Cold fusion has been making a comeback this year.

From being regarded as a largely dead science, cold fusion has grabbed the attention of mainstream media and the scientific community when high-profile demonstrations in Italy allegedly showed a cold fusion device generating 470 watts for five hours. The device, called the E-Cat or Energy Catalyzer was developed by Andrea Rossi, Italian inventor and entrepreneur and Sergio Focardi, a physicist at the University of Bologna. The E-Cat reportedly fuses nickel and hydrogen at low temperatures to release heat energy and shows that cold fusions isn't as dead as many scientists seem to think.

Cold fusion or Low Energy Nuclear Reaction is the process by which energy is produced by nuclear fusion through electrolysis. Cold fusion is largely shunned by mainstream science because fusion only occurs at temperatures of millions of degrees. Rossi's E-Cat uses a special catalyst to fuse hydrogen with nickel to produce enough heat to boil water. The steam produced is used to turn turbines that will generate electricity. It's a system that if proven could lead to clean and cheap source of energy. Since this technology could bring about free energy, there are scientists who would brave ridicule to look into this area. Rossi's method isn't the only LENR device around. More competitors are looking to unleash cold fusion technology to the world.

Impulse Devices, a California based company, is exploring sound drived fusion. The company uses the process of acoustic cavitation, the use of acoustic field to expand and collapse tiny bubbles to generate hot temperatures. As the bubbles shrink, the pressure and temperature of the vapor increase, reaching their maximum upon bubble collapse. According to Impulse's website the temperature and pressure of the gas inside the cavities can exceed temperatures on the surface of the sun. The high temperatures can cause atoms to fuse to release energy.

Star Scientific Limited is using a reaction called a muon catalyzed fusion. The Australian company uses a subatomic particle called the muon to fuse two hydrogen atoms together. Star Scientific claims it's working toward "economically and constantly producing pions, which immediately decay into muons." Once that is accomplished the fusion process will be more sustained.

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