Current Energy Usage Global Energy Use US Energy Use
Slide 3
RENEWABLE ENERGY The European Union aims to get 20% of its all
energy from renewable sources by 2020 Costa Rica gets 92% of its
energy from renewable resources. China aims to get 10% of its total
energy from renewable resources by 2020.
Slide 4
Electricity from RENEWABLE ENERGY In 2014, Germany generated
75% of electricity with a combination of renewable sources Denmark
now gets 40% of its electricity from wind and plans to increase
this to 100% by 2050. In 2004, California got about 12% of its
electricity from wind and plans to increase this to 50% by
2030.
Slide 5
Jobs & Economy: Renewable Energy According to the American
Council for an Energy-Efficient Economy (ACEEE), robust investment
in energy efficiency: could save $1.2 trillion by 2020, and the
United States could create 1.3 to 1.9 million jobs by 2050 through
the deployment of energy efficient technologies The International
Renewable Energy Agency (IRENA) estimates that 5.7 million people
worldwide were employed in the renewable energy sector, directly
and indirectly, in 2012. The largest number of jobs is found in
biofuels and solar photovoltaic, 1.38 million and 1.36 million,
respectively
Slide 6
Energy Use Conservation - Reducing energy waste is quickest,
cleanest, cheapest way to provide more energy, reduce pollution
reduce environmental degradation, preserve our dwindling supply of
resources Evaluate efficiency Incandescent light bulb: wastes 95%
Car motor: wastes 80% Nuclear power plant: wastes 86% Coal burning
power plant: wastes 66% Solution: Reduce waste & increase
Efficiency
Slide 7
Wasted Energy Unavoidable: 41% of US Commercial energy is lost
when energy changes form (2 nd law of thermodynamics) usually heat
lost to the environment Avoidable: 43% of energy is wasted
unnecessarily, by inefficient motors, appliances, wasteful usage 1
st law of thermodynamics: conservation of energy energy is neither
created nor destroyed, just changes form 2 nd law of
thermodynamics: When energy changes form, energy quality decreases.
We end up with less usable energy
Slide 8
Energy Efficient Appliances Bulbs: To make same amount of light
Incandescent : 60 Watts Fluorescent : 15 Watts LED : 8 Watts Heat
pumps 40 % electricity to produce same amount of heat Solar water
heaters : Reduce energy use by 50%
Slide 9
Living Roofs Roofs covered with plants have been used for
decades in Europe and Iceland. These roofs are built from a blend
of light-weight compost, mulch and sponge-like materials that hold
water. Figure 17-10
Slide 10
Saving Energy in Existing Buildings About one-third of the
heated air in typical U.S. homes and buildings escapes through
closed windows and holes and cracks. Figure 17-11
Slide 11
Efficient Design Example: Example: CA Academy of Sciences
Building Passive Solar Design South-facing double-paned windows
with adjustable shades Overhang blocks summer sun, but winter sun
enters windows Heat absorbant floor: and heat is stored and slowly
released in stone or concrete floors
Slide 12
Designing Buildings: Green Architecture Other design features
Super insulate Geothermal cooling / heating Utilize breeze /wind
for ventilation and cooling Roof color: light colors reflect
sunlight, dark colors absorb and store heat Green roofs with soil
and vegetation reduce cooling costs, create habitat, absorb runoff
and improve air quality Double paned windows and strong insulation
to prevent heat loss Recycled building materials Trees for shade
Skylights and natural lighting Radiant heating in floors Energy
efficient appliances
Slide 13
ENERGY EFFICIENCY: Cars The government Corporate Average Fuel
Economy (CAFE) Enacted in 1977 after Arab Oil Embargo Has not
increased since 1985. Stuck at 25 mpg for 30 years Scheduled to
increase to 35mph in 2016 Figure 17-5
Slide 14
How do we achieve energy sustainability? 1.Increase energy
efficiency Fossil fuels will last longer and renewables will be
able to support a larger portion of our energy needs. 2.Invest in a
wide variety of energy sources Provides stability and diversity
3.Shift subsidies away from fossil fuels to support research and
development of renewables will make renewables more cost effective
and the transition away from fossil fuels less damaging 4.Full cost
pricing Externalities include the social, environmental and health
costs of an energy source in its price. Will even the economic
playing field between fossil fuels and renewables
Slide 15
Capacity and Peak Demand We have to plan our energy capacity
around peak demand Capacity is the amount of energy a power plant
can provide at any given moment Peak demand most energy used at one
