Methane from Sun+CO2

Scupperer · Post by **Scupperer** » Wed Mar 25, 2009 6:41 pm

Catalytic coated carbon nanotubes use sunlight to convert CO2 directly to Methane:

http://www.physorg.com/news155471367.html

http://pubs.acs.org/doi/abs/10.1021/nl803258p (subscription link).

This new process produces conversion rates 20 times higher than previous attempts, and they've shifted the spectrum of conversion from ultraviolet to visible light. Unaided, it's still not a bona-fide solution to anything, but:

Even with their current nanotubes, Grimes calculates that a reflector that concentrates sunlight on a square metre of the nanotube film could yield 500 litres of methane over the course of eight hours...

...But he hopes that depositing copper nanoparticles more evenly onto the surfaces of the nanotubes and making other improvements will help boost their conversion rates by a factor of several thousand.

If they can achieve those improvements, and industrialize it, this has the potential to create a closed energy production/use cycle, and even to replace fossil fuel use altogether.

Would this sort of progress kill fusion research in its tracks?

Aero · Post by **Aero** » Wed Mar 25, 2009 6:53 pm

Would this sort of progress kill fusion research in its tracks?

No, IMO, but it would fit right in with Wind and Solar, maybe even displace them to a great extent. Wind and Solar haven't killed fusion research and by the same token, Carbon Dioxide conversion to fuels won't either. It could, ultimately, kill the electric car again though, depending when it comes on-line in volume.

Ships and spacecraft designers would still prefer a good working Polywell fusion reactor for many reasons.

Skipjack · Post by **Skipjack** » Wed Mar 25, 2009 8:02 pm

Hmm, what is efficient in this case?
I mean if converted to thermal energy how many kilowatt hours worth of methane do you get out of a certain area of cathalyst? They provide a number in parts per million but to me this does not say anything.
How does this number compare to new solar cells.
Further, I read that they are using platinum for the cathalyst. That does not seem very cheap. I wonder how the price for a m^2 of this compares to a m^2 of a high end photovoltaic cell.
Anyone here who can shoot some numbers arround?

MSimon · Post by **MSimon** » Wed Mar 25, 2009 8:39 pm

Skipjack wrote:Hmm, what is efficient in this case?
I mean if converted to thermal energy how many kilowatt hours worth of methane do you get out of a certain area of cathalyst? They provide a number in parts per million but to me this does not say anything.
How does this number compare to new solar cells.
Further, I read that they are using platinum for the cathalyst. That does not seem very cheap. I wonder how the price for a m^2 of this compares to a m^2 of a high end photovoltaic cell.
Anyone here who can shoot some numbers arround?

A dollar a watt (peak) is a good ball park number for solar cells.

Skipjack · Post by **Skipjack** » Wed Mar 25, 2009 10:00 pm

I was more interested in the numbers for that methane cathalyst device.
Also I never quite understood this dollar per watt number. To me this is a rather useless number. I would be more interested in the cost per KW/h. I mean even if it was 10 dollars per Watt. If these things were good for 200 years, it would still be worth it, I guess...

KitemanSA · Post by **KitemanSA** » Thu Mar 26, 2009 1:31 am

Skipjack wrote:I was more interested in the numbers for that methane cathalyst device.
Also I never quite understood this dollar per watt number. To me this is a rather useless number. I would be more interested in the cost per KW/h. I mean even if it was 10 dollars per Watt. If these things were good for 200 years, it would still be worth it, I guess...

The time value of money would kill you on that one. And I want to know where he gets his solar cells. That is closer to the price per watt for baseload power plants.

MSimon · Post by **MSimon** » Thu Mar 26, 2009 2:11 am

KitemanSA wrote:
Skipjack wrote:I was more interested in the numbers for that methane cathalyst device.
Also I never quite understood this dollar per watt number. To me this is a rather useless number. I would be more interested in the cost per KW/h. I mean even if it was 10 dollars per Watt. If these things were good for 200 years, it would still be worth it, I guess...
The time value of money would kill you on that one. And I want to know where he gets his solar cells. That is closer to the price per watt for baseload power plants.

Yeah. I was thinking wind. Solar is about 3X that.

Skipjack · Post by **Skipjack** » Thu Mar 26, 2009 10:42 am

The time value of money would kill you on that one.

Hmm, really? I am not too sure about that. After all electricity prices go up as the value of money goes down. Still, the question remainy as to how high the price/KWh is. Right now a KWh costs roughly 7 cents in the US, I believe. For the consumer it is arround 10 cents.
Here it is 15 Euro cents or a little less depending on your contract. Anyway, if you have a 1 KW solar cell array that costs you 10,000 (random number, not real world) USD to buy and it will produce 100,000 KWh before it needs costy maintenance, then you have the investment back in 12 years. So that thing needs to live for 15 years at least in order to make any sense at all (yeah, I did not include the fact that the sun does not shine at night and the price of the land and some other stuff, but the price is just a random number anyway). That still is a long term investment with rather little revenue. This is why I am interested in the cost KWh. Everything else is irrelevant.
The same would go for this methane cathalyst reactor thingy. If the cost per KWh is to high, it is worthless.

