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.
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.
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:
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.
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?
Solar power is a function of area. If you are comparing a small cell, say one that fits on a flashlight, to a small generator that fits in the same flashlight, then there will not be much solar power available.
If you are expand your solar cell to a square meter then you will make more power than an "in shape" cyclist can sustain for an hour (200 watts).
Rules of thumb:
• 1 square meter in full noontime sun gets about 1000 watts of sunlight.
• Solar panels are about 20% efficient, so 200 watts per square meter at noon.
• Total sun delivered during the day is equivalent to 4 noon hours in the summer, 2 noon hours in the winter.
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.)
Cranks have moving parts, and thus are more likely to break and need service. Additionally, those little combo flashlights (I have one too, I love them) have a very small solar panel. Notice the solar panel in the photo is at least as large as an 8.5x11 sheet of paper- I'm sure it produces much more current.
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.
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.
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?
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.
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.
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.
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.
[+] [-] protomyth|15 years ago|reply
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|15 years ago|reply
[+] [-] woodall|15 years ago|reply
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...
BMW Heat-Harnessing Technology - http://www.sacarfan.co.za/2009/10/bmw-heat-harnessing-techno...
http://www.innovationsforeveryone.com/Comment_Innovation.asp...
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.
[+] [-] hardy263|15 years ago|reply
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?
[+] [-] jws|15 years ago|reply
If you are expand your solar cell to a square meter then you will make more power than an "in shape" cyclist can sustain for an hour (200 watts).
Rules of thumb:
• 1 square meter in full noontime sun gets about 1000 watts of sunlight.
• Solar panels are about 20% efficient, so 200 watts per square meter at noon.
• Total sun delivered during the day is equivalent to 4 noon hours in the summer, 2 noon hours in the winter.
[+] [-] kragen|15 years ago|reply
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.)
[+] [-] sliverstorm|15 years ago|reply
[+] [-] joe_the_user|15 years ago|reply
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|15 years ago|reply
[+] [-] Fargren|15 years ago|reply
[+] [-] kragen|15 years ago|reply
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.
[+] [-] gchucky|15 years ago|reply
[+] [-] pmorici|15 years ago|reply
[+] [-] patrickgzill|15 years ago|reply
[+] [-] davidj|15 years ago|reply
[+] [-] bjoernw|15 years ago|reply
[+] [-] sliverstorm|15 years ago|reply
[+] [-] narrator|15 years ago|reply