Alternative energy sources to generate electricity?

[dejan]

Hi there,

I have a group project where we are to create (theoretically) a reliable power supply system for rural under developed areas in certain parts of the world.
Now our task is under electrical engineering so it must be related to the power and ways to generate power, minimise the cost and such...

We are for sure going to use solar power in our report (as is everyone else) and wind power too. However what advice i am after is if anyone is aware of any other alternative sources of energy? Other forms of power that aren't too popular? We are going to consider ethanol to power a diesel electricity generator and many small things, like light dimmers, light bulbs with small solar panels, bio energy to generate electricity, using waste...and such.

Would anyone be able to recommend other forms of sources that can generate electrical energy, but must be cost effective, not too difficult/time consuming to build (as in a hydro centre, power plants and the likes)...anything would be very much appreciated thanks.

 

[berkeman]

Other sources are water turbines (if you are close to a good water fall distance for a river or stream). You should also look into energy storage means, since nightime/cold times require some storage of energy from daylight/hot times.

 

[WFO]

Geothermal.
Look at Iceland.

 

[dejan]

Thank you!:)

 

[Danger]

If you deal with a coastal area, give some thought to wave power. As far as I know, that technology is still in the experimental stage, but it might be worth a look.
Rather than dimmer switches (which waste power on their own) and small bulbs, check to see if it would be economical to use high-intensity LED's instead. They seem to be getting cheaper every day. There is also 'light-pipe' technology that can channel sunlight to the interior of large buildings to minimize the need for artificial lighting during daytime. It's pretty expensive to install, but pays off in the long run.

 

[vsage]

I suggest not basing your project on solar power. There are problems with solar power such as the fact that the efficiencies are still in the 20% range on a pretty sparse power source (approx 1500W/m^2 for a sunny area). There are some interesting recent advances in solar power technology, but it seems like you want something different. The fact of the matter is they are pretty expensive without government subsidies and it takes quite a bit of area to power something like a refrigerator (500 watts) to store medicine.

If you want cheap energy, stick with the basics like hydrocarbon fuels, and work on how you can make the things that *consume* power more efficient.

 

[Uncle Shorty]

I was in an old building in brooklyn ny at the pratt institute. Ontop of the building there was a room with a massive pulley on a shaft going from the floor to the ceiling where a big fan was attached to the top. The fan was turning really fast. In that room there were airducts that went from that room down to the ceilings of all the classrooms the warmer air rose up the ducts to the fan room where a leather belt went from the shaft fan pulley to a generator on the other side of the room. I guess the heat from the students powered the building. Ancient Tech. made new again!

 

[sas3]

Thats like the Solar Towers http://www.worsleyschool.net/science/files/enviromission/page2.html

 

[GarageTinker]

Another idea you may want to consider looking at is fuel cell technology, though on that basis you need a suply of hydrogen. Maybe consider bio diesels.

 

[Danger]

That reminds me of something else that I meant to mention. Will ethanol work in a diesel engine? I suspect not, since it does work in gasoline motors.

 

[brewnog]

Not on its own. The low lubricity would quickly knacker fuel pumps, and the cetane number is too low. You can, however, mix ethanol (not methanol) into Diesel to enable you to run leaner, and get a more complete, efficient combustion.

 

[Danger]

Thanks, Brewski; I was unaware that you can mix it in with diesel.

 

[donnye]

what about vegetable oil?

What about just using strained vegetable oil in a diesel generator? I have heard as long as you keep the oil heated so it doesn't gel it will combust and power a diesel generator without the need to mix it into a bio fuel mixture.

 

[Ouabache]

Geothermal.
Look at Iceland.

Geothermal energy conversion to electricity sounds like a great idea.. http://www.nrel.gov/geothermal/geoelectricity.html [Broken] We should do more of that..

And as Danger suggested, tapping the energy of ocean waves would also be pretty handy (http://ocsenergy.anl.gov/guide/wave/index.cfm [Broken])

 

[cepheid]

While these are all excellent ideas in and of themselves, there is one phrase that really stands out in the original post: "a reliable power supply system for rural under developed areas."

