[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:13.41,0:00:14.63,Default,,0000,0000,0000,,Since April,
Dialogue: 0,0:00:14.63,0:00:16.78,Default,,0000,0000,0000,,I’ve been working the morning shift,
Dialogue: 0,0:00:16.81,0:00:18.87,Default,,0000,0000,0000,,and I’ve learned two things.
Dialogue: 0,0:00:18.87,0:00:23.25,Default,,0000,0000,0000,,Four o'clock in the morning -\Nthat continues to be painfully early.
Dialogue: 0,0:00:23.25,0:00:25.24,Default,,0000,0000,0000,,It has also taught me, though,
Dialogue: 0,0:00:25.24,0:00:28.87,Default,,0000,0000,0000,,that a sunrise\Ncan be stunningly beautiful.
Dialogue: 0,0:00:28.87,0:00:32.22,Default,,0000,0000,0000,,There's something magical\Nabout the light that we get from the sun.
Dialogue: 0,0:00:32.22,0:00:33.83,Default,,0000,0000,0000,,Light, of course, is photons,
Dialogue: 0,0:00:33.83,0:00:36.11,Default,,0000,0000,0000,,and the photon\Nis this interesting particle
Dialogue: 0,0:00:36.11,0:00:37.59,Default,,0000,0000,0000,,that has no mass,
Dialogue: 0,0:00:37.59,0:00:39.62,Default,,0000,0000,0000,,always travels at the speed of light,
Dialogue: 0,0:00:39.66,0:00:41.94,Default,,0000,0000,0000,,and it packs a real punch of energy.
Dialogue: 0,0:00:42.57,0:00:44.50,Default,,0000,0000,0000,,Now the photons we get from the sun
Dialogue: 0,0:00:44.50,0:00:47.05,Default,,0000,0000,0000,,come to us in a wide range\Nof energy levels,
Dialogue: 0,0:00:47.05,0:00:50.56,Default,,0000,0000,0000,,ranging all the way\Nfrom the very energetic blue light,
Dialogue: 0,0:00:50.56,0:00:51.68,Default,,0000,0000,0000,,that has so much energy
Dialogue: 0,0:00:51.68,0:00:55.16,Default,,0000,0000,0000,,that it can interact\Nwith the molecules of the air -
Dialogue: 0,0:00:55.16,0:00:58.58,Default,,0000,0000,0000,,and their scattering\Nis the reason the sky is blue -
Dialogue: 0,0:00:58.58,0:01:00.88,Default,,0000,0000,0000,,to the lazier red photons
Dialogue: 0,0:01:00.88,0:01:04.58,Default,,0000,0000,0000,,that travel unimpeded\Nin a straight line through the atmosphere,
Dialogue: 0,0:01:04.58,0:01:06.86,Default,,0000,0000,0000,,which is why a sunrise can be red.
Dialogue: 0,0:01:06.86,0:01:09.48,Default,,0000,0000,0000,,So we get all of\Nthese photons from the sun,
Dialogue: 0,0:01:09.48,0:01:11.91,Default,,0000,0000,0000,,all of these different energy levels.
Dialogue: 0,0:01:12.39,0:01:14.21,Default,,0000,0000,0000,,And here's the tragedy.
Dialogue: 0,0:01:14.21,0:01:19.24,Default,,0000,0000,0000,,When we try to harvest that energy,\Nwe're optimized for just one wavelength;
Dialogue: 0,0:01:19.54,0:01:22.06,Default,,0000,0000,0000,,everything else is sub-optimal.
Dialogue: 0,0:01:22.97,0:01:24.58,Default,,0000,0000,0000,,To understand why,
Dialogue: 0,0:01:24.58,0:01:27.54,Default,,0000,0000,0000,,let me explain to you\Nhow a solar panel works.
Dialogue: 0,0:01:28.17,0:01:31.42,Default,,0000,0000,0000,,A solar panel is made\Nout of a semiconductor material,
Dialogue: 0,0:01:31.42,0:01:34.36,Default,,0000,0000,0000,,and to get useful electricity\Nout of a semiconductor,
Dialogue: 0,0:01:34.36,0:01:37.64,Default,,0000,0000,0000,,you have to lift the electron\Nfrom its natural state
Dialogue: 0,0:01:37.64,0:01:39.42,Default,,0000,0000,0000,,to the conduction band.
Dialogue: 0,0:01:39.79,0:01:43.55,Default,,0000,0000,0000,,The amount of energy needed to do that\Nis called the bandgap.
Dialogue: 0,0:01:43.55,0:01:45.14,Default,,0000,0000,0000,,Now, there's three scenarios.
Dialogue: 0,0:01:45.14,0:01:48.82,Default,,0000,0000,0000,,One, the photon has exactly\Nthe same energy as the bandgap;
Dialogue: 0,0:01:48.82,0:01:51.98,Default,,0000,0000,0000,,in that case, you can lift the electron\Nto the conduction band
Dialogue: 0,0:01:51.98,0:01:54.42,Default,,0000,0000,0000,,where it can do useful work.
