RE: Telegraph - Letters to the editor (today)23 Jan 2020 15:29
colinh100, as far as I am aware (been following it for a while), no one is close to viable fusion, they can manage a few seconds here and there maybe even 30s but not sustainable, i.e. generating it's own tritium etc.
Interesting fact and reason for it taking so long, helium behaves like tritium but is cheaper and creates much less energy (10x) however you can trial with helium then move to tritium. However following a helium test the machine is safe to work on in days/weeks, following a tritium test it takes months/years for the machine's radiation levels to drop enough to enter the same room as it. So you need to be really really sure that the tritium tests will work, and you need the radiation to make more tritium, it's fairly rare and really expensive, so you need to breed tritium from lithium.
Fusion is at least a decade (probably 2) away from producing meaningful power to the grid, we've got loads or room to play in, and with a large installed base of storage, fewer fusion reactors are needed, which will effect the economics as you'll reuse the design less.