The Earth's resources are limited and depleting while the demand of the growing population that inhabits the planet has started to balloon over the years. This is why scientists have been on a quest to sustain the demands of humankind. One of the most important is the quest to find an energy source that won't hurt the planet, unlike what is currently happening.

In all fairness, mankind has taken leaps when it comes to solar power and wind power. Now, there are studies pertaining to additional methods of producing clean and renewable energy. 

The first on the list is body heat. A train station in Sweden has begun harnessing body heat from the thousands of commuters that use it. Stockholm Central Station was engineered by the real estate company, Jernhusen, to channel the collected body heat to keep a building across the road warm. Using body heat as a source of energy is not a new concept, however, transferring it to be used on a different building is fairly new. Other studies on using body heat are being made like engineering gadgets that can be worn so the one's body heat would power the said gadgets.

Second is turning carbon dioxide into stone. In a study, turning the said gas back into coal was made possible by pumping it back beneath the surface of the earth. The whole process takes two years. other projects have successfully captured carbon dioxide and stored it. However, the possibility for leaks is one problem that the researchers would like to avoid.

The third one is the power of movement or dancing. A Sustainable Dancefloor was invented by two Dutch engineers in 2005. It converts the kinetic energy generated when dancing into electricity. One step on the dancefloor measures to about two to 20 joules of energy.

This lights up the LED installed in the dancefloor. Tokyo employed this concept on all the electronic signs on their railway stations. Fourth is coffee waste. There is a substantial amount of liquid waste coffee production generates to get to the final product. Recently, a special fuel cell has been developed that eats the waste matter and in exchange, produce electricity. Also, a tech firm based in London, Bio-Bean, has discovered that coffee waste can be used as biofuel.

The last on the list is Algae fuel. Some algae have natural oils which can be used as a replacement for diesel and gasoline. Some say it can also be used as jet fuel. The algae would release carbon dioxide as well when burnt but will stay carbon neutral and will not increase the level of carbon dioxide. The drawback is the large area of land and water needed to process this source.