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Comment by Arnt | Hacker News Reader

The article sidesteps something that seems important to my naïve eye: Water is easy to store if you don't have very much of it, so this is the kind of thing you can do when the sun is shining and store for nights and rainy days. Storing water for a year or two would be hard, of course.

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Places with intermittent water have lots of water storage in reservoirs. The problem is that reservoirs are up in the hills away from the coast so it would cost a lot to pump it up.

But running the desalination when energy is cheap makes a lot of sense. Especially when not providing all the water but topping up when supply is low. The only problem is the capital costs of desalination plant that isn't used all the time.

Most of Texas consists of "build a dam at this convenient chokepoint and create a huge reservoir" for its freshwater. So I disagree. We don't do anything special. The biggest issue is invasive species taking up residence in the newly formed reservoirs.

Like birds? Or fish?

Mussels like Zebra and Quagga are common invasive species in reservoirs like this. Asian carp and other fish species as well.

Return on capital and deprecation tend to exceed energy input costs for most plants so it makes sense to run them 24x7x365 rather than over-size them and run them when energy costs are lower.

They tend to exceed energry costs because energy costs are dominated by the cost of purchasing oil, which is as easy to store as water. We're moving away from that now, towards a world where solar power plants produce power at stunningly low prices some of the time (like €0.01114/kWh on the top google hit just now) and those who need a lot of power and can adapt their usage to match solar power plants can make use of those prices.

There are also times where energy cost is negative and you'll actually get paid to consume it. Consumers don't typically see this of course

> They tend to exceed energry costs because energy costs are dominated by the cost of purchasing oil

The energy costs are tied to oil because thats the cheapest option. Well, besides coal. If solar were cheaper wed be using it.

Astonishing what people will write.

The current record price for solar is slightly over one cent per kWh and still people will write that oil is the cheapest option.

The installation rate for solar is such a steep graph that drawing it legibly is a real problem, see https://nitter.net/pic/orig/media%2FFOoa6xYXIAQKUnv.jpg for example, and still people will write that "if solar […] we'd be using it".

Solar is cheaper anywhere you get a decent amount of sun. Much of the resistance to solar is not due to cost, it's political: all those places with big coal economies get pissed off when their services are no longer needed, and vote you out of office if you push renewables too hard. Ditto for oil.

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