Energy - WZ UW
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Transcript Energy - WZ UW
Renewable energy
sources
dr Magdalena Klimczuk-Kochańska
Since Thomas Edison harnessed electricity and Nikolaus A. Otto popularized
the internal combustion engine, energy has received a central role in
commerce and everyday life.
Our current living standard could not be maintained without energy.
As the energy utilization increases "energy problem" in conjunction with the
underlying "environmental problem” continues to be a major topic in energy
engineering, as well as in the energy and environmental policies in the world.
Energy terms
Energy is the amount of work a physical system is capable of performing.
Energy cannot be created, consumed, or destroyed.
The catch is that entropy—the amount of energy not available to perform
useful work— increases every time e.g. someone moves lift a finger, because
energy is dissipated into the universe as heat.
Energy can also be converted or transferred into different forms.
Forms of energy
Kinetic energy is the energy of motion. It is possessed by any moving object.
Gravitational potential energy - energy associated with the gravitational pull
of the Earth (and Sun)
Electrical energy - energy associated with electrical forces which hold
together the atoms and molecules of all materials Incl. chemical energy;
electromagnetic energy; electricity (intermediate form of electrical energy)
Atomic or nuclear energy - energy bound up in the central nuclei of atoms.
Forms of energy
The kinetic energy of moving air molecules can be converted into rotational
energy by the rotor of a wind turbine, and then converted into electrical energy
by a wind turbine generator.
With each conversion, part of the energy from the source is converted into heat
energy.
The thermal efficiency (TE) of an energy source indicates the percentage of its
energy that can be used directly in the next link of the energy conversion system,
rather than being converted into heat.
E.g.
A coal-fired power plant is about 33 % efficient, meaning that it uses 3,000 mega watts
of energy stored in coal to generate 1,000 megawatts of electricity.
The other 2,000 megawatts are lost as heat energy. The TE of a typical car is about 26 %.
Some racing engines have a TE of 34 %.
The photovoltaic cells in solar panels are 7 to 17 % efficient.
Units of energy
Power is the rate of energy transfer per unit of time. Power is measured in
watts or horsepower. Energy is measured in joules (J) or kilowatt hours
(kWh).
A watt is one joule per second, so a 60-watt light bulb uses 60 joules of
energy per second, converting the electric energy into light energy and heat
energy.
One horsepower equals 746 watts. One calorie equals 4.18 joules, the energy
needed to raise the temperature of one gram of water by one degree Celsius.
A British thermal unit (BTU) equals 1,055 joules, the energy needed to raise
one pound of water one degree Fahrenheit. One kilowatt (kW) equals 1,000
watts and one megawatt (mW) equals one million watts.
Units of energy
The petajoule (PJ) is equal to one quadrillion (1015) joules.
210 PJ is equivalent to about 50 megatons of TNT. This is the amount of energy
released by the Tsar Bomba - the largest nuclear bomb - Russia, 1961
https://www.youtube.com/watch?v=RNYe_UaWZ3U
The zettajoule (ZJ) is equal to one sextillion (1021) joules.
The human annual global energy consumption is approximately 0.5 ZJ.
Energy terms
Mentions of energy “production” or “generation” refer to the conversion of
energy into a more usable form.
Energy “loss” means that energy is dissipated as heat, or for some other
reason becomes unavailable for useful work.
The fundamental task of most commercial electricity production is to make
turbines spin and thereby create an electrical current. Both nuclear fission and
coal combustion create steam that turns turbines.
The kinetic energy from wind and falling water turns turbines directly to generate
electricity.
You can generate electricity yourself by turning a properly rigged bicycle wheel or
the crank on some emergency radios.
A photovoltaic cell, in contrast, converts light energy into direct-current electricity
with no moving parts and no emissions.
