Pratique du Shadowing: Is Solar About to Get WAY Better? (I Did the Math) - Apprendre l'anglais à l'oral avec la vidéo
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Perovskite solar cells could hit 35% efficiency and cost half as much as silicon.
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But they're still years away from your roof.
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Meanwhile, silicon panels just lost their 30% federal tax credit here in the US, making them suddenly more expensive.
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So here's the $20,000 question.
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What's the better path in value?
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Should you wait for the next solar breakthrough technology to finally arrive?
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Or install silicon solar panels right now?
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Which gives you the better bang for your buck?
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I'm Matt Farrell.
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Welcome to Undecided.
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This video is brought to you by 8sleep.
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I get asked about solar a lot.
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People send me their quotes, their roof diagrams, their utility bills.
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But the question that comes up more than any other.. should I wait?
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Wait for the next breakthrough.
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Wait for the prices to drop.
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Wait for the technology to get better.
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I've installed solar on two different homes now, so I've gone through this decision myself.
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And here's the thing.
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That question never really goes away.
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There's always something newer on the horizon.
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So let's figure out if waiting actually makes sense.
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And to figure that out, we need to understand the technologies that we're considering.
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Today's silicon sells versus next-gen options like perovskite.
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When I say the word solar panel, you're almost certainly picturing silicon photovoltaics, or PV.
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That's for a good reason.
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They're pretty much everywhere nowadays.
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I've got 43 of them on the roof of my home, plus 4 more on a shed in the backyard.
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Silicon is very common on Earth.
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It's actually one of the most abundant elements and it's pretty cost efficient and effective as a photovoltaic material.
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Perovskite PVs work in very similar fashions to silicon PVs.
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From installation, purchasing and appearance, there's no difference.
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The big difference is their tunable band gap.
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So think of it like this.
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Every solar material has a sweet spot for converting light into electricity.
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Silicon is stuck at one setting.
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But perovskites can be tuned to match different conditions, which is why they can be so much more efficient.
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I've got videos that go into more detail if you're interested that I'll link to in the description.
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The tunability of perovskites also unlocks the power of tandem solar cells.
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We can tune the perovskites to eat a different wavelength of light from what the silicon can.
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A light in the range of 380 to 700 nanometers slams into the perovskite and works through that system as normal.
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But near infrared light at wavelengths of about 800 to 2500 pierces through the perovskites.
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that would just be lost, but a layer of silicon behind the perovskite can absorb it.
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By working in, well, tandem, the solar cells duo can let us double dip and extract more energy from that same beam of light.
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They can hit conversion efficiencies of near 35%, which is much better than silicon or perovskite on their own.
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One final thing before we get into the nitty gritty of the math.
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All of the advantages of perovskites come with some drawbacks.
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Perovskites are temperamental little crystals that degrade when exposed to moisture, heat, and prolonged UV radiation.
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That's a big problem for any device that's meant to soak up the sun, especially if it wants to compete with that 25 plus year longevity of the humble silicon cell.
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Overcoming this challenge has been at the forefront of perovskite research.
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A few companies like Oxford PV have claimed
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that they've conquered this with tandem PVs that are durable enough to compete with silicon and are already commercially deployed.
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The current crop of tandem cells have more modest efficiencies, around 25%, but are expected hit 30% within a few years.
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That's why it's really sparking this whole debate of get solar now or wait.
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Given Perovskite's advantages, you might think this is settled.
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Before we do the math though, I want to talk about something else that's got me all heated up and then cooled right back down again.
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That's today's sponsor, 8Sleep.
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I love it warm.
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Like, climb into a toasty bed, heavy blanket.
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This is the best part of my day warm.
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But I also can't sleep hot.
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The moment I'm actually asleep, I want it cool.
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My wife thinks I'm a nightmare.
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And she's not wrong.
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Which is why I've been using 8 Sleep since it was a Kickstarter project.
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Seriously, I've been using it since the original version.
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It warms up when I get in, exactly how I like it, then it cools back down as the night goes on.
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My wife runs her side completely different.
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Same bed, totally separate temperatures.
