Renewable Energy
Ch. 16

Format
 Write definition and
then
 Make a T-chart for
each type

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?

HydropowerHydropower

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

Wind Power

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

Biomass

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 leftLess than 400 left
in the wildin the wild
Less than 200 leftLess 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…?

GeothermalGeothermal
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