energy efficiency & renewable energy resources
TRANSCRIPT
Energy Efficiency & Renewable Energy Resources
Discuss with your table partner:
What is the difference between energy conservation and
energy efficiency? Give an example of each.
Improving the percentage of total energy input that does _______________.
If 1.2 million households replaced a 60 watt incandescent bulb with a 15 watt compact fluorescent bulb for light used 4 hrs/day, ~89,600,000 kWh/year would be saved —enough energy for 7,000 homes.
We could save as
much as ____ % of all
the energy we use by
improving energy
efficiency.
Four widely used devices
that waste energy
•Incandescent light
bulb
•Motor vehicle with an
internal combustion
engine
•Nuclear power plant
•Coal-fired power plant
Energy
Inputs
System Outputs
9%
7%
41% 85%
U.S.
economy
43% 8%
4% 3%
Nonrenewable fossil fuels Useful energy
Nonrenewable nuclear Petrochemicals
Unavoidable energy
waste Biomass Unnecessary energy
waste
Hydropower, geothermal,
wind, solar
Inefficient incandescent bulbs produce a large amount of heat.
Video on Energy Efficient Light Bulb Legislation
http://www.cbsnews.com/video/watch/?id=7393284n
• Lighting uses 19% of the world’s energy
• There are 4.4 billion incandescent bulbs in the US.
Discuss with your table partner:
Determine a list of strategies to improve energy efficiency.
Energy Efficiency Net energy efficiency: the net efficiency of the entire energy delivery process is determined by the efficiency of each step in the energy conversion process.
PBS Video on Smart Grid Technology
http://www.pbs.org/wgbh/nova/tech/power-grid.html
Cogeneration (Combined Heat and Power- CHP): the production of two useful forms of energy from the same fuel source
Example: __________________
__________________________.
Attic
• Hang reflective foil near
roof to reflect heat.
• Use house fan.
• Be sure attic insulation is
at least 30 centimeters
(12 inches).
Bathroom
• Install water-saving
toilets, faucets, and
shower heads.
• Repair water leaks
promptly.
Kitchen
• Use microwave rather
than stove or oven as much
as possible.
• Run only full loads in
dishwasher and use low- or
no-heat drying.
• Clean refrigerator coils
regularly.
Basement or utility room
• Use front-loading clothes washer. If possible run only full loads with
warm or cold water.
• Hang clothes on racks for drying.
• Run only full loads in clothes dryer and use lower heat setting.
• Set water heater at 140° if dishwasher is used and 120° or lower if no
dishwasher is used.
• Use water heater thermal blanket.
• Insulate exposed hot water pipes.
• Regularly clean or replace furnace filters.
Outside
Plant deciduous trees to
block summer sun and let
in winter sunlight.
Other rooms
• Use compact fluorescent
lightbulbs or LEDs and avoid
using incandescent bulbs
wherever possible.
• Turn off lights, computers, TV,
and other electronic devices
when they are not in use.
• Use high efficiency windows;
use insulating window covers
and close them at night and
on sunny, hot days.
• Set thermostat as low as you
can in winter and as high as
you can in summer.
• Weather-strip and caulk doors,
windows, light fixtures, and
wall sockets.
• Keep heating and cooling
vents free of obstructions.
• Keep fireplace damper closed
when not in use.
• Use fans instead of, or along
with, air conditioning.
Discuss with your partner:
Most sources of energy on Earth originate initially from
the sun’s energy.
On the next slide identify types of energy that originate
from the sun and 2 that do not originally come from the
sun.
Renewable Energy Resources
Originally Energy from Sun:
__________
________________
____________
__________
Energy Independent of Sun:
_____________
______________
Solar Energy Passive solar heating
•Sunlight is captured directly within a structure
•Heat is ____________________ ____________________________________________________
A passive solar & superinsulated design is the cheapest way to heat a home in regions where sunlight is available more than 60% of daylight hours.