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We've never thought about the thermostat since.
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But the real reason I keep coming back to it?
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The sleep quality.
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I travel a fair amount and I feel the difference every single time I'm away from home.
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My deep sleep drops.
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I wake up feeling foggy and not well rested.
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Coming home to the pod is genuinely one of the highlights of getting back.
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Use my code MATT at 8sleep.com slash Matt Ferrell for up to $350 off the Pod5 Ultra.
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Thanks to 8sleep and to all of you for supporting the channel.
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Alright, back to the math.
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So should you wait for Solar 3.0 or go with reliable silicon?
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A quick caveat, I'm working with US dollars here with average pricing, so there's going to be some generalizations.
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There There are tons of variables here.
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Your situation is going to be very different.
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Ok, what's our baseline?
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Let's go with a 6kW system.
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It's on the smaller end and should fit most roofs.
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It's large enough to see a real change in your bills.
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The average cost of installing a 6kW system in the United States is $15,900.
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That includes labor, panels, permits, and local rebates.
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A system of this size will save about $1500 annually on your electric bill.
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Obviously, this depends on how much electricity you use and how much energy your PVs produce.
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But again, we have to deal in averages here.
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How long will it last?
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The well-documented answer is 20-30 years.
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To keep things simple, let's just say 25 years.
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Here's the math.
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$1,500 for 25 years is $37,500 in lifetime savings.
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Subtract your install costs of $15,900 from that and you get the real savings of $21,600 on average.
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It's not too shabby.
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For payback, divide 15,900 by 1,500 annual savings.
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That's 10.6 years, which is roughly half the system's lifetime.
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It's actually better than that for most people, but we'll just let that go for now.
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I think just about anyone would be happy with the numbers we've got here, but they could be better.
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Location matters.
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A 6 kilowatt system in Phoenix, Arizona, known monument to man's arrogance,
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will generate around 35% more electricity than that same system near me in Boston.
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And while the federal tax credit ended on January 1st, your city, state or neighborhood may offer rebates.
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In markets like Australia, with better incentives and more sun, that same 6kW system costs around $4,300 and saves even more.
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So what about the next-gen technologies?
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What kind of cost savings are you looking at for perovskite tandem cells?
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Let's do our best to figure it out.
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I want to be very clear here, we're working with the best information available at the moment.
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And while some companies are targeting earlier release dates for residential markets like 2028,
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the current consensus prediction is that commercial residential perovskites won't become a mainstream option until like 2030.
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A lot can change even in a couple years and we could be way off, but to make things fair for materials and easier on us,
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let's assume that the installation cost for perovskite tandem cells is the exact same as silicon.
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It really should be.
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Also to keep everything square, we'll assume that we're going for a 6 kilowatt system again.
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So how much does a 6 kilowatts of perovskite tandem cells cost?
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Techno-economic analysis from the National Renewable Energy Lab suggests that American-made,
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25% efficient tandem panels could be as cheap as $0.29 to $0.42 per watt.
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This does assume that we can manufacture them at gigawatt scale factories, which I think is unlikely to happen by 2028 or maybe even 2030.
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We'll just roll with it for now and say that it's $0.35 per watt.
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But that's just the manufacturing cost, which is only about 12% of the total installation cost.
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To figure out how much it costs the consumer, we also have to work out how much it will cost to install per watt.
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That includes stuff like labor, shipping, the racks and rails that will attach to the roof, and you get the idea.
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So let's try to flatten some variables and assume the cost is identical to silicon.
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In 2026, silicon modules look to be around 21 cents per watt.
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Plugging that into our calculations for a 6kW silicon system, 12% of 15,900 is equal to $1,908.
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Meaning everything outside of the manufacturing costs is $13,992.
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So at $0.35 per watt, the manufacturing cost of 6kW of panels would be $2,100.
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Add the $13,992 back in and theoretically that means a 6kW perovskite system would run you about $16,092.
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That's not all that different.
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The bigger your system, the more the manufacturing cost difference adds up.
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But that's the upfront cost.
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How much will perovskite systems save you over time?
