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Comment by ekianjo | Hacker News Reader

100% solar? we are super far from that and we need anyway to produce energy even at night.

We don't need to produce at night, we just need to consume from batteries, the topic of this post.

Grid scale lithium ion storage costs about $0.30/kWh right now. Residential is probably about $.40-.50/kWh.

Dropping by a factor of two and some time shifting is most electrical use, and the electricity is similar to rates in many parts of the country, just with peak rates at a different time.

> Grid scale lithium ion storage costs about $0.30/kWh right now. Residential is probably about $.40-.50/kWh.

I think you meant .30c/Wh, right? Or perhaps you are referring to the cost to purchase off-peak energy stored in grid-scale Li-ion battery storage systems (If so, I'm curious where you got that number).

Otherwise, .30c/Wh for storage implies that a 100kWh battery pack would cost $30, when it clearly costs much more.

I'm talking about the cost to store energy and then deliver a kWh from the system later, accounting for the lifetime cost and output of the system. The grid storage number i get from Lazard's:

https://www.lazard.com/media/438042/lazard-levelized-cost-of...

And the residential I get from Tesla's estimated numbers for their residential system. The residential ones may therefore be a tad bit optimistic. But if you happen to know an electrician.... maybe then it's realistic, as a huge amount of the cost is not the battery itself.

We need to have energy at night. With enough storage capability, you don't have to produce it at night.

It doesn't just have to be solar. There's plenty of other forms of renewable energy (hydro, wind, tidal) that all become more viable and efficient if you can add storage.

Better grid technology will help too. If we can transmit energy efficiently over long distances, there's less storage required. Build a global grid and the whole planet can run on renewables: it's always sunny (or windy) somewhere.

> With enough storage capability, you don't have to produce it at night.

I'm not talking about powering one's home, I'm talking about powering cities and infrastructure - we are far away from having this kind of storage capability, and it's cheaper to produce electricity 24/7 than to build that kind of storage capacity anyway. It's all a matter of ROI.

Powering cities and infrastructure is qualitatively the same, it just takes more. And sure, the capacity is far from being there, but it's a matter of building it out.

As I said it's not just a matter of "can we build it", because obviously there's always a way to build it, but does it make financial sense instead of having a local powerplant running 24/7. So far, it's clearly not the case - capacity is way more expensive.

Fine, then. Wind at night

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