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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