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Oxford PV offers the most solid numbers here.
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Their modules hit a reported 26.9% efficiency.
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That's ahead of silicon's 20-24% range.
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Oxford is targeting 30% by 2030, but let's use today's conservative numbers.
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For our comparison, we'll assume 22% efficient silicon panels and keep everything else identical.
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At 26.9% efficiency compared to 22% for silicon, a perovskite tandem system is about 22.3% more efficient.
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With that 22.3% efficiency boost, perovskite saves you an extra $335 annually.
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That's $1,835 per year total.
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But perovskites don't last as long as silicon.
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Silicon currently max out around 15 years, though many companies are targeting 20 years by 2028.
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At 20 years, you're looking at a lifetime savings of about $36,690.
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Subtract the $16,092 for the install costs and you get the real savings of $20,600.
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That's worse than silicon's $21,600.
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If perovskites stay stuck at 15 years, it gets worse.
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However, if they match silicon's 25 year lifespan, that extra $335 per year adds up to over $8,000 more than silicon.
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Payback period is 8.8 years regardless.
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About 2 years faster than silicon.
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So is that the final word?
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Victory to Silicon?
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No. As we've mentioned before, I tried to make the math as general and simple as possible, so that we could get a handle on the situation.
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However, there's a lot of variables and caveats that we have to consider.
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Location matters.
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A lot.
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Sunnier places will outperform temperate regions like New England.
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Panel direction matters too.
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In the Northern Hemisphere, they generally face south, but if that side of your roof is shaded or limited, your output suffers.
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On the financial side, there's also incentives.
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While the federal tax credit just ended, your state or city might offer rebates.
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Again, I point to Australia, where friendlier incentives, policies, and a different level of tech maturity lets residents of even
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Australia's most expensive states install rooftop solar for cheaper than the cheapest American states.
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And the flip side of incentives are tariffs.
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Current tariffs on China and Southeast Asia affect most silicon panels on the US market, but not elsewhere.
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Whether those tariffs help or hurt perovskites depends on where they're manufactured and who's buying.
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When it comes to perovskites, there's still a lot of unknowns.
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I've made assumptions about costs and performance.
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By the time they actually hit the mass scale, the market could shift and throw our calculations just way off.
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In fact, they probably will.
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There's no guarantee that the first generation will be as cheap or efficient as expected, or as cheap as the second and third generations.
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The biggest factor is opportunity costs silicon installs take 1-3 days.
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Perovskites?
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The current consensus is that we're not expected to see residential commercial perovskites hit in a meaningful way until 2030.
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Oxford PV is targeting 2028, while conservative estimates say that it's 2035.
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That's years of lost savings while you wait.
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So what should you do?
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Here's my take.
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If you want to save money, be greener, or more energy resilient, whatever your personal motivation may be, don't wait.
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I've installed silicon panels twice and I have zero regrets.
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Even after moving after just 5 years.
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Silicon works.
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It's proven.
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You can get it installed relatively quickly and start saving immediately.
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If it doesn't make financial sense right now, that's fine too.
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Prices keep dropping for both technologies.
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But if you can swing it?
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The math says go now.
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Every month that you wait is a month of lost savings.
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So while the next generation of solar technology is exciting, I wouldn't wait.
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But what do you think?
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Do you want to wait for the next-gen solar to arrive?
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If so, why?
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Jump into the comments and let me know.
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You can also check out my extended cuts of my videos over on Patreon.
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And speaking of that, these videos take a team to make.
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A team of humans with real research, real interviews, real feedback from experts.
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No AI slop.
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If that matters to you, Patreon support helps a ton.
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The link's in the description if you'd like to join, but honestly, just watching like you are right now is awesome.
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So thank you.
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And check out my follow up podcast, still to be determined we'll keep this conversation going.
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Keep your mind open, stay curious, and I'll see you in the next one.
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Vocabulaire et conseils d’expression pour cette leçon
Cette vidéo contient 215 phrases et 2317 mots à répéter en shadowing. La partie parlée dure 13:11. Le locuteur parle à un rythme naturel d’environ 176 mots par minute, proche d’une conversation courante. Seuls 80 % des mots font partie des 3 000 mots les plus courants en anglais, le vocabulaire est donc exigeant.
