Our total energy use can be divided into three principal areas each of which consume approximately equal amounts of energy on an annual basis:

• Electricity Generation
• Space Heating
• Transportation

This energy use has been roughly constant over the last 5 years and is dominated (90%) by the use of fossil fuels.

Fossil Fuels come in 3 principal forms from which many other products are derived:

• Coal
• Natural Gas
• Crude Oil

Most traditional Energy production comes about via steam driven turbines so the heating of water is what is essential.

• Coal Fired Steam Plants
• Nuclear Fired Steam Plants
• Oil/Natural Gas Fired Steam Plants

The Need for Alternative Energy

• Basic concept of alternative energy sources relates to issues of sustainability, renewability and pollution reduction.

• In reality, Alternative Energy means any thing other than deriving energy via Fossil Fuel combustion

• Basic Barrier to all forms of alternative energy lies in initial costs!

• Currently we have no significant production line alternative energy source operating anywhere in the US!

We have about 50 more years of production from known reserves , after that we will either have to discover more reserves are shift away from our fossil fuel based energy economy.

Forms of Alternative Energy:

• Solar:
  Advantages: Always there; no pollution

  Disadvantages: Low efficiency (5-15%); Very high initial costs; lack of adequate storage materials (batteries); High cost to the consumer

• Hydro:
  Advantages: No pollution; Very high efficieny (80%); little waste heat; low cost per KWH; can adjust KWH output to peak loads; recreation dollars

  Disadvantages: Fish are endangered species; Sediment buildup and dam failure; changes watershed characteristics; alters hydrological cycle

• Wind:
  Advantages: none on large scale; supplemental power in windy areas; best alternative for individual homeowner

  Disadvantages: Highly variable source; relatively low efficiency (30%); more power than is needed is produced when the wind blows; efficient energy storage is thus required

• Geothermal:
  Advantages: very high efficiency; low initial costs since you already got steam

  Disadvantages: non-renewable (more is taken out than can be put in by nature); highly local resource

• Ocean Thermal Energy Conversion:
  Advantages: enormous energy flows; steady flow for decades; can be used on large scale; exploits natural temperature gradients in the ocean

  Disadvantages: Enormous engineering effort; Extremely high cost; Damage to coastal environments?

• Tidal Energy:
  Advantages: Steady source; energy extracted from the potential and kinetic energy of the earth-sun-moon system; can exploit bore tides for maximum efficiency

  Disadvantages: low duty cycle due to intermittent tidal flow; huge modification of coastal environment; very high costs for low duty cycle source

• Hydrogen Burning:
  Advantages: No waste products; very high energy density; good for space heating

  Disadvantages: No naturally occurring sources of Hydogren; needs to be separated from water via electrolysis which takes a lot of energy; Hydrogen needs to be liquified for transport - takes more energy. Is there any net gain?

• Biomass Burning:
  Advantages: Biomass waste (wood products, sewage, paper, etc) are natural by products of our society; reuse as an energy source would be good. Definite co-generation possibilities. Maybe practical for individual landowner.

  Disadvantages: Particulate pollution from biomass burners; transport not possible due to moisture content; unclear if growing biomass just for burning use is energy efficient. Large scale facilities are likely impractical.

• Nuclear Fusion: --> Forget it, we aren't smart enough yet. But suppose we become smart enough in a few hundred years. Can adoption of sustainable energy technology get us to this point?