Dialogue: 0,0:01:54.42,0:01:55.73,Default,,0000,0000,0000,,The second case,
Dialogue: 0,0:01:55.73,0:01:58.70,Default,,0000,0000,0000,,the photon has less energy\Nthan the band gap;
Dialogue: 0,0:01:58.71,0:02:00.24,Default,,0000,0000,0000,,in that case,
Dialogue: 0,0:02:00.24,0:02:01.69,Default,,0000,0000,0000,,the photons go unused
Dialogue: 0,0:02:01.69,0:02:04.76,Default,,0000,0000,0000,,because they don't have enough energy\Nto free any electrons.
Dialogue: 0,0:02:05.19,0:02:06.37,Default,,0000,0000,0000,,And then the third case,
Dialogue: 0,0:02:06.37,0:02:09.55,Default,,0000,0000,0000,,the photon has more energy\Nthan the bandgap.
Dialogue: 0,0:02:09.55,0:02:12.22,Default,,0000,0000,0000,,Well, that extra energy is wasted as well
Dialogue: 0,0:02:12.22,0:02:16.78,Default,,0000,0000,0000,,because you're still going to get\Njust one electron for one photon.
Dialogue: 0,0:02:17.34,0:02:19.57,Default,,0000,0000,0000,,The best we can do with today's technology
Dialogue: 0,0:02:19.57,0:02:23.59,Default,,0000,0000,0000,,is to harvest around 24 percent\Nof the available energy.
Dialogue: 0,0:02:24.13,0:02:28.14,Default,,0000,0000,0000,,And today’s solar panels are getting\Nvery close to that fundamental limit.
Dialogue: 0,0:02:28.83,0:02:29.83,Default,,0000,0000,0000,,This year,
Dialogue: 0,0:02:29.83,0:02:31.71,Default,,0000,0000,0000,,solar panels will provide
Dialogue: 0,0:02:31.71,0:02:35.68,Default,,0000,0000,0000,,around five percent\Nof the electricity we use globally.
Dialogue: 0,0:02:35.68,0:02:37.58,Default,,0000,0000,0000,,Clearly, that's not good enough.
Dialogue: 0,0:02:37.58,0:02:39.18,Default,,0000,0000,0000,,To change our energy mix,
Dialogue: 0,0:02:39.18,0:02:42.25,Default,,0000,0000,0000,,we have to install\Nmany, many more solar panels,
Dialogue: 0,0:02:42.25,0:02:45.54,Default,,0000,0000,0000,,and we have to increase\Nthe power of each panel.
Dialogue: 0,0:02:45.94,0:02:48.34,Default,,0000,0000,0000,,But we're up against\Nthe fundamental limit.
Dialogue: 0,0:02:48.76,0:02:51.09,Default,,0000,0000,0000,,So how do we get out of that box?
Dialogue: 0,0:02:51.74,0:02:54.76,Default,,0000,0000,0000,,Well, there is a solution;\Nit's called tandem.
Dialogue: 0,0:02:55.33,0:02:58.89,Default,,0000,0000,0000,,In laboratories in Europe\Nand the United States,
Dialogue: 0,0:02:58.89,0:03:00.74,Default,,0000,0000,0000,,mostly privately funded,
Dialogue: 0,0:03:00.74,0:03:02.62,Default,,0000,0000,0000,,breakthroughs have now made it possible
Dialogue: 0,0:03:02.62,0:03:07.90,Default,,0000,0000,0000,,to make a cost-effective tandem module\Nthat uses two semiconductors.
Dialogue: 0,0:03:07.90,0:03:12.28,Default,,0000,0000,0000,,The top material is a high bandgap\Nharvesting the high energy photons,
Dialogue: 0,0:03:12.28,0:03:17.20,Default,,0000,0000,0000,,and the bottom material is a low bandgap\Ncapturing the long wavelength photons.
Dialogue: 0,0:03:17.20,0:03:22.56,Default,,0000,0000,0000,,Tandem is going to increase\Nthe energy output of a solar panel by 35%.
Dialogue: 0,0:03:22.56,0:03:24.25,Default,,0000,0000,0000,,To make this possible,
Dialogue: 0,0:03:24.25,0:03:25.26,Default,,0000,0000,0000,,we have to solve
Dialogue: 0,0:03:25.26,0:03:29.11,Default,,0000,0000,0000,,all manner of difficult engineering\Nand manufacturing problems,
Dialogue: 0,0:03:29.11,0:03:30.63,Default,,0000,0000,0000,,and it's just now
Dialogue: 0,0:03:30.63,0:03:34.32,Default,,0000,0000,0000,,that cost-effective solutions\Nare becoming available
Dialogue: 0,0:03:34.32,0:03:38.38,Default,,0000,0000,0000,,and commercially viable tandem modules\Nare becoming a reality
Dialogue: 0,0:03:38.38,0:03:40.51,Default,,0000,0000,0000,,in the very near future.
