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Comment by Retric | Hacker News Reader

The most economical option is it have a massive oversupply of wind and solar as their significantly less expensive than any alternative.

You can model this as (cost per kWh of cheapest alternative) / (cost of rentable per kWh) = marginal oversupply you want. So, if hypothetically Solar was 2c/kWh and peaking natural gas was 6c/kWh then you would want to add more solar until 3kWh of new Solar only offset 1kWh of natural gas with the other 2kWh being wasted.

Which does not mean 2/3 of total solar energy would be wasted. Further, storage and energy markets also complicate things. However, it does illustrate why you want an over supply of the cheapest option even if not all of it gets used.

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There is a problem with the massive oversupply idea though. It assumes wind locations are fairly randomized and I don't think that is entirely true. Meaning you can build more in area "x", but if it isn't blowing a quarter mile away, it probably isn't blowing near you either. Think of this more as a conceptual argument. Now oversupply would help if it's just blowing a little bit I suppose.

Exactly. The big blocker to a full-scale rollout of renewables is storage and it has been this way for years. We're still facing the problem of the duck curve, which has been known for years: wind and solar peak at the wrong times because peak load is actually in the evening.

It doesn’t matter if supply sinks up 1:1 because demand doesn’t. If solar always produced the same energy evenly form exactly 10AM to 6PM EST for some parts of the day you could have an over supply of solar and at other parts of the day you would have an under supply. The same is true on the weekend vs weekday. Even seasonal power demand is less in spring and fall than summer and winter due to heating and cooling.

Though when selecting individual locations for wind, different locations favor different time of the day. And of course solar output varies significantly east/west and based on local weather conditions. That all gets modeled ahead of time and in practice get reflected in market rates.

The oversupply is coming, it seems almost inevitable by now. But a massive oversupply requires a large fall on the prices of electricity conversion and generators maintenance.

Even then, I do really expect a category of "peak demanders" to appear soon (storage is one kind, but there are other things one can do with intermittent almost free electricity). That will help increasing the spare capacity.

It’s going to be interesting to see what happens if daytime rates start to consistently dip below current night time rates.

I suspect an outgrowth of oversupply is storage will ramp up based on consistent access to very cheap rates. It makes a huge difference if you’re paying 0.4c/kWh or 4c/kWh to charge, especially when storage is significantly less than 100% efficient.

And where are you going to store this oversupply?

My point is you don’t need to store the oversupply. Grid spot prices hitting zero mean you can just dump the power as that excess is in effect worthless.

That said, consistent very low prices will likely result in someone using most of that power for something even if the power plant operators aren’t making money during that period.

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