> there is some truth
There's *all* truth to that. Let me put this simply; there is almost zero chance that fusion, in its current form, will *ever* be a practical power source.
Now when people read a statement like that they get their backs up about the future, and progress and science and all that. But that's not the issue. The issue is that *fusion isn't the only power source on the planet*. As long as one of these is "better" that fusion, then fusion won't happen. That's all there is to it.
So why do I state my conclusion so forcefully? Because math.
The Levelized Cost of Electricity is the key determinant in telling you whether or not a system will be built. The formula basically tells you what you have to charge for the power coming out of your system in order to break even. Anything above that number is gravy.
The formula, which you can read in depth here:
http://matter2energy.wordpress.com/2012/01/24/your-own-grid-parity-pv-system/
basically boils down to five numbers. The first is the amount of money you pay for the plant, and more specifically, the amount of interest you pay on the loans you took out to build it. The second is the cost of fuel to produce a given amount of power. The next is the peak power that the plant can produce, and next is the percentage of time that the plant actually does produce that. Finally there's the lifetime of the plant, which feed into all of the others. It's something like this:
price of your power = (all the money you put into the plant over its lifetime) / (all the power that you exported to the grid)
We measure money in dollars and cents. We measure power in kWh. This is why your power bill lists a figure in cents/kWh, and why the grid operators measure in $/MWh.
Ok, so fusion. So the price of fuel for a fusion reactor is low, about the same as a fission plant. So we can eliminate that figure for a rule-of-thumb calculation, and leaves us with the lifetime cost of the plant, the CAPEX+OPEX. Now we look at the other side, and we see two figures, the peak power and the percentage of time it runs. We can simplify by listing our CAPEX/peak power as a single number, dollars per watt.
So basically the entire cost structure comes down to the cost of the reactor, and the amount of time it spends running. The rest we can scale out linearly against other power sources.
So what do we know about these two factors?
Well in terms of percentage power, or capacity factor as we call it, fusion reactors are not competitive. Because of neutron embrittlement, they need to be shut down all the time so the reactor core liner can be removed and replaced. Newer designs place lithium-infused blocks inside the containment vessel; this means the vessel itself lasts longer but you still need to open it up all the time to get at those blocks. Generally we might expect a fusion plant to have a capacity factor on the order of a good hydro plant, on the order of 60%. For comparison, a fission plant is around 90%, a wind turbine is 30%, a solar panel is about 15%.
Ok, now the CAPEX. Any fusion reactor of practical output is going to be one of the most fantastically complicated devices ever made. They are utterly crammed with high-end materials, poisons, huge electrical and magnetic systems, high-end vacuum pumps, etc. Depending on the design, it's also flammable, and the fire will cause radioactive rain, so you still need a complete containment building. Now on top of this all, the energy density of a fusion system is *tiny*, so you need to build *enormous* reactors.
And that's where it falls apart. There is simply no way, under any reasonable development line, that the cost of building the plant, and servicing its debt, can possibly be made up by the electricity coming out. PV, one of the worst power sources in terms of cents/kWh, is currently running at about 15 to 20 cents/kWh. A fusion reactor almost certainly cannot be built that will produce power at under ten times that cost. And that's assuming it ever "works", which it doesn't.
This has nothing to do with the technology, it's inherent to the entire concept. Simply put, using a fuel that's widely described as a "very good vacuum" isn't going to produce a lot of total output.
Fusion research along the current lines is a colossal waste of money, and *everyone* knows it. It's entire existence relies entirely on fooling politicians - either by claiming that the system is needed for weapons research, or by the sorts of jingoistic arguments you see in this article.
Now someone will complain that we need to do this just in case it ever works. No, that's is absolutely wrong. The Soviets spent a huge amount of money making sure they had the best vacuum tubes in the world. How did that work out for them?