Large Scale Solar Energy Production

The key is to connect facilities to the power grid and sell power to the consumer at a competitive rate:

• Current costs are about 25-50 cents per KWH for Solar Generated Electricity
• Average price for the country from coal, hydro, nuclear, etc., is about 13 cents per KWH

De-Centralized vs. Centralized Mythology

• Decentralized idea --> individual rooftops of homeowners and businesses decouple the community from the power grid

• Centralized --> large facility in sunny climate is connected to the community via transmission lines (e.g. Eastern Oregon sends power to the Willamette Valley)

Because transmission losses are low (approximately 1% per 60 - 100 km) a solar PV facility that is within a few 100 km of the community is a more cost-effective investment than the decentralized model.

How Can Solar Large Scale Production Then Occur?

• Subsidize the industry so that the government absorbs most of the costs
• Wait for technological breakthrough --> amorphous silicates; thin films; 2 and 3 band systems
• Make the consumer pay the real costs of energy generated by other means
• TAX fossil fuel consumption!
• An Overview
• Example Pilot Project

What Large Scale Facilities Are There?

California has 90% of the current world's solar electricity production!

• Solar Thermal dominates over Solar PV production but that is changing
• Capacity is currently 371 Megawatts
• A new coal fired plant has a capacity of 1000 Megawatts
• Total capacity requirements of US are about 100,000 Megawatts
• Current solar production is thus 0.4% of total

How much is 370 Megawatts?

• 300,000 KWH over an 8 hour period
• Typical home would use about 10 KWH in this period
• So 30,000 homes could be supplied with power

What about PV production facilities?

• Capital costs are huge
• Operating costs are trivial
• Therefore it's difficult to meter the product - electricity
• PV power is not subject to price fluctuation like fuel-based power generation
• Reliability is high; annual variation in insulation is about 1% and failure rate of PV's is known so can be compensated for
  
  
  
• In many respects a large scale PV facility is like a hydroelectric dam high capital costs, low operating costs, river flow subject to fluctuation due to precipitation but Hydro is 15 times more efficient than PV panels (so KWH costs are 15 times less!)
• PV facility is ideal for supplementing the power grid
• PV is a cost-decreasing technology as the price drops by about 30% when manufacturing output doubles --> suggests that one should invest in this technology now
• Polluting technologies have enormous hidden costs which PV's don't have
• PV plants do fit in the corporate hierarchy!
  • PV cells are small, have no moving parts and do not require large organizations to maintain them and to schedule downtime and retrofits.

  • PV cells do not need organizational support to negotiate fuel contracts and to keep track of fuel inventories and purchases.

  • PV cells cannot be dispatched and hence do not respond to traditional >decision-making authority.

    Hence, rate increases should never occur for PV supplied electricity!

Conclusion: PV technology is likely to offer improved efficiency and lower manufacturing costs over time. If subsidies can be used to offset initial capital costs, then the price to the consumer becomes competitive.

Read More about PVs

Solar/Electric Cars

Currently there is a big Marketing Problem with Electric Vehicles. Consumers simply won't buy them. Here are some attempted marketing strategies:

• Reduced range of electric cars is irrelevant since most people drive less than 40 miles per day. This is true and electric cars are certainly practical for "getting around town".

• Fossil fuel use in internal combustion engines is the single largest environmental problem on the planet. This is debatable but certainly there are direct health hazards as well as global warming

• Conversion of gas powered cars to electric cars is a good form of consumer recycling true but we don't have noble consumers and conversions cost at least $9,000

• Electric cars are more efficient per dollar and yield better air quality this is mostly true; decreased fuel costs for EVs make them more cost-effective in the long run

• An electric car bought today, will only get better over time. Within the next 3 years, batteries will be available which will double and triple your per-charge-range. one can hope this is the case!

  Basic Idea:

  Array of solar collectors on the car's surface delivers electricity to batteries which then power the car and can be recharged.
  • Tradeoff between Range and Power
  • Battery storage technology is the key

  Example

  A practical motor vehicle needs about 30 KWH of deliverable energy for a range of 100 miles.

  For reasonable performance about 20 hp must be delivered to the drive train.

  Efficiency of energy delivery from batteries to drive train is about 40%

  • Delivered energy = 40% of stored energy
  • So you need 30 KWH/0.4 = 75 KWH of stored energy
  • Energy storage density of lead-acid batteries is .04 KWH per kilograms
  • So you need 75/.04 = 1875 = 4125 pounds of lead-acid batteries

  • Power: 20 hp/0.4 = 37.3 KW
  • Power density of lead-acid batteris is .07 W/kg
  • So you need 37.3/.07 = 533 = 1172 pounds

  So the range requirements are more severe than the power requirements.

  Improvements in battery technology are definitely required.

  Other types of batteries:

  Material	Energy Density (W-hrs/kg)	Power Density (W/kg)	Comments
  Lead Acid	40	70	Long Cycle Life
  Nickel Iron	55	100	Very Long Cycle Life
  Sodium Sulfur	90	100	300-350 C operating temp
  Lithium-Iron sulfide	100	> 100	400-450 C
  Nickel-Zinc	75	120	low cycle life

  Driving Habits and Requirements

  • Long distances - Interstate --> 75 mph and 400 mile range
  • Daily Commute --> 55 mph and 35 mile range
  • Puttering around town --> 35 mph and 20 mile range

  It is very unlikely that electric cars will ever have prodution line performance that satisfies the Interstate requirement.

  Most practical application is for in town commuting/shopping and this would then eliminate a major source of air pollution

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