time: can be many times normal use Reducing peak demand is a key
component of energy sustainability Options: Increase energy
efficiency Conservation during energy transfers Tiered pricing
plans Store energy (batteries, water uphill, solar heating) Back up
generators Smart Grid: Smarter systems that automatically adjust
energy usage to avoid blackouts and brownouts and that spread out
energy usage
Biomass Biomass is organic material from plant and animal
Direct burning : Wood, manure, MSW, crop residue, charcoal, etc
Convert to different forms: methane (natural gas) decomposing
organic waste ethanol (gasohol) - fermenting organic material from
corn, sugarcane, switchgrass, or agricultural residue biodiesel -
oil extracted or collected from waste oil, soybeans, algae,
etc
Slide 19
Slide 20
Biomass Potentially renewable Rate of harvesting < rate of
growth Max Sustainable Yield Otherwise: Deforestation Carbon
neutral Biomass is part of current carbon cycle Stored &
released in short time frame Theoretically, no net increase in
atmospheric carbon Fossil fuels: Carbon has been locked away for
millions of years Rapidly releasing what has been slowly
accumulating Results in Net increase in CO 2 in atmosphere
Gas Biofuel: Biogas Organic wastes go in bacteria convert to
methane biogas harvested for use.
Slide 23
Saprophytic bacteria (facultative anaerobes) break down fats,
proteins, and polysaccharides Acid forming bacteria break down
these monomers to short chain organic acids Methanogen bacteria
(strict anaerobes) produce methane gas Digester Biogas Biogas from
Methane Digestion BIOGAS Methane50-80% CO 2 15-45% Water5% Biogas
(methane) is an important renewable gas fuel made by fermenting
organic wastes, (animal dung), in a digester but can contribute to
climate change. Biogas uses less land than other biofuels and thus
reduces the amount of deforestation, runoff, soil erosion, and
energy consumption. Biogases occur in things like landfills or
agriculture and produces a strong smell but with methane digestion
the amount of methane released to the atmosphere is reduced. If the
waste is not going to landfills then there is a reduction in the
amount of waste as well.
Algae Grow Fast Have High Biofuel Yields Consume CO 2 Dont
Compete With Agriculture Microalgal Biomass Can Be Used or Fuel,
Feed and Food Can Be Grown in the Sea Can Purify Wastewaters Can Be
Used to Produce Many Useful Products The Algae Industry is a Job
Creation Engine
Slide 26
Biofuel Downsides crops for fuel vs. crops for food (takes food
away from people) Agricultural expansion land footprint
deforestation (esp. soy & palm in the tropics) Crops have
fossil fuel input (mechanized monoculture uses lots of
fuel/fertilizer/pesticide)
Slide 27
Slide 28
Biomass: Environmental Impacts Use of crops and crop land for
fuel creates competition for land and increases food prices Growing
crops for fuel creates all the problems associated with commercial
agriculture Fossil fuel dependent, fertilizer runoff, pesticides,
soil degradation, etc Impacts can be decreased by Growing less
intensive grasses on marginal land Using waste material (trash,
crop residue or logging waste) Using algae which can be grown in
brackish water, on rooftops, or other non-traditional agriculture
spaces and creates more fuel per area
Slide 29
Fig. 17-25, p. 405 Trade-Offs Solid Biomass
AdvantagesDisadvantages Large potential supply in some areas
Nonrenewable if harvested unsustainably Moderate costs Moderate to
high environmental impact No net CO 2 increase if harvested and
burned sustainably CO 2 emissions if harvested and burned
unsustainably Low photosynthetic efficiency Plantation can be
located on semiarid land not needed for crops Soil erosion, water
pollution, and loss of wildlife habitat Plantation can help restore
degraded lands Plantations could compete with cropland Often burned
in inefficient and polluting open fires and stoves Can make use of
agricultural, timber, and urban wastes
Slide 30
Hydropower Using the potential energy of flowing water to
generate electricity Renewable / Nondepletable suitable sites are
limited and we are maxed out in terms of conventional dams There is
little room for expansion in the U.S. Dams and reservoirs have been
created on 98% of suitable rivers. new technologies emerging for
using tides and waves
Slide 31
The kinetic energy of water can generate electricity
Hydroelectricity- electricity generated by the kinetic energy of
moving water. This is the second most common form of renewable
energy in the world. 7% of the electricity in the USmore than of
this is in the states of CA, WA, OR China is the worlds leader in
hydroelectricity followed by Brazil and the US.
