# Fusion power, economics

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1. Jul 7, 2015

### Stephanus

An interesting puzzle. D-T haven't worked yet, and I hear D-T is the "easiest" way to produce fusion power.

2. Jul 7, 2015

### lavinia

I agree that there are no fusion reactors today which makes the whole thing even more perplexing. Why even plan for it?

here are some stories, maybe apochryphal.

http://www.bbc.com/news/25141597
http://thediplomat.com/2014/06/moon-power-chinas-pursuit-of-lunar-helium-3/
http://www.technologyreview.com/news/408558/mining-the-moon/
http://www.washingtonpost.com/blogs...dacious-plan-to-mine-the-surface-of-the-moon/
http://www.mining.com/china-is-taking-lunar-mining-seriously-65595/
http://phys.org/news/2013-12-moon-pie-sky-china-experts.html

Last edited: Jul 7, 2015
3. Jul 27, 2015

### BWV

given that 150K TwH of sunlight hits the earth every day and PV cells are a semiconductor technology that has a Moore's law dynamic there will likely not be much of a need for fusion power in a couple of decades (when it will still be a decade or two away)

fusion is the energy source of the future and always will be. Its a complete waste spending significant resources on it

4. Jul 27, 2015

### rootone

It's not that fusion can't be done, the problem is getting it to be economically viable.
In the end this translates into a problem of scale, we just didn't build a big enough reactor yet.
Plans exist that will try address that problem of scale and which don't need any new physics.
https://www.iter.org/
This is actually under construction btw, more than just a plan.

Last edited: Jul 27, 2015
5. Jul 27, 2015

### BWV

Just corporate welfare for physists. More fruitful to harness the big fusion reactor we are orbiting

6. Jul 27, 2015

### rootone

I agree that ITER might not produce the desired result, and that improved methods of solar energy collection could well be more economically realistic.
However I don't agree with the idea of it being some kind of corporate vanity project, I doubt that the Chinese would be a major player if this were the case.

7. Jul 27, 2015

### Stephanus

But, does Moore's law still have effect on PV cells. For the price perhaps, but not for the energy intake. No matter how much you Moore-ing PV cell, the input energy is still the same as the energy that is received by 1 metre x 1 metre square of rectangular area on soil. While in fossil fuel, it's the concentration of millions of years sun light that is focussed on a single molecule hydrocarbon.

8. Jul 27, 2015

### BWV

9. Jul 28, 2015

### Staff: Mentor

True -- but it isn't improving with a Moore's law like rate. In fact, it is pretty stagnant.

Furthermore, the cost of the panels themselves is not anymore the largest cost of the solar installation. Other costs, like physical construction, electrical wiring and inverters/switchgear are a greater cost and are mature (not changing much at all).

10. Jul 28, 2015

### Staff: Mentor

Photovoltaics has 100% efficiency as natural absolute upper limit. A more realistic limit is something like 50% for large-scale use - that is a factor 3 compared to current commercial devices. There is still room for improvement, but not that much. Moore's law would help to include more structure into the cells, this is not relevant for solar cells.

Dismissing a possible source of cheap power completely based on incorrect assumptions about photovoltaics is ... questionable.

11. Jul 28, 2015

### BWV

It's a rough and in exact analogy to Moores law, but the thing that really matters is cost per KWh, which is declining rapidly as production scales combined with perhaps a doubling or tripling of efficiency. No one really doubts that 20 years from now, Solar Pv will be far cheaper and more efficient than it is today where it already is at about grid parity. The issue with fusion is no one has any idea if it will be a viable source of energy in 20, 50 or 100 years. No one has come close to generating more power from fusion than is input into the reaction, let alone at an economical cost. The most optimistic projections of working fusion plants 20 or 30 years from now propose capitalized power costs of 2-3 cents per KWh - currently where combined cycle gas is in the U.S. and where solar will be in a few years. There are higher and better uses for the tens of billions of dollars it will take to gamble on these speculative projects.

