what types of fuel are renewable, what are the advanagesof using them?

Answer 1

For motor fuel, renewable means that the carbon in the fuel came out of the current atmosphere, not some long-term storage system like an oilfield. The common forms today are biodiesel from oil-producing plants and ethanol from sugar-producing plants. Ethanol from cellulose is very promising technology that hasn't made it out of the lab yet. Methane from animal or municipal wastes is increasingly being used in fixed powerplant operations. This not only gives power, it turns methane into CO2, a considerably less potent greenhouse gas.
Biodiesel gives about the same miles/gallon as petroleum diesel, ethanol gives fuel economy enough lower than gasoline as to affect driving range. The primary advantage of renewables is that they add no new greenhouse gasses to the air, a secondary benefit is reduced import costs for fuel. This is extremely helpful to the Brazilian economy, which can export sugar and sugar products, fuel all stages of sugar production, and produce marketable motor fuel from sugar cane plantations.
Disadvantages are the diversion of water, fertilizer, and land resources away from the production of food (this has already severely affected the price of corn and tortillas in Mexico).

Answer 2

The only type of renewable fuel that is sufficient for our consumption is nuclear energy which unfortunately has some consequences. Wind and wave energy is renewable and sustainable but cannot supply our demands. Solar is nuclear so thats that.

You will likely hear many people tell you that biofuels such as "ethanol" are renewable because we can grow them. This is actually very far from the truth. Any plot of land that grows vegatation that will be removed can only be sustained by fertilizing the land. It is unsustainable right from go. Most fertilizers are mined and in finite supply. Eventually there would be no fertililizer left and no land left that anything can grow on. This would not take long, our food demands already tax the system heavily.

Nuclear energy is sustainable because it is the energy of the universe. It surrounds us everywhere and is the reason we live. The sun provides energy for life in the form of nuclear power, the Earth is still hospitable because nuclear decay is keeping the interior warm enough for plate tectonics which drives evolution.

Unfortunately not much energy is sustainable but many people are fooled into thinking this is so. Ask an old farmer what would happen to his fields is all the corn stalks were sold to make fuel instead of being recycled back into the Earth.

Answer 3

It's the picture of a broken government. edit: Wow, great answer from JS. DrM actually has it correct. The entire growth economy of the world is based on resource extraction (be it mining or agriculture or fishing) and the value added to those resources. Or, you could say, the equity markets of the world are a giant Ponzi scheme based on the future value of resources. What happens when the resources run out? What happens when the resource base is poisoned and will no longer produce or even sustain? What cornucopian capitalism fails to recognize is that resources are finite, both in what can be extracted and the volume of waste that can be assimilated. The answer is a sustainable economy. I can't say what that should look like, but making socialism the bogeyman doesn't solve any problem, it only serves to perpetuate the current system of graft and inequity. If our social systems were transparent and fair, capitol holders would work to protect the commons instead of exploiting them for every last dollar. JS has pointed out what is happening now and why. Vote third party, vote Green, vote anything but status quo. In a rational world there would be no need for subsidies. People would choose perpetually clean free energy from the sun (free as in free from recurring cost) instead of finite and toxic energy from carbon, even if the up front costs were greater - because they would realize that the long term costs were far worse. But we don't live in a fair transparent economy and in ignorance the we fall for the false choice.

Answer 4

All fuels are renewable, the question is what is the time cycle required. For "fossil" fuels the cycle time is measure in millions of years. For fuels such as ethanol, biodiesel or wood, the cycle is much shorter, sometimes less than one year. Uranium (i.e. nuclear power) renewal would be measured in the billions of years, since it is based on stellar decay.

Wind and solar are continuously renewed.

Answer 5

Ethanol is because you can grow it and its advantages are that we are not dependent on foreign oil.