Slide 32
Captures kinetic energy and uses it to turn a turbine. Amount
of electricity depends on the distance it falls or the flow rate or
both. Biggest dam: In US: Grand Coulee Dam in Washington In China:
Three Gorges Dam on Yangtze River
Slide 33
Hydroelectric Dam Afterbay Penstock Dam Powerhouse Transformer
Sluice gate Generator Turbine Reservoir
Slide 34
Types of Hydropower Water wheels used to grind grain or cut
wood ancient practice Run of the river Systems Water runs through a
channel and dam to create a small amount of electricity (water
turns turbine) Subject to flooding and drought so electricity
production can vary as river flow changes Water Impoundment Dams
Dam a river to create a large water gradient and water storage area
(lake) Falling water turns a turbine electricity Major up and
downstream impacts
Slide 35
Types of Hydropower Pumped Storage Systems excess electricity
is used to pump water upstream (storing potential energy) can then
be used to generate extra electricity during peak hours
Slide 36
Types of Hydropower Tidal Energy Uses the changing tides to
turn a turbine Tides are a very reliable source of energy Energy
captured both directions Need to protect fish
Slide 37
Types of Hydropower Wave Power Use the movement of waves to run
a generator Concerns about ocean habitat disruption Not as reliable
as the tides
Slide 38
3.5 m 145 m Power cable Feeds electricity back to land Anchor
Wave tube Power module Each module produces 250 kW of electricity
Each power module is connected by hinges and attached to hydraulic
rams. As the wave tube moves up and down, the rams shift hydraulic
fluid in the power module and drive a turbine and generator. Wave
Power
Slide 39
Slide 40
Dams: Environmental Impacts Upstream Major reservoir is created
upstream to provide drinking water, irrigation, recreation and
flood control Massive flooding changes habitat entirely and
displaces native plants, animals and people Siltation: Sediment
build up behind the dam requires dredging Standing water holds more
heat, have less oxygen and more water is lost to evaporation
Downstream Reduced water flow may alter riparian, wetland and
estuary habitats which alter flora and fauna Lack of nutrients from
blocked sediments reduces soil fertility Loss of seasonal water
flow (changes estuaries and flooding patterns) Dam itself Fragments
habitat Disrupts fish migration Increased anaerobic decomposition
(decomp under water) creates methane and CO 2 Blocks fish migration
(can be helped with fish ladders)
Slide 41
Fig. 17-20, p. 400 Trade-Offs Large-Scale Hydropower
AdvantagesDisadvantages Moderate to high net energyHigh
construction costs Large untapped potential High environmental
impact from flooding land to form a reservoir High efficiency (80%)
High CO 2 emissions from biomass decay in shallow tropical
reservoirs Low-cost electricity Long life span No CO 2 emissions
during operation in temperate areas Floods natural areas behind dam
May provide flood control below dam Converts land habitat to lake
habitat Danger of collapse Provides water for year-round irrigation
of cropland Uproots people Decreases fish harvest below dam
Reservoir is useful for fishing and recreation Decreases flow of
natural fertilizer (silt) to land below dam
Slide 42
Geothermal Can be used directly as a source of heat/hot water
or indirectly to produce electricity. Direct use can happen almost
anywhere, but sites for electricity production are limited. Common
in Iceland and currently practiced in the western US Energy stored
below the earths surface can be harvested for heat and energy
Nondepletable although some sites can be temporarily depleted of
hot water
Slide 43
Earths internal heat produces geothermal energy Geothermal
energy- using the heat from natural radioactive decay of elements
deep within Earth as well as heat coming from Earth. Wherever magma
comes close enough to ground water, the ground water is heated.
Where it does not rise to the surface naturally (Yellowstone
geysers, etc.) humans may be able to reach it by drilling. US,
China, and Iceland have substantial geothermal resources and are
the largest producers of geothermal energy. Iceland: 87% of their
home heating, 20% of its electricity. US 5% of its renewable
energy.