Art Carlson · Post by **Art Carlson** » Thu Mar 26, 2009 11:52 am

Skipjack wrote:Still, the question remains as to how high the price/KWh is.

I had a very interesting conversation about 2 weeks ago with the CTO of Schott Glass in Germany. He claimed the solar cells on his roof produce electricity for 40 Euro cents / kWh (compared to 20 cents market price for residential customers). He claimed that included everything - cost of the modules, installation, wiring, maintenance, hours of sunshine at his location, lifetime. He also expects the price to continue to drop. I expected numbers like that for solar thermal in desert regions (Spain, North Africa, Southwestern USA), but was moderately shocked that photovoltaics have made so much progress. (BTW, he also thought we should continue to use nuclear power, at least for some time.)

Barry Kirk · Post by **Barry Kirk** » Thu Mar 26, 2009 12:08 pm

Just saw this for the first time... There is an added benefit to going direct from solar to Methane.

It's a lot easier to store Methane for future usage than electricity.

Skipjack · Post by **Skipjack** » Thu Mar 26, 2009 1:19 pm

It's a lot easier to store Methane for future usage than electricity.

Yes, that is a benefit, but if the process of conversion from CO2 to methane is not more cost efficient than the entire process of doing the same via photovoltaics and say H2 instead of methane, then it would not have any benefit over photovoltaics. That was my point.

He claimed the solar cells on his roof produce electricity for 40 Euro cents / kWh

Whoa! It is THAT BAD? I am surprised that anyone ever put those on a roof if it is like that. I mean what is the point? At an efficiency like that, that is debateable whether this has any benefits for the environmen even. After all, you need to produce clean silicone, then the solar cells from it, then deliver them to where they will be needed and all that takes energy too and if that is via coal plants and a diesel engine, you get a very bad equation out of that.
So solar energy= bull, at least right now. Lets talk again when the cost has been divided by 4. Here we pay between 10 and 15 Euro cents per KWh (depending on provider), not 20, I think that number is to high, even in Germany, where energy prices are nuts anyway thanks to the idiot politicians there.

Scupperer · Post by **Scupperer** » Thu Mar 26, 2009 1:44 pm

It's a lot easier to store Methane for future usage than electricity.

Methane is also a good source for transportation fuel (over 400k cars in Europe run on Methane). It could also replace mined sources for natural gas lines.

cost efficient?

That's always the question. Lacking any information, only time will tell I suppose. I don't know my moles from my molls, but I'd wager not a great deal of platinum is actually used - it is, after all, a sheet of nano-particles.

power equivalency?

I did a boe, and figured about 450 watts/m^2/day, for the non-existent solar concentrated example of 500 l of methane/day given in the quote.

Another way to look at it; assume the price equivalency between methane and gasoline is roughly equal. So if a 1m^2 station costs less than $200/day to operate, then it could be profitable.

Warthog · Post by **Warthog** » Thu Mar 26, 2009 2:18 pm

Skipjack wrote: How does this number compare to new solar cells.

The first link gives an electrical equivalence of 0.1 watt per square centimeter for the methane catalyst. There are 10,000 square centimeters per square meter.

Skipjack wrote:Further, I read that they are using platinum for the cathalyst. That does not seem very cheap. I wonder how the price for a m^2 of this compares to a m^2 of a high end photovoltaic cell.
Anyone here who can shoot some numbers arround?

Depends on how thick the coating needs to be. Platinum is also used in car exhaust catalytic converters, and the amount keeps shrinking as better ways of fabricating are developed.

KitemanSA · Post by **KitemanSA** » Thu Mar 26, 2009 3:19 pm

Skipjack wrote:
The time value of money would kill you on that one.
Hmm, really? I am not too sure about that. After all electricity prices go up as the value of money goes down. Still, the question remainy as to how high the price/KWh is. Right now a KWh costs roughly 7 cents in the US, I believe. For the consumer it is arround 10 cents.

$10k has a cost of $500 at 5% interest. That is ~$1.37 per day. Your 1kW panel will produce on average 5kWh per day in a GOOD location. At the 10 cents per kWh mentioned, you save $0.50 per day. This means that you will add ~$0.87 to your debt every day. Inflation changes both numbers equally. You CAN'T make up that difference unless the price of power is much higher. If the price of power NOW were 27.4 cents, you would have break-even.

If the price of PV continues to sink while the price of other power continues to rise RELATIVE to it, they will cross and PV will be economical; as it is now in certain situations. It can be much cheaper than running new powerline for instance.

kurt9 · Post by **kurt9** » Thu Mar 26, 2009 4:25 pm

If it can be made cheap and robust enough, could this solar powered nanotube technology be considered the energy storage technology that finally makes solar energy useful? The solar power is used to make methane whenever the sun shines and the methane is then used or stored in tanks. When the sun does not shine (night or cloudy days), the methane is then used as motor fuel or burned to generate electricity.

Even if highly efficient, I don't think this would reduce the demand for polywell fusion or fission power. The methane generated by this process is worth more sold as motor fuel than used to make electricity. If polywell is successful, or one of the newer fission or fusion/fission hybrid technologies come on line, such will generate electricity more cheaply than this nanotube technology.

Talk-Polywell.org

Methane from Sun+CO2

Methane from Sun+CO2

cost of photovoltaic