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Photovoltaic Cell from Plant Proteins

timothy posted more than 10 years ago | from the apollo-powered-popeye-approved dept.

Biotech 36

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."

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Amazed it didn't happen sooner. (1, Insightful)

Spudley (171066) | more than 10 years ago | (#9602019)

Plants have this amazing ability to turn sunlight into usable energy. They're even quite good at it in the shade.

And now a scientist has worked out how to do it as well using plant protiens. Wow.

I'm frankly amazed this didn't come much sooner. Especially with the genetic technologies they're playing with these days.

Re:Amazed it didn't happen sooner. (2, Informative)

alienw (585907) | more than 10 years ago | (#9602359)

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.

Re:Amazed it didn't happen sooner. (2, Insightful)

torpor (458) | more than 10 years ago | (#9604741)

So the combination of silicon production abilities, and plant-cell growth efficiency, and a little of Moore and more... might give us extremely more powerful, much cheaper to produce, solar cells.

Hope so, anyway. I'd much rather be invading a country for their spinach than their oil.

Re:Amazed it didn't happen sooner. (1)

m.corum (661762) | more than 10 years ago | (#9604982)

IEEE Spectrum had a story on this late last year. I don'trecall exact numbers, but research showx that the amount of solar engery converetd by a plant was about twice as much as that of a standard Silicon solar cell.

Re:Amazed it didn't happen sooner. (2, Informative)

BerntB (584621) | more than 10 years ago | (#9603496)

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. []

There are certainly more.

Re:Amazed it didn't happen sooner. (2, Insightful)

kinema (630983) | more than 10 years ago | (#9603783)

I bet if you compared plants to silicon the plants would win on a TCO (total cost of ownership) basis. Silicon solar cells are far from cheap to produce not to mention all the chemicals used in their production are far from earth friendly.

Re:Amazed it didn't happen sooner. (2, Informative)

foolduplex (794129) | more than 10 years ago | (#9612704)

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 ( to sell the product, but guess what, it doesn't catch on. People still think silicon is better...

Business plan (3, Funny)

simonecaldana (561857) | more than 10 years ago | (#9602044)

1) Develop spinach based photovoltaic cells
2) Use Popeye in the logo
3) Profit!

Re:Business plan (0)

Anonymous Coward | more than 10 years ago | (#9602054)

1) Develop spinach based photovoltaic cells
2) Use Popeye in the logo
3) Spend all your profits on royalties for using Popeye on your logo.

Re:Business plan (1)

prof_peabody (741865) | more than 10 years ago | (#9602354)

no, no... 3) get bought out by large oil company looking for their green image before the technology becomes profitable. Oil company then makes profit from the technology. BP and Shell are buying their way into solar big...

Re:Business plan (0)

Anonymous Coward | more than 10 years ago | (#9602882)

you're on the write track, you just need a few important changes, you just need to do it like some "other" profitable entaprises i've seen

1. collect all spinach
2. capture poppeye with olive-oil bot
3. take his dna and patent it mosinato style
4. insert poppeye genes into the unsuspecting public(bwhahaha... haha)
5. profit!!! as everyone goes on mad destructive rampages to go buy your magic spinach

oh the sweet sweet laws of supply and demand!

p.s. $10,000 reward for this "poppeye" fellow, DOA

That's nothing. (-1, Offtopic)

Anonymous Coward | more than 10 years ago | (#9602068)

I've got a charcoal grill built entirely out of hamburger and frankfurters. To my knowledge it's the first edible grill that cooks itself.

Spinich growing space ships in the future? (1, Funny)

scupper (687418) | more than 10 years ago | (#9602337)

Wow, can you imagine giant cultivating ships for spinich for conversion into solar cell arrays? Would the first ship be called the USS Popeye? The companion ship the "Olive Oil"?

Re:Spinich growing space ships in the future? (1)

scupper (687418) | more than 10 years ago | (#9604055)

Man, cut me some slack here, redundant? Who had a bad day to day?

