1. Solar Power & Energy Independence
By Jamie Newton
The amount of the sun's energy that reaches the surface of the Earth every hour is greater than the total amount of energy that the world's human population uses in a year.

2. Overview Solar Energy Potential Non-Electric Solar Power
Technologies
Implications for Energy Independence
Solar Generated Electricity
Distribution Approaches

3. Solar Energy Potential
As of February 2006, Photovoltaic technology accounted for less than 1% of worldwide electricity generation.
The amount of solar energy that reaches the Earth’s surface every hour is greater than humankind’s total demand for energy in one year
See National Economic Council “Advanced Energy Initiative”, p.13 (Feb. 2006) available at
See

4. Non-Electric Solar Power
Solar Water Heating
Passive Solar Heating/Lighting

5. Solar Water Heating
Image Taken From

6. Solar Water Heating Advantages
Replacing or supplementing other water heating methods: natural gas, electricity
Disadvantages
More expensive in cooler climates
Image taken from

7. Passive Solar Heating/Cooling
Passive solar heating can use overhangs to shield the home from the sun in the summer, and warm the home when the sun is lower in the winter sky
See NESEA, Solar Energy for Homes -
Image taken from

8. Solar Heating/Cooling
Large south-facing windows allow sunlight in, which can be trapped as heat by floors and walls. For cooling, open the bottom windows (allowing cool air in) and top windows (letting hot air out), creating a “convection” current. This home near Traverse City, MI gets 85% of its heat from the sun.
- See
Image taken from

9. Non-Electric Solar Power & Energy Independence
Lowered Energy Consumption
Broadening of Energy Portfolio
Reduced Need for Fossil Fuel Imports

10. Solar Generated Electricity
Concentrating Solar Power
Photovoltaic (PV) Cells

11. Concentrating Solar Power
Require Direct Sunlight
Concentrating solar power systems cannot reflect diffuse sunlight, making them ineffective in cloudy conditions
Two Approaches
Power Tower
Parabolic Trough
Image from Charles F. Kutcher (ed.) “Tackling Climate Change In the US: Potential Carbon Emissions Reductions from Energy Efficiency and Renewable Energy by 2030”, p.82 (pdf). Published by American Solar Energy Society, PDF available at Note that darker colors indicate higher solar radiance.
Direct normal solar resource in the Southwest. Image courtesy of “Tackling Climate Change In the US: Potential Carbon Emissions Reductions from Energy Efficiency and Renewable Energy by 2030” (Charles F. Kutcher ed.). Darker colors signify greater solar radiance.

12. CSP Potential Existing US Generation Capacity (2003) = 1,000 GW
State
Available Area
Capacity (MW)
Arizona
19,200
2,467,700
California
6,900
877,200
Colorado
2,100
271,900
Nevada
5,600
715,400
New Mexico
15,200
1,940,000
Texas
1,200
148,700
Utah
3,600
456,100
Total
53,900
6,877,000
Data from from Charles F. Kutcher (ed.) “Tackling Climate Change In the US: Potential Carbon Emissions Reductions from Energy Efficiency and Renewable Energy by 2030”, p (pdf). Published by American Solar Energy Society, PDF available at CSP requires certain land features in conjunction with solar radiance; this data and map indicate the optimal areas for CSP generation plants.
Image from Charles F. Kutcher (ed.) “Tackling Climate Change In the US: Potential Carbon Emissions Reductions from Energy Efficiency and Renewable Energy by 2030”, p.83 (pdf). Published by American Solar Energy Society, PDF available at
- Direct normal solar resource in the Southwest, filtered by resource, land use, and topology. Image courtesy of “Tackling Climate Change In the US: Potential Carbon Emissions Reductions from Energy Efficiency and Renewable Energy by 2030” (Charles F. Kutcher ed.)
Existing US Generation Capacity (2003) = 1,000 GW
Total Potential CSP Generation in Southwest = 7,000 GW

13. Power Tower Solar One (CA) Solar Two (CA) Solar Tres (Spain)
Steam Heat Transfer
10 MW
Solar Two (CA)
Molten Salt Heat Transfer
Solar Tres (Spain)
15 MW
Diagram taken from
Graph taken from

14. Solar Two
Image taken from

15. Parabolic Trough
Sunlight focused on heat transfer fluid (HTF), which then runs steam turbine
See
Image taken from
Diagram taken from

16. Image taken from http://www. fplenergy

17. Parabolic Trough Generating Plant
- See
Image taken from
Image of parabolic trough power plant in Kramer Junction, CA, which supplies power for the greater Los Angeles area. This plant, in conjunction 4 other parabolic trough plants in California, can produce as much as 354MW of electricity.

