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PV+storage is how many hours of storage? Storing enough power to last a night is just getting close to commercially viable afaik, but storing enough power to last a winter is still quite expensive.


The best storage is no storage at all, it is demand-response.

Things like responsive appliances and EV chargers that can schedule their load rather than insisting that limitless power be available instantaneously. I don't care when the dishwasher runs as long as the dishes are clean by tomorrow, you know?

Of course right now, putting the word "smart" on an appliance doesn't imply any of that, and the way it ends up implemented will probably be terrible and a half. But theoretically, demand-response could dramatically reduce the need for storage. I think it truly has a large role to play, but the folks releasing insecure internet-of-shit devices have a lot to answer for first.


> I don't care when the dishwasher runs as long as the dishes are clean by tomorrow, you know?

You can already accomplish 95% of this now with any dishwasher made within the last 20 years that has a delay timer on it. Just load it up and tell it to run in 6 hours and then go to bed.

I don't want some 3rd party company driving a huge team of middlemen sucking up a gigantic pile of data in order to determine when it might be strategically useful for my dishwasher to be on. I don't want my dishwasher on the internet. I barely want it to have any electronics at all, because I want the damn thing to last for 20 years, not the scant 5 years people seem to be getting out of major appliances these days. You wanna talk carbon footprint and recycling, making things reliable would probably save us a million times more energy than would using the internet-of-things to run this stuff at night time.

I _might_ be willing to accept a compromise where my smart power meter uses an open protocol to inform devices in my house of the current energy cost for Time-of-Use billing and then the appliance decides when to start based on a threshold I set, but even that's more implementation than is really necessary here.

Also, there are only a few appliances that can really make use of that kind of thing. As a parent, I need to run laundry all the time, non-stop, because children are filthy monsters. I can't factor energy costs into that, because laundry takes a long time to run and many loads need to be run. It's only a small number of people who can stick their one weekly load into the dryer and tell it to wait for night - and again, a timer would do 90%+ of the work spreading the load around, you don't need a gigantic network of flimsy compute doing the work here.


I think we agree more than we disagree. An overnight timer is ideal right now while most base-load comes from coal and nuclear, and power is cheapest at night.

But as we move past combustion (I'm in Michigan and the amount of coal we burn for power is absolutely shameful) and into more solar, it's less predictable. I can't set a timer that knows when the sky will be cloudy.

This is why I'm so excited to see EVSEs that take data from PV inverters and have a "PV surplus only" mode, where the car is charged only when the sun shines, without ever importing grid power. Modulating 30kW of load is just as good as 30kW of storage, but costs nothing but a few lines of code.

And yeah, networks and middlemen can suck it. Keeping it local is always better.


> You can already accomplish 95% of this now with any dishwasher made within the last 20 years that has a delay timer on it. Just load it up and tell it to run in 6 hours and then go to bed.

With solar PV, sort of the opposite. Just load it up, and tell it to run in 4 hours, while you and most everyone else is at work :)


I agree, but I think you can't demand-response away all of winter. People still want to drive their EVs and heat their homes and industrial processes can't be time shifted for weeks or even months.

You'll need some storage. Right now that would probably be Hydrogen or Methane, and making those is pretty expensive. Perhaps something better will come along, or it gets cheaper with scale, but at the current CO2 price it's not competitive with fossil fuels.


Yes, but bulk of the demand is heat and industry, so you're quickly back to having to build a lot of "storage" in the form of buildings with high thermal inertia and spare capacity for production, so that you can keep the high energy plants idle at inconvenient times. Hard to say if that is more efficient than building actual energy storage.

Every little helps I guess, but getting people not to shower on cloudy days is not gonna move the needle materially.


Heat is fairly trivially stored for months on a mass scale, check out Polar-night Energy's system - basically, you heat up (usually with just resistive heating) a bunch of sand in a 40metre-wide insulated cylinder, and when you want to use that heat you use fans to blow air through ducts that are surrounded by the sand.

The amazing thing is that every single part of the tech is old and boring - resistive heating is literally as old as electricity, electric fans and ducting are trivial, heating sand is basically impossible to screw up, etc etc.


Sand can be used as a surprisingly effect store for electrical energy (round trip efficiency > 50%).

https://arpa-e.energy.gov/sites/default/files/2021-03/07%20D...

I am particularly taken by the fluidized bed heat exchanger. What an neat concept, and so compact.


You could just implement enough surge pricing that people/companies work around peak times on their own and build their own storage.


Industry often works around the clock already. You don't want to buy and install three times the equipment you need, and have it sit idle 16 hours of the day. You also don't want to shut down for winter just because the electricity is less abundant then.


Someone needs to pay for the storage and additional generation—both the direct costs and the externalities. Why not let the market figure out who pays for it?

If factories can’t afford to pay those prices, they’ll have to rework their business model, or maybe relocate to areas with cheaper power.


There really aren't many things that can be off for significant periods of time without making them useless.

Indeed I can't think of any that can be off for more than a day.

Can you?


Most EVs have enough battery to cover more than a week of daily commute. If you could charge for significantly cheaper and greener than you do right now, by simply telling it to only charge when the panels on the roof are producing a surplus, isn't that sort of a no-brainer?

Maybe you'd go back to grid mode when anticipating a weekend trip, or when the charge hits some sort of level of concern. And I expect polar places with cloudy winters would probably run a fair bit of conventional generation like we do now, in the winter. But during the sunny season, shut it down!


There are companies that will drive your "smart" thermostat and purport to save you money by strategically controlling it, but in the end if you want to save money on your house's climate control, you're going to end up being warmer/colder than you would like.


In our last house we had a box attached to the AC compressor that let the utility turn it off for 3 hours at a time, a prescribed number of times per month. We got a $10/month discount for this.

We never noticed any effect on comfort.


Nitpicky, but shouldn’t this pattern be called “supply-response” (as in, appliances programmed to respond to a supply glut) “Demand-response” sounds like it should be used for power sources that only spin up when demand exceeds the production rate.


It strikes me as weird too. They're calling it "demand which responds", but it's phrased funny.




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