Solar Energy Foundations

You’re staring at a solar quote, or maybe a spec sheet an installer left on your kitchen table, and there it is — a little string of letters and numbers you didn’t ask for and don’t remember agreeing to learn: AM1.5. Right next to it, a wattage rating that sounds fantastic. 400 watts. 440 watts. […]

You’re reading through a solar panel spec sheet, or maybe a climate article, and you hit the phrase “solar constant.” It sounds like it should be one of those simple, self-explanatory science terms. Then you notice it’s described as varying slightly, and suddenly it doesn’t sound very constant at all. Here’s the short version: the

Ever notice how you don’t cast a shadow on a heavily overcast day? Stand outside in the middle of a grey, drizzly afternoon and look down. Nothing there. Now do the same thing on a clear sunny day and you get a crisp outline of yourself on the pavement. That difference isn’t random. It’s actually

Picture this: sunlight lands on your roof, and somehow, a few seconds later, your fridge is running, your phone is charging, and your lights are on. It feels almost like magic. It isn’t. It’s physics, some clever engineering, and a process that’s actually pretty easy to understand once someone walks you through it without drowning

Solar energy has moved far beyond being an alternative energy technology. In 2025 alone, the world added more than 600 GW of new solar photovoltaic (PV) capacity, pushing total installed solar PV capacity globally to around 2.8 terawatts (TW). Solar accounted for more than three-quarters of all new renewable power capacity added worldwide that year.

Most people hear “solar panels” and picture one thing. One box. One technology. One decision. That’s not how it works. There are actually two completely different ways to harness sunlight, and they do different jobs. One turns sunlight into electricity. The other turns it into heat. Mix them up, and you could end up with

You’re staring at a solar panel spec sheet, or maybe a homework problem, and there it is — three terms that all seem to mean “sunlight,” used interchangeably by three different sources. Solar radiation. Irradiance. Insolation. If you’ve come away thinking they’re basically synonyms with fancier syllables, you’re not alone. Most explanations online don’t actually

Stand on a rooftop in Dhaka on a clear afternoon and look at the sunlight falling across the concrete buildings. That sunlight feels ordinary. But every hour, an enormous amount of energy is reaching Bangladesh from the Sun—energy that can be converted into electricity, heat, and useful power. Today, solar panels are becoming increasingly familiar

Stand on a rooftop on a bright afternoon and you’ll feel the sun doing something obvious — warming your skin, making you squint. What you won’t feel is the much stranger thing happening a few feet away, inside a solar panel: sunlight quietly getting converted into electricity, one photon at a time. That conversion has

Here’s something that sounds made up but isn’t: the sunlight hitting Earth in about ninety minutes carries enough energy to power the entire planet for a full year. Not a city. Not a country. The whole planet. That number stuck with me the first time I read it, because it reframes the whole conversation. We’re