Solar cell modules

[Roy Lewallen]

In my limited experience, you have to be a little careful using a
switching, or even a series pass, regulator with a solar panel. Most are
designed to regulate voltage coming from a relatively stiff source, and
some become unstable when hooked to a high impedance source like a solar
panel. This can often be overcome by putting a big capacitor across the
panel, and it can of course be overcome by designing the regulator to
function properly with the high impedance source in the first place. And
quite a few regulators work just fine without modification. But it's
something to keep in mind when using a regulator designed for more
conventional applications.

Roy Lewallen, W7EL

 

[Joerg]

That is exactly the point, Joel. Upsizing 20% is several times more expensive
compared to providing an intelligent switcher to match to the illumination or to
adapt a panel voltage that isn't matching the storage devices. That situation
won't change unless there is a tremendous breakthrough in technology or serious
new government subsidies.

As to reliability, a switcher that is designed correctly and conservatively
should easily outlasts the cells. Even for small installations it is easy,
especially in view of the large variety of micro controllers that retail for a
few Dollars. One of these plus a few discretes and an inductor can do the trick.

Regards, Joerg.

 

[John Popelish]

In my limited experience, you have to be a little careful using a
switching, or even a series pass, regulator with a solar panel. Most are
designed to regulate voltage coming from a relatively stiff source, and
some become unstable when hooked to a high impedance source like a solar
panel. This can often be overcome by putting a big capacitor across the
panel, and it can of course be overcome by designing the regulator to
function properly with the high impedance source in the first place. And
quite a few regulators work just fine without modification. But it's
something to keep in mind when using a regulator designed for more
conventional applications.

Just for efficiency reasons, I think you would want ot have enough
capacitance across the regulator input that the cell resistance drops
voltage only with respect ot the average output current, not the
switcher peak value. This can be a pretty big factor in the overall
efficiency. Using a switcher that has little ripple current on its
input (two phase boost, for instance) makes this much easier.

 

[Tim Wescott]

Just for efficiency reasons, I think you would want ot have enough
capacitance across the regulator input that the cell resistance drops
voltage only with respect ot the average output current, not the
switcher peak value. This can be a pretty big factor in the overall
efficiency. Using a switcher that has little ripple current on its
input (two phase boost, for instance) makes this much easier.

That's not the point. Because a switcher tends to draw a constant power
from a load it's input impedance has a negative resistive component. If
you match this with a source that has a too-high impedance it'll be
_unstable_; a big capacitor would just slow it down in this case.

Presumably what you need is a controller that detects when the supply
voltage gets down to some threshold, then regulates the supply-side
current rather than the load-side voltage.

Come to think of it that'd be a fun thing to design...

 

[John Popelish]

John Popelish wrote:

That's not the point. Because a switcher tends to draw a constant power
from a load it's input impedance has a negative resistive component. If
you match this with a source that has a too-high impedance it'll be
_unstable_; a big capacitor would just slow it down in this case.

Presumably what you need is a controller that detects when the supply
voltage gets down to some threshold, then regulates the supply-side
current rather than the load-side voltage.

Come to think of it that'd be a fun thing to design...

Very few switchers draw an instantaneously constant power from the
unregulated source. Almost all can draw an average constant power
(over the switching period). The difference means a lot when you
consider what the variations do to the total losses in the solar
cells. You missed my point, completely.

 

[Paul Keinanen]

John Popelish wrote:

That's not the point. Because a switcher tends to draw a constant power
from a load it's input impedance has a negative resistive component. If
you match this with a source that has a too-high impedance it'll be
_unstable_; a big capacitor would just slow it down in this case.

While there certainly are going to be stability issues, using a
switcher with say 50 % duty cycle will draw 0 A half of the time (i.e.
the PV cell is operating in the constant voltage mode) and 2 Iave the
other half of the time (i.e. the cell would operate in the constant
current mode) and never operate at the maximum power point (here
assumed to be at Iave).

Sufficient parallel capacitances and/or series inductances or some
push-pull arrangement will keep the current constantly at Iave and
thus at the maximum power point.

