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Some discussion here about storage, but I am interested in modeling around dynamic load shedding / smart grid / “virtual batteries”. Seems to me that as the en

Some discussion here about storage, but I am interested in modeling around dynamic load shedding / smart grid / “virtual batteries”. Seems to me that as the energy mix moves more towards renewable, to the extent that the renewable-skeptics’ prediction that variability is an issue comes true, then we would have to build gas peaker plants and start charging more for electricity at peak times. In response to this increased market rate delta it would become more viable to invest in dynamic pricing and load shedding/deferring tech. So there is a modeling exercise which looks at the peak time price premium for various levels of increase in peaker plants required as the input variable, and compares that to the viability of virtual batteries at those price deltas as the output. I haven’t seen anything along these lines.

megaman821 3y ago
I wonder why oversized hot water tanks don't get more play here. You can heat up the water with excess electricity at basically any time during the day and it should stay hot for about 24 hours if it is well insulated.
- applied_heat 3y ago
  In New Zealand they were remotely controlling residential customer hot water tanks and heaters with energy stored in hot oil using a “ripple” signal on the power lines … probably in the eighties by the age of the equipment I saw.
- hwillis 3y ago
  Because people want their hot water to be consistent. Even just a simple timer that kicks on the hot water in the morning would work, but most people want to have their sink still be hot even when they aren't showering. > it should stay hot for about 24 hours if it is well insulated. It takes 50 kWh to heat a 46 gallon tank up to 140 F. That's a ton of energy. Hotter, larger tanks lose even more energy. Instead, get a tankless heater, backing a small heat pump water tank. You get water as hot as you can possibly want, heated whenever you want, and it never goes cold.
  - megaman821 3y ago
    The whole point of over-sized water tanks isn't to be the most efficient, only to supply a lot of demand when at times of the day when there is surplus energy. Right now, solar and wind are being curtailed more and more. Also, water consistency isn't that big a problem. Today's 120v heat pump water heaters store water at higher temperatures and using a mixing valve to deliver the desired temperature of water. I am just saying, surely electric water tanks, mixing valves, and temperature sensors are orders of magnitude cheaper than the amount of batteries needed to heat an equivilant amount of water.
  - bluGill 3y ago
    Tanks can be insulated and larger tanks have less surface area per volume so keep heat longer. My parents 1988 switched their hot water to a plan where it was all heated at night. 6 people making no effort to conserve water ran out twice in all those years. Yes the.water was hotter in the morning. But the last shower of the day still needed to be mixed with some cold or it was too hot. Tankless is worse than a large tank. Tankless needs a lot more energy now, less over the full day, but when you turn the water on it needs a lot now. A tank easily adjusts to use power when the power company needs it. Sun shining or wind blowing, then heat water to use up whatever is extra. Clouds and no wind, just use the stored energy. Maybe a battery is more efficient, but tanks are cheap
    - PaulDavisThe1st 3y ago
      > Tankless is worse than a large tank. I think you missed that the proposal was a tankless heater backed by an air-source electric heat pump heated tank. The idea is that the heat pump may, or may not, get the water to the desired temperature; the on-demand heater just makes up the difference.
      - bluGill 3y ago
        You don't need that backup. Fix the problem, which is either you don't have enough storage or you don't have enough generation. As I tried to make clear people don't need much storage.
applied_heat 3y ago
The variability of wind/solar can also be handled without time of use pricing by the grid operator including terms in the energy purchase or interconnection agreement requiring the generating facility to maintain some degree of consistency to the output. Then it is up to the generator to figure out how to do that, perhaps with batteries. The problem we saw in Ontario when the market was introduced in 2001 or so was that it was politically unfavorable to have the extremely high prices, even for an hour let alone long term, that would encourage an investor to build a storage facility.
- theptip 3y ago
  I think ideally you set up the market so that supply or demand can move to meet these fluctuations. Agree it’s politically sensitive, but if you artificially flatten the price curve then you remove consumer incentives to participate in solving the problem. I suspect industrial/commercial power usage is the big area for innovation here, but would love to see a breakdown of where the low hanging fruit is.
hwillis 3y ago
> Seems to me that as the energy mix moves more towards renewable, to the extent that the renewable-skeptics’ prediction that variability is an issue comes true, then we would have to build gas peaker plants and start charging more for electricity at peak times. There are a lot of different types of variability. You're talking about sudden short-term variance in supply, which is easy to deal with- just build more renewables. Bad weather doesn't cover up entire states except for extreme events, and you can just turn it off when it isn't needed. You can build a lot of overcapacity if the alternative is to pay peaker plant rates. Increased variance like I interpret most people talking about it is those extreme weather events not necessarily hurricanes, but things like a week of no wind or heavy clouds happening to cover every panel in a distribution area. The fear being that you would still need gas plants or huge batteries to run for that one week a year, at extreme cost. The variance averages out most of the time, but not all the time. Virtual batteries work with the former, but not the latter. > In response to this increased market rate delta it would become more viable to invest in dynamic pricing and load shedding/deferring tech. It's definitely not a tech problem. It's an incentives problem. The tech was always incredibly simple, and it does literally exist already- you can buy internet-connected thermostats. All you need to do is connect Nest to your local electricity distribution company and tell it how many degrees colder/warmer you will tolerate per $ saved. 45% of a house's energy use is in controlling the temperature of air and water (and that's not counting the fridge, which is another 7%). It's as much on the suppliers as it is on consumers, IMO. Electrical distributors are some of the laziest, worst-run companies in the country. Half of them can't even do billing right; I know dozens of people who have been double charged or never charged or charged for their neighbor- nobody wants to read their electrical bill, so nobody cares. The average US household spends ~$2450 on electricity annually, and the amount you can save for how complicated it is is just below that mental threshold. I don't see it getting better without legislation. Most obviously, a push for subsidized smart meters that don't use 1930s tech to measure electricity. Then a standardized (extensible) API and/or reporting requirement, so that devices can know the current price of electricity. A standard for transmitting that info over the house circuits themselves, if you're feeling fancy. Direct-to-consumer subsidies from grid authorities for things like ancillary services, power factor correction, and frequency stabilization.
- 3y ago
nradov 3y ago
Dynamic pricing and load shedding can reduce the need for peaker plants and storage systems. But as a side effect it will also drive energy intensive heavy industries offshore. Certain types of industrial facilities can't just start and stop, and every minute they're offline they're losing money. Major countries have to keep certain strategic domestic industries operating regardless of the cost or environmental impacts; it's just too risky to depend on imports that could be interrupted at any time due to a war or other geopolitical crisis.

