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Solar Energy and Personal Behaviors

Emissions reductions need to be rapid and large

- 80% reduction by 2050 to avoid worst scenarios

solar wind

Urgent need for alternate energy sources

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Algae as a source of green liquid fuel

Diatoms are single-celled algae that make silica shells

Some produce 60% lipid by weight

Lipids can be converted to biodiesel or other petroleum substitute

Estimated oil production: 5,000-20,000 gallons/acre/year

At least 10 times yield of next best biofuel crop (palm oil)

>200 times higher yield than corn ethanol

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DOE: In open raceway ponds, enough biodiesel to replace ALL petroleum transportation fuels could be grown in

~10 million acres (~12.5% of the Sonora desert)

Can be produced domestically on otherwise economically undesirable land

- cost estimated by U.S. National Renewable Energy Laboratory to be $1.65 to $2.75/gallon

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Wind power could supply 16 times current U.S. electricity demand using only onshore turbines

- Michigan can supply 12 times our use

Solar is the most plentiful energy source

More energy reaches Earth from the sun in 1 hour than humans on the entire planet use in 1 year!

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Two main ways to capture solar energy

1. Photovoltaic (PV) panels- generates electricity directly

2. Concentrating solar power (CSP)- generates heat, then steam, then electricity

Three main methods for Concentrating Solar Power

1. Central tower: mirrors concentrate the sun's energy on a heat exchanger located on a central tower

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2. Parabolic trough: long, curved mirrors concentrate the sun's energy on a pipe that runs down the center of the trough

- this heats the oil flowing through the pipe, whichboils water in a conventional steam generator toproduce electricity

Mojave desert, CA

3. Parabolic dish: parabolic mirrors concentrate the sun's energy on a Stirling engine

- heat causes expandable fluid to drive a piston or turbine to produce electricity

New Mexico

- can be used on individual level or in large arrays

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We have very good solar sites in the U.S.

But August is much better than January

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A solar array 100 x 100 miles could provide all of US electricity needs today

Could solar energy be used to power Europe?

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Could solar energy be used to power Europe?

A small portion of the Sahara desert could supply all of Europe’s electricity (and the world’s)

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Excess energy captured during the day could be stored as heat and used to produce electricity at night

- can help “stabilize the grid”

- excess energy could be used to run desalinization plants

CSP could also help greenify the desert

Northern Egypt coast

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Greenhouses could even be located under parabolic trough arrays

Globally, can wind and solar supply enough energy?

0

2,000

4,000

6,000

8,000

10,000

12,000

GlobalDemand

WindPotential

SolarPotential

Ener

gy

(E

J/yr

)

Tod

ay 2100

≈

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USA1,000Sunpower

China1,000Sunneeg

China1,100Jinko

Germany1,400SolarWorld

China1,500Hanwha Solarone

China1,700Yingli

China1,900Trina

China2,000Canadian Solar

China2,500LDK

China2,400Suntech

CountryCapacity (MW)Company

Who are the global leaders in solar energy?

Sooo… we’re not doing it now because the cost is much higher than electricity from coal, right?

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Sooo… we’re not doing it now because the cost is much higher than electricity from coal, right?

Coal electricity doesn’t include many “external costs”- e.g. the cost of its CO2 emissions

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- e.g. the human health effects of pollutants

When all true costs are included, coal is more expensive than almost all green options

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The real problem involves not building better technologies but convincing regulators and

ratepayers that it is in society’s best interest to price electricity fairly and accurately.

(Sovacool 2008)

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“Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon

and climate problem for the next half-century.”(Pacala and Socolow, Science 2004)

7 emission reduction “wedges” needed to maintain emissions at 2004 levels through 2054- would keep CO2

level <500 ppm by 2054

What can I do in the meantime to minimize adverse impacts of climate change?

Household behaviors could provide one “wedge”

Household energy use accounts for ~38% of overall U.S. CO2 emissions

~ 8% of global emissions

more than any country’s emissions (except China’s)

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What can I do over the next 10 years to minimize adverse impacts of climate change?

Most important behavioral changes:

1. Replace 20.8-mpg vehicle with 30.7-mpg vehicle

Next time, buy a more fuel-efficient car

20 mpg 30 mpg

50 mpg

Increasing by 10 mpg saves $585 and 1.6 tons of CO2 per year

34 mpg

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What can I do over the next 10 years to minimize adverse impacts of climate change?

2. Weatherize your house: weather-strip, adequately insulate attic, and replace single-pane windows with triple-pane windows

- with 90% compliance, would reduce CO2 emissions by 21 million tons (3.4% of overall household emissions)

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What can I do over the next 10 years to minimize adverse impacts of climate change?

3. Next time, buy energy star appliances

- with 80% compliance, would reduce CO2 emissions by 12 million tons (1.9% of overall household emissions)

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What can I do over the next 10 years to minimize adverse impacts of climate change?

4. HVAC equipment: when necessary, replace older furnace and central AC unit with Energy Star model

- with 80% compliance, would reduce CO2 emissions by 11 million tons (1.7% of overall household emissions)

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5. Change to compact fluorescent light bulbs

One per household would have the same effect as taking 6 million cars off the road

Can save 7 tons of CO2 per year for a family of four

6. Turn the thermostat down (winter) or up (summer)

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- same as driving 3,300 fewer miles

- costs $1.50/month

7. Buy green electricity

One GreenBlock supports 150 KWh of electricity from wind and landfill methane

Unfortunately, energy conservation is not a solution

- really just delays the inevitable

50 mpg

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Emissions reductions need to be rapid and large

- 80% reduction by 2050 to avoid worst scenarios

solar wind

Urgent need for alternate energy sources

Who has the largest impact on Earth’s future?

8. Contact your representatives!

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9. Educate others

10. Vote

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