Energy comes from various sources like the sun, water, wind, biomass and fossil fuels. The sun is the primary source of energy on Earth, powering photosynthesis in plants and warming the planet. There are two main types of energy sources - renewable/non-conventional sources like solar, hydroelectric, wind and geothermal energy that can be replenished, and non-renewable/conventional fossil fuels like coal, oil and gas that are finite. Obtaining and using energy can impact the environment through deforestation, pollution, and increasing the greenhouse effect. Major engineering projects that harness and transmit energy include dams for hydroelectric power and flood control, bridges to span obstacles, canals to transport goods

1. Energy
Energy is essential forpoweringthe processes
of modernindustrial society: refiningores,
manufacturing products, movingvehicles,heating
buildings,and poweringappliances.
Sun
The primary source of most energyon Earth.
Sunlightwarms the planet. Plantsuse photosynthesis
to transform water and carbon dioxide intothe sugars
that powertheir growth and indirectlypower plant-
eatingand meat-eatinganimals.
The Sun providesthe heat that makes Earth
habitable.
2 KINDS OF ENERGY
Non-conventional Energy
Also knownas Renewable Energyand
Alternative Energy. These are the Energy whichare
replaceable.Air,water and soil are some examplesof
this.
Energy Sources
1. Solar Energy
Active solar energy isderivedby placing
speciallydesignedpanelssothat theyface the Sun.
Solar Energy doesn'tcause pollution.
2. HydroelectricEnergy.
Usesmoving water to turn turbine attached to
generatorsthat produceselectricity.Hydroelectric
power projectsalso can be built on escarpmentsand
fall lines,where there is tremendousuntappedenergy
in the fallingwater.
3. WindEnergy
It has beenusedthroughout human history. In
its more refinedaspects,ithas beenemployedto
power windmillsthat cause turbinesto rotate,
providinggenerators withthe power theyrequire to
produce electricity
4. Geothermal Energy
Energy that is deepinside the earth. It isan
energyfrom natural heattrapped beneaththe earth’s
surface. it can be captured and convertedto provide
useful amount of energy like electricity.It can
harnessedin hotspringsand volcanoes
5. Biomass
Derivedfrom agricultural and otherrotten
plant or animal that releasesgascalled methane that
can be collectedand burnedto release energy.
Conventional Energy
Also knownas Non- Renewable Energy.Energy
sources which are not replacedby natural processes
withinthe span of a person’slifetime.These are the
fossil fuels.
Fossil Fuel
It is a fuel formedfrom a fossilizedremainsof
livingorganisms that livedmillionyearsago, these are
the coal, crude oil and natural gas.
Energy affectsthe environmentin3 major ways
1. Deforestationand Erosion
2. Pollution
3. Greenhouse Effect
• Deforestationand Erosion
Firewoodgatheringin underdeveloped
countries.Although more efficientstovesand small
solar cookers have beendesigned,efficiencyincreases
are competingagainst population increases.
• Pollution
Energy productionalso frequentlycausestoxic
pollutantby-products. Sulfur dioxide (fromsulfur
impuritiesincoal and oil) and nitrogenox-ides(from
nitrogenbeingformedduring combustion) damage
lungsand corrode the surfaces of buildings.Lead
additivesin gasoline make internal combustion
enginesrun more efficiently,buttheycause low-grade
leadpoisoning.
• Greenhouse Effect
Carbon dioxide fromthe burning of fossil fuels
may be acceleratingthe, wherebyatmosphericcarbon
dioxide slowsthe planetary loss of heat.If the effectis
as strong as some research suggests,global

2. temperaturesmay increase several degreeson average
in the Twenty-firstcentury, with unknowneffectson
climate and sealevel.
ENGINEERING PROJECTS
1. Dams
Dams serve several purposes.
1. the generationofhydroelectricpower.
2. Dams also provide floodcontrol and irrigation.
3. Flood-control dams also can be usedto
regulate the flowof water usedfor irrigation
and other projects.
2. Bridges
Bridgesare builtto span low-lyingland betweentwo
high places.Most commonly,there isa river or other
body of water in the way, but other featuresthat
might be spanned include ravines,deepvalleys and
trenches,and swamps. A relatedengineeringprojectis
the causeway, in which land in a low-lyingarea is built
up and a road is then constructed on it. The longest
bridge in the world isthe Akashi Kaikyo in Japan near
Osaka. It was built in1998 and spans 6,529 feet(1,990
meters),connectingthe island of Honshw to the small
islandof Awaji.
3. Canals
Movinggoods and people by water is generally
cheaperand easier,ifa bit slower,than movingthem
by land. Before the twentiethcentury,that cost
savings overwhelmedthe advantagesof land travel—
speedand versatility.Therefore,humanbeingshave
wanted to move things by water wheneverpossible.
To do so,they had two choices:locate factories and
people nearwater, such as rivers,lakes,and oceans,or
bring water to where the factoriesand people are,by
diggingcanals.
The longestcanal in the world isthe Grand Canal in
China,which was builtin the seventhcentury and
stretchesa lengthof 1,085 miles(2,904 km.) The long
and dangerous sea journeyaround the tip of South
America. The SuezCanal in Egypt, which runs for 100
miles(162 km.)
4. Tunnels
Tunnelsconnect two placesseparated by physical
featuresthat wouldmake it extremelydifficult,ifnot
impossible,forthemto be connectedwithout cutting
directlythrough them. Tunnelscan be usedin place of
bridgesover water bodiesso that water traffic isnot
impededbya bridge span.
Tunnelsare oftenused to go through mountains that
might be too tall to climbover. Trains especiallyare
sensitive tochanges in slope,and train tunnelsare
foundall over the world.Less common are automobile
and truck tunnels,althoughthese are also found in
many places.
The Chunnel.Arguablythe most famous—andone of
the most ambitious—tunnelsinthe worldgoes by the
name Chunnel.Completedin1994, it connects Dover,
England, to Calais,France, and runs 31 miles(50km.).
5. Buildings
Historically,North America has beenhome to the
tallestbuildingsinthe world. Chicago has beencalled
the birthplace of the sky- scraper and was at one time
home to the world’s tallestbuilding.
The tallestof the city’s buildingswere the twin
towers of the WorldTrade Centerin Lower
Manhattan.