18. Photovoltaic Cells
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19. Photovoltaic Potential
“The basic resource potential for solar PV in the United States is virtually unlimited compared to any foreseeable demand for energy.”
Paul Denholm, Robert Margolis, & Ken Zweibel, “Potential Carbon Emissions Reductions from Solar Photovoltaics by 2030,” in Tackling Climate Change In The US: Potential Carbon Emissions Reductions From Energy Efficiency And Renewable Energy By 2030, p.99 (Charles F. Kutcher, ed., 2007)
PV is flexible enough that it can be adapted for use in many areas.
See Paul Denholm, Robert Margolis, & Ken Zweibel, “Potential Carbon Emissions Reductions from Solar Photovoltaics by 2030,” in Tackling Climate Change In The US: Potential Carbon Emissions Reductions From Energy Efficiency And Renewable Energy By 2030, p.99 (Charles F. Kutcher, ed., 2007)

20. Photoelectric Effect
Basic process by which a photovoltaic cell converts absorbed sunlight into electricity
“Photons” knock electrons free from the silicon structure, freeing them to enter electric current and power a “load” (like a light bulb)
IEA Photovoltaic Power Systems Programme -
Image taken from

21. Solar Generated Electricity Distribution Approaches
Centralized (CSP)
Advantages and Disadvantages
Distributed (PV Roof Installations)
Distributed PV Generation & Energy Independence

22. Centralized Advantages Disadvantages Traditional model of distribution
No fuel costs
Disadvantages
Non-Constant Power
Vulnerability
See
Image taken from
This PV Array is part of the Sacramento Municipal Utility District, generating 3.2 MW, enough for 2,200 homes.

23. Distributed Solar (PV)
Advantages
Net-metering
Grid Storage
Flexibility
Reduced vulnerability to terrorist attack
Almost no maintenance
Negligible environmental impact
Domestic Production (?)
Disadvantages
Cost
Extensive Individual Investment
Low Conversion Efficiency
CCR’s
Intermittency

24. Net-Metering Peak generation from PV occurs during the day
Net-metering allows users to “bank” electricity they generate, and credit it against the electricity they use
Most states won’t pay users if they generate more electricity than they use, but they can “zero-out” their accounts
As of 2007, net-metering is offered to some degree in 41 states and D.C.
California, New York, Texas
Net-metering is offered in Illinois by one or more individual utilities
EPAct of 2005 requires all states to offer net-metering by 2008
See P.Denholm and R. Margolis, “Very Large Scale-Scale Deployment of Grid-Connected Solar Photovoltaics in the United States: Challenges and Opportunities”, Conference Paper (April 2006), published by National Renewable Energy Laboratory
See

25. Grid-Connected PV
Graphs taken from P.Denholm and R. Margolis, “Very Large Scale-Scale Deployment of Grid-Connected Solar Photovoltaics in the United States: Challenges and Opportunities”, Conference Paper (April 2006), published by National Renewable Energy Laboratory

26. PV Flexibility Stand-Alone Battery Backup Generator Backup Hybrid
Water pumps
Fans
Battery Backup
Isolated Areas
Generator Backup
Hybrid
Remote applications
Grid Connected
Grid storage
Utility Scale
Easy & Quick to build
See

27. PV Applications Images taken from the following pages:

28. Reduced Vulnerability
Roof-by-roof power generation makes it too difficult for one strike to have a crippling effect
Vulnerability of centralized generation was illustrated in the August 2003 US blackout
caused by a series of “tripped” generation facilities and transmission lines
Within the first 2 hours:
3 Coal Fired Power Plants
9 Nuclear Power Plants
5 Major Transmission Lines
Estimated loss from the August 2003 blackout has been placed at $5-6 billion.
See Donald Aitken, “Transitioning to a Renewable Energy Future” p.13 (International Solar Energy Society, 2003) available at