Energy resources
Fossil energy resources are stocks of energy that have formed during ancient
geologic ages by biologic and/or geologic processes.
fossil biogenous energy resources (i.e. stocks of energy carrier of biological origin)
e.g., hard coal, natural gas, crude oil deposits
fossil mineral energy resources (i.e. stocks of energy carrier of mineral origin or
non-biological origin) e.g., energy contents of uranium deposits and resources to
be used for nuclear fusion processes.
Recent resources are energy resources that are currently generated, for
instance, by biological processes; e.g., the energy contents of biomass and
the potential energy of a natural reservoir.
Energy resources
Available energies or energy carriers can be further subdivided:
Fossil biogenous energy carriers primarily include the energy carriers coal
(lignite and hard coal) as well as liquid or gaseous hydrocarbons (such as
crude oil and natural gas). A further differentiation can be made between
fossil biogenous primary energy carriers (e.g. lignite) and fossil biogenous
secondary energy carriers (e.g. gasoline, Diesel fuel).
Fossil mineral energy carriers comprise all substances that provide energy
derived from nuclear fission or fusion (such as uranium, thorium, hydrogen).
Energy resources
The renewable energy refers to primary energies that are regarded as
inexhaustible in terms of human (time) dimensions.
They are continuously generated by the energy sources solar energy, geothermal
energy and tidal energy.
The energy produced within the sun is responsible for a multitude of other
renewable energies (such as wind and hydropower) as well as renewable energy
carriers (such as solid or liquid biofuels).
The energy content of the waste can only be referred to as renewable if it is of
non-fossil origin (e.g. organic domestic waste, waste from the food processing
industry). Properly speaking, only naturally available primary energies or primary
energy carriers are renewable but not the resulting secondary or final energies or
the related energy carriers. However, in everyday speech secondary and final
energy carriers derived from renewable energy are often also referred to as
renewable.
Energy resources
Renewable energy. ‘Energy obtained from natural and persistent flows of
energy occurring in the immediate environment’. An obvious example is solar
(sunshine) energy, where ‘repetitive’ refers to the 24-hour major period. Note
that the energy is already passing through the environment as a current or
flow, irrespective of there being a device to intercept and harness this power.
Such energy may also be called Green Energy or Sustainable Energy.
Non-renewable energy. ‘Energy obtained from static stores of energy that
remain underground unless released by human interaction’. Examples are
nuclear fuels and fossil fuels of coal, oil and natural gas. Note that the energy
is initially an isolated energy potential, and external action is required to
initiate the supply of energy for practical purposes. To avoid using the
ungainly word ‘non-renewable’, such energy supplies are called finite supplies
or Brown Energy.
Contrast between renewable (green) and
finite (brown) energy supplies. Environmental
energy flow ABC, harnessed energy flow DEF.
Energy sources
There are five ultimate primary sources of useful energy:
1.
The Sun.
2.
The motion and gravitational potential of the Sun, Moon and Earth.
3.
Geothermal energy from cooling, chemical reactions and radioactive decay in the
Earth.
4.
Human-induced nuclear reactions.
5.
Chemical reactions from mineral sources.
Renewable energy derives continuously from sources 1, 2 and 3 (aquifers).
Finite energy derives from sources 1 (fossil fuels), 3 (hot rocks), 4 and 5.
The sources of most significance for global energy supplies are 1 and 4.
Natural energy currents on earth, showing
renewable energy system. Note the great
range of energy flux 1 105 and the dominance
of solar radiation and heat. Units terawatts
1012 W.
For instance, total solar flux absorbed at sea level is about 12 × 1017 W. Thus
the solar flux reaching the Earth’s surface is ∼20 MW per person; 20 MW is the
power of ten very large diesel electric generators, enough to supply all the
energy needs of a town of about 50 000 people.
The maximum solar flux density (irradiance) perpendicular to the solar beam
is about 1 kW m−2 ; a very useful and easy number to remember. In general
terms, a human being is able to intercept such an energy flux without harm,
but any increase begins to cause stress and difficulty.
