[Peripherals] Wind or Water? Alternative Power for Developing Countries

Tue May 6 21:27:13 EDT 2008

Edward et al,

I have send this info before to one fellow that was interested in this 
issue.  If you need more info or data, please ask.

_*Water*_: there is HUGE difference in water availability.  I have work 
for mining companies from the 3,500 meters to the 5,000 meters here.  
There are villages were the creeks becomes a whole river during 4 to 5 
months and then get just very very small amount of water for the rest of 
the year... (less water than what you get from your shower)... the 
difference is so big that sometimes I have to design "recirculating" 
systems to provide water for trout factories (that are located WERE they 
should have never been located... but... it is a "good neighbor" policy 
that mining companies have here).  Distance from the "water source" is 
another problem (easier to solve, we can use some cabling to reach the 
batteries... but it is a factor to be taken in account).

_*Wind*_: Altitude doesn't comes with the wind.  You need to be 30 
meters over the soil surface (if you have your feet in soil that is at 
3,500 or 4,000 meters altitude... you need to put a "tower" and get 9 
meters more! then we mount the "turbine/rotor/alternator" at the top of 
the tower... (add the cost of the tower to the budget...) ... no free 
lunch... Wind  turbines should be sited at least 30 feet (9 m) higher 
than  anything within 500 feet (152 m).. that is the rule...  Check this 
image that I have assembly with proportional data:

Rule of thumb: The tower needs to be 2.5 times the height of the nearby 
buildings or tress ... and it will be better if there are not 
surrounding mountains (most of the towns and villages in Peru are 
located in the most protected place in the area: the small andean 
valleys... even the animals that are free in the "pampa" (flat sites) 
look for refuge at the side of a hill or anything similar.  I know just 
a few towns that are in "all plane" places (in "Puno" 
department/region/County)... but even on those places (located over the 
3,000 meters) there is not such a thing like the "neccesary wind speed" 
at flat level to move a serious "wind mill" to produce enough energy.

Other "not wind" reason (for THIS project!) is that the energy power 
available in the wind varies with the cube of its speed. This means that 
a wind "rotor+alternator" rated at 1,000 watts at wind speed of "28 
miles per hour"  might produce only 125 watts or less at half that wind 
speed, 14 mph.  So the huge variance add extra cost to guarantee the 
minimum necessary energy.  Normally you will need 8 to 13 mph winds to 
generate energy for a house... below 8 mph is a "hard" situation (for a 
house).

There are formulas for calculating output based on average wind speed 
and swept area: http://www.builditsolar.com/Projects/Wind/wind.htm (It 
has a lot of other useful info for wind devices).  Jim Green (National 
Renewable Energy Lab (NREL)) developed other similar calculations: 
annual energy output (AEO) in KWH = 0.01328 x rotor diameter (ft.) 
squared x average wind speed (mph) cubed.

Other "not wind" reason: Cost of the tower. 1 tower can work for many 
XOs... but we need to do comparison in costs (human driven vs wind driven).

For me the "pedaling on a modified spinning wheel" is the solution. 
But... time will say!

regards,

Javier

Edward Cherlin wrote:
> On Mon, May 5, 2008 at 11:08 AM, info at olpc-peru.info
> <info at olpc-peru.info> wrote:
>   
>> Edward,
>>
>>  Just for your info (about energy devices).
>>
>>  I don't know exaclty why (I have many ideas about why! (smile))... but I
>> think it can be of your interest.
>>
>>  Javier
>>
>>
>>
>> Hello Mel and all the people on the peripherals list,
>>
>>  I have been discussing the issue of energy with other fellow on the OLPC.
>>
>>  I am honest and I speak directly all the time: I think the solar energy is
>> not a realistic posibilitie in Peru: there is 100% sunny days in the Andes
>> JUST 6 months in a whole year.  The worst moments are the 4 to 5 months were
>> some villages (located over the 3,500 meters altitude) get 100% cloudy time,
>> very cloudy, huge rainfall.  According to all the investigation that I have
>> done (I can send to anyone if you are interested) the solar devices can
>> provide from 5% to 20% IF there is not a sunny day.  That is a BIG problem.
>>     
>
> That certainly does not eliminate solar from consideration entirely.
>
> http://ezinearticles.com/?Effects-of-Clouds-on-a-Solar-Panel&id=533893
> "Germany is typically a very cloudy country...In spite of its cloudy
> climate, though, Germany is by far the world's biggest user of solar
> panels."
>
> Other possibilities are
>
> *Wind
> *Water
> *Biofuels (ethanol, methane, biodiesel)
> *Animal power
> *Child power
>
> How are the winds up there in the Andes?
>
> Are villages located on or near mountain streams?
>
> What do the farmers grow at altitude? Potatoes make a good fuel crop.
>
>   
>>  My best understanding, based on previous experience when I have work for a
>> mining company is to build a mechanical device: human driven, leg driven.
>> But not a bycecle.  We have built it before but it was without "cost"
>> restrictions.  It is based on a spinning wheel (I have many here at my
>> sight).  But when I have put "cost" as a variable to take in account then I
>> have got the next ideas:
>>
>>  a) Using alternators, in Peru, is expensive.  Each alternator cost US$300
>> aprox.
>>  b) We need to import some magnets and assembly the alternator by ourselves.
>> The kids on the villages can do it as part of the "experience".  We must
>> provide the alternators, the copper wire, the circuit and components for the
>> rectifier, and... the battery (battery is other hard issue... short live...
>> expensive).  Assembly this "home made" alternator, connecting to the
>> spinning wheel (that can need a double wheel or a "pulley" chain) can be an
>> improvement (according to the first results that we can get).
>>  c) Legs are the ones that will be used.  Not in a bycecle but on a spinning
>> wheel.  It is totally possible generate enough energy for a regular laptor
>> with the legs, it will be easier for the XOs.  Providing energy for the
>> XServers is a totally different issue, I don't agree with the use of
>> XServers.  I suggest that one of the XOs MUST behave as a Server (or the
>> whole local XO network should behave as a "shared server" sharing processing
>> power... but that is a bigger task).
>>  d) Need more energy? Put bigger magnets or "more" copper wire.  Too heavy
>> to move? Change design: move the copper wire around the magnets.  Too heavy
>> yet? Use concatenated pulleys.
>>  e) Cost?: import the magnets from Korea or other asian manufacturer.
>>
>>  In this moment I don't have the time to develop this pilots (because I work
>> independently, earning bread and butter for daily living, as anyone, and my
>> spare time is not good enough to attack the problem in an efficient way).
>> So I am passing this info to you (and I can discuss and help more if there
>> is someone interested in develop this prototypes).
>>     
>
> I'll ask Engineers Without Borders and some other organizations.
>
>   
>>  If we don't get an asnwer for the energy problem then we will be delivering
>> (we ARE delivering) XOs to the towns and villages that "look" poor in the
>> eyes of the occidental culture but we are forgetting
>>     
>
> No, you are forgetting that Nicholas Negroponte made it clear from the
> beginning that the villages without electricity were the prime targets
> for the XO, and how many people have been working to make it succeed
> there.
>
>   
>> that in Peru the deep
>> poverty is located in those 80,000 villages (5 million people) with less
>> than 100 families in each villages, without electricity, less than FIVE
>> HUNDRED dollars as total ANNUAL income for the family (with the work of the
>> father, mother and children from 6 years old).
>>     
>
>  There are other target countries where the annual income is even less.
>
>   

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