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| Bill Stump puts the finishing touches on the racks fro a solar array on 18th street |
In 1973, when the engineering
department at UT finally decided that students could use calculators in class,
my husband Bill put his slide rule in the drawer and we headed to the
University Co-op for a major purchase.
He picked out the deluxe calculator that could do square roots as well
as add, subtract, multiply, and divide.
That was all it could do, but it set us back more than $200, which was
about 50 date-night enchilada dinners at El Patio. These days you can get a free calculator on a
key chain, but that’s the way technology evolves. The early adopters pay more.
Another technology with a
plummeting price is photovoltaic solar panels, as I can attest from personal
experience. In 2006 we bought ten solar
panels (a 2 kilowatt system), with the required DC to AC inverter and roof racking,
for $12,960. We installed them
ourselves, which requires at least one person who understands electricity, and
several others who are not afraid of heights.
If you don’t have the right kind of roof you will also have to put bolts
through the roof, in which case you will definitely need somebody who
understands roof flashing, because you will not like your solar panels if the
roof leaks. After a $2000 tax credit
from the federal government, our cost was about $5.50 a watt.
Please note that this cost of
$5.50 per watt has nothing to do with the cost that you might pay your utility
company for a kilowatt-hour of electricity, which is about 11 cents. A watt of generating capacity will produce a
watt-hour of electricity every hour that the sun shines, day after day, for the
next 30 or 40 years, maybe longer. There
are no moving parts to wear out, and maintenance is close to zero. For the last seven years those ten panels
have produced an average of 215 kilowatt-hours per month. At night, or when the house is using more
than the panels can provide, electricity is supplied by the grid. During the day when nobody is home the panels
are putting electricity back into the grid and the meter is essentially running
backwards. The switching back and forth
all happens automatically.
This year we purchased a much
bigger solar array for almost exactly the same price that we paid for the small
array eight years ago. The panels are
getting more efficient at converting sunlight to electricity, so now we can get
5.6 kilowatts of power in 21 panels.
Even including the racks and inverters, the cost has dropped to $2.13
per watt. Let’s say we get 750
kilowatt-hours per month from this new array.
At 11 cents per kilowatt-hour, the array would be producing about $82.50
worth of electricity a month. Over 30
years that equals $29,700 worth of electricity.
If the market price of electricity rises, so does the profitability of
the panels, because the sunshine stays free. It won’t be too long before utilities start
charging their customers more for electricity consumed at peak demand hours in
the late afternoon, and that is exactly when panels are producing the most
energy.
The precipitous drop in price
of solar panels explains why last year 3900 megawatts of new solar generation
capacity were installed in the United States.
Of new electricity sources installed in 2013, solar was second only to
natural gas.
Of course the really cool
thing about solar panels is that they produce clean electricity from sunshine,
which is plentiful to the point of being a nuisance. After the panels are built and installed,
there are no CO2 emissions, no particulates, no smog, no mercury, no fracking, no
water consumption, no noise, and no toxic spills. Texas has all this energy from the sun relentlessly
beating down on us. Might as well get
some benefit from it.
