Fission:
Nuclear power today supplies 18 percent of the worlds electrical needs. (49). In terms of emissions, nuclear energy is 'clean'. It does not put any greenhouse gases into the atmosphere. It does, however, leave nuclear waste which creates problems of where to store it. Also there remain concerns about nuclear accidents like those which occurred at Three Mile Island and Chernobyl.

The Nuclear Energy Institute

Fusion:
There is a 30 nation consortium working to build the worlds first nuclear fusion reactor. They have chosen France for the site of the reactor. Unlike fission reactors, which are used in existing nuclear power stations and release energy by splitting atoms apart [fusion generates] energy by combining them. Power has been harnessed from fusion in laboratories but scientists have so far been unable to build a commercially viable reactor, despite decades of research. (41).

Check out the General Atomics Fusion Education site, with a nice explanation of how fusion works.

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