natural radioactivity of the uranium ore body
that was mined to produce it.
can be connections between nuclear power and nuclear weapon
proliferation, since both require large-scale uranium enrichment
facilities. While civilian nuclear facilities are normally overseen
internationally by the IAEA, a couple of countries with such
facilities refuse oversight.
fuels are a non-renewable energy source, with unknown high
concentration ore reserves. There is a large amount of trace
concentration nuclear material in seawater and most rocks; however,
extraction from these is not currently economically competitive.
type of energy harnesses the power of the wind to propel the blades of
wind turbines. These turbines cause the rotation of magnets, which creates
electricity. Wind towers are usually built together on wind
power produces no water or air pollution that can contaminate the
environment, because there are no chemical processes involved in wind
power generation. Hence, there are no waste by-products, such as
towers can be beneficial for people living permanently, or
temporarily, in remote areas. It may be difficult to transport
electricity through wires from a power plant to a far-away location
and thus, wind towers can be set up at the remote setting.
power is intermittent in many locations, because consistent wind is
needed to ensure continuous power generation. When the wind speed
decreases, the turbine lingers and less electricity is generated, thus
the production at any time in these places is not fully predictable.
In some areas, however, winds are highly reliable, or seasonably
farms, depending on the location and type of turbine, can negatively
affect bird migration patterns and pose a danger to the birds
themselves. Newer, larger wind turbines have slower moving blades
which are visible to birds.
effect of large scale wind farms on the climate is unknown, just as
the effect of buildings, other manmade structures, and agricultural
windbreaks have unknown effects on the climate through the extraction
of energy from the prevailing wind.
wave energy converter pointing into the waves: it attenuates
waves, gathering more energy than narrow profile suggests
power is the extraction of energy from waves in large bodies of water such
as oceans and large lakes. Wave power is a form of renewable energy that
is on the rise. It should not be confused with Tidal power, which involves
construction of a dam or "power tower" (which is basically a
large tube which waves push air through to create power with turbines),
which are both structures connected to the land. Wave power is harnessed
by other means, including floating objects or machines on the floor of the
body of water.
highly abundant for countries with large coastlines.
minimal effect on the environment.
power is a renewable resource.
cane residue can be used as a biofuel
production involves using garbage or other renewable resources such as corn
or other vegetation, to generate electricity. When garbage decomposes the
methane produced is captured in pipes and later burned to produce
electricity. Vegetation and wood can be burned directly, like fossil
fuels, to generate energy, or processed to form alcohols.
production can be used to burn organic waste products resulting from
agriculture. This type of recycling encourages the philosophy that
nothing on this Earth should be wasted. The result is less demand on
the Earth's resources, and a higher carrying capacity for Earth
because non-renewable fossil fuels are not consumed.
is abundant on Earth and is generally renewable. In theory, we will
never run out of organic waste products as fuel, because we are
continuously producing them. In addition, biomass is found throughout
the world, a fact that should alleviate energy pressures in third
methods of biomass production other than direct combustion of plant
mass, such as fermentation and pyrolysis, are used, there is little
effect on the environment. Alcohols and other fuels produced by these
alternative methods are clean burning and are feasible replacements to
combustion without emissions filtering generally leads to air
pollution similar to that from fossil fuels.
liquid fuels from biomass is generally less cost effective than from
petroleum, since the production of biomass and its subsequent
conversion to alcohols is particularly expensive.
researchers claim that, when biomass crops are the product of
intensive farming, ethanol fuel production results in a net loss of
energy after one accounts for the fuel costs of fertilizer production,
farm equipment, and the distillation process. 
competition with land use for food production.
the other energy sources in this article, hydrogen fuel must be
manufactured with a net loss of energy. When manufactured from natural gas
it is, like gasoline, a derivative fuel; when produced using electricity,
it is a form chemical energy storage as in storage batteries.
