Good Horizon programme last night on BBC 2, presented by Professor Brian Cox. The subject was the prospects for power production from controlled nuclear fusion: we saw Tokamaks in Oxfordshire and Korea; a laser-initiated fusion system in California; and the Z-machine at Sandia - which looked like the Victorian laboratory of Dr Frankenstein, using stupendous electric currents to drive a magnetic-field-driven implosion normally used for hydrogen bomb research.
I wish the programme had said something about how power might be extracted from a working fusion reactor, but as the researchers themselves believe commercial reactors are more than 20 years away, perhaps there's no rush. See the Wikipedia article here for more details.
One of the more interesting facets of the programme was the great gap between the power we can currently supply and the requirement. Brian Cox set a target of 5 kW per person (considerably less than the per capita power currently used in advanced countres). Assuming a gobal population of ten billion, which I believe is the projection for mid-century, the total power required is 50 Terawatts.
According to the Wikipedia article here, in 2005 global power production was only 16 TW.
Looks like we'll be building a lot of reactors, of one kind or another.