
Africa’s Rural Poor Begin Harnessing the Sun - J3L2404
http://www.nytimes.com/2010/12/25/science/earth/25fossil.html?pagewanted=1&src=twr
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protomyth
It is interesting that people in the US who want off grid power are exploring
some of the same technologies that would be useful in Africa. A cost effective
way to store energy for night / no-wind for a full house is probably going to
be a big hit.

They mention de-forestation in the article. I do worry that if our next
"green" energy source isn't cheaper than oil/coal then the third world will
ignore the cleaner alternative.

~~~
davidj
I can't find the reference off hand, but I once heard that it takes 7 years of
operation for a solar panel to generate the same amount of energy to build a
panel, .. and the energy that it takes to build one comes from ... guess what
.. coal and gas.

~~~
kragen
That used to be true, but efficiencies have improved dramatically, and current
energy payback time is closer to 7 months than 7 years.

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woodall
Very off topic, but I have been very interested in Peltier units and Seebeck
engines for the last month or so; winter is indeed here. It would be
interesting to see these used in a wider scale, or if it is even possible.
Here are some links that describe them in more detail:

Thermoelectrical Generator Kit - ThermoGenKit -
<http://www.youtube.com/watch?v=8mFyiYh94YE>

Seebeck Effect - <http://www.metacafe.com/watch/1129994/seebeck_effect/>

Thermo-Electric Generators - [http://www.douglas-
self.com/MUSEUM/POWER/thermoelectric/ther...](http://www.douglas-
self.com/MUSEUM/POWER/thermoelectric/thermoelectric.htm)

BMW Heat-Harnessing Technology - [http://www.sacarfan.co.za/2009/10/bmw-heat-
harnessing-techno...](http://www.sacarfan.co.za/2009/10/bmw-heat-harnessing-
technology/)

[http://www.innovationsforeveryone.com/Comment_Innovation.asp...](http://www.innovationsforeveryone.com/Comment_Innovation.aspx?Id=4260)

<http://en.wikipedia.org/wiki/Thermoelectric_effect>

Using both heat and cold you can create a small amount of electricity from
these units. I have seen something like this used in a camp. They would place
one end of a metal rod into a fire and the other in a bucket of water. Then
they could create enough electricity, using some type of thermoelectric
circuit, to 'trickle charge' a cell phone or GPS.

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hardy263
I recently bought a small dual solar/dynamo powered flashlight. 30 minutes of
solar power can power the light for 10 minutes, but 1 minute of turning the
crank can power the light for 30 minutes.

If the sun is out for say, 12 hours a day, that means it can power my light
for 240 minutes. But turning my crank for 10 minutes would power the light for
300 minutes.

Is solar really efficient at all, because wouldn't getting a hand-turned
generator get more electricity than waiting for the sun?

~~~
kragen
1\. If your solar panel were 30 times bigger than it is, 1 minute of solar
power would power the light for 10 minutes too.

2\. Even a small solar panel can power your water pump/weather station/radio
repeater when you're ten miles away and don't have the time to spend all day
walking ther to spend a minute turning its crank.

3\. Solar panels break down less than hand-turned generators. They don't have
bearings or windings or gears. If you keep replacing the batteries, your
flashlight will ber a usable solar-powered flashlight much longer than it is a
usable dynamo-powered flashlight. (The "shake light" design, with a magnet
sliding back and forth in a tube through a coil, might be an exception there.)

4\. Solar panels keep working even without being fed more rice. Human labor
does not produce energy, regardless of what you may have heard in The Matrix;
it merely converts it quite inefficiently from chemical energy into mechanical
energy.

5\. An athlete working his hardest might consume 10 000 calories per day in
food, but can only convert some 2000 of those calories into work. If your
Lance-Armstrong-level athlete is turning a crank 12 hours a day and eating 10
000 calories, he's producing 200 watts during that time, 100 watts averaged
over the 24 hours. Three square meters of solar panel can do the same. Six
square meters can do twice as much. And the solar panels won't drop dead of
exhaustion after a month.

(Supposedly Lance averaged 5200 kcal/day during the Tour de France with a peak
power output of 1000W:
<http://www.wired.com/wired/archive/12.07/armstrong.html> \--- but presumably
ate more on uphill days than on level days.)

~~~
Untitled
> 3\. Solar panels break down less than hand-turned generators.

I live in an African country and solar panels have one huge disadvantage.
Solar panels are often used now to power boreholes (usually fully submersible
pumps which have become fairly cheap and easy to install, compared to so
called "mono-pumps" of the old days) and pumps near rivers that are far from
grid electricity. It is also used to power electric "energizers" for electric
fences.

The problem is that solar panels keep getting stolen. It is something that is
fairly valuable that should be outside. I can just imagine the amount of theft
that will go on when people have solar panels on the roofs of their
homes/shacks.

