THE POTENTIAL OF SOLAR ENERGY

1
THE POTENTIAL OF SOLAR ENERGY

• Solar Energy Applications
• EnvS 116
• Asim Zia
• Department of Environmental Studies
• San Jose State University

2
Overview

• Some fundamentals
• Sklars vision Solar energy is ready for use
  today
  
• Which statistics do we need to convert entire
  country on solar power/electricity?
  
• Solar power supply chain compared with biomass
  and coal fired power
  
• Internal processing steps
• Are shorter supply chains/internal processing
  chains better?
  
• Haydens take on solar energy potential
• Open discussion

3
Some fundamentals

• Solar system life another 4.5 billion years
• Sun delivers 15000 times more energy than the
  total energy consumed by human population
  
• Insolation is the amount of sunlight reaching a
  surface. Technically, it is the sum of diffuse
  and direct sunlight on a unit surface in a
  certain time, and is measured in BTU/SQ Feet.

4
Sklars vision Solar energy is ready for use
today

• Solar power (through PV and thermal)
• Solar water heating
• Solar pools/spas/hot tubs
• Solar cars
• Solar air cooling/heating
• Solar crop drying
• Instead of thinking for individual components, we
  need to think at systems level for optimum use of
  solar energy

5
Which statistics do we need to convert entire
country on solar power/electricity?

• Aggregate demand (e.g. in Germany it is 500
  billion kwh)
  
• Insolation (e.g. in Germany it is 1100 kwh/sq
  meter/year
  
• Capacities and footprints of solar power
  technologies (Germanys current PV capacity is
  10 of total insolation, or roughly 110kwh/sq
  meter/year. So, to produce 500 billion kwh,
  Germany will need 5000 sq km of solar panels,
  i.e. about 10 of total constructed space, such
  as roofs and walls )

6
Solar power supply chain compared with biomass
and coal fired power

• PV PV Installation (Onsite generation)
  Distribution
  
• Biomass Planting Harvest Shipping
  Pressing (Gassification conversion to pellets)
  Shipping Power Station National grid
  (medium voltage) Distribution (low voltage)
• Coal Mining Refining Shipping
  Coal-fired power station National grid (High
  voltage) National grid (Medium voltage)
  Distribution (low voltage)

7
Internal processing steps

• Sunlight Solar cell Inverter
  Electricity
  
• Fossil fuel Combustion chamber heat
  Steam Turbine Generator Electricity

8
Are shorter supply chains/internal processing
chains better?

• Solar power provides a decentralized solution to
  energy problem
  
• Low environmental impact
• Theoretically, low economic cost of shorter
  supply chain
  

• Shorter supply chains/conversion to PV will mean
  many people in current fossil economy will loose
  their jobs
  
• Can we really dismantle existing electricity
  transmission network? Do we need to?

9
Haydens take on solar energy potential

• Solar energy is only useful in special niches
  (e.g. remote areas), but it is not adequate to
  run an industrialized world
  
• Carter called for 20 solar/renewable share in
  electricity production by 2000. Actually it is
  only 0.25.
  
• Solar products are not meant for the urban
  environment where most people live
  
• Energy is not an important issue in broader
  economic issues (as only price of fuel is the big
  concern)

10
Haydens take (continued)

• Civilization stinks crowd Ehrlich uses IPxAxT
  to measure environmental impact, but in their
  chapter on energy, Impact (I) is measured as
  indirectly proportional to P
• Are developing countries eco-friendly because
  they are burning wood, or are developed countries
  better which can give charities to developing
  countries when disasters strike?

11
Haydens take (continued)

• Hayden makes fun of those environmentalists who
  whine that the solar energy could not take off
  because the price of oil unfortunately dropped.
  He says It is odd, isnt it, that anybody
  should whine that the price of a useful commodity
  is too low
• Why does solar energy need subsidies? Why it
  cannot compete in competitive markets?

12
Haydens take (continued)

• Solar energy is utterly inadequate to meet
  present needs, let alone to grow as demand
  increases.
  
• Roadblocks to solar energy
• Cost
• Big oil companies do not pose problems as Big
  oil companies like Exxon are in the business to
  make money if they can make it by selling
  electricity from big wind farms or big solar
  installations, they would be perfectly happy to
  do so.
• Sheer scale of solar projects large enough to
  accomplish anything useful
  
• Environmentalists (e.g. wind versus solar versus
  geothermal etc)