Hacker News Reader

Comment by chipsa | Hacker News Reader

If you put solar in the desert SW, and intend for it to power homes in New England, how much does the transmission lines to move that power cost? And how much do you lose in transit?

View on HN

There is an efficiency loss, but the problem is actually the cost of building and maintaining the infrastructure.

Theres plenty of resources out there around this idea.

I don't recall where I had seen it, but there was a study at some point on the cost of covering the Sahara in solar panels. The CO2 emissions from the resources for the transmission lines- in steel and concrete especially- meant it would be a net positive CO2 contributor even after shuttering fossil fuel power plants.

This means that we need to learn how to build transmission lines with less steel and concrete. Use more aluminum maybe? More plastics and carbon fiber? More glass?

plastics and carbon fiber are made with hydrocarbons generally. Aluminum might actually be worse, since aluminum requires very high amounts of energy to produce.

Solar energy used to produce aluminum has zero marginal cost. So, unless you assume use of fossil fuels to produce the power used to refine the aluminum, this is nonsense.

Hydrocarbons are not a problem per se. It's burning the hydrocarbons, specifically the carbon part, which has the detrimental effect on climate.

Plastics and carbon fiber effectively keep the carbon from becoming CO₂.

Aluminum takes a lot of energy, but, unlike steel, the process does not release any CO₂, and is fully electric. It can be powered by hydro (and often is), nuclear, or solar energy directly.That's the point.

Another idea I saw on yt a few months back:

Charge some solid state battery (it's not battery it was something better) and then transport it.

Similar on how we ship oil across the planet.

Robert A. Heinlein wrote a book called Friday that had something like this. They would use huge solar arrays to charge proprietary solid state batteries called Shipstones which were used everywhere. There wasn't even a power grid anymore because people would just buy a Shipstone and put it into their house and replace it every so often like coal in a coal bin.

I love Friday and just reread it last weekend. Often I think that Elon Musk believes he is a character in a Heinlein novel. Tesla is Shipstone, the cars are just a mechanism to build better batteries. SpaceX, that's just DD Harriman from the man who sold the moon/sail beyond the sunset. The Boring company is how you build Luna City ala The moon is a harsh mistress. Or maybe a space catapult. Or maybe, I'm just hoping for Heinleinian hero.

Anti-hero, more like. Or, in the instant case, over-funded buffoon.

I think the problem here is the weight of the batteries and the need for power to move them. Maybe hydrogen by electrolysis would be more favorable, but then you need to pipe in water.

You don't necessarily need to pipe the water to the electricity, you can move the electricity to where the water is (and if the electrolysis works with seawater, you don't need freshwater either). And then you can turn it into something like Methane or Ammonia for longer term storage. And the long term storage is important to level the power production over the course of months.

I think the issue at hand is that long distance transmission of electricity has transmission loss, and is expensive from an infrastructure standpoint. The broader point is that remote solar generation presents some challenges.

Yes, I made exactly that point above. But the point I'm making is that long distance transmission of water is also expensive from an infrastructure standpoint, possibly even more expensive than power (and also sometimes has transmission losses, depending on how they're moving it)

> But the point I'm making is that long distance transmission of water is also expensive

Oh yeah, in case I wasn't clear that's exactly what I meant also.

The dream of covering a chunk of the Sahara in PV to power Europe and Africa seems like tilting at windmills.

But not for the reason you think.

The right place to put PV for Europe is in Europe. You will want solar farms in the tropics producing ammonia to ship around to wherever the wind flags for a few weeks, and to Finland in winter.

Transmitting power is not, in fact, expensive.

Building an HVDC transmission line has capital cost, but marginal operating cost is near zero.

Transmission loss matters very little anymore. You just add more panels at the source. Marginal cost of the loss is zero. It is very, very cheap to deliver power by transmission line.

A big problem with that is energy density. Hydrocarbons are on the order of 50MJ/kg. Li-ion batteries are on the order of .5MJ/kg.

Lithium tech at this exact instant is not the end state of battery development.

So, not a big problem, a speed bump. Check back next year.

Reply on news.ycombinator.com