Also, the article failed to mention the real problem with using candles and
fire for lighting - frequent fires.

~~~
kragen
That's very interesting! What country are you in? What kind of pumps do people
use now?

I imagine that for applications in town, the theft problem will be less. If
you have ten or twenty houses clustered together, you can probably leave one
rifle home with one of the women in case someone tries to steal the solar
panels. I mean, that's the same problem as someone trying to steal a motor
scooter or whatever, right?

~~~
Untitled
> That's very interesting! What country are you in?

I lived in rural South Africa (not anymore though).

> I mean, that's the same problem as someone trying to steal a motor scooter
> or whatever, right?

What is funny for me is that motorcycles aren't as popular in the African
countries that I have been (e.g. China or India). But yeah, things that is not
inside the home is easily stolen. Things like car batteries or solar panels
are extremely popular items to steal.

> What kind of pumps do people use now?

In the old days they used mono-pumps (where the motor was above ground and
connected with rods).

Nowadays the pump is in one sealed unit that is connected with plastic piping
and electricity. Two people can install a pump in less than half a day and
everything is light. The price of pumps also dropped.

~~~
kragen
> What is funny for me is that motorcycles aren't as popular in the African
> countries that I have been

Could it be because they're too easy to steal, and there's less theft in China
and India?

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joe_the_user
This is fascinating...

Leon Trotsky, of all people, had a theory of "uneven and combined development"
<http://en.wikipedia.org/wiki/Uneven_and_combined_development>

Essentially, this says an under-developed area has an opportunity to leapfrog
the most develop areas, producing an entire new paradigm of development.

By the time African villages directly contact the West, they may have an
entirely different form of capitalism we may be emulating...

~~~
adlep
LoL... Out of all people you are quoting Trotsky? Really? How about quoting
Lenin, I am sure he had a lot of smart things to say as well...

~~~
bsk
LoL @ U

Instead of reading HN you should watch Fox News. No quotes of stupid ppl like
Lenin and Trotsky there...

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Fargren
How would one go about implementing this in poor suburban areas, like around
third-world-countries' metropoli? I live in Buenos Aires, where there a lot of
poor "villas" scattered all over the city and at the outskirts, and this seems
like something that would be great to implement here. Specially during the
summer when the exesive power consumption generates blackouts at least once a
week.

~~~
kragen
I haven't been to the villas, and I don't know anybody who lives there.
However, what I hear is that the people there already have grid power, which
they don't pay for, and they are very often targets of theft. I have to
imagine that hauling in an expensive solar panel in order to conserve energy
paid for by the electric company would be a very difficult sell there. I don't
think many of the shacks there have air conditioning, and the air conditioners
are the culprit there.

If the objective is to keep your TV and radio on during the blackouts, I think
a car battery is probably a better choice than a solar panel.

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gchucky
Somewhat tangential of a question, but does anyone have recommendations for
buying cheap solar panels in the states? Like, suppose I wanted a solar panel
to put in my apartment window so I could charge my phone. What would it take
to get something like that?

~~~
pmorici
SparkFun sells some solar panels, <http://www.sparkfun.com/categories/116> You
might need to attach them to some kind of 5v regulator though because a panels
output is going to vary with the intensity of the light it's exposed to.

~~~
kragen
Solar panels are photodiodes. Their junction voltage is determined by the
properties of the material, not by the light intensity, although of course at
sufficiently low light intensity they will cease to be reverse-biased. More
sunlight will just produce more current, not more voltage.

~~~
pmorici
All I know is that I hooked a small panel up to my multimeter and if I put it
in direct sun light it produced 5 volts and under indoor lighting conditions
the voltage was around 3 volts. So I don't really know how they work but I
know how to measure the voltage coming out of them.

~~~
kragen
You may be aware that direct sunlight is thousands of times more intense than
indoor lighting conditions. Probably if you'd hooked up a resistive load to it
while indoors, the measured voltage would have dropped to a fraction of a
volt; and if you'd used an oscilloscope instead of a multimeter to measure the
voltage, you would very likely have measured 5 volts.

Or I could be wrong, of course.

------
bjoernw
2 years ago I spent a summer in Kenya establishing reforestation projects with
local schools and many families already owned a car battery and a cheap solar
panel as well as one cell phone per person. This is not a new development.

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sliverstorm
It is very pleasing to hear that a small family far off the grid can afford an
$80 solar panel. It means they have at least _some_ means, and makes the
future look a bit brighter.

~~~
narrator
A full grown cow in the west can sell for $500 to $2000 depending on weight
and breed. The main input for a cow is pasture, which is plentiful in rural
Kenya. More importantly $80 for a solar panel is a lot cheaper, over time,
than the ride into town and back. Since this all makes practical economic
sense, it didn't require an aid agency to come their and tell them to do it
all.

~~~
sliverstorm
My thought is mainly I always hear they don't have two nickels to rub
together, and this disproves that.

~~~
erikpukinskis
You really thought that no one in Africa had any money at all? You think it's
just a bunch of dark skinned people squatting in the mud? Jesus.

~~~
sliverstorm
I didn't say that. "doesn't have two nickels to rub together" is an idiom.

~~~
erikpukinskis
It means "to not have any money", right?