Slide 44
Types of Geothermal Energy Low Temperature used directly for
hot water or space heating Hot water used for cooking or normal hot
water uses water may or may not go back into reservoir Hot water is
disseminated via a heat exchanger to heat buildings water back into
reservoir to be reheated and used again Ground source heat pumps
constant temps underground transfer heat from underground. Requires
energy to pump fluid. Winter: heat from underground is used to heat
a fluid which transfers heat to the house, fluid is then reheated
Summer: fluid cooled underground absorbs heat in the house and then
transfers the warmer fluid underground where it loses heat High
Temperature used to produce electricity High pressure steam turns
turbine makes electricity water back into reservoir to reheated and
used again Just like a coal plant, but no burning required
Slide 45
Can be installed anywhere regardless of whether there is
geothermal energy Ground source heat pump
Slide 46
Geothermal Plant
Slide 47
Geothermal Suitability Ground Source Heat Pumps can be used
anywhere Sites for direct use are somewhat limited Sites for
electricity generation are significantly limited to areas with high
geologic activity
http://www.nevadageothermal.com/s/Geothermal.asp
Slide 48
Geothermal in TX According to a report by the Southern
Methodist University Geothermal Laboratory, the hot water and
pressure between 8,000 and 25,000 feet below Texas could supply
more than 100 times the state's 2008 total electric consumption for
well over a century.Southern Methodist University
Slide 49
Environmental Impacts Geothermal heat and steam contain traces
of gases (H 2 S, SO x, etc) that can be harmful to humans and the
environment Sulfur compounds from geothermal plants can lead to
acid rain (but generally less than fossil fuel power plants)
Reduced by using scrubbers to clean out harmful gases or collecting
the gases for useful purposes Remote and pristine habitats can be
fragmented or impacted by road construction, drilling, etc to
access the geothermal reservoirs
Slide 50
Geothermal Power Advantages of geothermal power include: high
efficiency moderate CO 2 emissions low cost (in suitable areas) low
environmental impact Disadvantages of geothermal power include: few
suitable sites noise and odor pollution depleted easily if not
managed land subsidence due to extracted water
Slide 51
Solar Power Capturing radiant energy from the sun to generate
light, heat and electricity. Cannot be depleted Amount varies
depending on latitude, cloud cover, time of day and season Two
Types Active using technology to capture the suns energy often
changing the form Examples: solar panels, solar water heating,
concentrated solar plants Passive - Using the suns energy to heat
or cool without energy inputs, pumps or special technology
Examples: windows and blinds, solar oven
Slide 52
Solar Energy
Slide 53
Solar Power
Slide 54
Slide 55
Active: Photovoltaics Photovoltaic cells convert radiant energy
from the sun into electricity Cells are composed of silicon with
phosphorus and boron. Photons strike the solar panel and excite
electrons to create a flow of electrons Electrons flow through the
semiconducting materials to create electricity Electricity can be
stored in batteries for use at night Price of photovoltaic cellss
is high, but dropping
Slide 56
Photovoltaic A solar cell converts light into electric current.
The energy that is generated is usually converted directly to
electricity which is stored in a battery or used to heat water. On
their first tests the solar cells were only about 1% efficient
(similar to photosynthesis). Since the increase in technology the
percent efficiency has gone from 1% to 5% to 20% to 40% and now
some designs are reporting 85% conversion efficiency. Individual
Solar cell Photovoltaic cell can be installed on roofs to provide
electricity
Slide 57
Single solar cell Solar-cell roof Boron enriched silicon +
Junction Phosphorus enriched silicon Roof options Panels of solar
cells Solar shingles Producing Electricity with Solar Cells
Photovoltaic (PV) cells can provide electricity for a house of
building using solar-cell roof shingles.
Slide 58
Producing Electricity with Solar Cells Solar cells can be used
in rural villages with ample sunlight who are not connected to an
electrical grid. Figure 17-18
Slide 59
It is possible to get electricity from solar cells that convert
sunlight into electricity. Can be attached like shingles on a roof.
Can be applied to window glass as a coating. Can be mounted on
racks almost anywhere.
