Scientific American has a very interesting argument discussing the economic trends of photovoltaics. They extrapolate the date to predict that in the year 2020 photovoltaics will be as cheaper than the existing sources of energy.
Tag: solar energy
Clean Energy Project 2
My friends at the Clean Energy Project have started a second stage that focuses on quantum chemistry calculation. You might recall [previously: here and here] that the Clean Energy Project consists of screen saver that allows you to donate computer time to do calculations to discover better materials for solar energy.
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Time flies like an arrow. Fruit flies like a banana.
-Groucho Marx
Program: Quantum Effects in Biological Systems
This thursday, the second conference on Quantum Effects in Biological System will be held here at Harvard University. We are very excited to have experts from all over the world here. The aim of this series of conferences is to establish the new field of Quantum Biology. The conference program can be found here.
Picture of Obama Feigning Interest in Excitonics
Flipping through the NY Mag photo gallery titled A History of Obama Feigning Interest in Mundane Things, I found a picture of Excitonics Center‘s Vladimir Bulovic.
Click for A picture of Obama Feigning Interest in the Excitonics Center
The old story of Obama’s visit can be found here.
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Dr. Peter Venkman : Back off man. I’m a scientist.
-Ghost Busters
Excitonics Center
The MIT/Harvard Center for Excitonics has been chosen by the Department of Energy as an Energy Frontier Research Center.
The Research Laboratory of Electronics (RLE) at the Massachusetts Institute of Technology (MIT) will be home to one of 46 new multi-million-dollar Energy Frontier Research Centers (EFRCs) announced today by the White House in conjunction with a speech delivered by President Barack Obama at the annual meeting of the National Academy of Sciences. The EFRCs, which will pursue advanced scientific research on energy, are being established by the U.S. Department of Energy Office of Science at universities, national laboratories, nonprofit organizations, and private firms across the nation.
[…]
The new Center for Excitonics will be a comprehensive center on the science and applications of excitons. It will be based in RLE but include researchers throughout MIT, as well as Harvard University and Brookhaven National Laboratory.
Excitons are the crucial intermediate for energy transduction in low cost, disordered semiconductors. The Center’s researchers will tackle the following questions: How are excitons created and destroyed? How can we control the migration of excitons? How do they move through interfaces and around defects? How can we control the transition between coherence and incoherence, or localization and delocalization? And finally, how can we build excitonic devices that address society’s needs for a new generation of energy technologies? Potential technological outcomes from the Center’s activities include the development of efficient synthetic and room-temperature-reconfigurable light absorbing antennas with sub-5-nm feature sizes for solar cells; stable organic light emitting devices exploiting spin orbit coupling to achieve internal fluorescent efficiencies approaching 100%, and novel nanowire, nanowire heterostructure and nanowire-quantum dot aggregate materials for solid state lighting; and thin film, non-tracking solar concentrators with power efficiencies exceeding 30%.
These are very excitonic exciting news for us. We worked very hard in the proposal, and pushing a shadow Excitonic Center, waiting to see if the real center will be approved. The Excitonics Seminar series has been fantastic so far, with the best speakers in the field. We have very high expectations that the breakthroughs that will come out of our center will lead to more efficient solar energy technologies.
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I guess somebody up there likes me.
-The Sirens of Titan
Clean Energy Project, now for Mac and Linux too!
As I mentioned before, the Clean Energy Project is a way for people like you to donate your unused computer time to help us perform complex chemical calculations. These calculations will predict properties of new materials that might be used towards new solar energy panels. It was released for Windows, and quickly become popular in the international press.
The Clean Energy Project screensaver is now Available for Linux and MacOS too!
DisCover: Quantum rules Photosynthesis (follow up)
This is a follow up to the post about the Discover magazine article that discusses our group’s research studying quantum effects in photosynthesis. The issue (February) is out in stores now. I never liked Discover magazine much, but this time I had to purchase it.
Click here to see the full article.
Quantum mechanics is controlling my thoughts
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Kids were very different then. They didn’t have their
heads filled with all this Cartesian Dualism…
-Monty Python on Nostalgia
Quantum rules Photosynthesis
My main research project was featured in Discover magazine! The cover has some abstract flowery-looking explosion that represents quantum mechanics.
My work in the Aspuru-Guzik group focuses on the quantum aspects of excitonic transfer as applied to photosynthetic complexes and solar harvesting devices. The mistitled article can be found here:
Is quantum mechanics controlling your brain?
Then came the revelation: Instead of haphazardly moving from one connective channel to the next, as might be seen in classical physics, energy traveled in several directions at the same time. The researchers theorized that only when the energy had reached the end of the series of connections could an efficient pathway retroactively be found. At that point, the quantum process collapsed, and the electrons’ energy followed that single, most effective path. […]
Elated by the finding, researchers are looking to mimic nature’s quantum ability to build solar energy collectors that work with near-photosynthetic efficiency. Alán Aspuru-Guzik, an assistant professor of chemistry and chemical biology at Harvard University, heads a team that is researching ways to incorporate the quantum lessons of photosynthesis into organic photovoltaic solar cells. This research is in only the earliest stages, but Aspuru-Guzik believes that Fleming’s work will be applicable in the race to manufacture cheap, efficient solar power cells out of organic molecules.
