The Sun is our greatest renewable energy resource, but solar PV panels
are too expensive and inefficient to seriously cut national energy consumption.
We have a better solution that gets more solar heat for less cost.
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Solar Electricity ... or ... Solar Heating?
The Sun is our life-sustaining heat source, so it makes sense to harness
its power to heat our homes, offices, buildings, and industries. But this
is not the direction of today's renewable-energy technologies. The trend
is to make electricity from the Sun's power, in an attempt to substitute solar cells for fossil-fuel
electricity. This is inherently very inefficient and costly. A
photovoltaic (PV) solar panel generates 24V DC current, which has to be
inverted to 110 or 220 volt AC for homes and offices, an inefficient process
that loses 20% of power. The total solar power lost converting to
electricity is shocking -- only 10-15% of solar energy is captured by a
PV panel, 20% is lost by inversion and makes heat. In sunny climates, only
10% of solar heat can be made into electricity, and in cloudy climates,
only 5% is captured. Also solar PV electric panels and inversion
to AC produces heat, so on a large scale, millions of them can actually
worsen, rather than alleviate, global warming!
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Nevertheless, solar PV panels for making electricity from the sun's heat
are more environmentally friendly and more tolerable to people than are
huge wind turbines, which harvest more power. The biggest problem with
solar electric panels is they are too expensive for the power they produce,
as seen below. When their cost drops to 1/10th of today's cost, solar
electric panels could lead renewable energy. |
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Cost Inefficiency for Industries
Companies promoting solar electricity rarely mention the cost inefficiency.
On a big building scale, the costs are excessive and the payback period
is a show stopper. Chico University, at left, installed 1212 PV solar panels
at a cost of $2.8 million, to save $14,000 per year in electricity bills.
That is a cost saving of $11.50 per panel per year, and a payback period
of 200 years! Big installations should be more cost effective than
small ones -- but not in the case of this typical university installation.
Harvard University, left, installed 192 solar panels at a cost of $500,000,
or $2600 per panel, to get just 36 kilowatts of part-time power. At $14,000
per KW installed capacity, this is 3 times the price of solar PV panels
in large-scale solar PV farms.
At present, the cost of solar-electric is so high, and the payback so long,
that roof- top solar installations are far too cost prohibitive for the
bulk of offices, malls, and industries in the U.S. to afford. Therefore,
such solar-electric installations will not help significantly cut the nation's
electricity usage at current 2008 PV panel prices.
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Costliness for Homes
A typical "whole house" solar electricity installation costs
from $20,000 to $35,000, but an elaborate one, such as at right, costs
$50,000 to $60,000. If you are affluent, you can afford that. But
most middle to low income U.S. home owners, who make up the bulk of the
country's population, cannot. Typical savings are only 20 - 30% of
electricity bills, and the payback is 15-30 years. Solar water heating is much more cost effective than that,
with only a $3,000 entry cost,
a typical 5 year payback, and it can save 30-50% off your electricity bill,
a large part of which goes to heat water.
Many wrongly believe homes use only 1 KWh of electricity. But a 1
KW solar array supplies only 25% of house power, the rest comes from the
grid. Most big modern homes with spa and luxuries need at least a 4KW solar
array to deliver 70-80% of power from solar panels. It is expensive
whichever way you figure it -- covering an entire roof with modular solar
shingles (at right) can double the total building cost.
Until solar PV panels drop to $500-$800 per KW for commercial solar farms, and $1000-$2000 per KW for industrial - residential
usage, there is simply NO way to expect the majority of U.S. building owners to pay the price to go solar
electric. And without the majority of the population going to solar or wind to relieve grid demand, we cannot
make any major cut to the country's consumption of polluting fossil fuels like coal, oil
or diesel. The 0.5% of people who can afford it at 2008 prices, will not
make even a tiny dint in the nation's total consumption of fossil fuels
for grid power. |
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Conclusion of Building-scale Solar Electricity
Only when the U.S. deploys renewable solar energy devices across the nation, en masse,
with essentially every home, office and industry equipped with solar
panels to replace a big part of their grid power usage, will we see a major reduction in the
amount of dirty, polluting fossil fuels (and greenhouse
gases they produce) that are burned to generate grid power.
