6 ms·

Scientists pioneer a new way to turn sunlight into fuel

80 points by kjeetgill 8y ago

gns24 8y ago
The quote “Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed – around 1-2 per cent of what it could potentially convert and store” makes no sense to me; plants are usually in massive competition for access to light, so in what sense is there no need for it to be more efficient?
- ben_w 8y ago
  As a hypothesis (because I’m not a biologist) it might be important to optimise for other things at the expense of efficiency. Disease resistance, for example. Or perhaps absorbing more sunlight will cause them to overheat (is that why the leaves are not black?)
- vixen99 8y ago
  Unless we know all the factors involved in 'survival' we can't assume that it's enhanced by greater energy efficiency. The latter may be counter-productive in ways that are not immediately obvious. Given the state of inefficiency of conversion that's evolved (survived), clearly there has not been a need for efficiency besting 1-2 per cent.
  - AllegedAlec 8y ago
    That's not generally not how evolution works. Sure, a plant will do fine with the current efficiency of photosynthesis, but intuition would tell us that a plant would do more fine if its leaves were more efficient. It would grow faster, have more or better seed and would generally outcompete other plants of its species. That the efficiency is not higher than this leads us to believe that either: - there are strong evolutionary imperatives to not raise the efficiency any further (ie: "there has been a need not to", rather than "there has not been a need to). This could be due to a lot of reasons; oxidative stress, a plant's 'desire' to have a large leaf surface, a tendency to dry out the soil too quickly, etc etc. - With the current 'design' of chlorophyl, it is not possible to increase efficiency further, and it's quite hard to get out of the local optimum.
    - Drakim 8y ago
      The higher amount of energy (sugar?) might make the plant more prone to predation.
      - AllegedAlec 8y ago
        That would also be a possibility, yeah.
      - chopin 8y ago
        That could be countered with venom, especially if you have plenty of energy available. Many plants already go that route, even now.
- hinkley 8y ago
  In full sun a plant can absorb far more light than it can handle. Apparently one of the little tricks of chloroplasts is how they shunt that power away without sustaining damage. Could we just do something with that power? It’s a bit like turning the rotor blades when the wind is too high to keep the thing from ripping itself apart. But imagine if you could make a turbine that generated tons more electricity in a gale force wind. Think what you could do with that much concentrated power.
  - pjc50 8y ago
    In both cases it's a straightforward cost-benefit tradeoff: sure, you can build a turbine that works in gales. But they're rare. So in practice the turbine design is tuned against a statistical model of expected wind speeds to deliver the best $/kWh ratio over its design life. > Think what you could do with that much concentrated power. That sounds more like a headache (now you have to uprate the whole power-handling systems) than a benefit.
  - SuoDuanDao 8y ago
    I've not been able to kill the idea of a plant that uses excess energy to create hydrogen which it uses to float its seeds far and yonder. Didn't know that there's already a lot of excess energy that could be used for such a project, though I suspect the knowledge of genegeneering needed to make it happen is a ways off still.
    - sofon 8y ago
      That's such a neat idea. I wonder why floating plants don't already exist. I'm also surprised that I've not seen it in Scifi.
      - adrianN 8y ago
        How would an evolutionary pathway to floating look like?
        stephengillie 8y ago
- skookumchuck 8y ago
  Plants turn their leaves throughout the day to fully face the sun. It seems they can't afford to be less efficient.
- 21 8y ago
  It's called photoprotection: > High sunlight can raise plant growth rates but can potentially cause cellular damage. The likelihood of deleterious effects is lowered by a sophisticated set of photoprotective mechanisms, one of the most important being the controlled dissipation of energy from chlorophyll within photosystem II (PSII) measured as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity remains uncertain because it momentarily reduces the quantum efficiency of photosynthesis. https://en.wikipedia.org/wiki/Photoprotection https://en.wikipedia.org/wiki/Photoprotection https://en.wikipedia.org/wiki/Non-photochemical_quenching https://en.wikipedia.org/wiki/Non-photochemical_quenching
- scotty79 8y ago
  Optimisation methods tend to get stuck in local optima. I'm sure nature sqeezed out every ounce of possible performance out of the current photosynthesis but that doesn't mean there can't be vastly superior process doing basically same thing but different enough that it won't spontaneously get discovered by evolution in next billion years.