Slide 60
Active: Solar hot Water System A heat collecting liquid is
heated on the roof and transferred to the water storage tank where
it heats the water. Fluid returns to the roof to be reheated. Setup
costs associated with buying and installing the system, but then
you get free hot water (still have to pay the water itself though)
May require energy to pump the water around
Slide 61
Active: Concentrated Solar Thermal Systems Power Towers
Rotating mirrors track and aim sunlight at a tower Fluid collects
heat to make steam to generate electricity Parabolic Troughs
Reflective troughs focus sunlight on a fluid filled tube which
heats up to make steam to generate electricity Large land
requirements: Usually placed in a desert habitat with no trees and
year round sun Some threats to fragile desert ecosystems Do not
produce electricity at night Go To:
http://ca.pbslearningmedia.org/asset/ate10_int_newsolar/
http://ca.pbslearningmedia.org/asset/ate10_int_newsolar/
Slide 62
Passive Solar Absorbs & stores heat from the sun directly
within a structure Window placement (under an overhang to let
winter sun in and keep summer sun out) Windows (double or triple
paned with low e glazing to prevent heat loss) Flooring (concrete
or stone with good thermal inertia to absorb and store heat) House
orientation (south facing in the US) Insulation (sufficient to keep
heat in or out) Albedo effect (dark colors to absorb heat, light
colors to reflect it) Green roof Deciduous tree for shade in summer
(no leaves in winter Building into side of hill
Slide 63
Passive Solar
Slide 64
Solar Suitability
Slide 65
Trade-Offs Passive or Active Solar Heating
AdvantagesDisadvantages Energy is freeNeed access to sun 60% of
time Net energy is moderate (active) to high (passive) Sun blocked
by other structures Need heat storage system Quick installation No
CO 2 emissions Very low air and water pollution High cost (active)
Very low land disturbance (built into roof or window) Active system
needs maintenance and repair Moderate cost (passive) Active
collectors unattractive
Slide 66
Wind Energy the most rapidly growing source of electricity
Nondepletable convert wind (kinetic) into electricity Wind turns a
turbine directly to create a flow of electrons
Slide 67
Wind Turbines & Wind Farms Best in rural areas with lots of
wind Must be near transmission lines Requires lots of land, but
land can be used for other things (farming, ranching, habitat) or
they can be placed off shore.
Slide 68
Wind energy capacity: US has the largest capacity, followed by
Germany, China, India, and Italy. US only produces 1% of its
electricity via wind. Denmark: largest user at 21% of their
electricity
Slide 69
Land Turbines Pros Clean, inexpensive energy source that runs
off of a nondepletable energy source Can share space with other
land uses: ranching/farming Cons Requires lots of space Noisy/eye
sore Threatens migrating birds and bats Public resistance Not
suitable everywhere Construction costs/metal Requires a back-up
source or batteries for storage
Slide 70
Offshore Wind Farms Turbines located 3-20 miles off shore
Offshore winds are stronger and often more reliable Concerns
include Impact on marine wildlife during construction and possibly
operation Impact on bird and mammal migration Transfer of
electricity (loss over longer distances)
Slide 71
Slide 72
Wind Suitability
Slide 73
Hydrogen Fuel Cells Hydrogen and oxygen are combined to produce
electricity 2 H 2 + O 2 energy +2 H 2 O No pollution! Only water
vapor Continues to produce electricity as long as supplied with
fuel
Slide 74
Hydrogen Fuel Cell Car Benefit: 80% efficient - H 2 O only
waste product Problem: H 2 gas is rare in nature Have to generate
using energy (electrolysis) & explosive dangerous for
collisions with H 2 tanks, have to build distribution network
Hydrogen for Cars -
http://ca.pbslearningmedia.org/asset/eng06_vid_fuelcells/http://ca.pbslearningmedia.org/asset/eng06_vid_fuelcells/
Slide 75
The Economics of Renewable Energy
Slide 76
Future Energy Solutions Energy use in the near future will be a
mix of renewable and non renewable energies. As technology
improves, current renewable energy sources will become more
efficient and more common. A move away from large central power
producers will see an increase in more efficient regional power
producers. Household energy production, such as home solar water
heating or battery storage, will play a major part in meeting the
worlds future energy demands. Renewable energy technologies will
continue to become more efficient and affordable. Water heating and
electricity needs will increasingly become the task of small home
based solar power devices.
Slide 77
Energy Solutions Government strategies 1.Subsidize energy
resources to encourage use: tax breaks, rebates, research grants,
regulations to stimulate development 2.Raise price to discourage
use: tax, eliminate subsidies, regulations to restrict development
3.Public education: advantages and availability 4.Develop long
range policies to transition to more sustainable energy
sources
