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Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

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Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#221

Post by Dylan16807 »

WalterBright wrote: post #217
Dylan16807 wrote: post #208

Earlier quoted context omitted.

I'd say it's more "slightly elastic" than "very elastic". A lot of people won't spend the mental energy to optimize anything more than the most major consumptions, and even then most of what they can do is rearranging loads, not reducing them.

It's not about reducing them, it's time-shifting them. The big electric consumers are A/C, heating, refrigeration, hot water heating, and car battery charging. All of those are very amenable to time shifting, and this shifting can be automated.

I would only categorize car battery charging as very amenable to time shifting, and the various kinds of heating and cooling as slightly to moderately amenable.

With refrigeration especially, you want to keep it in a very narrow temperature band. You could design a fridge that keeps an ice reservoir worth several hours, but without that you have very little ability to time shift.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#222

Post by dev_dull »

logfromblammo wrote: post #155
Firerouge wrote: post #50

Earlier quoted context omitted.

A power wall that's paid to be charged during peak generation, and gets paid again to discharge during peak consumption would be pretty fantastic.

Why would a power utility allow customers to perform time-of-day arbitrage when they could do that themselves without upgrading all the meters?

Lid shifting. PGE actually pays a subsidy for you to do it via a battery.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#223

Post by nostrademons »

WalterBright wrote: post #217
Dylan16807 wrote: post #208

Earlier quoted context omitted.

I'd say it's more "slightly elastic" than "very elastic". A lot of people won't spend the mental energy to optimize anything more than the most major consumptions, and even then most of what they can do is rearranging loads, not reducing them.

It's not about reducing them, it's time-shifting them. The big electric consumers are A/C, heating, refrigeration, hot water heating, and car battery charging. All of those are very amenable to time shifting, and this shifting can be automated.

That's an interesting idea. The current residential home appliance setup is totally not amenable to it - I don't even know where my refrigerator & hot water heating on-switches are, I rarely touch the A/C & heating, and I'm certainly not going to remember the rates at a give time of day as a consumer (I likely wouldn't even be home or awake when they're lowest). But if rates actually varied throughout the day, I could imagine smart-thermostats and smart-switches being a very lucrative new market. Manufacture a piece of silicon & copper and it saves you a hundred dollars a month in electricity; I like the idea.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#224

Post by WalterBright »

Dylan16807 wrote: post #221
WalterBright wrote: post #217

Earlier quoted context omitted.

It's not about reducing them, it's time-shifting them. The big electric consumers are A/C, heating, refrigeration, hot water heating, and car battery charging. All of those are very amenable to time shifting, and this shifting can be automated.

I would only categorize car battery charging as very amenable to time shifting, and the various kinds of heating and cooling as slightly to moderately amenable. With refrigeration especially, you want to keep it in a very narrow temperature band. You could design a fridge that keeps an ice reservoir worth several hours, but without that you have very little ability to time shift.

With minor engineering changes, you can timeshift quite a bit.

Consider hot water heaters. When power goes out, mine will keep water hot enough for a shower for 2 days. Two days. That means the design can be changed to heat water up to, say, 200 degrees, and then mix it with cold water to bring it down to 100 or so when demanded, and one should never need to run the heater more than a couple hours a day when power is cheap.

Storing hot and cold water can also timeshift heating/cooling your house with a simple and inexpensive system (little more than a controller and a water tank). Much, much cheaper than battery storage.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#225

Post by Dylan16807 »

WalterBright wrote: post #220
Dylan16807 wrote: post #208

Earlier quoted context omitted.

I'd say it's more "slightly elastic" than "very elastic". A lot of people won't spend the mental energy to optimize anything more than the most major consumptions, and even then most of what they can do is rearranging loads, not reducing them.

BTW, people often asserted that demand for gas is inelastic. There's plenty of evidence it is very elastic - just the constant variation of pump prices is a sure sign of demand and supply being constantly adjusted. And fuel economy most definitely affects peoples' choices in cars.

That's a much longer term elasticity. That's equivalent to flat-out raising electric rates and having people deal with hotter temperatures inside. That elasticity already exists, for the most part. Variable pricing probably doesn't get you a lot more of it.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#227

Post by Dylan16807 »

WalterBright wrote: post #224
Dylan16807 wrote: post #221

Earlier quoted context omitted.

I would only categorize car battery charging as very amenable to time shifting, and the various kinds of heating and cooling as slightly to moderately amenable. With refrigeration especially, you want to keep it in a very narrow temperature band. You could design a fridge that keeps an ice reservoir worth several hours, but without that you have very little ability to time shift.

