Once you understand Kardashev Scale, it becomes utterly obvious that essentially all energy generation will be solar.
Also, just do the math on solar on Earth and you soon figure out that a relatively small corner of Texas or New Mexico can easily serve all US electricity.
One square mile on the surface receives ~2.5 Gigawatts of solar energy. That’s Gigawatts with a “G”. It’s ~30% higher in space. The Starlink global satellite network is entirely solar/battery powered.
Factoring in solar panel efficiency (25%), packing density (80%) and usable daylight hours (~6), a reasonable rule of thumb is 3GWh of energy per square mile per day. Easy math, but almost no one does these basic calculations.
One of many cases where it’s much easier to predict the long-term trajectory than the path to get there, and most people still don’t.
I like to put the numbers in a form that less mathy folks seem to find intuitive. If you wanted to replace all of the world’s current primary energy use with current solar panels, and had enough storage to make it all work, then the land area you’d need is approximately South Korea. Huge, but also not really that big. (Note: current global solar panel manufacturing capacity is enough to get us about a half to a third of the way there if we fully utilize it over the next 25 years).
In practice I think over the next handful of decades we’re going to need 3-10x that much electricity, but even that doesn’t really change the conclusion, just the path. But also, we can plausibly expect solar panel efficiencies and capacity factors to go up as we start moving towards better types of PV tech. For example, based on already demonstrated performance values, a 2 or 3 junction tandem bifacial perovskite solar panel (which no one currently manufactures at scale, and which seemed implausible to most people including me even two years ago) could get you close to double the current kWh/m2 we get from silicon, and the power would be spread much less unevenly throughout the day and year.
I finally googled what Elon Musk has said about solar power, and found that he did a similar calculation recently on twitter:
One of many cases where it’s much easier to predict the long-term trajectory than the path to get there, and most people still don’t.
I like to put the numbers in a form that less mathy folks seem to find intuitive. If you wanted to replace all of the world’s current primary energy use with current solar panels, and had enough storage to make it all work, then the land area you’d need is approximately South Korea. Huge, but also not really that big. (Note: current global solar panel manufacturing capacity is enough to get us about a half to a third of the way there if we fully utilize it over the next 25 years).
In practice I think over the next handful of decades we’re going to need 3-10x that much electricity, but even that doesn’t really change the conclusion, just the path. But also, we can plausibly expect solar panel efficiencies and capacity factors to go up as we start moving towards better types of PV tech. For example, based on already demonstrated performance values, a 2 or 3 junction tandem bifacial perovskite solar panel (which no one currently manufactures at scale, and which seemed implausible to most people including me even two years ago) could get you close to double the current kWh/m2 we get from silicon, and the power would be spread much less unevenly throughout the day and year.