Fusion energy has tantalized scientists for more than half a century as a possible source of limitless, reliable power.
But the technology to create the power of a star on Earth and use it to produce electricity remains at least five decades away, according to U.S. government experts.
In the same way that coal- burning plants sired nuclear power plants, researchers see fusion as the next step in the evolution of electric power plants.
It's all about building a better firebox: a way to consume fuel efficiently to generate steam to spin a turbine and make electricity. Scientists see great potential in fusion power: It is run on special forms of hydrogen, a plentiful, low-cost fuel that produces no long-lasting radioactive waste.
Though fusion creates a nuclear reaction, which can only be done at 100 million degrees (which in itself is problem) , a fusion reactor cannot melt down as nuke plants do, according to Anne Davies, fusion program di rector in the U.S. Department of Energy's office of science. She said the reactors use too little fuel to explode. And unlike coal plants, fusion releases no harmful greenhouse gases.
The difference between today's nuclear power plant with a fission reactor and tomorrow's fusion reactor is how they create energy. Nuclear fission reactors produce energy by splitting atoms; fusion reactors create energy by fusing atoms.
Fusion research grew out of the Manhattan Project, the massive scientific effort during World War II that developed the atomic bomb. The atomic bombs dropped on Japan 60 years ago this month released energy by fission.
At the time, scientists speculated that the fusion process could be harnessed to release even greater destructive power. After the Soviet Union exploded its atomic bomb in 1949, U.S. scientists started top-secret fusion research and, in 1952, they detonated the first hydrogen bomb.
Classified research continued on bombs and fusion reactors. But it became apparent by the late 1950s that creating a controlled fusion reaction to generate electricity was a highly complex problem.
So in 1958, at an Atoms for Peace conference in Geneva, Switzerland, the United States and United Kingdom declassified their fusion research. Other countries followed suit. Since then, fusion research has been a collaborative effort among scientists around the world.
In the following decades, scientists have made advances and technical progress. The U.S. government has spent more than $10 billion on fusion research.
After about two decades of talks, the European Union and five nations, including the United States, agreed in June to pool resources and create an international test reactor in France to show the feasibility of controlled fusion energy production. The $5 billion experimental reactor is expected to be operational by 2016.
The goal is to achieve a fusion reaction that will release more energy than is used and be a source of safe, clean power.
In turn, that research is expected to lead to building a demonstration power plant sometime after 2035.
Under this optimistic timetable, the hope is that a private company will build a fusion power plant by 2050 that would provide electricity to homeowners, said Davies of the Department of Energy.
"There's a lot of skepticism about whether this will work," she said. "I'm optimistic and confident, given how far we have come, that we will make it work. I'm also confident it will be economical."
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