Power from the Sun: Solar, Hydro and Wind

1
Power from the SunSolar, Hydro and Wind

• Dennis Silverman
• U. C. Irvine
• Physics and Astronomy

2
Solar Power

• Most of all energy we use comes or has come from
  the sun.
• Fossil fuels arise from fossil plants and animals
  converted to carbon (coal), or hydrocarbons
  (methane and petroleum).
• We are 1/3 to 1/2 through the process of burning
  hundreds of millions of years of fossil fuel
  accumulations in two centuries.

3
Free Solar

• The sun would heat the planet to 0 Fahrenheit
  without the atmosphere.
• The sun runs the greenhouse that keeps the earth
  warmed up to an average of 58 F with the
  greenhouse gas atmosphere.
• It evaporates the oceans to provide the rain and
  fresh water for crops and drinking water and
  hydropower.
• It powers the weather to provide winds.
• It grows our crops and forests through
  photosynthesis
• Solar energy provides our daylight and moonlight.
• It heats our buildings in the daytime, and the
  sea and land hold heat for the night.

4
Pharoah Akhenaten and Queen NefertitiMonotheism
of Aten, the Sun, 1353-1336 BC Possible father of
Tutankhamen (King Tut)
5
Solar Manipulation

• The next best way to use solar is to modify its
  effects.
• Reflective roofs to keep buildings cool
• Reflective windows to keep out direct sunlight
  during the summer, and keep heat in during the
  winter
• Windows and skylights for indoor daytime lighting

6
Paint Your House White? Santorini
7
Direct Solar Energy

• Mediterranean climates now using rooftop or
  nearby solar water heating Greece, Israel,
  Japan. It is 80 efficient.
• Solar clothes drying

8
Solar Photovoltaic Electricity

• Silicon wafers doped to form photovoltaic cells
• Power is free, but
• Large wafers still thick and crystal grown as
  chips, so still expensive
• Cost still 3 to 10 times as expensive as fossil
  fuel power
• Efficiency only 10 to 15, so large areas needed
• Daily and yearly average only 1/5 of maximum
  power capacity installed
• Dont need storage if send excess power back over
  the grid
• Storage could be in charging car batteries or in
  hydrogen fuel, or
• Concentrate on using more energy during the
  daytime
• Silicon valley investigating thin film disk
  technology to make cheaper

9
Unelectrified Areas

• Two billion people do not have electricity
• To save on kerosene lanterns, solar cells with
  batteries and lcd lights have been developed for
  nighttime lighting
• Also used to charge freeway phones

10
Californias Million Solar Roofs

• California SB1 (Senate Bill 1) to provide rebates
  to equip solar power installations
• Goal is 3 gigawatts solar by 2017
• This could be 3 kw/household, at 9/watt is
  27,000/household
• Companies rebated per kwh generated
• New homes must offer solar option by 2011
• 500,000 more homes can be added to generating
  electricity into the power network
• 2.8 billion CA cost, 30 Federal rebate, up to
  18 billion total cost, but for less average
  electricity than a nuclear plant at 2-3 billion.
• Could only nearly pay if it brings down costs
  through economies of scale,
• or if it leads to technological breakthrough
  through research and competition
• Only 100 million for solar water heating

11
U. S. Solar Resources
12
U. S. Tracking Mirror Solar
13
Solar Trough Mirrors

• Suitable For Large Systems
• Grid-connected Power
• 30-200 MW size
• Heats mineral oil to hundreds of degrees
• Then vaporizes a fluid to drive a turbine

14
Dish with Sterling Engine

• Modular
• Remote Applications
• Demonstration Installations
• High Efficiency
• Conventional Construction
• Heat expands gas and drives piston

15
Solar Tea? Tibet, Dreprung Monastery
16
Solar Tower

• Suitable For Large Systems
• Grid-connected Power
• 30-200 MW size
• Potentially Lower Cost
• Potentially Efficient Thermal Storage
• Molten Salt heated, averages out solar input
• Can store heat overnight

17
Cost Of Energy(Max Lechtman)

• Trough Dish/Engine Tower
• 2000 11.8 17.9 13.6
• 2010 7.6 6.1 5.2
• 2020 7.2 5.5 4.2
• 2030 6.8 5.2 4.2
• Cents/kWh in 1997

18
Hydropower

• Of the renewable energy sources that generate
  electricity, hydropower is the most often used.
  It accounted for 7 percent of total U.S.
  electricity generation and 75 percent of
  generation from renewables in 2004
• Over one-half of the total U.S. hydroelectric
  capacity for electricity generation is
  concentrated in three States (Washington,
  California and Oregon) with approximately 27
  percent in Washington, the location of the
  Nations largest hydroelectric facility the
  Grand Coulee Dam

19
How Hydropower Works
20
(No Transcript)
21
World-wide, about 20 of all electricity is
generated by hydropower.
22
Glen Canyon Dam and Power Station
23
Aswan Dam on the Nile River
24
Wind Power - Mykonos
25
Clipper Ship
26
World Wind Capacity. Total now 74 Gigawatts
worldwide, with 65 in Europe. Market growing at
32 a year. 3.3 of European electricity now
from wind. 1 of U.S. electricity.
27
Wind Generation Physics

• Power proportional to the cube of the wind
  velocity.
• (v² from Bernoulli pressure for force on
  wingshaped propeller, times a distance per second
  of rotating propeller, which is proportional to
  v.)
• Most of energy from small bursts.
• ½ of energy comes in 15 of the time.
• Average capacity factor is 35 of the maximum.
• Wind turbines best spaced 3-5 times the rotor
  diameter perpendicular to the wind, and 5-10
  times the diameter parallel to the wind.

28
Virginias Switzerland Wind Power Proposal

• 39 towers of 400 feet height
• 2 million per tower at 1 megawatt
• So about a 40 megawatt peak project
• Enough power for 15,000 homes x
• 12,000 kwh/yr / 9,000 hours/year
• 20 million watts average
• Implies a 50 duty cycle
• To compare to a 1 gigawatt nuclear plant, would
  require 50 such projects, or about 2,000 wind
  towers and 2 billion.

29
England, Germany, Netherlands10 Gigawatt
Foundation Project

• Proposal for 2,000 wind turbines of 5 megawatts
  each to make 10 gigawatts
• Could power more than 8 million homes
• Would cover 3,000 square kilometers
• In the southern North Sea

30
Here Comes The Sun (by George Harrison)
Conclusions

• All renewable energy is local Adapt to locally
  available sources of renewable energy
• Energy conservation is still the cheapest form of
  making energy available
• In California, solar water heating is the next
  cheapest source of energy
• Hydro should be maintained
• Solar arrays are efficient and should be
  supported
• Wind power is about the cost of nuclear. Have to
  find the right location. Siting a problem with
  views, noise, birds.
• Nuclear power is omitted from renewable, but
  should be included as it also is non-polluting
  for greenhouse gases.
• Solar photovoltaic needs more research and
  improvement, and is currently a wasteful
  investment.