Dialogue: 0,0:03:40.51,0:03:43.66,Default,,0000,0000,0000,,This is the most important\Ninnovation in solar
Dialogue: 0,0:03:43.66,0:03:48.11,Default,,0000,0000,0000,,since solar was first conceived\Nin Bell Labs, in 1954.
Dialogue: 0,0:03:48.61,0:03:50.74,Default,,0000,0000,0000,,Wherever they're going to be deployed,
Dialogue: 0,0:03:50.74,0:03:53.73,Default,,0000,0000,0000,,tandem is going to increase\Nthe energy yield per acre.
Dialogue: 0,0:03:53.73,0:03:56.41,Default,,0000,0000,0000,,They're going to make\Nevery installation more efficient.
Dialogue: 0,0:03:56.41,0:03:58.29,Default,,0000,0000,0000,,This is such an important technology.
Dialogue: 0,0:03:58.29,0:04:02.47,Default,,0000,0000,0000,,We have to urgently deploy it\Neverywhere where it's needed most,
Dialogue: 0,0:04:02.87,0:04:04.70,Default,,0000,0000,0000,,places like India.
Dialogue: 0,0:04:05.11,0:04:08.75,Default,,0000,0000,0000,,India is at the forefront\Nof the battle against climate change.
Dialogue: 0,0:04:08.75,0:04:11.50,Default,,0000,0000,0000,,Its people are hungry for new solutions,
Dialogue: 0,0:04:11.50,0:04:14.100,Default,,0000,0000,0000,,and they have some of the lowest\Nenergy use per capita in the world.
Dialogue: 0,0:04:14.100,0:04:16.80,Default,,0000,0000,0000,,India deserves an opportunity
Dialogue: 0,0:04:16.80,0:04:20.66,Default,,0000,0000,0000,,to industrialize with something\Nmore appealing than coal,
Dialogue: 0,0:04:20.66,0:04:23.76,Default,,0000,0000,0000,,and tandem modules\Ncan be that opportunity.
Dialogue: 0,0:04:23.76,0:04:28.34,Default,,0000,0000,0000,,Imagine powerful tandem modules\Nsplitting water into oxygen and hydrogen.
Dialogue: 0,0:04:28.76,0:04:31.86,Default,,0000,0000,0000,,Thanks to the increased energy yield\Nof the tandem module,
Dialogue: 0,0:04:31.86,0:04:34.89,Default,,0000,0000,0000,,clean hydrogen can become\Neconomically feasible.
Dialogue: 0,0:04:34.89,0:04:37.36,Default,,0000,0000,0000,,And once you have clean hydrogen,
Dialogue: 0,0:04:37.36,0:04:42.44,Default,,0000,0000,0000,,now you can store vast amounts of energy\Nfor long periods of time
Dialogue: 0,0:04:42.44,0:04:45.70,Default,,0000,0000,0000,,and fuel industrial processes\Nsuch as steel making.
Dialogue: 0,0:04:46.14,0:04:48.74,Default,,0000,0000,0000,,Tandem modules are transformational.
Dialogue: 0,0:04:48.74,0:04:51.93,Default,,0000,0000,0000,,By themselves, they are not good enough.
Dialogue: 0,0:04:51.93,0:04:53.86,Default,,0000,0000,0000,,Winning the battle\Nagainst climate change
Dialogue: 0,0:04:53.86,0:04:55.58,Default,,0000,0000,0000,,is a huge challenge.
Dialogue: 0,0:04:55.58,0:04:58.04,Default,,0000,0000,0000,,It's a battle we are currently losing.
Dialogue: 0,0:04:58.39,0:05:03.09,Default,,0000,0000,0000,,We're not decreasing but we're increasing\Nour CO2 admissions.
Dialogue: 0,0:05:03.12,0:05:04.53,Default,,0000,0000,0000,,To change that,
Dialogue: 0,0:05:04.55,0:05:07.26,Default,,0000,0000,0000,,we need a dramatic psychological shift.
Dialogue: 0,0:05:07.28,0:05:09.63,Default,,0000,0000,0000,,We need to get past a tipping point,
Dialogue: 0,0:05:09.63,0:05:12.15,Default,,0000,0000,0000,,a point in time where the majority of us
Dialogue: 0,0:05:12.15,0:05:17.40,Default,,0000,0000,0000,,believes that we are responsible for\Nand need to take care of our planet.
Dialogue: 0,0:05:17.80,0:05:20.42,Default,,0000,0000,0000,,Today, we're nowhere\Nnear that tipping point,
Dialogue: 0,0:05:20.42,0:05:24.01,Default,,0000,0000,0000,,but with the advent of tandem,\Nour tools are getting better.
Dialogue: 0,0:05:24.01,0:05:27.41,Default,,0000,0000,0000,,And now it's up to all of us\Nto put them to good use.