megaman821 3y ago

I wonder why oversized hot water tanks don't get more play here. You can heat up the water with excess electricity at basically any time during the day and it should stay hot for about 24 hours if it is well insulated.

applied_heat 3y ago
In New Zealand they were remotely controlling residential customer hot water tanks and heaters with energy stored in hot oil using a “ripple” signal on the power lines … probably in the eighties by the age of the equipment I saw.
hwillis 3y ago
Because people want their hot water to be consistent. Even just a simple timer that kicks on the hot water in the morning would work, but most people want to have their sink still be hot even when they aren't showering. > it should stay hot for about 24 hours if it is well insulated. It takes 50 kWh to heat a 46 gallon tank up to 140 F. That's a ton of energy. Hotter, larger tanks lose even more energy. Instead, get a tankless heater, backing a small heat pump water tank. You get water as hot as you can possibly want, heated whenever you want, and it never goes cold.
- megaman821 3y ago
  The whole point of over-sized water tanks isn't to be the most efficient, only to supply a lot of demand when at times of the day when there is surplus energy. Right now, solar and wind are being curtailed more and more. Also, water consistency isn't that big a problem. Today's 120v heat pump water heaters store water at higher temperatures and using a mixing valve to deliver the desired temperature of water. I am just saying, surely electric water tanks, mixing valves, and temperature sensors are orders of magnitude cheaper than the amount of batteries needed to heat an equivilant amount of water.
- bluGill 3y ago
  Tanks can be insulated and larger tanks have less surface area per volume so keep heat longer. My parents 1988 switched their hot water to a plan where it was all heated at night. 6 people making no effort to conserve water ran out twice in all those years. Yes the.water was hotter in the morning. But the last shower of the day still needed to be mixed with some cold or it was too hot. Tankless is worse than a large tank. Tankless needs a lot more energy now, less over the full day, but when you turn the water on it needs a lot now. A tank easily adjusts to use power when the power company needs it. Sun shining or wind blowing, then heat water to use up whatever is extra. Clouds and no wind, just use the stored energy. Maybe a battery is more efficient, but tanks are cheap
  - PaulDavisThe1st 3y ago
    > Tankless is worse than a large tank. I think you missed that the proposal was a tankless heater backed by an air-source electric heat pump heated tank. The idea is that the heat pump may, or may not, get the water to the desired temperature; the on-demand heater just makes up the difference.
    - bluGill 3y ago
      You don't need that backup. Fix the problem, which is either you don't have enough storage or you don't have enough generation. As I tried to make clear people don't need much storage.