The Secrets of a Passive House
When completed, the Landau residence now under construction in Norwich, Vt., will be one of about a dozen buildings certified as “passive houses” in the United States. Their strict building standard sets limits on total energy consumption and peak heating and cooling demand. A heat exchanger circulates fresh air throughout the house and reuses warmth from the inside air. The result is a house that typically uses 90 percent less energy for heating than a conventional house. | Related Article »
The Secrets of a Passive House
When completed, the Landau residence now under construction in Norwich, Vt., will be one of about a dozen buildings certified as “passive houses” in the United States. Their strict building standard sets limits on total energy consumption and peak heating and cooling demand. A heat exchanger circulates fresh air throughout the house and reuses warmth from the inside air. The result is a house that typically uses 90 percent less energy for heating than a conventional house. | Related Article »
http://www.nytimes.com/2010
/09/26/business/energy-
environment/26smart.html?e
mc=eta1&pagewanted=print
Passive Home Design
Solar Energy
Active solar heating
•solar collectors absorb solar energy & a _____________ supplies the building’s space or water heating needs
Rooftop Solar Hot Water on Apartment Buildings in China
Pros
•solar energy is free
•net energy yield is high for passive & moderate for active
•technology is well developed & easily installed
•_________________
•does not emit polluting or greenhouse gases
Cons
•___________________________
•solar collectors are ugly to some people
•active systems are costly
Active & Passive Solar Heating
Solar Energy: Producing Electricity Ways to Generate Electricity from Sunlight 1. Photovoltaic cells (solar panels)
•solar energy converted into electrical energy by photovoltaic cells
•sunlight striking _____________ atoms creates an electrical current
•electrical energy can be stored in batteries for use when the sun is not shining
Fig. 16-17a, p. 415
Single solar cell
Boron-
enriched
silicon
Junction
Phosphorus-
enriched silicon
Roof options
Solar shingles Panels of solar cells
TRADE-OFFS
Solar Cells
Advantages Disadvantages
Fairly high net
energy yield
Need access to sun
Work on cloudy days
Low efficiency
Easily expanded or
moved
Need electricity
storage system or
backup Quick installation
Environmental costs
not included in market
price No CO2 emissions
Low environmental
impact
High costs (but
should be competitive
in 5–15 years)
Low land use (if on
roof or built into walls
or windows)
High land use (solar-
cell power plants)
could disrupt desert
areas
Last 20–40 years
Reduces dependence
on fossil fuels
DC current must be
converted to AC
Solar collectors reflect light. And are ___________________
________________________________________________.
Solar Energy: Producing Electricity Ways to Generate Electricity from Sunlight 2. Concentrated Solar Thermal (CST)
Hydroelectric dams
Hoover Dam
Video: Hydropower http
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Grand Coulee Dam
Built 1933-1942
550 ft high
Required 12 million cubic yards of concrete
(Fun Fact: enough concrete to make a 4 ft. sidewalk that wraps around the equator twice)
Currently produces enough power for ~___________________ in 11 states.
607 ft high, __________________
1,200 towns and villages flooded during construction
Chinese government says in addition to providing needed energy will help control flooding on Yangtze
18,200 Megawatts
Three Gorges Dam Video (2006)
http://www.cbsnews.com/video/watch/?id=1736433n
Pros
•No emission of greenhouse gases
•High net energy yields
•Technology well-developed, inexpensive once in place Cons • Dams______________________________ •Alters downstream habitat:
reduces _______________ to downstream habitats _______ water which can result in warmer water
less dissolved oxygen due to higher temperature and less mixing.
• Dams interfere with fish runs •Requires abundant water & large elevation differences •Water supplies are often seasonal • In arid areas, loss of H2O in reservoirs due to evaporation
Pros
•unlimited source of energy at favorable sites
•moderate to high net energy yield
•easy to build & expand
•emit no pollutants or greenhouse gases
•_______________ ________________
Producing electricity from wind
Solutions: Wind Turbine and Wind Farms on Land and Offshore
Advantage of offshore sites: winds less turbulent
Review of weather to explain why ocean winds more consistent:
Wind is caused by :
____________________________________________________
____________________________________________________
____________________________________________________.
Cons
•economical only in areas with steady winds
•____________________are necessary since winds are not always steady (____________ energy source)
•mass production takes up a great deal of land space
•noise pollution
•may interfere with____________
Video- Largest Offshore Wind Farm in England
http://abcnews.go.com/Technology/video/worlds-biggest-off-
shore-wind-farm-opens-england-turbines-electricity-power-green-
energy-technology-11713700
Video- The Battle over Cape Cod Wind Farm
http://www.cbsnews.com/video/watch/?id=6386549n
Using water heated from volcanic activity to create electricity.
The Krafla Geothermal Power Station in Northern Iceland
Video on Geothermal Energy for Electricity http
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Pros:
• No greenhouse emissions
• Plentiful supply in some areas
• Moderate net energy yields
• ___________________________
Iceland
Cons:
• ___________________
____________________
• Scarcity of easily
accessible sites
• Extraction of water can
cause subsidence of land
(land can sink)
•Costly in all but most
concentrated sources
TRADE-OFFS
Advantages Disadvantages
Geothermal Energy
Very high efficiency Scarcity of suitable sites
Moderate net energy
at accessible sites
Can be depleted if used
too rapidly
Environmental costs
not included in market
price Lower CO2 emissions
than fossil fuels
CO2 emissions
Low cost at
favorable sites Moderate to high local
air pollution
Low land use and
disturbance Noise and odor (H2S)
Moderate
environmental
impact
High cost except at the
most concentrated and
accessible sources
Geothermal Heat Pumps:
The ground temperature _______________________________.
Geothermal pumps move a fluid through underground tubes that
will be heated in the winter and cooled in the summer.
Geothermal Ground Source Heating/Cooling Video
http
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