Paul

 

[mike]

The solar cell operates as a (badly) regulated power supply with
current limiting. At low load currents, the cell operates nearly as a
constant voltage source, but after a specific current (for a given
illumination) it operates nearly as a constant current source and
deliver approximately that current even into a short circuit.

The largest power from the cell (for a specific illumination) is
obtained at the point it switches from constant voltage to constant
current mode, in which both the voltage is quite close (within 30 %)
of both the maximum voltage (as measured at open circuit) and maximum
current (as measured at short circuit).

This maximum power point varies with illumination, but if the switcher
always loads the cell at this maximum power point, the largest
available energy at a specific time is extracted from the cell
independent of illumination.

Even if the losses in the maximum power point tracker is 10-20 %,
usually more energy can be obtained than running the module in some
non-optimal constant voltage or constant current mode.

Paul

Anybody got any real data on this stuff.
I set out to build a constant power solar battery charger.
I was gonna just put a PIC to measure the voltage/current and
ratchet the switcher duty cycle up and down around peak power.

Went out in the yard at noon and plotted some curves. Yep,
there's a pronounced power peak right around 14V.
At lower intensities, the shape of the curve is the same, but
it moves sideways. Ok, my pulse width strategy should track that.
Cool.
Then I turned the panel ever so slightly away from the sun.
I was amazed at how dramatically things changed with just
a small angle. Looks like I'd gain WAY more watt-hours/day
by tracking the sun
than by anything else I could think of.

mike

--
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Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[J.S.Blackburn]

Anybody got any real data on this stuff.

There's no shortage of information about this. Useful
keywords are "insolation" and "solar insolation" (the word
"solar" is slightly redundant but it's commonly included).
In summer, you can expect a maximum of 1 kWatt per square
metre to reach the surface of the earth. The units most
commonly used are kW-Hour per square metre per day - I'll
call them Units here.

Insolation tables for the USA can be seen at:
http://www.suntrekenergy.com/sunhours.htm
These figures are somewhat suspect - the difference between
"high" and "low" seems too small (a maximum of 6 Units is
rather low), especially when compared with the following,
which contains some good maps:

http://www.wattsun.com/resources/insolation_maps/map_index.html

On this page, click on Flat Plate Collector, Single Axis
Tracker and Double Axis Tracker. The latter can produce up
to 14 Units in summer. The improvement when tracking the
sun's angle is very large. It pays to live in California.

I have seen a similar table somewhere for the UK, showing
that 5 Units is the best that can be expected, and maybe
less than 1 Unit in winter.

Bear in mind that the efficiency of Solar Cells is less than
20% in the very latest state-of-the-art devices, typically
10%, and maybe as low as 5% in reject/hobbyist cells.
Generating hot water directly from flat solar collectors is
probably more efficient, and certainly cheaper, but not much
use if it's electricity you want.

If, on a bad day, the cell voltage is less than the battery
voltage, you can still charge the battery. Look at:

http://www.elecdesign.com/Articles/ArticleID/6262/6262.html#
This article appeared in Electronic Design, Sept 14 1998.

It describes a circuit for a Maximum-power-point-tracking
solar battery charger. The principle is simple: the
duty-ratio of a switch-mode power supply is continuously
modulated at about 50Hz. The change in output on each cycle
is used to determine whether a higher or lower duty-ratio
would increase the output power. A phase-sensitive detector
and feedback loop determines whether to increase or decrease
the average duty-ratio. It settles at the point of maximum
power.

As the article points out, it works for other energy sources
such as water-wheels and other devices where the shape of
the "energy curve" is not precisely known.

When used as a battery charger the voltage of the battery is
fairly constant, so "maximum power" means "maximum
current". At the solar cell end, we are working at maximum
power, although the voltage may vary. The "maximum power
transfer" condition is when 50% of the power goes to the
load, and 50% is dissipated in the cell. I don't know if
this is precisely true in a solar cell, but it certainly
implies considerable power dissipation in the cell, which
may shorten its life. On the other hand, a cell of 1 square
metre will have 1000 watts of solar power falling on it, and
may generate 100 watts of electrical power, of which we may
get 50 watts into our battery. The 50 watts dissipated in
the cell is much less than the 1000 watts from the sun - so
maybe it doesn't matter.