Interestingly, power flux densities of ∼1kW m−2 begin to cause physical
difficulty to an adult in wind, water currents or waves.
However, the global data of figure are of little value for practical engineering
applications, since particular sites can have remarkably different
environments and possibilities for harnessing renewable energy.
Obviously flat regions, such as Denmark, have little opportunity for hydropower but may have wind power. Yet neighboring regions, for example
Norway, may have vast hydro potential.
Tropical rain forests may have biomass energy sources, but deserts at the
same latitude have none (moreover, forests must not be destroyed so making
more deserts).
Thus practical renewable energy systems have to be matched to particular
local environmental energy flows occurring in a particular region.
All energy systems can be visualized as a series of pipes or circuits through
which the energy currents are channeled and transformed to become useful
in domestic, industrial and agricultural circumstances. Figure is a Sankey
diagram of energy supply, which shows the energy flows through a national
energy system (sometimes called a ‘spaghetti diagram’ because of its
appearance).
Sections across such a diagram can be drawn as pie charts showing primary
energy supply and energy supply to end-use.Note how the total energy enduse is less than the primary supply because of losses in the transformation
processes, notably the generation of electricity from fossil fuels.
Energy flow diagrams for Austria in 2000, with a population of 8.1 million. (a)
Sankey (‘spaghetti’) diagram, with flows involving thermal electricity shown
dashed. (b)–(c) Pie diagrams. The contribution of hydropower and biomass (wood
and waste) is greater than in most industrialized countries, as is the use of heat
produced from thermal generation of electricity (‘combined heat and power’).
Energy use for transport is substantial and very dependent on (imported) oil and
oil products, therefore the Austrian government encourages increased use of
biofuels. Austria’s energy use has grown by over 50% since 1970, although the
population has grown by less than 10%, indicating the need for greater efficiency
of energy use.
Source: International Energy Agency, Energy Balances of OECD countries 2000–2001.
Energy terms
Energy resources
Renewable energy sources can be divided into:
Solar energy available annual energy 3 900 000 000 PJ/year
Planetary energy available annual energy 94 000 PJ/year
Geothermal energy available annual energy 996 000 PJ/year
Energy stored in wind or rain, which can also be technically exploited,
originate from natural energy conversion.
Energy consumption
Global energy consumers receive 42 % of their electricity and 28 % of all
marketed energy from coal.
Petroleum and other liquids (including biofuels) – 34%, are the largest source
of marketed energy, followed by coal, natural gas – 23 %, renewable resources
(other than biofuels) – 9%, and nuclear power – 6%.
Energy consumption
Utilization of renewable energies is not at all new - in the history of mankind
renewable energies have for a long time been the primary possibility of
generating energy.
Industrial Revolution changed the energy trend: lignite and hard coal became
increasingly more important.
Later on, also crude oil gained importance easy transportation & processing,
raw material: Crude oil (primary energy applied today). Natural gas for space
heating, power provision and transportation
Important due to abundantly available and only requires low investments in
terms of energy conversion
As fossil energy carriers increase for energy generation in Industrial countries.
Renewable energy becomes secondary importance of total energy generation
Energy consumption
However, Undesirable Side effects of fossil fuel utilization, increasingly
sensitized to possible environmental and climate effects, realized in the
beginning of 21st Century.
Price increase for fossil fuel energy on the global energy markets in the last
few years
Results: The search for environmental, climate-friendly and social
acceptable, alternatives suitable to cover the energy demand has become
increasingly important.
Utilization of renewable sources of energy.
Energy consumption
Energy consumption
On a regional level these fractions are strongly dependent on local and
national characteristics due to varying national energy politics or available
primary energy resources.
For instance, in Asia the major share of the given demand for fossil primary
energy carriers is covered by coal (this applies in particular to the People’s
Republic of China), whereas this energy carrier is of almost no importance in
regions such as the Middle East.
