A photon walks into a bar … | Frank van Mierlo | TEDxBeaconStreet
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0:13 - 0:15Since April,
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0:15 - 0:17I’ve been working the morning shift,
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0:17 - 0:19and I’ve learned two things.
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0:19 - 0:23Four o'clock in the morning -
that continues to be painfully early. -
0:23 - 0:25It has also taught me, though,
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0:25 - 0:29that a sunrise
can be stunningly beautiful. -
0:29 - 0:32There's something magical
about the light that we get from the sun. -
0:32 - 0:34Light, of course, is photons,
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0:34 - 0:36and the photon
is this interesting particle -
0:36 - 0:38that has no mass,
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0:38 - 0:40always travels at the speed of light,
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0:40 - 0:42and it packs a real punch of energy.
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0:43 - 0:44Now the photons we get from the sun
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0:44 - 0:47come to us in a wide range
of energy levels, -
0:47 - 0:51ranging all the way
from the very energetic blue light, -
0:51 - 0:52that has so much energy
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0:52 - 0:55that it can interact
with the molecules of the air - -
0:55 - 0:59and their scattering
is the reason the sky is blue - -
0:59 - 1:01to the lazier red photons
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1:01 - 1:05that travel unimpeded
in a straight line through the atmosphere, -
1:05 - 1:07which is why a sunrise can be red.
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1:07 - 1:09So we get all of
these photons from the sun, -
1:09 - 1:12all of these different energy levels.
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1:12 - 1:14And here's the tragedy.
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1:14 - 1:19When we try to harvest that energy,
we're optimized for just one wavelength; -
1:20 - 1:22everything else is sub-optimal.
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1:23 - 1:25To understand why,
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1:25 - 1:28let me explain to you
how a solar panel works. -
1:28 - 1:31A solar panel is made
out of a semiconductor material, -
1:31 - 1:34and to get useful electricity
out of a semiconductor, -
1:34 - 1:38you have to lift the electron
from its natural state -
1:38 - 1:39to the conduction band.
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1:40 - 1:44The amount of energy needed to do that
is called the bandgap. -
1:44 - 1:45Now, there's three scenarios.
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1:45 - 1:49One, the photon has exactly
the same energy as the bandgap; -
1:49 - 1:52in that case, you can lift the electron
to the conduction band -
1:52 - 1:54where it can do useful work.
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1:54 - 1:56The second case,
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1:56 - 1:59the photon has less energy
than the band gap; -
1:59 - 2:00in that case,
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2:00 - 2:02the photons go unused
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2:02 - 2:05because they don't have enough energy
to free any electrons. -
2:05 - 2:06And then the third case,
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2:06 - 2:10the photon has more energy
than the bandgap. -
2:10 - 2:12Well, that extra energy is wasted as well
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2:12 - 2:17because you're still going to get
just one electron for one photon. -
2:17 - 2:20The best we can do with today's technology
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2:20 - 2:24is to harvest around 24 percent
of the available energy. -
2:24 - 2:28And today’s solar panels are getting
very close to that fundamental limit. -
2:29 - 2:30This year,
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2:30 - 2:32solar panels will provide
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2:32 - 2:36around five percent
of the electricity we use globally. -
2:36 - 2:38Clearly, that's not good enough.
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2:38 - 2:39To change our energy mix,
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2:39 - 2:42we have to install
many, many more solar panels, -
2:42 - 2:46and we have to increase
the power of each panel. -
2:46 - 2:48But we're up against
the fundamental limit. -
2:49 - 2:51So how do we get out of that box?
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2:52 - 2:55Well, there is a solution;
it's called tandem. -
2:55 - 2:59In laboratories in Europe
and the United States, -
2:59 - 3:01mostly privately funded,
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3:01 - 3:03breakthroughs have now made it possible
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3:03 - 3:08to make a cost-effective tandem module
that uses two semiconductors. -
3:08 - 3:12The top material is a high bandgap
harvesting the high energy photons, -
3:12 - 3:17and the bottom material is a low bandgap
capturing the long wavelength photons. -
3:17 - 3:23Tandem is going to increase
the energy output of a solar panel by 35%. -
3:23 - 3:24To make this possible,
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3:24 - 3:25we have to solve
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3:25 - 3:29all manner of difficult engineering
and manufacturing problems, -
3:29 - 3:31and it's just now
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3:31 - 3:34that cost-effective solutions
are becoming available -
3:34 - 3:38and commercially viable tandem modules
are becoming a reality -
3:38 - 3:41in the very near future.
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3:41 - 3:44This is the most important
innovation in solar -
3:44 - 3:48since solar was first conceived
in Bell Labs, in 1954. -
3:49 - 3:51Wherever they're going to be deployed,
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3:51 - 3:54tandem is going to increase
the energy yield per acre. -
3:54 - 3:56They're going to make
every installation more efficient. -
3:56 - 3:58This is such an important technology.
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3:58 - 4:02We have to urgently deploy it
everywhere where it's needed most, -
4:03 - 4:05places like India.
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4:05 - 4:09India is at the forefront
of the battle against climate change. -
4:09 - 4:11Its people are hungry for new solutions,
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4:11 - 4:15and they have some of the lowest
energy use per capita in the world. -
4:15 - 4:17India deserves an opportunity
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4:17 - 4:21to industrialize with something
more appealing than coal, -
4:21 - 4:24and tandem modules
can be that opportunity. -
4:24 - 4:28Imagine powerful tandem modules
splitting water into oxygen and hydrogen. -
4:29 - 4:32Thanks to the increased energy yield
of the tandem module, -
4:32 - 4:35clean hydrogen can become
economically feasible. -
4:35 - 4:37And once you have clean hydrogen,
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4:37 - 4:42now you can store vast amounts of energy
for long periods of time -
4:42 - 4:46and fuel industrial processes
such as steel making. -
4:46 - 4:49Tandem modules are transformational.
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4:49 - 4:52By themselves, they are not good enough.
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4:52 - 4:54Winning the battle
against climate change -
4:54 - 4:56is a huge challenge.
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4:56 - 4:58It's a battle we are currently losing.
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4:58 - 5:03We're not decreasing but we're increasing
our CO2 admissions. -
5:03 - 5:05To change that,
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5:05 - 5:07we need a dramatic psychological shift.
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5:07 - 5:10We need to get past a tipping point,
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5:10 - 5:12a point in time where the majority of us
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5:12 - 5:17believes that we are responsible for
and need to take care of our planet. -
5:18 - 5:20Today, we're nowhere
near that tipping point, -
5:20 - 5:24but with the advent of tandem,
our tools are getting better. -
5:24 - 5:27And now it's up to all of us
to put them to good use.
- Title:
- A photon walks into a bar … | Frank van Mierlo | TEDxBeaconStreet
- Description:
-
Among experts there is a consensus developing on how we can address climate change. In this talk Frank van Mierlo explains the enabling technologies, which include tandem solar, and lays out a compelling vision for a better world.
In case you wondered:
A photon walks into a bar
and the bartender asks,
Do you have any luggage?
The photon says,
No I am traveling light.Frank van Mierlo, CEO 1366 Technologies Inc
Armed with engineering degrees from MIT and Stanford, Frank van Mierlo has been working for the last 12 years to enable the energy transition away from fossil fuel. A large team of world-class professionals are helping him in his quest.
This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDxTalks
- Duration:
- 05:29
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Amanda Chu edited English subtitles for A photon walks into a bar … | Frank van Mierlo | TEDxBeaconStreet |