With minor engineering changes, you can timeshift quite a bit. Consider hot water heaters. When power goes out, mine will keep water hot enough for a shower for 2 days. Two days. That means the design can be changed to heat water up to, say, 200 degrees, and then mix it with cold water to bring it down to 100 or so when demanded, and one should never need to run the heater more than a couple hours a day when power is…

Sure, that works well if you're willing to wait 20 years for devices to be replaced.

Though batteries keep improving and eating in to the amount you can save by doing that.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#228

Post by dojomouse »

mpax wrote: post #136
nostrademons wrote: post #85

Earlier quoted context omitted.

The article suggests that solar + wind with natgas for peaks is exactly where we're headed. At least in the regions being talked about (mostly Europe + California). The Forbes article you linked is about New England. New England will probably be the last region to get decent renewable adoption. Solar panels don't work as well because they're far north and get a number of cloudy days, the winds are not that strong out…

Regarding the cloudyness... Has anyone ever tried to levitate photovoltaics into the stratosphere? Blimpy-space-elevator kinda thing? Is such a thing even possible?

I looked into this in a lot of detail about 5 years ago. There were a couple of studies, and one somewhat-active company I saw (Stratosolar - didn't seem to be very well resourced/capable).

My main focus was on aerodynamic modelling and panel positioning methods for various structure sizes, and the resulting LCOE. Main issues I found were: - Weather conditions in the stratosphere aren't well understood; most of the time pretty benign, but there are a bunch of extremes which could have a significant impact on the structural requirements. - It's basically a tradeoff of panel-cost/conventional-installation-cost vs aerostat-cost/non-conventional-installation-cost. The aerostat is definitely not going to be cheap, so having your panels on an aerostat has to result in a bunch more energy per PV-element than having them on the ground. - Having the aerostat option come out on top gets more difficult as PV gets cheaper. Let's say you get 2x energy from PV on an aerostat vs installed on the ground. That means the aerostat option will be competitive with the ground option as long as the total installed cost (per watt) is less than 2x the terrestrial installed cost. If the terrestrial installed cost reduces by a factor of two (and it's reduced by more than that since I did the analysis!), you suddenly have to reduce the marginal cost of your aerostat option by 50% just to remain competitive! - To be economic and sufficiently robust to expected weather, these structures have to be enormous; the architecture that seemed most promising to me (from memory) was cylinders of length 4km and diameter 1km (roughly 1GW electrical output peak, more like 500-600MW annualised). They're at least semi opaque, and are tethered around 20km altitude (and can drift within a ~10km radius around the tether point). At that altitude they're visible from several hundred kilometers away, and they look huge - 15x the width and length of the largest cruise ships. - It doesn't help THAT much with seasonal variation away from the equator. Summer output in northern europe is still 2-3x winter output, so you need long term storage or an energy dump.

So... I think it's super interesting, but I don't think it'll ever be commercially attractive vs either terrestrial installations, or space. The main nice thing is that it's still pretty easy to get the power back down to earth with high efficiency... in contrast to orbital solar.

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#229

Post by WalterBright »

Dylan16807 wrote: post #225
WalterBright wrote: post #220

Earlier quoted context omitted.

BTW, people often asserted that demand for gas is inelastic. There's plenty of evidence it is very elastic - just the constant variation of pump prices is a sure sign of demand and supply being constantly adjusted. And fuel economy most definitely affects peoples' choices in cars.

That's a much longer term elasticity. That's equivalent to flat-out raising electric rates and having people deal with hotter temperatures inside. That elasticity already exists, for the most part. Variable pricing probably doesn't get you a lot more of it.

I lived through the gas crisis. People were able to instantly change their use of gas to adapt. A simple example: people no longer drove to the store to buy a loaf of bread. They shifted to one trip and buying several days worth. They started carpooling. They started tuning up their cars (an ill-tuned car can be very inefficient).

Re: Power Worth Less Than Zero Spreads as Green Energy Floods the Grid

#230

Post by WalterBright »

nostrademons wrote: post #223
WalterBright wrote: post #217

Earlier quoted context omitted.

It's not about reducing them, it's time-shifting them. The big electric consumers are A/C, heating, refrigeration, hot water heating, and car battery charging. All of those are very amenable to time shifting, and this shifting can be automated.

That's an interesting idea. The current residential home appliance setup is totally not amenable to it - I don't even know where my refrigerator & hot water heating on-switches are, I rarely touch the A/C & heating, and I'm certainly not going to remember the rates at a give time of day as a consumer (I likely wouldn't even be home or awake when they're lowest). But if rates actually varied throughout the day, I coul…

You bet. There'd quickly be add-ons to adapt existing systems to do this, and powerful incentives for the manufacturers of those systems to bring out new designs to take full advantage.

My electric bill is hundreds of dollars a month. Cutting it in half would be very motivating to me to buy new systems.

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