Loss of energy
Mathematically: Energy= Exergy (Available part)+Anergy (Unavailable part)
The first law of thermodynamics deals with energy which is on a quantity
basis.
The second law of thermodynamics deals with exergy which refers to the
quality of energy.
Exergy is the useful portion of energy that allows us to do work and perform
energy services.
Source: W.A.Hermann, Quantifying global exergy resources, Energy, 31 (12), 2006, p.1685–1702, doi:10.1016/j.energy.2005.09.006
Loss of energy
Energy is conserved, but not all that energy is available to do useful work. So, yes, it has
something to do with reversibility and irreversibility.
Both energy and exergy are things you could compute for ideal systems. For real systems,
the real amount of available energy will depend on some aspects that it's not feasible to
model. But for a real system energy is conserved and exergy is the energy available to do
useful work.
For instance:
The ocean is full of energy, billions of times more than we could ever use, but it's at nearly
room temperature, so it's not available energy.
The center of the earth has lots of thermal energy, at a high temperature, so it would be ideal,
except we can't get to it.
The earth and Moon have lots of kinetic energy, but we can't tie a rope around it and harness
the energy, so it's unavailable.
Sunlight has considerable energy, but the physics make it difficult to impossible to grab more
than 15% of it, and the costs of physical devices per square meter are still pricing that energy
considerably higher than other sources, so that energy is more theoretical than practical.
Renewable energy sources
Solar energy
Solar energy comes from the light of the sun, which means it is a renewable
source of energy. We can use the sun light to create pollution free electricity.
The solar cell is the system used to convert the sunlight energy into electrical
energy
Solar energy
The main source of easily accessible renewable
energy is the sun.
On average the rate of solar radiation
intercepted by the earth’s surface is about 8000
times as large as the average rate of world
primary energy consumption.
Solar energy
Solar energy
Solar radiation is available both directly and indirectly.
Directly as solar radiation directly converted into useful energy, for instance
electricity or heat.
Indirectly in the form of power from wind, biomass, hydro, and marine sources.
Solar energy
Solar thermal signifies the thermal use of solar energy in general.
Conversion of solar energy to heat requires a light-absorbing material, or a
collector, which is able to distribute the absorbed radiant energy over
internal degrees of freedom associated with kinetic energy of motion at the
molecular level.
Absorption of solar energy will rise the temperature of the collector or
transfer energy to a reservoir, if the collector is connected to one.
“Passive” system “natural” heat flow paths between collectors and load
areas.
“Active” system energy is added (pumps, etc.) to bring the collector heat
gain to the load areas.
Solar energy
Solar energy may be converted to electricity by one of two means:
Solar thermal conversion - Conversion of solar radiation to heat that in turn is
added to a thermodynamic cycle to produce mechanical work or electricity.
Photovoltaic conversion - Direct conversion of the solar radiant-energy photons to
electricity without the benefit of a thermodynamic cycle or working fluid. The
term ‘photovoltaic’ is derived by combining two words: the Greek word for light
‘photos’ the name of the electromotive force ‘volt’.
Solar energy
Natural processes transform solar energy into other types of energy that can be
utilized by technical energy converters.
Types of indirect energy
Evaporation
Precipitation
Water flow
Melting of snow
Wave movements
Ocean currents
Biomass production
Heating of Earth’s surface and the atmosphere
Wind.
Hydro energy
Hydro-electric power is currently easily the largest of the Renewable Energy
Sources.
One of the most mature RE technologies.
About 160 EJ is stored in rivers and seas, which is equivalent to roughly 40 % of the
global energy demand, of which about one-quater is technically exploited (Europe
well exploited).
Controversial Hydro-electric power plants have a negative impact on nature and
local conditions.
Hydro energy is derived from flowing water in rivers, water streams in mountains
or from man-made installations where water flows from a high-level reservoir
down through a tunnel and away from the dam.
