> No amount of batteries can protect a solar/wind grid from an arbitrarily extended period of "bad" weather.
Sure there is, let's do some math. Just like we can solve all of the Earth's energy needs with a solar array the size of Lithuania or West Virginia, we can do some simple math to see how many batteries we'd need to protect a solar grid.
Let's say the sun doesn't shine for an entire year. That seems like a large enough N such that we won't hit N+1. If the sun doesn't shine for an entire year, we're in some really serious trouble, even if we're still all-in on coal.
Over 1 year, humanity uses roughly 24,000 terawatt-hours of energy. Let's assume batteries are 100% efficient storage (they're not) and that we're using lithium ion batteries, which we'll say have an energy density of 250 watt-hours per liter (Wh/L). The math then says we need 96 km³ of batteries protect a solar grid from having the sun not shine for an entire year.
Thus, the amount of batteries to protect a solar grid is 1.92 quadrillion 18650 batteries, or a cube 4.6 kilometers along each side. This is about 24,000 year's worth of current world wide battery production.
That's quite a lot! If we try for N = 4 months for winter, that is to say, if the sun doesn't shine at all in the winter, then we'd need 640 trillion 18650 cell, or 8,000 years of current global production, but at least this would only be 32 km³, or a cube with 3.2 km sides.
Still wildly out of reach, but this is for all of humanity, mind you.
Anyway, point is, they said Elon was mad for building the original gigafactory, but it turns out that was a prudent investment. It now accounts for some 10% of the world's lithium ion battery production and demand for lithium-ion batteries doesn't seem to be letting up.
Well, you have to take into account that if something like that were to happen, within 1 week we'd have curfews and rationing everywhere. So those 24 000 TWh probably become 5-6 000, or something like that.
Plus we'd still have hydro, wind, geothermal, etc, etc.
Sure there is, let's do some math. Just like we can solve all of the Earth's energy needs with a solar array the size of Lithuania or West Virginia, we can do some simple math to see how many batteries we'd need to protect a solar grid.
Let's say the sun doesn't shine for an entire year. That seems like a large enough N such that we won't hit N+1. If the sun doesn't shine for an entire year, we're in some really serious trouble, even if we're still all-in on coal.
Over 1 year, humanity uses roughly 24,000 terawatt-hours of energy. Let's assume batteries are 100% efficient storage (they're not) and that we're using lithium ion batteries, which we'll say have an energy density of 250 watt-hours per liter (Wh/L). The math then says we need 96 km³ of batteries protect a solar grid from having the sun not shine for an entire year.
Thus, the amount of batteries to protect a solar grid is 1.92 quadrillion 18650 batteries, or a cube 4.6 kilometers along each side. This is about 24,000 year's worth of current world wide battery production.
That's quite a lot! If we try for N = 4 months for winter, that is to say, if the sun doesn't shine at all in the winter, then we'd need 640 trillion 18650 cell, or 8,000 years of current global production, but at least this would only be 32 km³, or a cube with 3.2 km sides.
Still wildly out of reach, but this is for all of humanity, mind you.
Anyway, point is, they said Elon was mad for building the original gigafactory, but it turns out that was a prudent investment. It now accounts for some 10% of the world's lithium ion battery production and demand for lithium-ion batteries doesn't seem to be letting up.