NIF seeks to [create fusion] with 192 giant lasers, which occupy a space as large as three football fields. Fired simultaneously, the laser beams blast a peppercorn-size speck of frozen hydrogen suspended in a 30-foot-wide target chamber with about 500 trillion watts of power—about 1,000 times the amount of energy used by the entire United States during that same few trillionths of a second. (Because the lasers fire so briefly, NIF uses only about $20 of electricity for each burst.) Crushed to less than a thousandth of its original volume, the hydrogen becomes 100 times denser than lead and hotter than the center of a star; the nuclei fuse and release bursts of energy. According to NIF's computer simulations, the fused hydrogen should generate more energy than the lasers put in—a process called ignition. Nature, unfortunately, has stubbornly refused to cooperate. There has been no ignition at the National Ignition Facility. When physicists first turned on all the lasers at NIF in February 2009, they set a goal of reaching ignition by October 1, 2012. NIF's lasers routinely cause fusion, but the energy pumped in by the lasers still exceeds the energy created by the fusing hydrogen. The failure to meet that ignition deadline is the main reason the President, with the support of at least some in Congress, decided to cut NIF's budget.And why won't the world cooperate with our computer projections? It seems that the models assume the hydrogen pellet will stay round, but in fact it always turns lumpy; it also has to be coated with a thin layer of plastic, and some of the plastic always mixes into the pellet, further messing up the works.
So the dream of fusion power will remain a dream for a few more decades at least.