By controlled, I mean that the energy is released a way that can be harnessed for electrical generation. To win the energy may be in the form of heat, but that heat must be more than enough to generate the energy used to ignite. The reaction must either be sustained for more than one minutes or if it is a shorter pulse, the pulse must be repeated within 24 hours.
I believe that the mostly likely way for me to win this bet is with a laser-ignited inertially-confined deuterium/tritium reaction. That said, there are lots of other ways for me to win the bet, including tokomaks, muon-catalyzed fusion, Boron 5 reactions, or even some form of cold fusion. George Dyson has generously pointed out that the lowest tech method of winning would be confined to underground explosions used to create steam.
Note that this is a bet about the technical, not the economical, feasibility of fusion. It may well be that other energy sources are less expensive, in particular hydrocarbon sources, such as natural gas, coal and oil. I am also optimistic about the economic feasibility of new kinds of fission reactors, particularly those that breed their own fuel.
I am interested in fusion because, as far as I can see, it is the only “wild card” in the energy deck that could, by itself, solve the entire problem of electricity generation without the risk of ecological disaster. I am not against renewable sources like wind and solar, but since they are intermittent and location-restricted they cannot directly replace coal-fired plants without advances in storage and power distribution. I also believe that they have more unfavorable environmental impacts than is generally understood, in both their deployment and manufacture. Part of the reason that I placed this bet is to encourage adoption of the term “synthetic solar”, which is suggestive of the potential relative environmental-friendliness of fusion.
Challenge Danny Hillis to a bet on this prediction!