Vocabulaire clé de cette vidéo
15 mots de la vidéo à retenir, avec leur prononciation et leur sens :
| Mot | Prononciation | Sens |
|---|---|---|
| silicon nom | /ˈsɪləˌkɑn/ | silicium |
| install verbe | /ɪnˈstɔl/ | installer |
| efficient adjectif | /ɪˈfɪʃənt/ | efficace |
| efficiency nom | /ɪˈfɪʃ.ən.si/ | rendement |
| mathematics nom | /mæθ(.ə)ˈmæt.ɪks/ | mathématiques |
| watt nom | /wɑt/ | watt |
| incentive nom | /ɪnˈsɛntɪv/ | intérêt, motivation |
| lifetime nom | /ˈlaɪf.taɪm/ | durée de vie, vie |
| residential adjectif | /ˌrɛzɪˈdɛnʃəl/ | résidentiel |
| installation nom | /ˌɪn.stəˈleɪ.ʃən/ | installation |
| variable adjectif | [ˈvæɹ.i.ə.bl̩] | variable |
| compete verbe | /kəmˈpiːt/ | rivaliser, concourir |
| arrive verbe | /əˈɹaɪv/ | arriver |
| tune nom | /tjuːn/ | mélodie, air |
| identical adjectif | /ɪˈdɛntɪkl̩/ | identique |
Les verbes à particule que vous entendrez
| Mot | Sens |
|---|---|
| check out verbe | mater, regarder |
| figure out verbe | cerner |
| add up verbe | additionner |
| back down verbe | baisser d'un ton |
| come up verbe | se montrer, sortir du bois |
| get back verbe | retourner |
| go away verbe | partir, s'en aller |
| go through verbe | traverser |
Prononciation à surveiller
Le locuteur utilise 44 contractions et formes réduites, comme I've, I'm, we'll. Prononcez-les sous leur forme courte, telles que vous les entendez.
- Les sons « th »: mathematics /mæθ(.ə)ˈmæt.ɪks/, breakthrough /ˈbɹeɪk.θɹuː/, wavelength /ˈweɪvˌlɛŋ(k)θ/, thermostat /ˈθɝməstæt/
- Les sons « sh » et « zh »: efficient /ɪˈfɪʃənt/, efficiency /ɪˈfɪʃ.ən.si/, residential /ˌrɛzɪˈdɛnʃəl/, installation /ˌɪn.stəˈleɪ.ʃən/, calculation /ˌkælkjuˈleɪʃn̩/
- Mots longs — placez bien l’accent: efficiency /ɪˈfɪʃ.ən.si/, mathematics /mæθ(.ə)ˈmæt.ɪks/, electricity /ɪˌlɛkˈtɹɪsɪti/, residential /ˌrɛzɪˈdɛnʃəl/, installation /ˌɪn.stəˈleɪ.ʃən/
Comment s’entraîner avec cette vidéo
- Écoutez la vidéo en entier une fois sans parler et notez les mots que vous ne connaissez pas.
- Commencez à la vitesse 0,75×, répétez phrase par phrase, puis revenez à la vitesse normale quand cela devient facile.
- Enregistrez-vous et comparez avec l’original, en faisant attention à des mots comme silicon, install, efficient.
La grammaire de cette vidéo
Les structures que le locuteur utilise le plus, avec les mots exacts de la vidéo :
| Structure | Dans la vidéo |
|---|---|
| Present perfect continu have/has been + -ing — une action commencée avant et toujours en cours | I've been using |
| Present perfect have/has + participe passé — une action passée qui compte encore maintenant | I've installed · has been · have claimed |
| Voix passive be + participe passé — l’accent est mis sur ce qui arrive, pas sur qui le fait | is brought · can be tuned · be lost |
| Propositions relatives who / which + proposition — une précision sur une personne ou une chose | conditions, which is · years, which is · cost, which is |
Qu'est-ce que la technique du Shadowing ?
Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.