12. Jul 28, 2015

2012 energy usage for the world was estimated at 424 TWH/day. Current PV cells produce about 18 W/sq ft. To meet that demand would currently require 4.67 1012 sq ft of cells. A current but cheap 135 w 20% efficient panel is about 7.5 sq ft and costs around 200 USD. This gives 622 billion panels at a cost of 124 T USD. (US GDP = $17 T). I think more efficient panel are a ways off and will cost more. Installation cost will increase too. Along with inverters, charge controllers and storage batteries ( the technology of which must also improve). will surely double the cost of materials. So with the installation cost land acquisition cost we're talking about a chunk of change. A typical totally independent household installation with 100% yearly irradiation using about 50 KW H/day would currently require 9 KW array to generate at least 50 KWH of electricity plus at least enough storage capacity for the low light hours. It would use on average 4000 AH per day (12V storage system) and need a battery bank delivering at least 166 A on average for 24 hours . Typical large capacity storage batteries have a max AH rating around 250 AH at cost around 500 USD. You would need twice the capacity to store 4000 Ah to maximize battery like so you would need 32 such batteries almost equal to the cost of the PV array. In real life most would need more PV cells and storage due to clouds, seasonal variation of the declination of the sun and length of the day. One final note the Ivanpah Thermal Electric Solar Generator in California is currently only able to reach about 40% of its one million MWH /yr capacity after 15 month of operation. It cost 2.2B USD and uses 4000 acres of prime solar territory in the Mohave desert. You would have thought estimating the capacity would have been a no brainer, so much for estimates. So I'm thinking efficiency in energy usage. 13. Jul 28, 2015 ### BWV No one energy source will ever generate 100% of global power, but the area requirements you describe are not unachievable - rooftops could be a third or more of the area notwithstanding future increases in efficiency (http://www.nrel.gov/docs/fy14osti/60593.pdf) Solar is not ready for prime time yet, it will be another generation before it can generate a meaningful percentage of global electricity, but its problems are dwarfed by those in developing viable fusion reactors 14. Jul 28, 2015 ### rootone As far as I know the ITER project is the first actual attempt so far to build a fusion reactor at an economically viable scale. It is based entirely on known physics and engineering knowledge gleaned as a result of earlier experimental reactors, it's no shot in the dark based on guesswork. We can't say that fusion is not economically viable end-of, because the whole point of the project is to prove that it is (or isn't) viable. Designed to produce 500 megawatts of output power while needing 50 megawatts to operate it's comparable to a small-medium size fission plant. It's not intended as a commercial generating station though, rather as a proven prototype on which commercial designs could be based. I'm certainly not opposed to improving the effectiveness of solar collection methods, but if economically viable fusion reactors are achievable then why not do so? Do both, - each has it's own unique advantages, and best area of applicability, and they both pose less environmental hazard than much of currently existing power plants. Last edited: Jul 28, 2015 15. Jul 29, 2015 ### mfb ### Staff: Mentor Yes it is declining, but in no way comparable to the millionfold increase in number of transistors Moore's law gave in the last decades. You have to make very optimistic calculations to get grid parity today: - assume that solar power is always needs exactly as produced, so storage does not matter. This assumption is highly unrealistic, and storages are expensive - compare the production costs to electricity price households pay, instead of comparing the production costs to production costs of other power sources. This means you have to ignore the costs for the grid infrastructure - exactly the point you need more with photovoltaics to balance load and production. You also ignore taxes. - assume that subsidies continue to flow as they do now but do not account for them. Germany alone (!) invested more than 100 billion euros in photovoltaics already, and commited to invest at least 100 billions more. That is ten times the costs of ITER. That's exactly why we should investigate it. This is speculation. 20 billion euros, distributed over 3 billion people and 10 years, is 60 cents per average person and year.$0.62 per US citizen, taking into account the actual distribution of the costs and the current exchange rate (and the very crude total cost estimate). I'd happily spend twice that amount to have a second ITER.
As comparison: 200 billions over 20 years for 80 million in Germany are 125 euros per year for photovoltaics.

16. Jul 30, 2015

### gleem

One wonder how implementation of fusion will unfold. Fission reactors where suppose to provide clean, almost limitless energy when introduced. Not much was talked about the inherent hazards of a fission reactor or waste disposal. We eventually settled on a technology that only used 4% of the fuel in the rods was used before they where "poisoned" and had to be replaced loosing 96% of the promised energy. Reactor safety was (is?) not totally understood.

What promises for fusion will go unfulfilled, or overstated. Will we just create another "mess" to clean up?

17. Jul 30, 2015

### rootone

Apart from the fact they are both 'nuclear', a fusion reactor is an entirely different technology to a fission reactor.
Fusion reactors produce no appreciable amount of waste by products at all.
(What it does produce is Helium which is in fact rather useful stuff)

18. Jul 30, 2015

### gleem

Not directly but It will make lots of neutrons which will activate the containment vessel. ITER is suppose to obtain data on this issue. ITER is a breeder for tritium so it is not just a simple "Sun in a bottle". How long will the bottle last? Sure I say go for it but don't put all your energy concerns "eggs" in one basket for now. I am doubtful I will see ITER go on line in my lifetime and I am doubtful that most of you will see a viable commercial reactor in yours.

19. Jul 30, 2015

### Staff: Mentor

The vessel will become activated. It is studied how that effect can be mitigated. Medium lifetimes are the most problematic. Anything living shorter than about a year (half-life) can be stored until it is decayed, everything living billions of years has a tiny activity and no relevant heat production, and can be stored underground forever.

Fusion power plants won't work completely without problematic waste, but they do not produce all the problematic (trans)actinides fission power plants generate and the amount will be significantly smaller.

20. Aug 7, 2015

### mheslep

Moore's law derives from ever increasing circuit density and complexity on a given size of semiconductor. PV cells have no such connection. Neither does the storage technology required for when the big fusion reactor in sky lights the other side of our sphere.

21. Aug 7, 2015

### mheslep

Not necessarily so for all fission, but for thermal spectrum U235 fission which happens to be the dominate form of fission reactor at the moment. It need not be so. The Russians are currently operation two fast reactors that burn actinides, and the U.S. has a couple startups with low volume waste designs.

Last edited by a moderator: Dec 5, 2015
22. Dec 5, 2015

### Burnerjack

What I see is little to no change from the consumer's point of view. If Fusion were indeed made exceptionally cheap, massive build out effort to ensue, increased efforts to break distribution bottlenecks. All made possible by a wider profit margin. The price for delivered power will remain at what the market will bear. However, much change in the balance of delivered energy as far as point of use fuels vs. grid supplied energy goes. Morale of the story: Investor Benefit. Cleaner environment.

23. Dec 5, 2015

### mheslep

In the US, some 2/3 to 3/4 of the price of grid delivered electric power is due to construction and maintenance of the grid. In this sense the promises of "too cheap to meter" was never true. So even zero fuel cost to the utility would not much reduce the cost to deliver residential power.

24. Dec 5, 2015

### Staff: Mentor

The infrastructure price can go down if losses become less important. Probably not a large effect, but large enough to be considered.

25. Jun 16, 2016

### Iain53

I'm not in a position to critique the pros and cons of competing technologies such as Edit: link removed
but I would think that there needs to be a shift from the approach that's been used in the past. Large, continental power grids are far too complex and vulnerable, I like the idea of developing power sources that are much smaller and thus much safer. Local generation and consumption makes more sense than multibillion dollar, huge plants, whether conventional or nuclear.

Last edited by a moderator: Jun 24, 2016