Which efficiency? (2, Informative)

Markus Registrada (642224) | more than 10 years ago | (#9602377)

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%.

Re:Which efficiency? (1)

barawn (25691) | more than 10 years ago | (#9606084)

The only measure of efficiency that matters much is peak Watts per dollar cost. ... in a really super-narrow view of the world, sure.

There are other things that matter besides cost... like size and weight. If a space-based satellite needs 1 KW of power, and you're comparing solutions that are 10% efficient and dirt cheap, and 100% efficient and 100X more expensive, you'd probably choose the 100% efficient version, as it's 10X smaller and 10X less weight.

Of course, you might say this does turn into cost for space-based applications (because weight turns into cost), but no one would want to send up something that's massively larger than it needs to be - the potential for damage is too high.

That being said, the article's misleading - commercially available solar cells can be found above 20% easily. It's just the really cheap ones that are 10-12% that these would be challenging.

Watch out biotech patents (2, Funny)

samjam (256347) | more than 10 years ago | (#9602434)

Well.... spinach, eh?

They'll be bio-hackers trying to crack the genetic drm; or taking illegal cuttings to try and increase the power they get without paying more money to the patent licensee.

Or maybe high-level UV will mutate the plant to become profific and it will spread like triffids and overpower the grid.

I really want to be able to grow more power when I need it, and if I have too much I can eat some, for kicks.


Only 20%? (4, Informative)

Kevin Burtch (13372) | more than 10 years ago | (#9602731)

What about this [] ?

And it's nothing compared to this [] !

The reported results are not for spinach (4, Informative)

manganese4 (726568) | more than 10 years ago | (#9602902)

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 (4, Informative)

cagle_.25 (715952) | more than 10 years ago | (#9603258)

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.

Denaturation and degradation (1)

hung_himself (774451) | more than 10 years ago | (#9604272)

Not to say that oxidation wouldn't be a problem too but when their concerns about protein stability are probably more about whether it can maintain the proper active shape or fold and whether it can avoid being chewed up by the many organisms and proteases out there.

Re:Oxidation issues (1)

manganese4 (726568) | more than 10 years ago | (#9606443)

Although not clear in the actual paper, the oxidation potentials of the special pair in PSI and Rb. spaeroides is roughly 0.5 V vs S.H.E. On the other hand, the reduction potential of the FeS complex of PSI is almost 1 V. Luckily, proteins are most resilliant to high reduction potential than high oxidation potential.

In higher plants under full sunlight, the PSI complexes can function for days without need for replacement by the plant. In fact, under full light conditions the plant actually will increase the # of PSI complexes in the chloroplast. This should be comapred with the fate of the PS II complex which has a half-life of hours under full sun conditions due to its high (1.1 V) oxidation potential. The loss of PSII in favor of PS I is also why plants go from a dark green color to a light green in the sun.

Re:Oxidation issues (1)

cagle_.25 (715952) | more than 10 years ago | (#9607233)

+3 informative. Thanks. :-)

That's misleading (5, Informative)

durandual (687371) | more than 10 years ago | (#9603822)

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!

Re:That's misleading (1, Interesting)

Anonymous Coward | more than 10 years ago | (#9612981)

It's even more misleading. There are two different measures of efficiency here. The first is quantum efficiency, i.e., electrons out per photon in. The second is conversion efficiency in terms of electric power per illumination power. The "spinach cell" is claimed to have 12% quantum efficiency. The silicon cell has 20% power conversion efficiency but its quantum efficiency is very close to 100% at certain wavelengths. I'd estimate the spinach cell to have a power conversion efficency well below 1%.

The worlds first trully green source of power? (1)

Andy Mitchell (780458) | more than 10 years ago | (#9604918)

If it use chlorophyll I guess it quite literally is green, in colour :-)

I'm green with envy...

