Shadowing Practice: Is Solar About to Get WAY Better? (I Did the Math) - Learn English Speaking with Video
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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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And the Pod 5 is what that idea has grown into.
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The Pod sits right on top of your existing mattress.
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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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8sleep's autopilot learns from your patterns and automatically adjusts temperature throughout the night.
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It also tracks your sleep stages, heart rate variability and more.
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No wearables needed.
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The best part is that you still get 30 days to try it in your home
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and return it if you don't like it.
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but I'm confident you're going to love it.
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Trust me, your body will thank you for this investment in better sleep.
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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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Vocabulary and speaking notes for this lesson
This video has 215 sentences and 2317 words to shadow. The speech runs for 13:11. The speaker talks at a natural 176 words per minute, close to everyday conversation. Only 80% of the words are among the 3,000 most common in English, so the vocabulary is demanding.
Key vocabulary in this video
15 words from the video worth learning, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| silicon noun | /ˈsɪləˌkɑn/ | A nonmetallic element (symbol Si) with an atomic number of 14 and atomic weight of 28.0855. |
| tandem noun | /ˈtændəm/ | A carriage pulled by two or more draught animals (generally draught horses) harnessed one behind the other, both providing pulling power but only the animal in… |
| install verb | /ɪnˈstɔl/ | To connect, set up or prepare something for use |
| efficient adjective | /ɪˈfɪʃənt/ | Making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy. |
| efficiency noun | /ɪˈfɪʃ.ən.si/ | The extent to which a resource is used for the intended purpose. |
| mathematics noun | /mæθ(.ə)ˈmæt.ɪks/ | An abstract representational system studying numbers, shapes, structures, quantitative change and relationships between them. |
| watt noun | /wɑt/ | In the International System of Units, the derived unit of power; the power of a system in which one joule of energy is transferred per second. |
| incentive noun | /ɪnˈsɛntɪv/ | Something that motivates, rouses, or encourages. |
| electricity noun | /ɪˌlɛkˈtɹɪsɪti/ | Originally, a property of amber and certain other nonconducting substances to attract lightweight material when rubbed, or the cause of this property; now… |
| installed verb | /ɪnˈstɔːld/ | readied for use |
| lifetime noun | /ˈlaɪf.taɪm/ | The duration of the life of someone or something. |
| residential adjective | /ˌrɛzɪˈdɛnʃəl/ | Of or pertaining to a place of personal residence or to a location for such places. |
| installation noun | /ˌɪn.stəˈleɪ.ʃən/ | An act of installing. |
| variable adjective | [ˈvæɹ.i.ə.bl̩] | Able to vary or be varied. |
| compete verb | /kəmˈpiːt/ | To be in battle or in a rivalry with another for the same thing, position, or reward; to contend. |
Phrasal verbs you will hear
| Word | Meaning |
|---|---|
| check out verb | To record the departure or withdrawal of someone or something (such as guests, employees, books, etc.). |
| figure out verb | To come to understand; to discover or find a solution; to deduce. |
| add up verb | To take the sum of; to total. |
| add up to verb | To have a particular effect in combination. |
| back down verb | To take a less aggressive position in a conflict than one previously had, or has planned to have. |
| come up verb | To emerge or become known, especially unexpectedly. |
| follow up verb | To take further actions remaining after an event; to continue, revisit, or persist; especially, to maintain communication or verify. |
| get back verb | Return to where one came from. |
Pronunciation to watch
The speaker uses 44 contractions and reduced forms, such as I've, I'm, we'll. Say them the short way, as you hear them.
- The “th” sounds: mathematics /mæθ(.ə)ˈmæt.ɪks/, breakthrough /ˈbɹeɪk.θɹuː/, wavelength /ˈweɪvˌlɛŋ(k)θ/, thermostat /ˈθɝməstæt/
- The “sh” and “zh” sounds: efficient /ɪˈfɪʃənt/, efficiency /ɪˈfɪʃ.ən.si/, residential /ˌrɛzɪˈdɛnʃəl/, installation /ˌɪn.stəˈleɪ.ʃən/, calculation /ˌkælkjuˈleɪʃn̩/
- Long words — get the stress right: efficiency /ɪˈfɪʃ.ən.si/, mathematics /mæθ(.ə)ˈmæt.ɪks/, electricity /ɪˌlɛkˈtɹɪsɪti/, residential /ˌrɛzɪˈdɛnʃəl/, installation /ˌɪn.stəˈleɪ.ʃən/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like silicon, tandem, install.
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Present perfect continuous have/has been + -ing — an action that started earlier and is still going on | I've been using |
| Present perfect have/has + past participle — a past action that still matters now | I've installed · has been · have claimed |
| Passive voice be + past participle — the focus is on what happens, not who does it | is brought · can be tuned · be lost |
| Relative clauses who / which + clause — extra information about a person or thing | conditions, which is · years, which is · cost, which is |
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.