Well lets see, I'm no expert but the primary sources of "green" power are Solar, Wind, and Hydro. Other sources of power are Fossil Fuel based (i.e. Coal, Oil) and Nuclear. These are the primary sources of power (I am sure if I am missing any I will be informed of it hehehehe) All of these sources of power have their upside and downside. Generally speaking Solar, Hydro (water power) and Wind have a higher cost to setup initially, while Coal and Fossil fuels are cheaper because everybody is doing it.
Solar power could be defined as any power from the sun. This includes Photovoltaic panels, Solar Distillation, solar cookers and several others, there are even some engines powered by Heat from the sun. BTW there are lots of nifty ideas on this board for all kinds of do-it yourself projects... www.motherearthnews.com is another great source, there is a hotdog cooker there which is solar powered. Downside is hazardous chemicals used to make cells and inital cost of making/buying solar cells. But the hazardous chemicals are no worse to the enviroment than are Coal/Nuclear/Fossil fuel plants and actually are very similar to the chemicals used to make Silicon cells http://www.eere.energy.gov/solar/myths.html that is a great lil article about solar cells (Thanks Pyrocasto!) Upside is it will continue to produce power for 30+ years far beyond the payoff of the initial cost (you will pay it off in 4 years and the remaining 26 or more years is essentially free to you)
Hydro Electric power is any power from water. This is usually meant from running water like a stream or river or a lake that has been damed. Hydro Electric is actually one of the major sources of power. Usually a Hydro generator works by either being level with the water and turning from the flowing of the water, or by being under the water (like a waterfall) and having the water pour over it. Downside is possible ecological and some Hydro setups require altering the landscape. Ecological and altered landscape in that if you setup a lake to run off and give you power then you change the types of fish that can live there (water gets colder some fish don't like it anymore) However this is not the only way of setting up a hydro plant, it can be done in a much more enviromentally safe way on a river which will greatly reduce the impact to wildlife. Upside to Water power is its cheap and has been used for a very long time (water powered mills have been around for a long time crushing wheat to make flour and for other purposes)
Wind Power is any power from the wind. This is usually a wind generator. Not sure about where you live but in Oklahoma we have several places with Wind power, around Tulsa and Oklahoma City there are some large Wind Generators. Basically how it works is a generator is hooked up to a giant set of blades. There are lots of really in depth articles here on this site and on the home page that describe step by step how to set one up. Downside is sometimes these are noisy, the blades can break off in high winds and it is not as consistant as water or solar power, however with a battery backup system this problem is solved. Upside is its cheap, its been used for a very very long time (The people of Denmark and several other places have been making windmills for a long time)
Nuclear power is made from Uranium 235 or Plutonium 239 being bombarded by radiation which starts up a chain reaction called Fission. Fission is basically one atom gets hit by radiation, splits, and its pieces fly out and hit other atoms and they in turn split, this keeps on going till all the material is consumed. The speed of the reaction is regulated by Lead or graphite rods which are inserted or pulled out of the reactor's core. Lead and graphite slow the reaction down. We use this energy is used the same way an old steam engine works, you have a heat source right over water, water becomes steam and moves the turbine blades, water cools and returns to heat source. BTW Nuclear power creates a lot of heat. Downside is its very toxic. US Goverment is still trying to figure out exactly what to do with all the depleted uranium we have from old nuclear reactors, and the other uranium we have from nukes that have been dismantled. One suggestion is to put it all in a HUGE underground bunker, but then their are safety and security risks involved with that. At any rate, Nuclear power means toxic by product that won't go away for thosands of years. Upside is it makes a WHOOOLE lot of power, I recall one specific facility that could provide power for a 1 gigawatt laser, if I remember correctly the facility was pretty big too.
Coal and Oil are the more common methods of power production. Power is made by a steam engine setup, burn oil or coal to heat water, to make steam to power turbine. Downside is all kinds of really nasty pollution, Coal was used as one of the main power sources especially about 100 years ago and the result was most major cities had a nasty film of soot and ash everywhere. We still burn coal today (not in trains anymore they are diesel) in powerplants, but their have been measures to reduce pollution. Upside is everybody else is doing it, its convienient to just plug into an existing power grid and pay off the power company.
The key is to look at the big picture, find out how much it would cost to purchase/build a system with Hydro or Wind or Solar then spread it out over the life of the system. FOr instance, if a solar panel says its good for 30+ years on warranty then take the price and divide by 30, figure out how much it would cost per year or per month, then check that against some normal figures for a house. BTW OG&E has a nifty lil calculator for figuring up energy costs http://oge.apogee.net/rescalc/
Anyway I hope this helps.