J.S.Blackburn,
London UK.

 

[Duane C. Johnson]

Hi J.S.;

There's no shortage of information about this. Useful
keywords are "insolation" and "solar insolation" (the word
"solar" is slightly redundant but it's commonly included).
In summer, you can expect a maximum of 1 kWatt per square
metre to reach the surface of the earth.

This is miss leading.
While there are places, nearer to the equator, that
can have 1KW/m^2 at noon this is not the norm.

The rule of thumb is 1KW/m^2 normal to the sun
not flat on the ground.
Or about 100W/ft^2.
This is a tilted surface directly facing the sun.

The units most commonly used are
kW-Hour per square metre per day -
I'll call them Units here.

Insolation tables for the USA can be seen at:
http://www.suntrekenergy.com/sunhours.htm
These figures are somewhat suspect - the difference between
"high" and "low" seems too small (a maximum of 6 Units is
rather low), especially when compared with the following,
which contains some good maps:

On this page, click on Flat Plate Collector, Single Axis
Tracker and Double Axis Tracker. The latter can produce up
to 14 Units in summer. The improvement when tracking the
sun's angle is very large. It pays to live in California.

I have seen a similar table somewhere for the UK, showing
that 5 Units is the best that can be expected, and maybe
less than 1 Unit in winter.

Bear in mind that the efficiency of Solar Cells is less than
20% in the very latest state-of-the-art devices, typically
10%, and maybe as low as 5% in reject/hobbyist cells.
Generating hot water directly from flat solar collectors is
probably more efficient, and certainly cheaper, but not much
use if it's electricity you want.

If, on a bad day, the cell voltage is less than the battery
voltage, you can still charge the battery. Look at:

http://www.elecdesign.com/Articles/ArticleID/6262/6262.html#
This article appeared in Electronic Design, Sept 14 1998.

It describes a circuit for a Maximum-power-point-tracking
solar battery charger. The principle is simple: the
duty-ratio of a switch-mode power supply is continuously
modulated at about 50Hz. The change in output on each cycle
is used to determine whether a higher or lower duty-ratio
would increase the output power. A phase-sensitive detector
and feedback loop determines whether to increase or decrease
the average duty-ratio. It settles at the point of maximum
power.

As the article points out, it works for other energy sources
such as water-wheels and other devices where the shape of
the "energy curve" is not precisely known.

When used as a battery charger the voltage of the battery is
fairly constant, so "maximum power" means "maximum
current". At the solar cell end, we are working at maximum
power, although the voltage may vary. The "maximum power
transfer" condition is when 50% of the power goes to the
load, and 50% is dissipated in the cell. I don't know if
this is precisely true in a solar cell, but it certainly
implies considerable power dissipation in the cell, which
may shorten its life. On the other hand, a cell of 1 square
metre will have 1000 watts of solar power falling on it, and
may generate 100 watts of electrical power, of which we may
get 50 watts into our battery. The 50 watts dissipated in
the cell is much less than the 1000 watts from the sun - so
maybe it doesn't matter.

J.S.Blackburn,
London UK.

Duane

--
Home of the $35 Solar Tracker Receiver
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[John Popelish]

Then I turned the panel ever so slightly away from the sun.
I was amazed at how dramatically things changed with just
a small angle. Looks like I'd gain WAY more watt-hours/day
by tracking the sun
than by anything else I could think of.

Yep. It doesn't take much of an angle from perpendicular for a
silicon cell to act as a pretty fair mirror.

 

[Watson A.Name \Watt Sun - the Dark Remover\]

The argument usually goes that getting, say, 10-20% more power from a better
charge controller (one of these so-called 'maximum power point controllers')
can be cheaper (in additional expenditures) than getting 10-20% larger
panels. It's sometimes difficult to show, though, particularly on small
systems -- but MPPT controllers have been getting cheaper for awhile, now,
and I expect that eventually all but the cheapest/smallest will have this
functionality.