Unfortunately, the pretty good article about quantum effects in photosynthesis is ruined by its title, title that refers only to the final section of the article containing some wild speculations on quantum mechanics and consciousness. Please, don’t take that last part seriously. Although there is strong experimental evidence supporting the role of quantum effects in photosystems, there isn’t anything that suggests a connection between quantum mechanics and consciousness.
Solar Energy Harvesting
What about solar energy?
What about it?
Life on Earth depends on extracting energy from the solar radiation that reaches the planet, or eating stuff that does it. Professor Sun is the main source of energy required for us to live. Professor Sun generates energy by transforming Hydrogen into Helium by means of nuclear fusion, a process that excretes energy in the form of light that in turn reaches our planet after 8 minutes.
How much of this energy is being used by life on the planet? The question is a complex one, but I decided to do some back of the envelope calculations to the order of magnitude of the light that could be used in principle, is used in practice, and would be needed for Human consumption.
Energy of the Light that Reaches the Atmosphere (1LRA) per year: 10^25 Jules/year ~ 1LRA/y.
This is the total energy that gets to the planet every year, most of it useless to life.
Energy of the light that could be absorbed by photosynthetic organisms: 10^24 J/y ~ 1LRA/month.
This is the total energy that could in principle be used by living organisms. This calculation accounts for light of frequencies that cannot be used by photosynthetic complexes, and also for light falling on areas on the planet where it couldn’t be used anyway. For example, a lot of the energy that hits the surface of the oceans is reflected. The one transmitted gets scattered and some of it is lost.
In order to get a sense of the scale of these processes, we should compare it to the energy consumption of the human race.
Energy consumption of humans: 10^21 J/y ~ 1LRA/minute.
We humans consume about 1minute of the total solar energy that reaches the planet in a year. This includes not only energy spent on machines, but also the actual food we eat. Remember, those plants that we eat, or that our cows eat, harvest energy from the sun. Plants store their unused energy in the form of carbohydrates.
The energy (think: calories) of all the living things that can harvest energy from the sun gives us of an upper bound of much energy could be extracted from processing them.
Energy stored in the total photosynthetic biomass: 10^21J
This is about the total energy of all photosynthetic organisms. If you kill each bacteria, algae, plant in the world and magically extracted all of its energy in a perfectly efficient manner, it would barely provide the human race with energy for one year. And of course, there would no more plants to replant!
Proposals that suggest extracting energy from the stored carbohydrates, such as ethanol-from-corn, are even worse; only a small fraction of the total biomass of the planet is carbohydrates. In other words, we cannot plant enough to ever extract enough energy to fulfill our current energy needs.
Comparing this number to the amount of fossil fuel highlights how small it is. Of course, how much fossil fuel there is in the planet is not known, much less how much of it can we actually reach. Do not take these numbers too seriously, but think about them to have an idea of the order of magnitude of how much energy there is in photosynthetic organisms represent.
Guesstimated Fossil Fuel Reserves: 10^22J
Guesstimated Total Fossil Fuel in Earth, including the unreachable fuel: 10^23J
The fossil fuel reserves are 10 times more than the total current photosynthetic biomass! This is very suggestive: any source of energy that uses biological systems to directly extract energy from the sun, such as harvesting algae, will not be a major factor in any long term energy solution for the human race.
However, look at that very first number. There is a lot of energy falling into the planet. Harvesting this energy directly, by means of photovoltaic solar panels, is a reasonable strategy.
Donate computing time for the environment
There is the environmental need and the political will to take solar energy seriously. Our group at Harvard is leading several theoretical and computational efforts to develop more efficient solar panels. One of our efforts (not my project) is to use computational chemistry tools to find novel materials that would lead to better solar technologies. This is mostly performed by trial and error. A lot of it.
A certain molecular arrangement is “proposed” randomly, and the computer calculates its molecular energy to see if it makes sense (if it is a realistic material) and then if it is useful for solar panels. This trial and error approach takes a long time, requires a lot of computational power, but it can be parallelized in a straight-forward manner.
How can you help us?
By downloading the Harvard Clean Energy Project software. With it, you can donate your unused computer cycles, when the computer is on but not using the processor much, to help perform the combinatorial calculations. With these small computing contributions from thousands of students it is expected that the calculations will be done ten times faster than in a supercomputer.
Right now it is only available for Windows, but in the next few weeks it should be compatible with Linux and Mac too.
The project has had a lot of visibility, the other day BBC called our office!
Minus Two Fish 