Thread by @EdConwaySky

🌞Here's a short story abt how I went to Morocco to see one of the world's biggest solar plants.
It didn't go quite as I expected

This is the Noor complex near Ouarzazate.
It's massive. Bigger than the capital of Morocco.
Europe (& UK) plan to import solar power from Morocco.
🧵

This place is interesting because it's actually not a traditional solar plant.
Most solar power these days is PV or photovoltaic👇
Solar energy hits the silicon panel and is converted straight into electricity.
Noor has a section devoted to PV. But in this case it's a sideshow...

The main business here is a different type of solar power.
Most of the panels here are not PV but mirrors.
They concentrate solar energy and capture its heat. That heat is used to heat water, to turn it into steam which runs a turbine.
Like a conventional power station!

There's actually a few ways you can do this.
In one part of the complex the mirrors are concave and they heat up a pipe carrying a kind of industrial oil which passes through those pipes you can see.
That hot oil is piped towards the plant and helps to run turbines & create power

Why bother doing it this way? Because you can use that heat to STORE the solar energy, heating up special types of salt which retain their heat. That means you can get power from here even when it's dark.
Normal PV only works when the sun's shining...

The other way of doing this - the more spectacular way - is to use mirrors to concentrate a LOT of solar rays on ONE particular place.
Which is where that big tower comes in.
There's molten salt running through the top of the tower. The sun heats it to 565 degrees C

Walk around this bit of the complex and you can hear all those the mirrors (technical term: heliostats) moving every minute or so as the sun moves, so they can bounce the light towards the tower.
You can actually SEE them seeking out the tower in this Timelapse 👇

Again, the point here is that molten salt stays hot for ages. This place can store energy for seven hours.
In theory it can produce power constantly, as long as the sun is shining. And since this is the edge of the Sahara it has some of the most reliable sun in the world

There's a plan to lay a massive cable from the south of Morocco all the way to England so the UK can import renewable power (solar and wind) from another part of Morocco. For backup when the wind's not blowing in N Sea. That's the idea at least ft.com/content/fc3a1c…

All of which is why we went to Morocco to see this solar plant.
I was making a film about the national grid and wanted to make the point that sometimes in future we may be able to get our power from elsewhere. An international grid. So we thought, let's go to Noor for a day...

But here's the twist. As you can probably see, when we arrived it was cloudy.
"This is very unusual," they told us. "Only happens a few days each year."
"Ah," we said. "Ok we'll come back tomorrow."
So we spent a night in Ouarzazate. Lovely place. Thoroughly recommended.

The following day we came back hoping for sun.
But it was even more overcast.
By now it had been cloudy for so long that the plant's storage was effectively depleted. It wasn't contributing to the grid at all. Well, a teeeny bit from the PV bit.
But near enough zero

We were unlucky. It IS mostly sunny.
But as I said in our film👇it's a useful reminder that sometimes even the "backup" needs backup.
As we push towards net zero everyone's after easy answers. But this will be more challenging & complex than many assume

Sidenote:
It actually wasn't the first solar storage plant I've been to.
I also went to one in Chile a few yrs ago. And, get this, it was also NOT operational. The wind was too strong for the mirrors.
Perhaps I'm cursed. Still longing to see one of these towers light up in person