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Very Small Scale Power Generation in Developing World Answered

Hello Everyone,

I volunteer for a non-profit which distributes solar lanterns primarily to students as well as people who are in need of the lights.  Things have been going well but a lot of people have inquired about us providing access to a higher powered version for various reasons and we've noticed that some households go back to their old ways when the lanterns don't receive enough sun during the day. 

Temporarily we are solving the problem by having local entrepreneurs charge batteries for the families for a small fee but we feel that this should not be a permanent solution. It's not the price that's the issue it's that sometimes the people have to walk for a number of kilometers to get to the nearest charging station or have to cross dangerous terrain (I have personally experienced this).

Over the last 3 years we have helped over 5000 families by giving them solar lights so we would like to modify all those units to have more stable energy generation. Our current version has an output of 5 watts. We are looking to buy or build a unit which produces a maximum 8wh an hour until the fuel source runs out or something that can generate in a more slower rate such as 40wh in 16 hours so we can let it run overnight and have the power stored in a battery.

We are primarily a donation driven group so something with low cost and maintenance would be really great.  We highly subsidize the price to a large percentage of the households but we also provide them free for the lowest 10% of households who can't even afford the lowered price.
I personally think that something which can generate electricity from hydrocarbons due to their high energy density and easy access would be ideal but I'm not an engineer so what do I know.  I'm not sure if this helps in any way but a number of years ago we transitioned a large number of houses from wood fired stoves to gas and as all the families that we help actually have access to gas I was wondering if any good technology exists where electricity can be generated by gas that can meet the low cost and maintenance criteria.  I've looked into thermoelectric generators but they are really inefficient and people will be wasting money to heat their house in a country where average temperatures are in the 30'sC

I also see a future issue regarding battery degradation as we use small lead acid batteries and while thinking of a way to solve this I came up with the following idea and is one of the reasons that I'm posting on instructables.

What if a pedal powered flywheel generator was built with a 200W generating capacity and 40Wh worth of 'storage'.  When you pedal you will spin up the flywheel and it will store the energy until you need the electricity again and we could also wire up the solar panel that we already use to spin up the flywheel.  So when the sun is out the panel is used and on rainy days and during the night you pedal for a couple of minutes for one hour of lights.  If the flywheel can store the energy for a number of hours then someone could pedal for a couple of minutes at a time throughout the day and not have to do it at night.

This is just an idea that I came up with and if anyone has any ideas I'll be really interested in knowing about it (obviously the above solution is not ideal because they have to put some work into generation but it's the best that I can do).  I've quite recently been looking into different types of fuel cells powered by m/ethanol and others like solid oxide cells and they seem interesting (does anyone here have any experience in building these type of cells?).  This community has a lot of intelligent members who think outside the box so I'm confident that we can come up with something.

This ended up being a bit longer than expected and if you've read this far, thank you.
I wasn't sure about what section to post this in, square peg is the one I chose out of 5 so if this is wrong please feel free to move it to the correct section.

Help and advice will be very much appreciated.
Kindest Regards


Flywheels must be very precisely engineered to store energy for a useful length of time, and that increases the cost.

Thermo electric doesn't need the house to be heated, you could install it in the vents or chimneys of the cookers, whether they are gas or solid fuel.

There are other processes as well - roof-top wind turbines, small hydroelectric plants, biogas generators etc etc.

It would be easier to make useful suggestion if we knew more about the context (climate, local geography, size and number of buildings etc).

With traditional systems I realise it will be expensive but I was talking about this http://www.kickstarter.com/projects/1340066560/velkess-energy-storage. We have 10 times less power generation and storage requirement that the prototype that he's already built.

One of the prototype systems was a solar and wind combo but was ruled out because the people didn't like the appearance (the height) and they were also a little afraid of lightning.

If the thermoelectric module generates electricity from the heat of a cooker wouldn't they only be able to generate electricity while cooking (average cooking time here is less than 2 hours) or they will have to run the cooker when they are not cooking which will be a waste of money. This method also relies on batteries.

I live in Sri-Lanka where it is pretty hot and the people we help are spread across many different areas with varying terrain and housing densities. Whatever the idea it should be able to be implemented in each individual house.

Like I said I feel that some method which uses a liquid fuel would be best, everyone can get access to it and store it for a long time. We have the usual petrol, diesel, lpg and I believe that we can also get our hands on 99% ethanol and methanol.

Thermoelectrics can charge batteries (have you really had trouble with battery degradation, or are you just expecting it?).

If you are set on using hydrocarbon fuels, then the simplest option is to use the tried and tested internal combustion engine to run a generator.

If you want to use the Velkess system, then I suggest contacting them directly, but even their "simplified" system is going to require maintainance that the typical household cannot do themselves.

As far as I am aware, if you want to run single-household systems, batteries are the way to go. If you want to use more complex/expensive systems, then you are going to have to look at scale to make things more affordable per home - small communities being supplied by larger, single installations (and, I think, still relying on batteries for storage).

We started noticing the battery problems near the beginning of this year. The current plan is to replace the batteries once the degradation has reached a certain point but I personally don't think that this is the way to go.

After actually doing proper research into flywheels I agree that they're are not such a good idea. I was also thinking of compressed air storage but the overall efficiency seems quite low.

I was also thinking about a take on our current strategy where we have people charge the batteries using the grid for a fee. What if we used deep cycle batteries and upped the capacity to around 500Wh and offer a delivery service? This would mean that you could use the PV panel to keep the battery topped up and if the charge level ever gets too low a replacement battery is delivered to your door and the old one taken away to charge.

That sounds like a good idea, if it fits your finances.