estimating solar energy requirements to meet u.s. energy needs: an outreach event
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Estimating solar energy requirements to meet U.S. energy needs: an outreach event . Daniel Esposito, 1 Vernon Alt 2 1 Columbia University 2 Northrup Grumman Corporation. An Introduction to Energy and Power. Energy is the capacity to do work and has the unit of Joules (J) - PowerPoint PPT PresentationTRANSCRIPT
Estimating solar energy requirements to meet U.S. energy needs:
an outreach event
Daniel Esposito,1 Vernon Alt2
1Columbia University2Northrup Grumman Corporation
20 mW
60 W
1.2 kW
1 GW
An Introduction to Energy and Power• Energy is the capacity to do work and has the unit of Joules (J)• Power is the rate of energy consumption or generation and has
the unit of Watts (W), equal to one Joule/second.
3,500,000,000,000 W
= 3.5 TW= 3.5x1012 TW
Primary Power Use in the U.S.
Today’s Question: How Many Solar Panels are Needed to Power the U.S.?
B.) Virginia102,000 km2
A.) Connecticut13,000 km2
D.) Alaska1,507,000 km2
C.) Texas684,000 km2
(40,000 mi2)
(5,000 mi2)
(267,000 mi2)
(588,000 mi2)
Photovoltaic Energy Conversion
ElectricityLight
Load
U.S. Energy consumption= 3.5 TW
Solar Panel
Area?
Why Solar Energy?1. Solar is abundant
130,000 TW
Why Solar Energy?1. Solar is abundant2. Solar is widely available across the globe
Why Solar Energy?1. Solar is abundant2. Solar is widely available across the globe3. Solar is a renewable resource
Why Solar Energy?1. Solar is abundant2. Solar is widely available across the globe3. Solar is a renewable resource4. Solar is environmentally friendly. It does
not emit green house gases or other pollutants while operating
Description of a Solar Cell 4 main components of a solar cell:
Sun light
3. back contact2. front contact1. Semiconductor
4. wires(+)(-)
Electricity
Leads
Measuring electrical power produced by aa solar cell
1. Voltage (units: Volts)2. Current (units: Amps)3. Area (units: cm2)
Multimeter
Quantities to be measured
Power = (Voltage) x (Current) [=] Watts
Calculating Required Area of Solar Panels:
1. Find electrical power from a single solar panel (Ps ) :
(unit: Watt)
2. Find number of Solar Panels required to get 3.5 TW:
Number of Panels = 3,500,000,000 ,000 Watts
(Power from 1 panel)x(6/24)
3. Find total area occupied by solar panels
Total Area = (Number of panels) x (Area of 1 Panel)
Ps = (Voltage) x (Current)
Virginia102,000 km2
Connecticut13,000 km2
Alaska1,507,000 km2
Texas684,000 km2
(40,000 mi2)
(5,000 mi2)
(267,000 mi2)
(588,000 mi2)
How did you do???
Why Isn’t Solar Energy More Prevalent?
1.$$$$$$$$$$2.Solar Intermittency
Why Isn’t Solar Energy More Prevalent?
Price trends in U.S., 1976-2009^
^ J. Newman, J. Electrochem. Soc., 2012.
3. Efficiency
Final Questions?
Extra Slides
What is Electricity, and how do we quantify the energy/power in electricity?
•Electricity is the flow of negatively charged electrons •Three major metrics to describe electricity:
1. Voltage (V) 2. Current (I) 3. Power (P)
electron(-)
(+)
V
Power= Current x Voltage
Unit: WattUnit: Volt Unit: Amp
(-)
(+)
𝑷=𝑰𝒙𝑽 ❑
•Light is made of photons•The more photons being emitted by a light source, the brighter the light source appears, and the more power being released by the light source
Power Power
low
high
What is Light?
How do we measure the power contained by Light?
1. Brightness (B)
Flux meter
2. Power, also known as Irradiance (PL )
unit: lux
unit: mW / cm2
Detector
PL = B/1,000
=60 billion light bulbs
=3 billion toasters
=4 thousand nuclear plants
3,500,000,000,000 W
Primary Energy Use in the U.S.
Technology (Math & Science)
Policy Business•Politicians•Psychologists•Sociologists•Urban planners
•Economists•Bankers•Marketing
•Engineers (Chemical Electrical, Mechanical, Civil)•Scientists (Chemists, Physicists, Biologists)•Technicians & skilled workers
How do we make Solar Panels more common
Sustainable Energy Future
Where does Energy Come From?
(Oil)
2 MAJOR Problems with fossil fuels
1. Fossil fuels are non-renewable
2 MAJOR Problems with fossil fuels
2. Global Warming / Pollution
Fossil Fuels(Coal, oil, natural gas)
Energy
2 MAJOR Problems with fossil fuels
Fossil Fuels(Coal, oil, natural gas)
Energy
2. Global Warming / Pollution
Some outgoing light is trapped by the earth’s atmosphere and warms turns it into heat
Some light is radiated back into space by earth
Much of the sun’s radiation is absorbed by the Earth
Greenhouse Gas Effect
One More Important Metric: Efficiency
ElectricityLight
PL PPV
One More Important Metric: Efficiency
Power produced by the solar panel
Power from the sun or light
Conversion efficiency=
ElectricityLight
PL PPV
PPV
PL
=
Electrical Loads
2 Amps
20 mAsmall lights
Refrigerator
80 mARadio