applied_heat 3y ago

The variability of wind/solar can also be handled without time of use pricing by the grid operator including terms in the energy purchase or interconnection agreement requiring the generating facility to maintain some degree of consistency to the output. Then it is up to the generator to figure out how to do that, perhaps with batteries. The problem we saw in Ontario when the market was introduced in 2001 or so was that it was politically unfavorable to have the extremely high prices, even for an hour let alone long term, that would encourage an investor to build a storage facility.

theptip 3y ago
I think ideally you set up the market so that supply or demand can move to meet these fluctuations. Agree it’s politically sensitive, but if you artificially flatten the price curve then you remove consumer incentives to participate in solving the problem. I suspect industrial/commercial power usage is the big area for innovation here, but would love to see a breakdown of where the low hanging fruit is.

hwillis 3y ago

> Seems to me that as the energy mix moves more towards renewable, to the extent that the renewable-skeptics’ prediction that variability is an issue comes true, then we would have to build gas peaker plants and start charging more for electricity at peak times. There are a lot of different types of variability. You're talking about sudden short-term variance in supply, which is easy to deal with- just build more renewables. Bad weather doesn't cover up entire states except for extreme events, and you can just turn it off when it isn't needed. You can build a lot of overcapacity if the alternative is to pay peaker plant rates. Increased variance like I interpret most people talking about it is those extreme weather events not necessarily hurricanes, but things like a week of no wind or heavy clouds happening to cover every panel in a distribution area. The fear being that you would still need gas plants or huge batteries to run for that one week a year, at extreme cost. The variance averages out most of the time, but not all the time. Virtual batteries work with the former, but not the latter. > In response to this increased market rate delta it would become more viable to invest in dynamic pricing and load shedding/deferring tech. It's definitely not a tech problem. It's an incentives problem. The tech was always incredibly simple, and it does literally exist already- you can buy internet-connected thermostats. All you need to do is connect Nest to your local electricity distribution company and tell it how many degrees colder/warmer you will tolerate per $ saved. 45% of a house's energy use is in controlling the temperature of air and water (and that's not counting the fridge, which is another 7%). It's as much on the suppliers as it is on consumers, IMO. Electrical distributors are some of the laziest, worst-run companies in the country. Half of them can't even do billing right; I know dozens of people who have been double charged or never charged or charged for their neighbor- nobody wants to read their electrical bill, so nobody cares. The average US household spends ~$2450 on electricity annually, and the amount you can save for how complicated it is is just below that mental threshold. I don't see it getting better without legislation. Most obviously, a push for subsidized smart meters that don't use 1930s tech to measure electricity. Then a standardized (extensible) API and/or reporting requirement, so that devices can know the current price of electricity. A standard for transmitting that info over the house circuits themselves, if you're feeling fancy. Direct-to-consumer subsidies from grid authorities for things like ancillary services, power factor correction, and frequency stabilization.

3y ago

nradov 3y ago

Dynamic pricing and load shedding can reduce the need for peaker plants and storage systems. But as a side effect it will also drive energy intensive heavy industries offshore. Certain types of industrial facilities can't just start and stop, and every minute they're offline they're losing money. Major countries have to keep certain strategic domestic industries operating regardless of the cost or environmental impacts; it's just too risky to depend on imports that could be interrupted at any time due to a war or other geopolitical crisis.