In using hydrogen as a fuel, there are two basic alternatives: (1) a fuel
cell can convert the chemicals hydrogen and oxygen
into water, and in the process, produce electricity, or (2) hydrogen can
be burned (less efficiently than in a fuel cell) in an internal combustion
is colorless, odorless and entirely non-polluting, yielding pure water
vapor (with minimal NOx) as exhaust when combusted in air. This
eliminates the direct production of exhaust gases that lead to smog,
and carbon dioxide emissions that enhance the effect of global
is the lightest chemical element and has the best energy-to-weight
ratio of any fuel. Because of this, hydrogen can be economically
competitive with gasoline or diesel
as a transportation
can be produced anywhere; it can be produced domestically from the
decomposition of the most abundant chemical on earth: water.
Consequently, countries do not have to rely on OPEC
countries for fossil fuels. Hydrogen can be produced from domestic
sources and the price can be established within the country.
combined with fuel-cell regeneration 
is more than 50% efficient; more efficient than pumped hydro and many
other forms of mechanical storage.
storage with double-walled tanks is stable over long periods of time;
hydrogen which outgases from the interior can be pumped back in.
than some volcanic emanations, hydrogen does not exist in its pure
form in the environment, as a gas, because Earth's gravity is not
strong enough to hold it at bay at the existing temperature
(temperature provides the escape velocity. Helium also isn't
retained.) There is concern that a hydrogen economy based on
nonhydrocarbon or unreacted hydrogen sources would negatively affect
Earth's overall hydrogen budget due to leaks into the atmosphere, and
then from the atmosphere into outer space.
is impossible to obtain hydrogen gas without expending energy in the
process. There are three ways to manufacture hydrogen;
electrolysis from water - The process of splitting water into
oxygen and hydrogen using electrolysis consumes large amounts of
energy. It has been calculated that it takes 1.4 joules of
electricity to produce 1 joule of hydrogen (Pimentel, 2002).
breaking down hydrocarbons - mainly methane. If oil or gases are
used to provide this energy, fossil fuels are consumed, forming
pollution and nullifying the value of using a fuel cell. It would
be more efficient to use fossil fuel directly.
reacting water with a metal such as Sodium, Potassium, or Boron.
Chemical by-products would be sodium oxide, potassium oxide, and
boron oxide. Processes exist which could recycle these elements
back into their metal form for re-use with additional energy
input, further eroding the energy return on energy invested.
is currently a lack of infrastructure and distribution network
required to support the widespread use of hydrogen as a fuel. It would
cost a lot of money and energy to build hydrogen plants and to replace
every car and bus with a hydrogen engine and fuel tank.
is complicated to handle, store, and transport. It requires heavy,
cumbersome tanks when stored as a gas, and complex insulating bottles
if stored as a cryogenic liquid. If it is needed at a moderate
temperature and pressure, a metal hydride absorber may be needed.
Transport is also a problem, because hydrogen leaks effortlessly from
containers, reducing the efficiency of the fuel. These hassles make
hydrogen power very expensive.
efficient fuel cell designs are expensive since they need Platinum
as a catalyst. If we were to replace every Internal combustion engine
with a Fuel cell then we could potentially use all the Earth's
Platinum reserves in two years.
oil is generated from sunlight and CO2 by plants. It is safer to use and
store than gasoline or diesel as it has a higher flash point. Straight
vegetable oil works in diesel engines if it is heated first. Vegetable oil
can also be transesterified to make biodiesel which burns like normal
CO2 is first taken out of the atmosphere to make the vegetable oil and
then put back after it is burned in the engine, there is no net
increase in CO2. So vegetable oil does not contribute to the problem
of greenhouse gas.
has a high flash point and is safer than most fuels.
to vegetable oil could be relatively easy as biodiesel works where
diesel works, and straight vegetable oil takes relatively minor
World already produces more than 100 billion gallons a year for food
industry, so we have experience making it.
has the potential to produce far more vegetable oil per acre than
for biodiesel around the World is significant and growing.
production methods would require enormous amounts of land to replace
all gasoline and diesel.
in vegetable oil production is already resulting in deforestation.
forest land to vegetable oil production can result in a net increase
of vegetable oils (and vegetation used to make it) will increase
energy involves building a dam
across the opening to a tidal basin, called an estuary. The dam, called a
barrage, is composed of turbines, located within tunnels in the dam that
rotate when a tide comes in, generating electricity.
power is free once the dam is built. This is because tidal power
harnesses the natural power of tides and does not consume fuel. In
addition, the maintenance costs associated with running a tidal
station are relatively low.
