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Solar Power
Mojave desert, ca
Solar Energy Passive solar heating – orient largest
walls and windows toward sun
Active solar heating - Solar panels have pipes with water -warm air pumped into house
Widely used in China and parts of Europe
Solar energy and hot summers The sun can work
against you in hot areas– Can use wind to cool
buildings– Living roof absorbs
most of the heat from the roof
– Awnings can block sun
– Underground earth tubes pipe cool air from under ground into house
Tower in Japan that takes advantage of wind for cooling
Solar for electricity Solar collectors concentrate heat to a
power tower to create steam that can spin turbines
Computer controlled mirrors track the sun Con: Expensive Con: Need a desert location Sahara in Africa?
Solar cookers – Pros:
Free
Non-polluting
Inexpensive to produce
Solar Cells for electricity
Photon of light excites electrons in the cell to produce electricity
Pros Can store extra
energy in a battery or send it back into the electrical grid
Pros Safe, little
maintenance, no moving parts
No pollution Long lasting Can be integrated
into existing building materials like roof tiles, windows, walls
Good way to provide people in developing nations electricity
Large systems already in place in India, Portugal, Arizona, Korea, Germany
Plans to put them on every public building in Southern CA - would provide electricity to over 150,000 homes
Solar cells on a New Jersey Public High School
Cons: High Start up cost And - over time the
high initial cost is repaid in energy savings
And - in areas not connected to a grid, cheaper than building a whole new power plant
And - cost continues to decrease
What are the pros and cons of solar power?
Hydropower Hydropower - trap
flowing water behind dams to create reservoirs – Release flowing
water as needed to create electricity
– Most widely used form of renewable energy - ~20% of the world’s energy
Is wave power the future? Up and down motion of waves Try to harness that kinetic energy to
make electric energy
Pros and Cons of Wind Power Wind turbines getting more
efficient– Stronger, can tap into
higher, more reliable winds Increased interest in
offshore wind farms– Winds over ocean often
stronger and steadier
https://www.youtube.com/watch?v=ON9G4mIsNvQ
Con: Offshore wind farms not
pretty - visual pollution The Great Plains in the
US are the Saudi Arabia of wind power (potentially)
Pros Abundant, can’t
run out of it Cheap to build
and operate But… Windy areas
often sparsely populated, so we need a way to transport that electricity to cities– This will take
updating our electrical grid system - $$$ - an investment in our future
Con Sometimes its not windy
– Then we need a backup source of power– Or we need a way to store wind power (in
batteries, in fuel cells?)
Con Turbines kill birds and
bats– Most deaths (~ 40K
per year in US) from outdated older turbines
– Buildings, windows, and electrical towers kill over 1 billion birds/year
– Cats kill over 1 million– Not building towers in
migration paths helps
Pro Farmers can make
a lot of money off a turbine AND still use land for food– 1 turbine on 1/4
acre of land can make $300,000 in electricity each year
Is the tradeoff worth it?– Visual pollution vs. clean wind power
What are the pros and cons of wind power
Pros and Cons of Biomass Energy
Biomass = plants and/or animal waste that can be burned directly as fuel or converted into gas or liquid biofuels
Biomass uses Used mostly for heating and cooking
– Wood, wood chips, charcoal (made from wood)
– Manure– Supplies 95% of the energy needs in the
poorest countries
Creating Biofuels Liquid biofuels - can be
used in place of petroleum based products– Biodiesel– Ethanol
Biggest producers of biofuel– Brazil- currently runs ~ 1/2 of
all cars on ethanol– The United States– The European Union – China
Pro: renewable If it is harvested sustainably Repeated cycles of grow and harvest
depletes soil --> erosion
Pros: Can be grown
almost anywhere No net increase in
CO2 emissions if managed properly
Available now
Cons: Decrease
biodiversity Increase soil
erosion Push small
farmers off their land
Raise food prices
Other sources for ethanol Switchgrass Municipal waste Palm Oil
Palm Oil The oil palm tree produces high-quality,
versatile oils.
But it only grows in the tropics, where its cultivation can have disastrous impacts on people and the environment.
Palm oil comes from the fruit of the oil palm tree It can be separated into a wide range of distinct oils with different
properties.
Today it is: used as a cooking oil the main ingredient for most margarine used in confectionary, ice cream and ready-to-eat meals the base for most liquid detergents, soaps, and shampoos the base for lipstick, waxes, and polishes used as an industrial lubricant used as a biofuel
Palm Oil Global production of palm oil has doubled over the last
decade. By 2000, palm oil was the most produced vegetable oil Worldwide demand for palm oil is expected to double
by 2020.
New plantations are being developed and existing ones are being expanded in Indonesia, Malaysia and other Asian countries, as well as in Africa and Latin America.
But this expansion comes at the expense of tropical forest – which forms critical habitat for a large number of endangered species.
Dead maroon leaf-monkey lying in a new palm oil plantation in Borneo, Indonesia.
Clearcutting the monkey's forest home for oil palm plantations deprives it of its natural habitat
A variety of large mammals live in these areas, including:
Tigers Sumatran rhino
Cannot live in palm oil plantations
Less than 400 left Less than 400 left in the wildin the wild Less than 200 left Less than 200 left
in the wildin the wild
A variety of large mammals live in these areas, including:
Asian elephants
Can live in plantations, but eat oil palm fronds and seeds, so are a pest and are often killed
Poisoned elephants near a palm oil plantation
A variety of large mammals live in these areas, including:
orangutans Can live in plantations, but eat oil palm fronds and seeds, so are a pest and are often killed or sold illegally
A poacher proudly shows an orangutan baby that he has caught in Indonesia. A baby orangutan can fetch up to $30,000 USD when sold as a pet on the illegal wildlife trade market.
In addition, fires set to clear natural forests for oil palm plantations are thought to have burned thousands of these slow-moving apes to death as they were unable to escape the flames
In addition to this: Soil erosion Air pollution Soil and water pollution from massive
pesticide use
at what cost?
But… The business provides jobs for people Lifts them out of poverty Allows them to send their children to school Small scale operations can be sustainable…?
Geothermal Geothermal EnergyEnergy
Geothermal Energy Geothermal energy: heat stored in
– Soil– Underground rocks– Fluids in the earth’s mantle
Hydrothermal reservoirs– Natural hot springs - underground– Drill down - use heat - return cooled
water to be reheated naturally – Iceland
Pros Geothermal heat pump
system– Energy efficient and
reliable– Environmentally clean– Cost effective to heat or
cool a space
Cons High cost of moving heat to areas
further away could be depleted if overtapped
Hot, dry rock: another potential source of geothermal energy?– Technology from oil
drilling used to drill into it– Pump water down,
comes back up heated– Pricey right now