29. Distributed Solar Power and Energy Independence
The ultimate in Energy Independence – self-sufficiency
Consumers becoming “producers”

30. PV Disadvantages Price Community Associations – CCR’s Intermittency
Efficiency
Community Associations – CCR’s
Intermittency

31. Price
Still not “price-competitive” with traditional sources of electricity
“If you don't include the environmental costs of coal-fired electricity when comparing them with solar, it becomes very difficult. [Saving money] is not what motivates me and if that's all that motivates the consumer, then perhaps solar isn't for them.”
Dr. Richard Corkish, University of New South Wales, School of Photovoltaic and Renewable Energy Engineering
“Paying for Itself”
Ability of a PV system to “pay for itself” depends on the size of the installation, electricity demands it is meeting.
Residential PV system may “pay for itself” within first half of its estimated lifespan (30 years)
Peter Vincent, “How Solar Ran Out of Puff,” Sydney Morning Herald,

32. Price Reductions
Year
$/W (Goal)
Residential Installation Cost (2-4 kW)
2005
$8.50
$17,000-34,000
2010
$5.50
$11,000-$22,000
2015
$3.25
$ ,000
2030
$2.00
$4000-8,000
Graph taken from Charles F. Kutcher (ed.) “Tackling Climate Change In the US: Potential Carbon Emissions Reductions from Energy Efficiency and Renewable Energy by 2030”, p.86 (pdf). Published by American Solar Energy Society, PDF available at
See See National Economic Council “Advanced Energy Initiative”, p.13 (Feb. 2006) available at
Goals for DOE’s Solar America Initiative for cost reduction in PV Residential (2-4kW) Systems:
2015 = cents/kWh
2030 = 6-8 cents/kWh
$148M in 2007 Funding for Solar America Initiative to spark R&D

33. Efficiency
Conversion Efficiency – the percentage of solar energy shining on a device that is converted into electrical energy
Typical Efficiencies
Single Crystalline Silicon = 14%
Thin Film = 7%

34. CCRs As of 1999, 42 Million Americans lived in community associations
Many of these communities seek to establish aesthetic uniformity, protecting homeowner and developer investment and lessening the risk of undesirable activities in the community
The Declaration of Conditions, Covenants, and Restrictions are one method used to ensure that homes retain a common design theme w/in a community
See Thomas Starrs, Les Nelson, Fred Zalcman, “Brining Solar Energy to the Planned Community: A Handbook on Rooftop Solar Systems and Private Land Use Restrictions.” (1999) Available at

35. Typical CCR Provisions Restricting Solar Systems
Prior Approval of Architectural Committee
Explicit Restrictions on Placement of Solar Equipment
Height Restrictions
Restrictions on secondary buildings or structures
Requirements that utilities be screened
Restrictions on the placement of improvements
Specifications regarding roofing materials
Restrictions pertaining to architectural style
See Thomas Starrs, Les Nelson, Fred Zalcman, “Brining Solar Energy to the Planned Community: A Handbook on Rooftop Solar Systems and Private Land Use Restrictions.” (1999) Available at

36. Architectural Restrictions
Arizona HOA is battling resident over black solar collector which doesn’t match his light-brown roof
Some state laws have attempted to limit the ability of CCRs to restrict solar improvements
See
Image taken from

37. Intermittency
Obviously, solar power requires sunlight to generate power
This means that:
No power is can be generated at night
Power generation may be reduced by cloud cover
However, PV will still work with overcast skies
Generation techniques requiring direct sunlight (CSP) are ineffective w/o optimum conditions
Solutions:
Generators, Batteries, Hybrid Facilities
Hydrogen

38. Hydrogen Hydrogen can be used as an energy carrier
Hydrogen can be created from water through a process called “electrolysis”
DC current is used to split water into hydrogen and oxygen
Energy from renewable sources, like solar power, can be used to manufacture hydrogen
Commercial feasibility of solar generated hydrogen is far off
See Kroposki, Levene, Harrison, Sen, & Novachek, “Electrolysis: Information and Opportunities for Electric Power Utilities” (September 2006), available at

39. Solar Power and Energy Independence
Lessen Reliance on Fossil Fuel
Stabilize Energy Costs
Re-conceptualize Distribution of Energy
End-user production
Distributed system lessens large-scale vulnerability
Production Method for Hydrogen Economy