- strainer 8y ago
  That statement makes no sense to me but neither does the popular idea that species evolve to compete with each other limited only by immediate material resources. I imagine some mechanism of foresight or conservatism must develope in a diverse population for the population to survive in total. Such a mechanism may have had to be present in the earliest lifeforms or else long periods of accumulating complexity and diversity, seem open to frequent and potentially unrecoverable upheaval, by the temporary competitiveness of mutations fit only for immediate material demands.
- wahern 8y ago
  I think the particular hypothesis in the following has been rejected, but the article introduces some of the interesting variations in photosynthesis and hints at different evolutionary pressures behind their emergence. To the point about the efficiency of chlorophyll-based photosynthesis, Chlorophyll, the main photosynthetic pigment of plants, absorbs mainly blue and red wavelengths from the Sun and reflects green ones, and it is this reflected light that gives plants their leafy color. This fact puzzles some biologists because the sun transmits most of its energy in the green part of the visible spectrum. -- https://www.livescience.com/1398-early-earth-purple-study-suggests.html https://www.livescience.com/1398-early-earth-purple-study-su...
Gys 8y ago
'...to achieve unassisted solar-driven water-splitting.' (into water and hydrogen) 'Their method also managed to achieve more efficient absorption of solar light than natural photosynthesis.'
- village-idiot 8y ago
  I wonder how much more efficient. This process would have benefits where high density energy is needed, hydrogen powered container ships being a popular plan of mine. But if you don’t have space constraints, involving a hydrogen fuel cell only adds inefficiencies. Most fuel cells are in the 64-80% efficiency range, which the theoretical max being 84%. This might be worse off than the PV->battery->use pipeline that we’re used to.
vfclists 8y ago
I want to be her student, à la Macron, though I suspect I am older.
- aloisdg 8y ago
  Sexist and out-of-context.
- dang 8y ago
  Please don't do this here.
keypress 8y ago
I'd love to know more. If this is as simple as having liquid water pumped through tubing with algae this sounds great. How natural a system can this be? How pure does the water have to be?
ksec 8y ago
Off Topic: ( A question I have in my head for a long long time ) What are the purpose of these PR article from University to other Academic Science magazines? If it was to attract investors or sponsorship, surely companies and individual have other means of access to how to invest or not, and not looking at every magazine / papers / Website announcement. There are countless battery "breakthrough" and we all know they are at least another 5 years away from commercialise, or in most cases, never. Apart from inner nerds wanted to know, what value do they provide? What purpose do they serve?
- myopicgoat 8y ago
  In Oxbridge, colleges compete for public exposure because ultimately that’s what leads to donation & to get top undergrads applying who, eventually, will donate £££ to the college once they land a good job. So there’s quite a lot of PR relating to sports & academic achievements. What’s a bit ironic in this case is that no research is really done at colleges, and grads tend not to be central to college life, it’s really the authors & the research lab who deserve the creds!
- lucozade 8y ago
  > What are the purpose of these PR article from University to other Academic Science magazines? If it was to attract investors or sponsorship Pretty much this though probably for attracting students too. > surely companies and individual have other means of access to how to invest or not, and not looking at every magazine / papers / Website announcement. Sure they do, some have existing relationships etc. But it doesn't follow that this sort of release isn't useful. For example, I'm in industry and, occasionally, we are looking at something that I believe could benefit from external expertise. Sure I have academic and consultancy contacts but I've also Googled what I'm interested in and found relevant press releases or, more often, papers. A phone call or email exchange has often led to a collaboration or pointers in a useful direction.
- conjectures 8y ago
  Universities are always under pressure to show impact. They need artifacts to show to funders (govt ministers) and demonstrate relevance. The explanation 'our lab turned water into fuel using algae' is generally intelligible, while the Nature reference lends a credibility the intended lay audience isn't intended to cash. Also, there is some element of just wanting people to be aware of cool stuff that got done. Universities are primarily there to produce scientific breakthroughs, not bring technologies to market. The value is in undertaking high risk research.