Last nite (Tue, 9pm) I watched a prog on PBS that was about getting
people to use more renewable resources, hosted by Cameron Diaz (hot
blonde movie star), who drives a Prius. They talked about getting every
home to have a solar panel, and selling power back to the utility co.
She also said that if everyone in the U.S. drove a hybrid vehicle, we
could completely eliminate oil shipments from the middle east. Well,
I'd go out and buy a Prius, but one of the guys at work has had his new
Prius since xmas and it took him 4 months or so to get it after
submitting a $500 earnest check to several dealerships to get on their
waiting list. They say they're trying to make more of them, but I think
they really don't want the prices to fall, since they're expensive to
make. In any case I'd like more solar power, but the initial outlay is
_not_ cheap.

 

[Anthony Matonak]

Last nite (Tue, 9pm) I watched a prog on PBS that was about getting
people to use more renewable resources, hosted by Cameron Diaz (hot
blonde movie star), who drives a Prius. They talked about getting every
home to have a solar panel, and selling power back to the utility co.
She also said that if everyone in the U.S. drove a hybrid vehicle, we
could completely eliminate oil shipments from the middle east. Well,
I'd go out and buy a Prius, but one of the guys at work has had his new
Prius since xmas and it took him 4 months or so to get it after
submitting a $500 earnest check to several dealerships to get on their
waiting list. They say they're trying to make more of them, but I think
they really don't want the prices to fall, since they're expensive to
make. In any case I'd like more solar power, but the initial outlay is
_not_ cheap.

While I'm all for using more renewable resources, and especially
ones that are environmentally friendly, it doesn't make sense to
cause yourself financial pain doing so. It makes sense to buy the
must fuel efficient vehicle that fits your needs but not to overspend
simply because it's a little better on the gas mileage.

That said, there are many things you can do that are quite affordable.
First, you could conserve energy. Replace old appliances with more
efficient ones, insulate your home better, weather-strip, storm windows,
compact fluorescent lights, activate the power saving on your computer,
use xeriscaping and all that lot. If you are a typical homeowners then
conservation alone could be as effective as putting up a $30,000 solar
panel setup.

Then you could buy more affordable renewable energy equipment such as
solar water heaters, air heaters, ovens, stoves and the like. You could
also change your diet to include less animal products. Raising animals
to produce food takes many times more resources (which often means
energy) as plants alone require.

There are also many alternatives to a Prius. One option would be to
get a diesel powered car and use biodiesel or get it converted to
run on straight vegetable oil. Another option is to buy an electric
car. Currently the only ones available are "city cars" which turn
out to be glorified golf carts but they are suitable for very local
driving and can sometimes work as a second car. Some folks have even
had great success with bicycles of various flavors. If you simply
must have a hybrid vehicle then a much wider selection of them should
be available within the next 10 to 15 years.

Anthony

 

[Duane C. Johnson]

Hi John;

mike wrote:

Bingo, that is my opinion also.

Yep. It doesn't take much of an angle from perpendicular
for a silicon cell to act as a pretty fair mirror.

Basically the power output will be:
COS(angle) * Watts
Watts is the output of the panel when aimed normal to the sun.
Angle is how far off of normal the panel is oriented.
0deg = 100%
8deg = 99%
11deg = 98%
18deg = 95%
30deg = 87%
45deg = 70%

However somewhere around 45deg or a bit more the cover glass
begins to act more like a mirror and the panel outputs much
less than allowed by the COS rule. Some panels can improve
on this with anti reflective coatings. These coatings may
not have a long lifetime though.

Now if you use a solar tracker the panel can be oriented
close to the ideal angle throughout the day. This significantly
improves the energy captured per day.

As an example:
At summer solstice where I live, 45deg latitude, the sun
subtends an angle of 270deg. That's an 18 hour day.

6 hours of the day the sun is actually behind a fixed panel.

Another 6 hours or so the sun is at an angle where the output
is low or negligible.

Only during 6 hours or so will the panel output significant
power. And the average power output is less than optimal.

A solar tracker in my location can theoretically harvest
3 times as much energy as a fixed panel.
OK, practically, due to weather and thick atmosphere the
output is 2.4 times according to the NREL data.