A dam is built to trap water, usually in a valley where there is an existing lake. •
Water is allowed to flow through tunnels in the dam, to turn turbines and thus
drive generators and the electricity is produced
Hydro energy
Hydro energy
Tidal energy is the energy due to the water waves created in the ocean. The
tidal energy is also called hydropower.
It is a hydropower due to raise and fall of water wave in ocean. The raise and
fall of water wave is due to the gravitational forces of the moon and sun as
well as the revolution of the earth.
The raising and falling waves are used to rotate the turbines and hence the
electricity is produced.
Hydro energy
The ocean tides are the direct consequences of the
gravitational interaction between the Earth, Moon and
Sun.
Planetary energy. The different celestial bodies, in
particular our moon, exchange mutual forces with
Earth.
The motion of the celestial bodies results in
continuously varying forces at any specific point on
the Earth’s surface.
Hydro energy
There are two basic approaches to tidal energy exploitation.
Tidal Barrage Exploiting the cyclic rise and fall of the sea level through
extrainment.
Stillpictures Tidal Stream Generators Harnessing local tidal currents by
turbines.
Hydro energy
Bioenergy
Bioenergy (biomass) is mankind's oldest source of energy.
Humans have been using biomass as an energy source for many thousands of
years.
Wood was the most important material for heating and cooking for a long
time until it was superseded by coal, crude oil and natural gas.
Biomass energy / bioenergy, is the energy stored in non-fossil organic
materials such as wood, straw, vegetable oils and wastes from the forest,
agricultural and industrial sectors.
Bioenergy
Bioenergy is arguably the one truly Renewable Energy Resource
Renewable energy resource - each new crop or harvest represents a partial
renewal of its resource base. (Wood fuel is a RES if “consumption rate” ≤
“renewal rate”.)
Major World Energy Source ’Biomass’ from plants is one of the major world
fuel sources (about 9 % of the global primary energy use, 2001) Biofuels
Interest in biofuels – ethanol and biodiesel – is at an all-time high.
Stored bioenergy can be used on demand.
Bioenergy
Wind power
The history of wind power goes back many centuries: irrigation, land
draining, grain milling, transportation, etc.
More than 100 years ago, wind power had a dominant role in the energy
supply of many countries (mechanical power).
Wind energy is the kinetic energy associated with the movement of
atmospheric air • Wind energy systems convert kinetic energy to more useful
forms of power. • Wind energy systems for irrigation and milling have been in
use since ancient times • From beginning of the 20th century it is being used
to generate electric power.
Wind power
Wind is simple air in motion. Wind is caused by the uneven heating of the
earth’s surface by the sun.
During the day, the air above the land heats up more quickly than the air over
water.
The warm air over the land expands and rises, and the heavier, cooler air
rushes in to take its place, creating winds.
This winds are used to rotate turbine blades which spins the generator to
produce electricity
Wind power
Geothermal energy
Geothermal energy is contained as thermal energy in the Earth’s interior.
The origin of this thermal energy? - gravitational contraction of the earth when it
was formed. - heat from the decay of the small quantities of radioactive materials
contained within earth’s core.
What is the problem? In the Earth’s interior, temperatures are somewhere between
3000°C and 10,000°C. Despite the fact that this heat is present in huge,
practically inexhaustible quantities, it is unevenly distributed, seldom
concentrated, and often at depths too great to be exploited industrially.
Not strictly renewable? If steam or hot water are extracted at a greater rate than
heat is replenished from surrounding forks, a geothermal size will cool down after
a number of years and become exhausted.
Geothermal power stations can utilize geothermal heat and convert it into
electricity and/or feed it into district heating systems (e.g., Old Faithful, the most
famous geyser in Yellowstone)
Geothermal energy
The earth can be compared with egg. The outer layer
of the earth is called crest and the center layer is
called Mantle and inner layer is called Core (Iron).
For every 100 meters you go below ground, the
temperature of the rock increases about 3 degrees
Celsius.
