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I don't have a lot of hope for people changing their behaviour based on time of day pricing. Sure aluminum smelters etc might have to flag it for a day once ev

I don't have a lot of hope for people changing their behaviour based on time of day pricing. Sure aluminum smelters etc might have to flag it for a day once every 5 years but they do that currently because there isn't enough power for everyone so please help us out and shutdown for a day instead cause we are going to dump you anyway because we have to decide between giving you power or this other major load such as a big city. Perhaps there is some gradient to this and it is achieved with price signals - but basically the forecast has to be 1000+ $/MWH for a whole day instead of just a couple high prices intervals or hours, and it has to be order of magnitude higher $/MWH not just $200/MWH instead of $80. If it is a low-wind evening and prices on the grid are higher than normal what fraction of people are going leave their electric cars with depleted batteries instead of charging them? Say a charge takes say 8 hours, there isn't a lot of room overnight to shift the load around. How many people will refrain from charging because it is going to cost you $50 instead of $10? I think the answer to that can be seen from how much people refrain from driving when fuel costs go up. Given that traffic never gets better I would say none! 1) electricity is cheap. it will have to get a lot more expensive for anyone to care enough to change the way they are using it 2) a lot of the demand is inflexible, regardless of price. lights are going to be on, dinner is going to be made when kids are hungry, car is going to be charged overnight because must go to work tomorrow. there is going to come a point where all wind and solar must have a certain amount of firm capacity - say it has to be able to deliver 50% of nameplate rating for 5 days straight - and this is going to significantly add to the $/MWH cost of renewables. Then after 5 cloudy days in a row (unthinkable!) the output of the solar farm is 10% of nameplate until it is sunny again.

Faark 7y ago
> How many people will refrain from charging because it is going to cost you $50 instead of $10? [..] Given that traffic never gets better I would say none! Are you honestly trying to argue it doesn't have any effect? "What day of the week is best to fill your tank" is like an age-old question. Obviously within reason. Not if your tank is empty and you have to be somewhere. Less so for people who think this to be beneath them. And probably also less so in places with cheap fuel (US i hear?). But it certainly changes behavior and is a good & easy first step.
- generatorguy 7y ago
  Do people with electric cars only charge once per week? I concede There could be some demand response if people could know that they can charge for less every Sunday night. But as you say when you are empty you are a price taker. I live near Vancouver which features the most expensive gas in North America, and decent public transportation, and I believe traffic is the only thing that keeps people from driving more, not cost. So demand seems inflexible over the long term, and with electric cars I think you have even less flexibility to choose your time and place to charge, unless charging becomes ubiquitously available.
  - deleted 7y ago
    [deleted]
  - greglindahl 7y ago
    Yes, many people with big-battery electric cars can charge less than daily.
  - fulafel 7y ago
    Tesla ranges (320+) are over 20 times the average commute (16 miles). I think the more realistic scenario is that people charge less if the power is expensive, to full otherwise. Managed by a programmed policy. Also, commute length will start trending down as we leave the cheap-gas phase of history behind - EVs are also too CO2 intensive to sustain the car based lifestyle.
tomatocracy 7y ago
We've had time of day based pricing in the UK for years - it's called "Economy 7" (and there are variants like Economy 10). Historically this was designed for electric storage heaters which were switched on a separate circuit at night and you had two sets of wiring into the house but nowadays it can be done based on pure time of day by a smart meter. People who have those tariffs do tend to alter behaviour to suit them - it mainly makes sense for homes with electric space and water heating, where it's more "set and forget" (and people also do change behaviour by eg putting washing machines or tumble dryers on late at night when the cheaper tariffs apply too). Over time I imagine we might see more dynamic algorithms in use to pick and choose times when electricity is used together with more dynamic per-unit pricing.
- generatorguy 7y ago
  Great examples. These measures in the U.K. were put in place to shift demand due to constraints in total system capacity - total generation, total transmission, total distribution capacity. Eg a substation transformer couldn’t handle normal daily loads plus heating, so heating load is shifted to night. What happens when power at night becomes more expensive due to increases demand such as car charging or low supply such as high renewable penetration and no wind? It’s all about having the firm capacity to deliver power for hours on end. So the $/mwh of wind or solar power has to go up because grids are going to say you can only have more if you can supply firm capacity. This is already happening in Hawaii. I implemented hot water tank load switching through smart meters on at a town with its own power plant of only 850 kw so they wouldn’t run out of power at dinner time when the river was low (and we didn’t have to fire up the diesel either)
  - tomatocracy 7y ago
    Yes, there will always be baseload demand. But I think with the right setup more demand matching is possible for domestic and commercial buildings with relatively little effort. One way this could work is that you have eg a smart heating thermostat which plans which hours of the day/night to turn heating on and then buys power to cover that in a day-ahead market, with the aim of minimising cost on that basis. Wind and solar power are relatively preditable a day out so you wouldn't be paying too much to power traders for providing day-ahead liquidity vs on-demand pricing. Likewise, EVs all end up parked somewhere during the day - the challenge is ensuring that as many of those places as possible (car parks, workplaces, etc) have charging points too; you could do something very similar there with an algorithm deciding whether to charge based on a spot price and how much is in the battery (say, owner programs car to top up to 65% and then only continue charging if power is cheap).
fulafel 7y ago
We'll have to change to beat climate change and it means dramatically refucing fossil fuel use by regulations, taxes, price controls etc. When supply is limited, the price is the mechanism that decides who gets the juice and who doesn't. In plain terms, the price will become as high as necessary to reduce demand to the level of supply. And this can make storage profitable too. I think your examples are actually all flexible use cases. Car can be charged any time, if price is unpredictable you won't leave your battery empty on a work night. But also you don't necessarily need a car. Lighting is a silly example because it consumes negligible energy, but if you look at history it's actually very flexible. Dinner also takes negligible energy but it's also very flexible (see how people cook in places without cheap eletricity - biofuels).