Other times of the year the improvement is not as much.
But even at winter solstice the improvement in output
is 1.4 times the fixed panel.

Solar trackers, at least the electronic bits, are really
low in cost, $35 for mine. The total cost including the
tracking mount is much cheaper than the cost of adding more
PV panels for the same outputs.

There are places where the tracking costs aren't cost effective.
The california sea coast and in maybe 50 miles or so is an
example. The local weather has lots of fogs which lower the
solar insolation except when the sun is high in the sky.

One must study the NREL data to see how cost effective
your location may be.

Duane

--
Home of the $35 Solar Tracker Receiver
http://www.redrok.com/electron.htm#led3X [*]
Powered by \ \ \ //|
Thermonuclear Solar Energy from the Sun / |
Energy (the SUN) \ \ \ / / |
Red Rock Energy \ \ / / |
Duane C. Johnson Designer \ \ / \ / |
1825 Florence St Heliostat,Control,& Mounts |
White Bear Lake, Minnesota === \ / \ |
USA 55110-3364 === \ |
(651)426-4766 use Courier New Font \ |
[email protected] (my email: address) \ |
http://www.redrok.com (Web site) ===

 

[Joel Kolstad]

Last nite (Tue, 9pm) I watched a prog on PBS that was about getting
people to use more renewable resources, hosted by Cameron Diaz (hot
blonde movie star), who drives a Prius.

Nice idea, although in her particular case I'd be willing to bet that she
could be driving a Hummer and it'd be a small drop in the amount of energy
she uses for transportation! (Due to all those jet rides...)

They talked about getting every
home to have a solar panel, and selling power back to the utility co.

I'm all for net metering (power company has to pay you the same for a
kilowatt-hour as what you would have had to pay to buy it from them), and
happily it is becoming more common in the U.S. Panels and controllers are
continuing to get cheaper as well. Additional government support could
really help improve how many people would seriously consider sticking
photovolataic panels on their roofs -- I imagine right now it's well under
1% of the population.

She also said that if everyone in the U.S. drove a hybrid vehicle, we
could completely eliminate oil shipments from the middle east.

We could do that as-is... there's plenty of oil in Alaska, after all, we've
just made the choice that protecting the environment up there is more
important right now than not importing oil from the middle east. (This is a
very involved topic -- if anything, the choice of where we get our oil from
is far more political than technical in nature anyway.)

---Joel Kolstad

 

[Joel Kolstad]

That said, there are many things you can do that are quite affordable.

Yes, such as building better-insulated dwellings. I find it appaling that
here in Oregon where I live, the building codes don't require some apartment
complexes to have any insulation whatsoever in their attics. These places
additionally inevitably end up with electric heat, so the end result is that
a small savings to the guy who builds the apartment complex ends up being a
huge cost in additional energy to the renter as well as the corresponding
impact on the environment.

There are also many alternatives to a Prius.

Although I understand the reasoning behind it, it's quite ironic how many
people out there who live within an arguably quite reasonable bikable
distance to their place of employment instead drive to work and then drive
to a fitness club afterwards to work out. Although I am all for people
using their cars as much as they want so long as fuel taxes or whatever more
or less make up for the impact to the environment, but unfortunately it's
hard to translate that impact into monetary terms.

---Joel

 

[Watson A.Name \Watt Sun - the Dark Remover\]

While I'm all for using more renewable resources, and especially
ones that are environmentally friendly, it doesn't make sense to
cause yourself financial pain doing so. It makes sense to buy the
must fuel efficient vehicle that fits your needs but not to overspend
simply because it's a little better on the gas mileage.

It's not a "little" better, it more than double - 50+ MPG compared to 25!

[snip]

You could
also change your diet to include less animal products. Raising animals
to produce food takes many times more resources (which often means
energy) as plants alone require.

Right, but it's **you** (see above) that said to not cause yourself
financial pain. Well, I _try_ to do my part to eat little or no beef,
instead eat chicken. But I _have_ to pay a premium to do so, even tho
it's cheaper to bring chicken to the table, just because of supply and
demand issue. People consume less beef so the price drops below
chicken, not because it's cheaper. So I and everyone else hasto pay
extra for, helping save resources. Just what you said _didn't_make_ sense_.