So, if you went about 10,000 feet below ground, the
temperature of the rock would be hot enough to boil
water.
Deep under the surface, water close to the hot rock
can reach temperatures of more than 148°C.
Geothermal energy
This is hotter than boiling water
(100°C). It doesn't turn into steam
because it is not in contact with the air.
When this hot water comes up through
a crack in the earth, we call it a hot
spring and it is used to rotate the
turbines and the electricity is produced.
Geothermal energy
The most active geothermal resources
are usually found along major plate
boundaries where earthquakes and
volcanoes are concentrated.
Most of the geothermal activity in the
world occurs in an area called the Ring
of Fire.
Biofuel
Plants use photosynthesis to grow and produce biomass.
Also known as biomatter, biomass can be used directly as fuel or to produce
liquid biofuel. Agriculturally produced biomass fuels, such as biodiesel,
ethanol and bagasse (often a by-product of sugar cane cultivation) can be
burned in internal combustion engines or boilers.
Typically biofuel is burned to release its stored chemical energy. Research
into more efficient methods of converting biofuels and other fuels into
electricity utilizing fuel cells is an area of very active work.
Liquid biofuel is usually either a bioalcohol such as
such as biodiesel and straight vegetable oil.
Biodiesel can be used in modern diesel vehicles with little or no modification
to the engine and can be made from waste and virgin vegetable and animal
oil and fats (lipids).
ethanol fuel or a bio-oil
Biofuel
Virgin vegetable oils can be used in modified diesel engines.
In fact the Diesel engine was originally designed to run on vegetable oil rather
than fossil fuel. A major benefit of biodiesel is lower emissions.
The use of biodiesel reduces emission of carbon monoxide and other
hydrocarbons by 20 to 40%
Advantage of renewable energy
resources
It is fact that the consumption of conventional sources of energy has caused
more environmental damage than any other human activity.
The use of fossil fuels such as oil and coal produce high concentration harmful
gases in the atmosphere and creates so many problems such as Ozone
depletion and global warming.
The Non-conventional energy sources, such as the sun and wind, can never be
exhausted and therefore are called renewable. They cause fewer emissions
and are available locally.
Consumption of renowable energy
Renewable energy supplies 18% of the
World’s final energy consumption.
Renewables: Traditional biomass Large
hydro “new” renewables
Consumption of renowable energy
Renewable energy comprises about 5% of
global power generating capacity and
supplies about 3,4% of global electricity
production.
Consumption of renowable
energy
In early 2007, the EC adopted new
binding targets for 2020, including 20
percent of final energy and 10 percent
of transport fuels.
Source: REN21, Renewables 2007 – Global
status report.
Applications of renewable energies
solar heat provision by passive systems (i.e. architectural measures to use solar energy),
solar thermal heat provision by active systems (i.e. solar thermal collector systems),
solar thermal electrical power provision (i.e. solar tower plants, solar farm
plants, Dish/Stirling and Dish/Brayton systems, solar chimney plants),
photovoltaic conversion of solar radiation into electrical energy (i.e. photovoltaic systems),
power generation by wind energy (i.e. wind turbines),
power generation by hydropower to provide electrical energy (i.e. hydropower plants),
utilization of ambient air and shallow geothermal energy for heat provision (i.e. utilization of
low thermal heat by means of heat pumps),
utilization of deep geothermal energy resources for heat and/or power provision (i.e.
utilization of the energy stored in deep porous-fractured reservoirs by means of open and
closed systems) and utilization of photosynthetically fixed energy to provide heat, power and
transportation fuels (i.e. energy provision on the basis of biomass).
Within energy politics and energy industry, discussions on environmental
effects caused by the use of a certain energy source or energy carrier are of
major importance.
This is why for every option of using renewable energy sources for the
provision of useful energy; also selected environmental effects will be
addressed.
This assessment will be performed for environmental effects related to
manufacturing, ordinary operation, malfunctions and the end of operation.