Faark 7y ago

> How many people will refrain from charging because it is going to cost you $50 instead of $10? [..] Given that traffic never gets better I would say none! Are you honestly trying to argue it doesn't have any effect? "What day of the week is best to fill your tank" is like an age-old question. Obviously within reason. Not if your tank is empty and you have to be somewhere. Less so for people who think this to be beneath them. And probably also less so in places with cheap fuel (US i hear?). But it certainly changes behavior and is a good & easy first step.

generatorguy 7y ago
Do people with electric cars only charge once per week? I concede There could be some demand response if people could know that they can charge for less every Sunday night. But as you say when you are empty you are a price taker. I live near Vancouver which features the most expensive gas in North America, and decent public transportation, and I believe traffic is the only thing that keeps people from driving more, not cost. So demand seems inflexible over the long term, and with electric cars I think you have even less flexibility to choose your time and place to charge, unless charging becomes ubiquitously available.
- deleted 7y ago
  [deleted]
- greglindahl 7y ago
  Yes, many people with big-battery electric cars can charge less than daily.
- fulafel 7y ago
  Tesla ranges (320+) are over 20 times the average commute (16 miles). I think the more realistic scenario is that people charge less if the power is expensive, to full otherwise. Managed by a programmed policy. Also, commute length will start trending down as we leave the cheap-gas phase of history behind - EVs are also too CO2 intensive to sustain the car based lifestyle.

tomatocracy 7y ago

We've had time of day based pricing in the UK for years - it's called "Economy 7" (and there are variants like Economy 10). Historically this was designed for electric storage heaters which were switched on a separate circuit at night and you had two sets of wiring into the house but nowadays it can be done based on pure time of day by a smart meter. People who have those tariffs do tend to alter behaviour to suit them - it mainly makes sense for homes with electric space and water heating, where it's more "set and forget" (and people also do change behaviour by eg putting washing machines or tumble dryers on late at night when the cheaper tariffs apply too). Over time I imagine we might see more dynamic algorithms in use to pick and choose times when electricity is used together with more dynamic per-unit pricing.

generatorguy 7y ago
Great examples. These measures in the U.K. were put in place to shift demand due to constraints in total system capacity - total generation, total transmission, total distribution capacity. Eg a substation transformer couldn’t handle normal daily loads plus heating, so heating load is shifted to night. What happens when power at night becomes more expensive due to increases demand such as car charging or low supply such as high renewable penetration and no wind? It’s all about having the firm capacity to deliver power for hours on end. So the $/mwh of wind or solar power has to go up because grids are going to say you can only have more if you can supply firm capacity. This is already happening in Hawaii. I implemented hot water tank load switching through smart meters on at a town with its own power plant of only 850 kw so they wouldn’t run out of power at dinner time when the river was low (and we didn’t have to fire up the diesel either)
- tomatocracy 7y ago
  Yes, there will always be baseload demand. But I think with the right setup more demand matching is possible for domestic and commercial buildings with relatively little effort. One way this could work is that you have eg a smart heating thermostat which plans which hours of the day/night to turn heating on and then buys power to cover that in a day-ahead market, with the aim of minimising cost on that basis. Wind and solar power are relatively preditable a day out so you wouldn't be paying too much to power traders for providing day-ahead liquidity vs on-demand pricing. Likewise, EVs all end up parked somewhere during the day - the challenge is ensuring that as many of those places as possible (car parks, workplaces, etc) have charging points too; you could do something very similar there with an algorithm deciding whether to charge based on a spot price and how much is in the battery (say, owner programs car to top up to 65% and then only continue charging if power is cheap).

fulafel 7y ago

We'll have to change to beat climate change and it means dramatically refucing fossil fuel use by regulations, taxes, price controls etc. When supply is limited, the price is the mechanism that decides who gets the juice and who doesn't. In plain terms, the price will become as high as necessary to reduce demand to the level of supply. And this can make storage profitable too. I think your examples are actually all flexible use cases. Car can be charged any time, if price is unpredictable you won't leave your battery empty on a work night. But also you don't necessarily need a car. Lighting is a silly example because it consumes negligible energy, but if you look at history it's actually very flexible. Dinner also takes negligible energy but it's also very flexible (see how people cook in places without cheap eletricity - biofuels).