There are also many alternatives to a Prius. One option would be to
get a diesel powered car and use biodiesel or get it converted to
run on straight vegetable oil. Another option is to buy an electric
car.

Again, you're asking for people to make a financial sacrifice when
buying an electric vehicle. The last I checked, it cost $46,000 to
purchase a RAV4 EV, with a good chunk of that going to the installation
of an electric charger in the owner's garage. According to you, that
financial pain 'doesn't make sense'.

If you simply
must have a hybrid vehicle then a much wider selection of them should
be available within the next 10 to 15 years.

In the next 10 to 15 years, the situation may be much, much worse. The
big worry in the near term seems to be China, with 1/5th of the world's
population, which may have a growing economy that will gobble up an ever
growing part of the world's non-renewable energy resources. In 10-15
years, it may be too late! The price of fuel in europe is already over
$5 a gallon, and we Americans are currently bitching about having to pay
over $2! Well, wait until it goes up to $3, or more! All those SUV
owners in the U.S. will be taking tbe bus to work. Time will tell!

 

[Charles W. Johnson Jr.]

While I'm all for using more renewable resources, and especially
ones that are environmentally friendly, it doesn't make sense to
cause yourself financial pain doing so. It makes sense to buy the
must fuel efficient vehicle that fits your needs but not to overspend
simply because it's a little better on the gas mileage.

It's not a "little" better, it more than double - 50+ MPG compared to 25!

[snip]

You could
also change your diet to include less animal products. Raising animals
to produce food takes many times more resources (which often means
energy) as plants alone require.

Right, but it's **you** (see above) that said to not cause yourself
financial pain. Well, I _try_ to do my part to eat little or no beef,
instead eat chicken. But I _have_ to pay a premium to do so, even tho
it's cheaper to bring chicken to the table, just because of supply and
demand issue. People consume less beef so the price drops below
chicken, not because it's cheaper. So I and everyone else hasto pay
extra for, helping save resources. Just what you said _didn't_make_ sense_.

There are also many alternatives to a Prius. One option would be to
get a diesel powered car and use biodiesel or get it converted to
run on straight vegetable oil. Another option is to buy an electric
car.

Again, you're asking for people to make a financial sacrifice when
buying an electric vehicle. The last I checked, it cost $46,000 to
purchase a RAV4 EV, with a good chunk of that going to the installation
of an electric charger in the owner's garage. According to you, that
financial pain 'doesn't make sense'.

If you simply
must have a hybrid vehicle then a much wider selection of them should
be available within the next 10 to 15 years.

In the next 10 to 15 years, the situation may be much, much worse. The
big worry in the near term seems to be China, with 1/5th of the world's
population, which may have a growing economy that will gobble up an ever
growing part of the world's non-renewable energy resources. In 10-15
years, it may be too late! The price of fuel in europe is already over
$5 a gallon, and we Americans are currently bitching about having to pay
over $2! Well, wait until it goes up to $3, or more! All those SUV
owners in the U.S. will be taking tbe bus to work. Time will tell!

Anthony

Surprisingly enough some SUV owners actually need the SUV at the time of
purchase, I personally drove through snow 70cm deep on a regular basis prior
to my recent job change. Just because the people in southern California
don't need it doesn't mean no one does.

Charles

 

[Anthony Matonak]

It's not a "little" better, it more than double - 50+ MPG compared to 25!

The definition of "little" can vary.
Would you consider 5 MPG a "little" ?

http://www.fueleconomy.gov/feg/bestworst.shtml
Shows the Prius at 60/51 mpg with a couple of VW's in the 38/46 range.
This is only 1.6/1.1 times and not double, especially when considering
highway driving instead of city driving. This means you can purchase
a vehicle with good fuel efficiency without buying a Prius or even
a hybrid.