are very reliable because it is easy to predict when high and low
tides will occur. The tide goes in and out twice a day usually at the
predicted times. This makes tidal energy easy to maintain, and
positive and negative spikes in energy can be managed.
energy is not strictly "renewable": because all energy
produced from tidal generation results in an equal loss of the earth's
rotational energy it consumes the earth's rotational inertia, very
slightly slowing it down. Tidal power relies on the gravitational pull
of the Moon and the earth's rotation, which pull the sea backwards and
forwards, generating tides.
provides power only for around 10 hours each day, when the tide is
moving in or out of the basin.
barrage construction can affect the transportation system in water. Boats
may not be able to cross the barrage outside of a lock system.
erection of a barrage may affect the aquatic ecosystems surrounding
it. The environment affected by the dam is very wide, altering areas
numerous miles upstream and downstream. For example, many birds rely
on low tides to unearth mud flats, which are used as feeding areas.
energy production is limited to 2.5 terawatts. This is the total
amount of tidal dissipation or the friction measured by the slowing of
the lunar orbit.
Tower, Manchester, England, was clad in PV panels at a cost of £5.5
million, started feeding electricity to the national grid in November 2005
power involves using solar
cells to convert sunlight into electricity, using sunlight hitting
solar thermal panels to convert sunlight to heat water or air, using
sunlight hitting a parabolic mirror to heat water (producing steam), or
using sunlight entering windows for passive solar heating of a building.
In one minute if harnessed, enough solar energy falls on the earth to
provide all humanity enough energy need for a year.
power imparts no fuel costs.
power is a renewable resource. As long as the Sun exists, its energy
will reach Earth.
power generation releases no water or air pollution, because there is
no combustion of fuels.
sunny countries, solar power can be used in remote locations, like a
wind turbine. This way, isolated places can receive electricity, when
there is no way to connect to the power lines from a plant.
energy can be used very efficiently for heating (solar ovens, solar
water and home heaters) and daylighting.
is free to produce but panels can be costly.
power is not always completely predictable because it depends on the
amount of sunlight that reaches the Earth at any given time. This
precludes solar power generation during the night when sunlight does
not reach the part of the Earth in which the cell is located and
limits solar power generation when cloud cover scatters portions of
the electromagnetic spectrum. To solve this deficiency solar
generators can be coupled to a hydroelectric power plant through the
power grid. Excess power generated by solar cells during the day can
be used to pump water above the dam. The hydroelctric power plant then
supplies the power at night.
forms of solar power are not currently cost competitive. A
photovoltaic power station is expensive to build, about 10% efficient,
and the energy payback time - the time necessary for producing the
same amount of energy than needed for building the power device - for
photovoltaic cells is between 1.8 and 3.3 years, depending primarily
energy harnesses the heat energy present underneath the Earth. The hot
rocks heat water to produce steam. When holes are drilled in the region,
the steam that shoots up is purified and is used to drive turbines, which
power electric generators.
energy does not produce air or water pollution if performed correctly
a geothermal power station is implemented, the energy produced from
the station is practically free. A small amount of energy is required
in order to run a pump, although this pump can be powered by excess
energy generated at the plant.
power stations are relatively small, and have a lesser impact on the
environment than tidal or hydroelectric plants. Because geothermal
technology does not rely on large bodies of water, but rather, small,
but powerful jets of water, like geysers, large generating stations
can be avoided without losing functionality.
energy is only sufficient as source of power in certain areas of the
world. These regions require the presence of hot rocks near the
surface to warm the water. The depth of these rocks must be shallow
enough that one can drill down to them, and the type of rock also
plays a role as it must be easy to drill through.
geothermal sites are prone to running out of steam, when their water
is not heated at a high enough temperature to generate steam pressure.
This can render the site useless in terms of energy production for
holes underground may release hazardous gases and minerals from deep
inside the Earth. It can be problematic to dispose of these subsidiary
products in a safe manner.
deep holes and pumping water into them may cause unexpected seismic
events, such as earthquakes, in the surrounding area.
new sources of energy are only rarely discovered or made possible by new
technology, distribution technology continually evolves. The use of fuel
cells in cars, for example, is an anticipated delivery technology. This
section presents some of the more common delivery technologies that have
been important to historic energy development. They all rely in some way
on the energy sources listed in the previous section.
is a flexible delivery technology that is used in the whole range of
energy development regimes from primitive to highly advanced.