80 points by kjeetgill 8y ago

The quote “Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed – around 1-2 per cent of what it could potentially convert and store” makes no sense to me; plants are usually in massive competition for access to light, so in what sense is there no need for it to be more efficient?

ben_w 8y ago
As a hypothesis (because I’m not a biologist) it might be important to optimise for other things at the expense of efficiency. Disease resistance, for example. Or perhaps absorbing more sunlight will cause them to overheat (is that why the leaves are not black?)
vixen99 8y ago
Unless we know all the factors involved in 'survival' we can't assume that it's enhanced by greater energy efficiency. The latter may be counter-productive in ways that are not immediately obvious. Given the state of inefficiency of conversion that's evolved (survived), clearly there has not been a need for efficiency besting 1-2 per cent.
- AllegedAlec 8y ago
  That's not generally not how evolution works. Sure, a plant will do fine with the current efficiency of photosynthesis, but intuition would tell us that a plant would do more fine if its leaves were more efficient. It would grow faster, have more or better seed and would generally outcompete other plants of its species. That the efficiency is not higher than this leads us to believe that either: - there are strong evolutionary imperatives to not raise the efficiency any further (ie: "there has been a need not to", rather than "there has not been a need to). This could be due to a lot of reasons; oxidative stress, a plant's 'desire' to have a large leaf surface, a tendency to dry out the soil too quickly, etc etc. - With the current 'design' of chlorophyl, it is not possible to increase efficiency further, and it's quite hard to get out of the local optimum.
  - Drakim 8y ago
    The higher amount of energy (sugar?) might make the plant more prone to predation.
    - AllegedAlec 8y ago
      That would also be a possibility, yeah.
    - chopin 8y ago
      That could be countered with venom, especially if you have plenty of energy available. Many plants already go that route, even now.
hinkley 8y ago
In full sun a plant can absorb far more light than it can handle. Apparently one of the little tricks of chloroplasts is how they shunt that power away without sustaining damage. Could we just do something with that power? It’s a bit like turning the rotor blades when the wind is too high to keep the thing from ripping itself apart. But imagine if you could make a turbine that generated tons more electricity in a gale force wind. Think what you could do with that much concentrated power.
- pjc50 8y ago
  In both cases it's a straightforward cost-benefit tradeoff: sure, you can build a turbine that works in gales. But they're rare. So in practice the turbine design is tuned against a statistical model of expected wind speeds to deliver the best $/kWh ratio over its design life. > Think what you could do with that much concentrated power. That sounds more like a headache (now you have to uprate the whole power-handling systems) than a benefit.
- SuoDuanDao 8y ago
  I've not been able to kill the idea of a plant that uses excess energy to create hydrogen which it uses to float its seeds far and yonder. Didn't know that there's already a lot of excess energy that could be used for such a project, though I suspect the knowledge of genegeneering needed to make it happen is a ways off still.
  - sofon 8y ago
    That's such a neat idea. I wonder why floating plants don't already exist. I'm also surprised that I've not seen it in Scifi.
    - adrianN 8y ago
      How would an evolutionary pathway to floating look like?
      - stephengillie 8y ago
skookumchuck 8y ago
Plants turn their leaves throughout the day to fully face the sun. It seems they can't afford to be less efficient.
21 8y ago
It's called photoprotection: > High sunlight can raise plant growth rates but can potentially cause cellular damage. The likelihood of deleterious effects is lowered by a sophisticated set of photoprotective mechanisms, one of the most important being the controlled dissipation of energy from chlorophyll within photosystem II (PSII) measured as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity remains uncertain because it momentarily reduces the quantum efficiency of photosynthesis. https://en.wikipedia.org/wiki/Photoprotection https://en.wikipedia.org/wiki/Photoprotection https://en.wikipedia.org/wiki/Non-photochemical_quenching https://en.wikipedia.org/wiki/Non-photochemical_quenching
scotty79 8y ago
Optimisation methods tend to get stuck in local optima. I'm sure nature sqeezed out every ounce of possible performance out of the current photosynthesis but that doesn't mean there can't be vastly superior process doing basically same thing but different enough that it won't spontaneously get discovered by evolution in next billion years.
strainer 8y ago
That statement makes no sense to me but neither does the popular idea that species evolve to compete with each other limited only by immediate material resources. I imagine some mechanism of foresight or conservatism must develope in a diverse population for the population to survive in total. Such a mechanism may have had to be present in the earliest lifeforms or else long periods of accumulating complexity and diversity, seem open to frequent and potentially unrecoverable upheaval, by the temporary competitiveness of mutations fit only for immediate material demands.
wahern 8y ago
I think the particular hypothesis in the following has been rejected, but the article introduces some of the interesting variations in photosynthesis and hints at different evolutionary pressures behind their emergence. To the point about the efficiency of chlorophyll-based photosynthesis, Chlorophyll, the main photosynthetic pigment of plants, absorbs mainly blue and red wavelengths from the Sun and reflects green ones, and it is this reflected light that gives plants their leafy color. This fact puzzles some biologists because the sun transmits most of its energy in the green part of the visible spectrum. -- https://www.livescience.com/1398-early-earth-purple-study-suggests.html https://www.livescience.com/1398-early-earth-purple-study-su...

