Photovoltaic Cell from Plant Proteins

TheSync writes "FuturePundit has a story about work at MIT to develop a photovoltaic cell from spinach chloroplast proteins to generate electricity. These cells convert 12% of the light energy into electricity, and researchers hope to reach 20% efficiency, better than commercial silicon solar cells."

Re:Amazed it didn't happen sooner.

[alienw]

Actually, I read somewhere that only about 1% of solar energy actually gets converted to something useful inside a plant. Silicon cells are much more efficient, they just happen to cost more than plants.

Which efficiency?

[Markus Registrada]

The only measure of efficiency that matters much is peak Watts per dollar cost. Of course that's variable, increasing along the learning curve as the manufacturing process improves, so you have to guess where it will end up. The absolute energetic efficiency (joules of electrical energy out per joules of electromagnetic energy in only needs to be above maybe 10%.

Only 20%?

[Kevin Burtch]

What about this [slashdot.org]?

And it's nothing compared to this [slashdot.org]!

The reported results are not for spinach

[manganese4]

I just read the article in Nano letters. The reported 12% efficiency was not for Spinach proteins. The authors simply demonstrate that Spinahc PSI proteins can be interated into a working device but report no statement of efficiency.

Instead the authors extracted the distinctly different photosynthetic proteins from Rb. sphaeroides. Also, it is not clear if the author's efficiency calculation take into account the inherent loss of energy due to using excitation energy higher than the energy of the charge separated state of the RC. Or if they are simply comparing photons in and number of electrons out.

Oxidation issues

[cagle_.25]

From the article ...

My take on chlorophyll-photovoltaic cells is that they will be feasible some day but it is hard to say when. Their potential advantage over more conventional biomass approaches to energy is that thay would not need to be tended to the way plants in fields or in vats must be. Their potential advantage over more conventional silicon photovoltaic cells is that they may some day be much cheaper to make. But one question that arises is whether the proteins in the chloroplasts can be treated to be made stable for long periods of time.

This is a non-trivial concern. The electron generation can probably occur by multiple pathways, only some of which are reversible. As a result, the proteins become oxidized over time, and lose potency. Some of the links in the article hinted at this problem.

Re:Amazed it didn't happen sooner.

[BerntB]

I'm frankly amazed this didn't come much sooner.

You should read up on physical-/biochemistry sometime. It's really damn hard. Here is one project. [biokem.lu.se]

There are certainly more.

That's misleading

[durandual]

to say that 20% efficient is better than silicon solar cells is simply misleading... how many people will think that that means it's more efficient than solar cells thinking that silicon is the most efficient. For example the galium arsenide solar cells are anywhere from 22-27% efficient.

What you probably should have said wast that it was more efficient than some types of solar cells. The batch of 27% efficiency solar cells that my group just rejected are a heck of a lot more efficient than spinach ever will be at 20%... be careful you accurately present comparison information in a none misleading method. Thanks!

A Spinach-Powered Laptop?

[rpiquepa]

This was the subject of a column I published on my blog [weblogs.com] a week ago. You'll find references to recent articles by Nature, Science News Online and the research paper published by Nano Letters.

you get current flow

[zogger]

just by having two different conducting metals trouching, and applying any sort of heat.(picky physics majors feel free to correct my terminology and description if this is wrong, just looking for a ball park term for casual conversational purposes here). It's called a thermocouple.

Back when I used to work on a dairy, the farmer had a kerosene lamp that ran a table top radio! He got this gizmo when he was in the navy in ww2 and doing one of the murmansk lend-lease runs to the soviets. He bought it in a shop there and brought it back, and it was still working in the mid 70's when I saw it.. It looked like a normal kerosene lamp, you lit it and it threw light, but the body had fins on it, similar in appearance to the fins on an air cooled engine. I don't know what materials it used, but once you lit it and it warmed up, it gave enough power (had wirez coming from it, natch) to run a radio. I don't have a link handy, but I am fairly sure you can still buy these.

With that said, yes, cool on the proteins to electricity. It's cool, nice to see more work being done but...

....For the time being, just growing wood/other biomass stuff and using it is pretty effective and the tech is out there for joe homeowner right now, no waiting required, step right up and lay down your CC and get what you want. You can even get exterior furnaces now that heat your home, provide the hot water, PLUS run a small boiler and turn a steam turbine to give you electricity. It is semi common for alternate energy enthusiasts. An aquantinace of mine at Sensible Steam Consultants [sensiblesteam.net], goes all over the world and designs and builds and installs these types of multi use systems using wood, coal other biomass like ag waste, etc.

well, I went and looked for that lamp:

here is a modern version of the lamp for sale [serras.net]. Scroll down to the radio-lamp set of links. Site is in french but it looks like a lamp, throws good light probably, also gives you 5 watts of power for various purposes. I can't find a good link to the older russian lamps, just a bunch of places that say they still exist and are still used in siberia a lot. The one I saw worked well enough to run an older tube job radio, and it worked *well*.

Here is an example of a company that builds very advanced biomass energy conversion solutions [gocpc.com], from decent homeowner sized on up.

We HAVE a lot of alternative energy solutions right now,from electricity generation/conversion to vehicles to heating and cooling solutions,it just needs more widespread adoption by individuals and homeowners and businesses and not wait for the "other guy" to do it. There is something for everyone out there now, low budget to high budget, pick your application you are interested in. There are literally dozens if not hundreds of different and "alternative" ways to "do" what we are doing now when it comes to using "energy". More R&D is good,it should continue, BUT this subject has had more than enough R&D already,we are WAY beyond that now, it needs mass adoption and deployment, whether it's PV panels to wind generators to like what this last linked company does, use biomass in a straight forward manner that is efficient and productive. There is literally no other reason to wait now, we kept saying "next century we would have alternative energy choices". Guess what! that century got here, the predictions were *true*, and we DO have "alternative energy" choices right now,they are being wholesaled and retailed, you can get them, they work.

Re:Amazed it didn't happen sooner.

[foolduplex]

In fact it did. Similar cells were demonstrated about a decade ago at the Swiss Federal Institute of Technology in Lausanne, Switzerland. A company has been launched (www.greatcell.com) to sell the product, but guess what, it doesn't catch on. People still think silicon is better...