Biofuels.

Biofuels are produced from living organisms or from metabolic by-products(organic or food waste products). In order to be considered a biofuel the fuel must contain over 80 percent renewable materials. It is originally derived from the photosynthesis process and can therefore often be referred to as a solar energy source. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases. 'First-generation' or conventional biofuels are biofuels made from sugar, starch, and vegetable oil. Second generation biofuels are biofuels produced from sustainable feedstock.
Biodiesel was probably the first of the alternative fuels to really become known to the public. The great advantage of biodiesel is that it can be used in existing vehicles with little or no adaptation necessary. Cars running on BioEthanol, which is produced from agricultural crops, sugar cane or bio-mass, are governed by the same law of physics as those using gasoline. That means both emit CO2, as an inevitable consequence of the combustion process. But there is a crucial difference: burning ethanol, in effect, recycles the CO2 because it has already been removed from the atmosphere by photosynthesis during the natural growth process.
Along with the traditional methods we have new advancements in the renewable energy production. One of such examples include Engineers Tapping Algae Cells for Electricity :With the help of photosynthesis plants convert light energy to chemical energy. This chemical energy is stored in the bonds of sugars they use for food. Photosynthesis happens inside a chloroplast. Chloroplasts are considered as the cellular powerhouses that make sugars and impart leaves and algae a green hue. During photosynthesis water is split into oxygen, protons and electrons. When sunrays fall on the leaves and reach the chloroplast, electrons get excited and attain higher energy level. These excited electrons are caught by proteins. The electrons are passed through a series of proteins. These proteins utilize more of the
electrons’ energy to synthesize sugars until the entire electron’s energy is exhausted. Now researchers intercepted the electrons just after they had been excited by light and were at their highest energy levels. They put the gold electrodesinside the chloroplasts of algae cells, and tapped the electrons to create a tiny electrical current. It may be the beginning of the production of “high efficiency” bioelectricity. This will be a clean and green source of energy but minus carbon dioxide. The cell remains alive throughout the whole process. When cells start the photosynthesis, the electrodes attract electrons and produce tiny electric current.