Gys 8y ago

'...to achieve unassisted solar-driven water-splitting.' (into water and hydrogen) 'Their method also managed to achieve more efficient absorption of solar light than natural photosynthesis.'

village-idiot 8y ago
I wonder how much more efficient. This process would have benefits where high density energy is needed, hydrogen powered container ships being a popular plan of mine. But if you don’t have space constraints, involving a hydrogen fuel cell only adds inefficiencies. Most fuel cells are in the 64-80% efficiency range, which the theoretical max being 84%. This might be worse off than the PV->battery->use pipeline that we’re used to.

vfclists 8y ago

I want to be her student, à la Macron, though I suspect I am older.

aloisdg 8y ago
Sexist and out-of-context.
dang 8y ago
Please don't do this here.

keypress 8y ago

I'd love to know more. If this is as simple as having liquid water pumped through tubing with algae this sounds great. How natural a system can this be? How pure does the water have to be?

ksec 8y ago

Off Topic: ( A question I have in my head for a long long time ) What are the purpose of these PR article from University to other Academic Science magazines? If it was to attract investors or sponsorship, surely companies and individual have other means of access to how to invest or not, and not looking at every magazine / papers / Website announcement. There are countless battery "breakthrough" and we all know they are at least another 5 years away from commercialise, or in most cases, never. Apart from inner nerds wanted to know, what value do they provide? What purpose do they serve?

myopicgoat 8y ago
In Oxbridge, colleges compete for public exposure because ultimately that’s what leads to donation & to get top undergrads applying who, eventually, will donate £££ to the college once they land a good job. So there’s quite a lot of PR relating to sports & academic achievements. What’s a bit ironic in this case is that no research is really done at colleges, and grads tend not to be central to college life, it’s really the authors & the research lab who deserve the creds!
lucozade 8y ago
> What are the purpose of these PR article from University to other Academic Science magazines? If it was to attract investors or sponsorship Pretty much this though probably for attracting students too. > surely companies and individual have other means of access to how to invest or not, and not looking at every magazine / papers / Website announcement. Sure they do, some have existing relationships etc. But it doesn't follow that this sort of release isn't useful. For example, I'm in industry and, occasionally, we are looking at something that I believe could benefit from external expertise. Sure I have academic and consultancy contacts but I've also Googled what I'm interested in and found relevant press releases or, more often, papers. A phone call or email exchange has often led to a collaboration or pointers in a useful direction.
conjectures 8y ago
Universities are always under pressure to show impact. They need artifacts to show to funders (govt ministers) and demonstrate relevance. The explanation 'our lab turned water into fuel using algae' is generally intelligible, while the Nature reference lends a credibility the intended lay audience isn't intended to cash. Also, there is some element of just wanting people to be aware of cool stuff that got done. Universities are primarily there to produce scientific breakthroughs, not bring technologies to market. The value is in undertaking high risk research.