Biogas Power
There are a few different ways that you can make biogas but in most cases what we are referring to is methane. Basically methane is produced by the anaerobic break down of biological material. Basically you can turn manure into a gas that can be used as fuel by letting microorganisms digest it in the absence of oxygen. You can also make it out of a number of other biological materials but most research is being done on manure and sewage since they need to be disposed of anyway. There are a few other things that will need to be mixed in with the methane like oxygen and carbon dioxide to get a biogas but basically you are getting energy out of biological waste.
Obviously the great advantage of biogas is that it is completely renewable, cows will always make manure. This is a big part of what makes it so popular. Biogas can reduce the dependency that a lot of countries have on foreign oil. Biogas is also convenient since it can be used pretty much anywhere that you use gasoline or natural gas without any major modifications being required.
Another great advantage of biogas is that it not only reduces green house emissions but it actually solves an environmental problem. We have all heard that cows are a major source of greenhouse gases. It is actually their manure that is the major source of greenhouse gases. By using it as a fuel source we can actually reduce the amount of these gases that get released into the atmosphere. In addition biogas burns much cleaner than fossil fuels so it can significantly reduce the emissions that are released.
There are a couple of problems with biogas that need to be overcome. The first is getting enough of it. Surprisingly the amount of cow manure and sewage that we produce only allows us to make enough biogas to meet a small percentage of our fuel needs. The other problem with biogas is that it does tend to lose a lot of its energy being transported to the user. Biogas is best for applications where it is being used directly on site. For example if you a plant that generates electricity you would want to make and burn your biogas right there to produce the electricity in order to get the maximum benefit out of it.
Biogas is one of the more promising of alternative fuel sources simply because it can be used without large investments in infrastructure being required. Although it is probably somewhat limited by the amount that we can actually produce it is an excellent supplement to other energy sources. Ultimately future technology may allow biogas to play a bigger role. After all it can be made out of a lot more things than manure or sewage. However for now it tends to take a backseat to other fuel sources that are considered to be more likely to completely replace fossil fuels.