Dejan, I realize you are probably treating this project solely as an engineering project, and not as a development project. As a result, you probably don't want a lecture on what are considered to be "good development practices", according to the latest paradigm in international development. I'm going to give you one anyway , for the following reason.

In the past, development projects have been treated simply as technological problems to be solved, and once they were solved, a team would go in, implement it (whether it be slapping down some solar panels or building a well in the middle of a village), and then leave. Under these circumstances, the project was highly unlikely to succeed in the long term, and often didn't. First of all, it often involves a sophisticated techological solution that is not affordable, understandable, or maintainable by the local population. Furthermore, a project that is carried out without significant local participation and input is unlikely to take social and cultural factors into consideration: factors that could affect the long term outcome of the project.

Unfortunately, this scenario describes the last 40+ years of development work quite well in many instances. When you think about it, do we, as developed nations, really want to go in with what we consider to be the best solution, and give it to the people in need, thereby creating a dependency on Western technology, equipment, and ideas? Would it not be better to work on projects in partnership with the people themselves, to give them the means to take control of their own futures. If the people were involved in the project from its inception, slowly raising the captial for it, labouring on the construction, and training on the use and proper maintenance of whatever was being built, this would create a sense of accomplishment, ownership, and pride. Furthermore, it would increase the likelihood of the technology being proliferated by local people, to benefit even more people in the surrounding area, even after the NGO's involvement in the project had ceased. The idea is not just to train the people, but to train them to be trainers. It's a further extension of the "give a man a fish...teach him to fish..." adage.

Technologies that do satisfy the criteria of being affordable, readily constructed from local materials, easily understood, maintained, and proliferated are known in the lingo as "Appropriate Technologies." Solar panels are clearly not.

And now for the part that actually helps you:

One example would be the multifunction platform (MFP) project in Ghana and other West African nations that involves the use of a diesel engine to provide mechanical power to mills for grinding grain and other agroprocessing that is often done laboriously by hand. The MFP can also charge car batteries (which are a very common source of electricity in rural areas anyway), and light light bulbs. More info can be found here:

http://www.ewb.ca/en/whatwedo/overseas/projects/mfpghana.html [Broken]

(incidentally, this website is for Engineers Without Borders, a group I'm involved with at my local university chapter. I'd encourage you to peruse their website).

Practical Action also has a lot of great ideas, some of which have been mentioned (berkeman mentioned the water turbines).

http://practicalaction.org/?id=energy

I hope these links will prove useful. Who knows? Your group might even get bonus points for being the only one to be aware of these issues...

 

[russ_watters]

What about just using strained vegetable oil in a diesel generator? I have heard as long as you keep the oil heated so it doesn't gel it will combust and power a diesel generator without the need to mix it into a bio fuel mixture.

The problem with biodiesel is it requires an awful lot of farmland be dedicated to making fuel.

 

[FrogPad]

The fact of the matter is they are pretty expensive without government subsidies

Interesting how America has an entire Army to defend its' oil supplies around the world.

The fact of the matter is they are pretty expensive without government subsidies and it takes quite a bit of area to power something like a refrigerator (500 watts) to store medicine.

http://www.polarpowerinc.com/products/pdf/spr-10.pdf [Broken]

How about the dual compressor model at 24V, ~7A -> ~170 W

I suggest not basing your project on solar power. There are problems with solar power such as the fact that the efficiencies are still in the 20%

http://www.nrel.gov/docs/fy04osti/36330.pdf

The CS500 is using cells around ~35% efficiency.


And I don't have a source for it, but I thought terrestrial irradiance is around 1342 W/m^2 - this is a standard used for measure at air mass 1.5.

 

[brewnog]

The problem with biodiesel is it requires an awful lot of farmland be dedicated to making fuel.

I think the OP was talking about using SVO rather than biodiesel. It's definitely viable, and I've got a few engines running on it at the moment being operated by green energy companies. Land area only really becomes an issue when you want to try and convert a significant proportion of diesel engines over to using SVO or biodiesel. The amount needed to run one (or a few) engines isn't problematic, particularly if you're farming something like rape seed oil.