Currently, coal, petroleum and their derivatives are delivered by
shipping via boat, rail, or road. Petroleum and natural gas may also
be delivered via pipeline. Refined hydrocarbon fuels such as gasoline
and LPG may also be delivered via aircraft.
Natural gas pipelines must maintain a certain minimum pressure to
Grid: towers and cables distribute power
grids are the networks used to transmit and distribute power from
production source to end user, when the two may be hundreds of
kilometres away. Sources include electrical generation plants such as
a nuclear reactor, coal burning power plant, etc. A combination of
sub-stations, transformers, towers, cables, and piping are used to
maintain a constant flow of electricity.
may suffer from transient blackouts and brownouts, often due to
weather damage. During certain extreme space
weather events solar wind can interfere with transmissions.
also have a predefined carrying capacity or load that cannot safely be
exceeded. When power requirements exceed what's available, failures
are inevitable. To prevent problems, power is then rationed.
countries such as Canada,
are among the highest per capita consumers of electricity in the
world, which is possible thanks to a widespread electrical
distribution network. The US grid is one of the most advanced,
although infrastructure maintenance is becoming a problem. The
electrical power industry is one of the most heavily subsidized.
provides a realtime overview of the electricity supply and demand for California,
Texas, and the Northeast of the US. African countries with small scale
electrical grids have a correspondingly low annual per capita usage of
electricity. One of the most powerful power grids in the world
supplies power to the state of Queensland, Australia.
most fuels can be stored, electricity in itself cannot. For that reason,
many methods of energy storage have been developed, which transform
electrical energy into other forms of energy. A method of energy storage
may be chosen based on stability, ease of transport, ease of energy
release, or ease of converting free energy from the natural form to the
natural forms of energy are found in stable chemical compounds such as
fossil fuels. Most systems of chemical energy storage result from biological
activity, which store energy in chemical bonds. Man-made forms of
chemical energy storage include hydrogen fuel, batteries and
explosives such as cordite and dynamite.
can be used to store energy, by using excess energy to pump water into
the reservoir. When electrical energy is required, the process is
reversed. The water then turns a turbine, generating electricity.
Hydroelectric power is currently an important part of the world's
energy supply, generating one-fifth of the world's electricity. :.
example of gravitational energy storage is the counter-weight on
energy may be stored in capacitors. These are often used to produce
high intensity releases of energy (such as a camera's flash)
may also be stored pressurized gases or alternatively in a vacuum.
Compressed air, for example, may be used to operate vehicles and
power tools. Large scale compressed air energy storage facilities
are used to smooth out demands on electricity generation by
providing energy during peak hours and storing energy during
off-peak hours. Such systems save on expensive generating capacity
since it only needs to meet average consumption rather than peak
can also be stored in mechanical systems such as springs or
flywheels. Flywheel energy storage is currently being used for
uninterruptible power supplies.
consumption from 1989 to 1999
production from 1989 to 1999
consumption per capita (2001). Red hues indicate increase, green
hues decrease of consumption during the 1990s
from current knowledge to future energy development offer a choice of
energy futures. Some predictions parallel the Malthusian catastrophe
hypothesis. Numerous are complex models based scenarios as pioneered by Limits
to Growth. Modelling approaches offer ways to analyze diverse
strategies, and hopefully find a road to rapid and sustainable development
of humanity. Short term energy crises are also a concern of energy
technologies for new energy sources, such as new renewable energy
technologies, nuclear fission and fusion are promising, but need sustained
research and development, including consideration of possible harmful side
effects. Artificial Photosynthesis is another energy technology being
researched and developed.
J. 2004. "Emergency
preparedness and response: compensating victims of a nuclear
accident." Journal of Hazardous Materials, Volume 111, Issues
1-3, July, 89-96.
S. and K. Kaygusuz, Renewable Energy for a Clean and Sustainable
Future, Energy Sources 26, 1119 (2004).
analysis of Power Systems, UIC Nuclear Issues Briefing Paper 57
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