Energy planning
Complete energy systems must be analysed, and supply should not be considered
separately from end-use. Unfortunately precise needs for energy are too
frequently forgotten, and supplies are not well matched to end-use. Energy
losses and uneconomic operation therefore frequently result. For instance, if a
dominant domestic energy requirement is heat for warmth and hot water, it is
irresponsible to generate grid quality electricity from a fuel, waste the majority
of the energy as thermal emission from the boiler and turbine, distribute the
electricity in lossy cables and then dissipate this electricity as heat.
Principles of renewable energy such inefficiency and disregard for resources
often occurs. Heating would be more efficient and cost-effective from direct
heat production with local distribution. Even better is to combine electricity
generation with the heat production using CHP – combined heat and power
(electricity).
Energy planning
System efficiency calculations can be most revealing and can pinpoint unnecessary
losses. Here we define ‘efficiency’ as the ratio of the useful energy output from a
process to the total energy input to that process. Consider electric lighting produced
from ‘conventional’ thermally generated electricity and lamps. Successive energy
efficiencies are: electricity generation ∼30%, distribution ∼90% and incandescent
lighting (energy in visible radiation, usually with a light-shade) 4–5%. The total
efficiency is 1–1.5%. Contrast this with cogeneration of useful heat and electricity
(efficiency ∼85%), distribution ∼90% and lighting in modern low consumption compact
fluorescent lamps (CFL) ∼22%. The total efficiency is now 14–18%; a more than tenfold
improvement! The total life cycle cost of the more efficient system will be much less
than for the conventional, despite higher per unit capital costs, because:
(i)
less generating capacity and fuel are needed,
(ii)
less per unit emission costs are charged, and
(iii)
equipment (especially lamps) lasts longer.
Energy planning
Energy management is always important to improve overall efficiency and
reduce economic losses. No energy supply is free, and renewable supplies are
usually more expensive in practice than might be assumed.
Thus there is no excuse for wasting energy of any form unnecessarily.
Efficiency with finite fuels reduces pollution; efficiency with renewables
reduces capital costs.
Unexpected sources of renewable
energy
Underground liquid magma
In Iceland, one of the world's most ambitious (and outlandish) renewable
energy projects is now underway. The tiny northern nation is taking
geothermal energy to a new level by tapping into liquid magma deep under
the Earth's surface, where temperatures can reach 1,000 degrees Celsius. The
hot magma is thought to be capable of producing 10 times more electricity
than typical geothermal sources, so the cost-benefit is in favor of the Iceland
Deep Drilling Project, which will source liquid magma from five kilometers
below the surface using an enormous drill nicknamed "Thor."
Unexpected sources of renewable
energy
Wind energy from trees
Sourcing wind energy from trees doesn't make much sense at first, until you
learn how it works. The secret energy-generating power comes from the way
trees sway in high winds. Earlier this year, researchers published the results of
a study that showed how the vibrations of tree movement could be
successfully converted into useable energy. The proof of concept was
demonstrated on tiny tree-like L-shaped steel beams wrapped with
polyvinylidene fluoride (PVDF), a piezoelectric material. Although the amount
of electricity produced was small -- around two volts -- the output would be
magnified if a life-size piezoelectric array could be built to work with fullgrown trees in natural forests.
Unexpected sources of renewable
energy
Bacteria and dirt batteries
Taking a cue from energy-producing bacteria, scientists at Harvard University
built a battery that's essentially powered by dirt. The creation of the
microbial fuel cell (MFC) batteries is an energy storage breakthrough primed
to aid residents of countries with absent or unstable power grids, such as
regions of Africa where many people still live off the grid. MFC batteries are
notoriously low in cost and can be constructed from local resources that look
nothing like the batteries in your flashlight or cell phone. Instead, an MFC
battery is built inside of a five-gallon bucket, which is filled with saltwater
and holds a graphite-cloth anode, a chicken-wire cathode, mud, manure and
a layer of sand to act as an ion barrier in the salty electrolyte solution.