At left, in Germany, government subsidies and low-interest loans proliferated
solar power to many homes. The U.S. is 20 years behind Germany in proliferating
solar power across the nation, so it is unrealistic to think that the U.S.
can utilize solar to make major reductions in greenhouse gas pollution
and dependance on fossil fuels for electricity in the next 20 years. But
if solar PV panels were 1/10th of today's 2008 costs, this would all happen
very quickly. |
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In the mean time, while solar-electric panels struggle to become a
mature and affordable technology economical for mass deployment, PC Research has perfected an innovative new
solution that many people can affordably deploy right now, to cut their electricity bills by 50% or more.
If every home and business could use it, the U.S. could cut burning of dirty polluting
coal by 25%, and totally eliminate burning oil, diesel and gas for electricity
generation! Recall what we said at the beginning -- solar heating
is much more efficient than solar electricity. When you compare the
efficiency and economics of solar heating vs. solar electricity, the difference
is overwhelming.
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| Efficiency Factor |
Solar Electric |
Solar Air Heating |
Solar Water Heating |
| % of Sun's total power or heat lost |
50-80% |
0-20% |
10-30% |
| % lost by inversion, air circulation, and heat conduction |
10-25% |
30% |
10-20% |
| Heating Capacity loss |
60-90% |
30-50% |
20-50% |
| BTUs / year at 250 days x 6 hrs/day |
90 million |
202 million |
36 million |
| BTUs captured per yr w/ energy loss |
19 million |
121 million |
24 million |
Table copyright © 2008 by PC Research, do not copy data
Typical solar installation for 1500 sq. ft. home is 450 sq. ft. area for solar air heat, 80 sq. ft. for solar water,
200 sq. ft. for solar electric; 300 BTU per hour per sq. ft. = full power of sun incident on earth.
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Efficiency of Solar Heating vs. Solar Electricity
Comparing efficiencies of solar electric power vs. direct solar heating
of either air or water, the table at left shows that solar electric panels
lose by a huge margin. Solar heating of water is very efficient because
there is direct contact between the water and hot pipes. Direct solar
heating of air is the most efficient of all -- up to 80% of solar energy
is transferred to the air. As hot air is added to cold in a building,
a 30% to 50% heat loss due to recirculation of the air occurs in our testing.
Even factoring in this heat loss, solar heating of air is more than twice as efficient as solar electric panels (due to their big loss in capturing
solar power and conversion loss). Solar air heating also beats solar
water heating for efficiency (BTUs captured per year in table at left).
Is this surprising? Of course not. Solar energy is heat, not electricity, so it makes sense that using the sun's heat to directly
heat a large air mass is the most efficient. Solar heat is direct power,
electricity is not.
The conclusion of this efficiency comparison is that direct transfer of
solar energy into heat is 10 times more efficient than trying to convert
that heat to electricity, especially AC power that homes need for heat.
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Economics of Solar Heating vs. Solar Electricity
The economic comparison at right is even more convincing of the cost effectiveness
of harnessing the sun's power directly as heat. First, a larger area holding
a big volume of air can be built onto a house than the area for a solar-electric
panel array. Only so many sq. ft. are need for solar water heating
to backup an electric water heater. However, the volume of solar heated
air, and its capacity, is virtually unlimited.
While solar water heat is comparable to solar electric KW output, the effective
capacity of solar heated air is 6x to 7x greater, conservatively. In terms
of $ invested per KWh output, solar air heating far outstrips solar electric
by 20 times (due to the high cost of solar PV panels), and has twice the
heating capacity of solar water heating or more.
Solar electricity, at today's prices, costs almost 1/3rd of your house
cost, and you hope it pays back before you die. Solar water heating
payback is realistic and it cuts out a big part of your electricity usage.
With solar air heating, done our way, you get very fast payback, a nice
addition in value to your home, and a big quality of life boost, all for
a small investment. Our solar air heating technology is the
most cost effective, most efficient way to capture the sun's energy, and
boost your property value and enjoyment at the same time. It is a
winner! |
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| Economic Factor |
Solar Electric |
Solar Air Heating |
Solar Water Heating |
| Average size of Installation |
200 sq.ft. |
450 sq.ft.
3600 cu. ft. |
80 sq. ft. |
| Average cost of installation |
$30,000 |
$8,500 |
$4,000 |
| Total KWh per year |
5,570 |
35,500 |
6,860 |
| KWh per year per $1000 invested |
186 KWh |
4,200 KWh |
1,715 KWh |
| Years to payback total investment |
22 years |
4-8 years |
7-10 years |
Table copyright © 2008 by PC Research, do not copy data
Assumed BTUs per KWh = 3412; grid power = 25c per KWh.
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New Breakthroughs in Sustainable and Renewable Energy;