Right, but it's **you** (see above) that said to not cause yourself
financial pain. Well, I _try_ to do my part to eat little or no beef,
instead eat chicken. But I _have_ to pay a premium to do so, even tho
it's cheaper to bring chicken to the table, just because of supply and
demand issue. People consume less beef so the price drops below
chicken, not because it's cheaper. So I and everyone else hasto pay
extra for, helping save resources. Just what you said _didn't_make_
sense_.

You could chose to eliminate chicken as well as beef, eggs and dairy.
I'm no expert in either nutrition or food prices but I think you could
quite affordably manage a diet that does not include meat of any kind.
Perhaps you should look at a group such as misc.consumers.frugal-living
and ask for recipes. You could also look up many of the resources on
the web for vegetarians and vegans.

Again, you're asking for people to make a financial sacrifice when
buying an electric vehicle. The last I checked, it cost $46,000 to
purchase a RAV4 EV, with a good chunk of that going to the installation
of an electric charger in the owner's garage. According to you, that
financial pain 'doesn't make sense'.

I agree, a RAV4 EV might not make sense on a financial basis. The last I
heard they don't make them anymore. Any you do find are collectors
items and will be priced accordingly. In fact, it might actually be
rather difficult to find a brand new EV, even the golf cart style like
the Chrysler GEM, as they keep getting discontinued. That said, a small
neighborhood electric vehicle only costs in the neighborhood of $5,000
to $6,000 when they can be found.

In the next 10 to 15 years, the situation may be much, much worse. The
big worry in the near term seems to be China, with 1/5th of the world's
population, which may have a growing economy that will gobble up an ever
growing part of the world's non-renewable energy resources. In 10-15
years, it may be too late! The price of fuel in europe is already over
$5 a gallon, and we Americans are currently bitching about having to pay
over $2! Well, wait until it goes up to $3, or more! All those SUV
owners in the U.S. will be taking tbe bus to work. Time will tell!

There are many worries in the world and it's always too late for
some things. Time will certainly tell but there ARE some things
that folks can do now if they like and without putting themselves
in debt for the rest of their lives.

Anthony

 

[mike]

While I'm all for using more renewable resources, and especially
ones that are environmentally friendly,

I once read that it takes more energy to make, deliver, install a solar
panel than the total energy you get out of it over it's 20 year
lifetime. If that's true, (small scale PV) solar makes little sense
from an environmental standpoint.

mike



it doesn't make sense to

cause yourself financial pain doing so. It makes sense to buy the
must fuel efficient vehicle that fits your needs but not to overspend
simply because it's a little better on the gas mileage.

That said, there are many things you can do that are quite affordable.
First, you could conserve energy. Replace old appliances with more
efficient ones, insulate your home better, weather-strip, storm windows,
compact fluorescent lights, activate the power saving on your computer,
use xeriscaping and all that lot. If you are a typical homeowners then
conservation alone could be as effective as putting up a $30,000 solar
panel setup.

Then you could buy more affordable renewable energy equipment such as
solar water heaters, air heaters, ovens, stoves and the like. You could
also change your diet to include less animal products. Raising animals
to produce food takes many times more resources (which often means
energy) as plants alone require.

There are also many alternatives to a Prius. One option would be to
get a diesel powered car and use biodiesel or get it converted to
run on straight vegetable oil. Another option is to buy an electric
car. Currently the only ones available are "city cars" which turn
out to be glorified golf carts but they are suitable for very local
driving and can sometimes work as a second car. Some folks have even
had great success with bicycles of various flavors. If you simply
must have a hybrid vehicle then a much wider selection of them should
be available within the next 10 to 15 years.

Anthony

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[Joel Kolstad]

I once read that it takes more energy to make, deliver, install a solar
panel than the total energy you get out of it over it's 20 year
lifetime. If that's true, (small scale PV) solar makes little sense
from an environmental standpoint.

My understanding is that improvements in the efficiency of the panels has no
longer made that true... although of course to some degree it depends on
where you end up installing the panels!

An easy way to determine whether or not the statement could be true is to
see whether or not the cost of the energy produced by the panel over its
life -- using regular market rates -- exceeds its cost. If so, obviously
the panel must be producing more energy than was requried to build it, since
all the labor and materials the manufacturer put into the panel weren't
free!