Unexpected sources of renewable
energy
Swedish trash
As the world's human population continues to increase, so too does our waste
production, creating a double-edged challenge to urban planners who are
looking for renewable energy sources as well as efficient waste management
processes. In Sweden, those two efforts are being combined and the nation
is already successfully diverting 99 percent of its garbage from landfills and
sending much of it to waste-to-energy (WTE) plants that turn it into
electricity. Fully half of Sweden's annual 4.4 million tons of household waste
goes through the WTE process, which burns waste and harvests energy from
the resulting steam. Sweden's processes are so efficient that the nation
actually imports 800,000 tons of trash from nearby countries to its 32 WTE
plants, keeping even more garbage out of landfills.
Unexpected sources of renewable
energy
Living Bricks
Could your house be an energy-generating machine? These Living Bricks take
advantage of the metabolic power of microbes to convert sunlight,
wastewater and air into clean energy. Similar to Harvard's microbial fuel cell
(MFC) battery made from dirt, these living bricks would put natural processes
to work in order to benefit human lives. The early prototypes generate small
amounts of electricity, but it's enough to power an LED lamp or another small
device. Someday, the inventors hope to develop the technology to a point
where entire structures can be built from "bioreactor walls" that could which
could theoretically be constructed to emit their own light.
Unexpected sources of renewable
energy
Las Vegas kinetic streetlights
Millions of people walk the sidewalks of Las Vegas each year, and now some of
those footsteps are generating clean renewable electricity. New York-based
EnGoPLANET is harvesting energy typically lost to the ether by installing special
streetlights powered by kinetic energy pads embedded in the walkways. These
smart street lights are a world's first, proving that even small measures can help
combat climate change by reducing dependence on fossil fuel forms of energy. The
solar-kinetic streetlights are one element in the broader plan to make Las Vegas a
net-zero emissions city powered completely by renewable energy.
Source: Six unexpected sources of renewable Energy,
https://www.engadget.com/2016/11/26/six-unexpected-sources-of-renewableenergy/ [28.11.2016]
Individual assignment - Energy Sources
Research
Purpose: Although most of the energy consumed in the world comes from
fossil fuel sources, there are many other potential sources of energy
available. In all cases, there are pros and cons to our use of these sources.
Some of the energy sources are limited by their availability or environmental
impact; others need technological improvements before they can become
widely used. For scientists and engineers, research is the best way to learn
about unknown topics. This assignment calls you to examine information
about energy sources and how those sources are used to produce electrical
energy. You will begin to become an expert on one source of energy and
report your findings back to the class. Then, you will meet with a group to
discuss the various pros and cons that affect our use of different energy
sources.
Individual assignment - Energy Sources
Research
Sources:
Biomass
Fossil fuels
Geothermal
Hydropower
Uranium
Solar
Wind
Individual assignment - Energy Sources
Research
Research Questions Energy Source:
1.
Where can the energy source be found? What is amount of the source in your country, EU, world?
2.
How easy is it to gain access to these sources?
3.
How do we obtain this energy? (How does it work?) What are the consequences of using these sources (fuels)?
4.
What are the costs (direct and indirect) of using these sources? Are there viable alternative sources of fuel?
5.
What is the current cost of the source of energy?
6.
Are there different types or uses of this source? If yes, what are the differences?
7.
What are the environmental impacts of your energy source?
8.
What are the economic impacts of your energy source? How much does it cost per kWh?
9.
What countries frequently use this source of energy? What percentage is it used in your country, EU, world?
10.
What are the most common applications for this energy source? (at farms, in industry etc.) Could this source
be used in a family home?
Individual assignment - Energy Sources
Research
Assignment to be prepared invidually
Form: multimedia presentation in PowerPoint
Deadline: 12/11/2016 – presentation at classroom, 5-7 minutes