A Spinach-Powered Laptop? (2, Informative)

rpiquepa (644694) | more than 10 years ago | (#9606840)

This was the subject of a column I published on my blog [] 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 (2, Informative)

zogger (617870) | more than 10 years ago | (#9607841)

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 [] , 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 [] . 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 [] , 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:you get current flow (1, Interesting)

Anonymous Coward | more than 10 years ago | (#9615337)

Most of these alternative things are great, but they are not cheap out of the pocket. Of course, we start talking about externalized costs, etc. Sure, geoheatpumps are great, but they are very expensive (most of the labor is in digging the hole or trenches for the heat exchange pipes), compared to even a high-end conventional heat pump.

Same goes for composting toilets, external water heaters/boilers/furnaces, etc.

Plus, tricky things like environmental air quality, what to do with the compost from the composting toilet, how will these solutions work with high-density housing (i.e., condos, apts), etc.?

Oh, and don't forget local zoning and building codes... Most people in a residential neighborhood would probably not respond to Mr. Granola putting in a composting toilet in his backyard, and would coerce the local govment to put the kibbosh on it because of "safety" and "sanitary" concerns.

Plus, how many of the communities in areas that would benefit from things like PV or hot-water heaters on house roofs have CCD's (Covenants, etc.) that prevent people from doing things to their houses outside of a narrowly defined set of criteria?

If you can't even paint your house a color not on the approved set of color schemes or leave a car parked on your driveway...

And, not everyone can have their own wind generator. If you have the space, great. But if you live in an apt or condo, or the typical suburban residential plot (big house, small lot), there is no way you will be able to put up your own wind generator, even on your roof.

So there will always be a pressing need for centralized utility service. It ain't going away.

But these new sources are great for those of us who have decided to free ourselves from residential living, especially when the local or state government says that you have to replace your septic system, hook up to the water system because your well sucks, and you can't get a new permit for either...

Wattage (0)

Anonymous Coward | more than 10 years ago | (#9609082)

Several things to consider: that this has been done already in some other systems/setups, what is the wattage of the current and what is the max current?

greenish complexion (1)

gonzo_bozo (652898) | more than 10 years ago | (#9609938)

I already have a greenish complexion according to people. I now have a dream. I want to be a deep green quasi-autotroph nudist.

Re:greenish complexion (0)

Anonymous Coward | more than 10 years ago | (#9616929)

... and dance for Orion merchant princes.

Plants are not that eficient, (1)

fraxinus-tree (717851) | more than 10 years ago | (#9611948)

even by themselves. They hardly utilise 1% of the energy they get from the light, and even that 1% is not about the spinach. The poor plant is used in photosynthesis research because of the easily-extracted chloroplasts (compared to other vegetables available), not because they are somehow better.

obligatory Ringworld reference... (1)

constantnormal (512494) | more than 10 years ago | (#9616605)

So with the lower efficiency of this plant-based photovoltaic conversion, you'd have to have some REALLY BIG plants to get significant amounts of power.... and what would they do with this capability?

Why, use it to drive out competing plants, of course. Or maybe cross-fertilize with Venus flytraps and stun/fry small animals as food in order to spread into areas with poor soil. Maybe a good niche would be as a desert plant, lurking around watering holes.

Yes, I know the Slaver sunflowers used mirrors, not electrically-charged lasers or biological Tesla coils, but you can't expect mere fiction to be as creative as reality!

They applied for the patent already.... (1)

fishfinger (685260) | more than 10 years ago | (#9619994) plants will have to license the technology from these guys! :-)

PV plus GMO (1)

celeritas_2 (750289) | more than 10 years ago | (#9629194)

I'm not sure whether this is feasable at all....but. If I were a genetic engineer (not college educated yet) I would be concentrating on combining a tree with the genes from an electricity-producing organism like an electric eel. Solar energy > photosynthesis chemical energy > bio-electric energy > slashdotting energy I seem to think I'm pretty clever for this so if anybody thinks this has any footing email me ranmyaku at gmail dot com
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