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RENEWABLE ENERGY WORLD


Our world is faced with a growing crisis of global warming cause by greenhouse gas emissions, primarily consisting of CO2. Oil prices have skyrocketed, and no reductions are likely ever again.
A renewable energy society IS possible, and the transition is less costly than many would believe.
Although the US already has a small portion of its energy needs provided by renewable energy sources, including hydroelectric, wind, solar, geothermal, ethanol made from corn, and biodiesel, the US investment in solar still lags other major countries.
Of these, solar power has the least maintenance, and the potential for everyone to have their own power source. Cost has always been a big issue, but with Photon Energy Systems low cost modules, these costs drop dramatically. We are within reach of power systems, fully installed, of $2/watt.

US CONVERSION OF OIL CONSUMPTION TO SOLAR POWER

Lets look at what it would take to build enough solar power systems to replace the entire US consumption of oil.

Variables Value Units
US oil consumptions (2004) 2.04E+07 barrels/day
US gas consumption 3.13E+11 gal/year
Energy equiv 1 gal in Prius 8 kwh
US energy consumption 2.50E+12 kwh
Capacity factor 18 %
CA equiv array 1576.8 kwh/year/kw
Power of US equiv solar array 1.59E+09 kw
Solar power typical 137.64 watt/sq meter
Size of US equiv solar array 4452.75 sq miles
Side of equiv square 66.73 miles
Installed cost rate $2.00 per watt
Total cost $3,173,333,333,333
US population 3.00E+08
Cost per person $10,577.78
Interest rate 6.00%
Payment period 20 yr
Total cost per person ($75.78) cost per mo
Size of array per person 5.29 kw
Size for average home of 4 21.16 kw
Cost per home $42,311.11
Array size 153.70 sq meter
Array size in square feet 1,654 sq feet



Size of fab

Typical fab capacity 20 MW/yr
Typical fab size 36000 sqft
Time to fab  20 yr
Total fab capacity needed 79333 MW/yr
Fab size needed 5.45 sq miles
Typical fab cost $6,000,000.00
Fab cost rate $300,000.00 $/MW/yr
Total fab cost $23,800,000,000.00


Bottom line? It would cost every person in the US $10.6k, potentially spread out over 20 years, to build enough solar power to completely replace the entire US oil consumption.
And once such a system is in place, from that point on, for at least 25 years and longer, the system continues to generate power at very little cost - there is almost no maintenance. Flat panel solar energy systems in general will last much longer than 25 years  if designed properly, degradation is primarily due to interconnect corrosion, NOT the cells themselves.
New studies show that silicon crystalline and polycrystalline PV has the lowest long term degradation of any flat plate PV technology:
See osterwald_wcpec.pdf
The above described scenario is worst case - other renewable energy sources will take a large portion of this burden. Aircraft will have a bigger issue with fuel. Battery powered aircraft are not likely, although experimental solar/electric aircraft have now demonstrated the ability to fly continuously - see the Solong project.

ENERGY STORAGE

Of course the sun doesn't shine all day, and winter energy levels are typically 1/2 of summer. Cloudy days will have reduced energy levels. So to make a solar system work as a replacement for oil used  as an energy source, there needs to be a storage medium. Currently a few residential customers use sealed lead-acid batteries as a battery backup. A typical home system of 5kw can use a 20kwh battery backup, typically good for 1-2 days - and is recharged during the day. The cost is minimal - less than $3000. Lifetime is expected to be 7 years or more - since the array is grid connected, the batteries are only used when the grid fails.

HOME POWER

We've made a simple Excel spreadsheet to make it easy to evaluate costs of solar PV systems, and their benefits.
Download solar_power_home_costs.xls

Here's a typical example:
Solar Power Costs        
Power needed 9460 kwh/yr    
Fraction coverage 100 %    
AC output needed 6.00 kw    
Module area 8.00 sqft    
Area needed 505 sqft    
Modules 63      
Power per module 100 watts    
DC power 6315 watts    
Inverter efficiency 95 %    
AC power 5999 watts    
Module cost rate $3.00 watt    
Module Cost $18,946      
Inverter cost rate $0.50 watts    
Inverter cost $3,158      
Installation cost rate $1.00 per watt    
Installation cost $6,315      
Battery backup days 1 day    
Battery storage needed 26 kwh    
Battery cost rate $90 kwh    
Battery cost  $2,333      
Battery replacement time 7 yr    
Rebate rate $2.50 watt    
Rebate amount $14,999      
         
Total cost $15,753      
Loan rate 7 %    
Loan period 5 yr    
Monthly payment -$312      
         
Capacity factor 18 %    
CA equiv array 1576.8 kwh/year/kw    
Output per year 9460 kwh    
         
         
Degradation rate -0.30 %/yr    
Maintenance cost per year per kw $10.00      
Maintenance cost per year batteries $333.23      
Maintenance cost per year $60 yr    
Maintenance cost per year w/ batteries $393 yr    
         
Output after year: 25 50 75 100
% 92.8 86.1 79.8 74.0
Total power delivered - kwh 227943 439392 635541 817496
Cost w/ maint w/out batteries $17,252 $18,752 $20,252 $21,752
Cost per kwh amortized w/out batteries $0.08 $0.04 $0.03 $0.03
Cost including maintenance w/ batteries $25,583 $35,414 $45,244 $55,075
Cost per kwh amortized w/ batteries $0.11 $0.08 $0.07 $0.07
         
Typical CO2 emission from oil 583 kg/MWh    
Power per lifetime per MW of PV (MWh) 39420 78840 118260 157680
Emissions saved (kg) 132891 256166 370520 476600
         
Typical gas consumption per MWh 125 gal    
Gas saved (gal) 28493 54924 79443 102187



EVOLUTION OF TRANSPORTATION


Hybrid vehicles greatly increase gas milage - from a typical 30mpg to 50mpg and more for comparable size cars (Camry vs Prius). Increasing the battery storage to allow for a typical daily commute of 40 miles, charged by a solar array, would require around 10kwh - easily provided by the above system. Except for longer trips, this would reduce gas consumption to zero. This approach is being supported now by many groups such as the California Cars Initiative

ELECTRIC CARS


Electric cars with reasonable ranges of 300 miles are now doable - technology pioneered by companies such as AC Propulsion
and Tesla Motors.
Cost and recharge time are still issues - but there is a potential hidden benefit. The large battery packs represent a huge potential storage while the car is plugged in.