+ SOLAR AND ALTERNATIVE ENERGY ENVIRONMENTAL SCIENCE CHAPTER 17
Dec 22, 2015
+SOLAR ENERGY Most of the Earth’s energy
comes from the sun
Most living organisms get their energy from the sun
Fossil fuels are the remains of long dead organisms that relied on the sun
The sun is vital to the water cycle – there is no “new sources” for fresh water
Hydroelectric power comes from flowing water
Uneven heating of the Earth by the sun creates wind
Wind can also generate electricity
+SUN AS FUEL
Thermonuclear fusion creates the sun’s energy
TWO Hydrogen nuclei fuse together to create ONE larger nucleus.
Hydrogen has an atomic number of 1 the new larger nucleus has an atomic number of 2 so the element is now Helium
Some of the energy from the two hydrogen nuclei is released when they fuse
This energy is in the form of visible light and infrared
+SOLAR POWER
ADVANTAGES
“FREE” ENERGY
CLEAN – (no mining, wastes)
NONPOLLUTING – (no CO2, toxic gases produced)
COST OF EQUIPMENT MAY BE RECOVERED OVER TIME
DISADVANTAGES
SUNLIGHT IS NOT CONSTANT – (no sun at night, cloudy, rainy days)
SOLAR EQUIPMENT IS EXPENSIVE
CURRENT TECHNOLOGY IS NOT EFFICIENT
+PASSIVE SOLAR HEATING Sunlight energy used to heat
building directly
Can NOT be used to produce electricity
Buildings must be DESIGNED for passive solar
Building materials must be light ABSORBENT (stone, brick, concrete)
Windows, skylights and glass enclosures should face SOUTH
Good INSULATION and dark materials inside to maximize sunlight energy
+ACTIVE SOLAR SYSTEMSOLAR COLLECTORS
Made of three parts:
Large flat box with an insulated black metal base
Tubes filled with water are located above the base
Top layer is a thick piece of glass
Tubes collect the sun’s energy as heat and pumps move the hot water into the house. The hot water can be used as is or converted to steam to generate electricity
Uses energy from sunlight to produce heat and electricity
Needs fans, tubes, pumps, tanks to work
Solar collectors gather energy from the sunlight
Largest solar energy plant uses oil filled tubes heated by curved mirrors in the Mojave Dessert in California and Nevada
+PHOTOVOLTATIC CELLS PRODUCES ELECTRICITY
DIRECTLY FROM SOLAR ENERGY
TWO THIN WAFERS OF SILICON SEMICONDUCTORS
ENERGY FROM THE SUN HITS THE SILICON AND KNOCKS ELECTRONS FREE
THE ELECTRONS MOVE ALONG THE BOTTOM LAYER –PRODUCING ELECTRICAL CURRENT
EX: calculators, outdoor lights, watches, flashlights, cell phone and laptop chargers, cars
+HYDROELECTRIC ENERGY Flowing water contains
KINETIC energy (energy from movement)
Moving water generates electricity by turning turbines
Huge dams are built across waterways (rivers and streams)
Controls the movement of water ensures a constant flow to generate electricity
Creates lakes which can be used as recreation areas, control flooding downstream, water storage for irrigation and homes
ADVANTAGES
Nonpolluting
Available where ever there is water
Cheaper than fossil or nuclear fuels
DISADVANTAGES
Changes habitat, dries wetlands
Can harm/kill native species
Raises water temperature downstream
Changes soil causing erosion and soil depletion
+TIDAL ENERGY
OCEAN MOVEMENT CONTAINS MASSIVE ENERGY
TURBINES ROTATE FREELY (IN OR OUT) WITH OCEAN TIDES
USED IN CANADA AND IRELAND
ADVANTAGES:
FREE ENERGY
CONSTANT ENERGY
DISADVANTAGES:
VERY EXPENSIVE EQUIPMENT
HAS TO BE LOCATED IN AN INLET OR BAY
LONG DISTANCE FOR ELECTRICITY GENERATED TO TRAVEL
+WIND ENERGYADVANTAGES:
FREE, CLEAN, CHEAP
DISADVATAGES:
WIND ISN’T CONSTANT
NEED LARGE SPACE FOR WIND FARMS
DISTANCE ELECTRICITY NEEDS TO TRAVEL
Wind energy has been used since ancient times for pumping water, moving ships and grinding grain
Today we use aerogenerators or turbine generators
Traditional or horizontal have three blades and are on long poles
Vertical have two long blades that rotate like an upside down eggbeater
Wind speed must be 15 miles per hour or greater for traditional
Vertical can generate electricity at lower wind speeds
+GEOTHERMAL ENERGY Energy from naturally
occurring radioactive decay heats the Earth from inside
This heat melts rock - called magma (volcanoes)
Heated rocks warm ground water (hot springs) and turn ground water into steam (geysers like “Old Faithful”)
Geothermal energy can be used to heat hot water and buildings and generate steam to turn turbines to make electricity.
Since 1904, Laradello, Italy has used geothermal energy to produce electricity
+GEOTHERMAL ENERGY COUNTRIES THAT HAVE
VOLCANIC ACTIVITY – AND USE GEOTHERMAL ENERGY TO GENERATE ELECTRICITY:
ICELAND (80% of the country)
ITALY
USA (in California and Hawaii)
NEW ZEALAND
AUSTRAILIA
CHINA
INDIA
+NUCLEAR FUSION
OCCURS WHEN TWO ATOMIC NUCLEI JOIN TOGETHER (FUSE) TO BECOME ONE LARGER NUCLEUS
NUCLEAR FUSION IS THE SOURCE OF THE SUN’S ENERGY (TWO HYDROGEN NUCLEI JOIN TOGETHER TO MAKE A HELIUM ATOM)
FUEL IS DEUTERIUM – A HYDROGEN ISOTOPE
THE BIGGEST SOURCE OF DEUTERIUM IS THE OCEAN (SEAWATER)
NO CURRENT TECHNOLOGY AVAILABLE TO TURN FUSION ENERGY INTO ELECTRICITY