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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.
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