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Grid-interactive water heaters (GIWHs) add bidirectional control to electric resistance water heaters, allowing a utility or third-party aggregator to rapidly toggle them off and on. This functionality turns a fleet of water heaters into a flexible energy-storage medium, capable of increasing and decreasing the load on the grid on a second-by-second basis.
Electric water heaters have been controlled by utilities for over 30 years. The limitation is that there are only a modest number of electric water heaters installed.
Yeah, in south Florida you could get a discount if you let the power company control your water heater, pool pump and AC. I'm not sure about the benefits of increasing the load. It makes some sense, but most heaters have only one high temp cutoff setpoint. Unless you want T&P valves going off and water heaters exploding, overriding a thermostat is not a good idea.
A water-heater is not a very good device for storing energy.
As soon as it's heating element goes off, the water begins to slowly cool. If you wanted to begin using that heat 6 hours later, I would suspect that most of the heat would be gone.
There are thermal-banks designed for home heating and storing heat, but I think they start at 1,000 gallon sizes and they are more expensive.
A water-heater is not a very good device for storing energy.
They are trying to prevent waste, the grid is very inefficient and there is a lot of wasted electric. When electric is generated it has to be either immediately used or stored. If they have an excessive amount of electric they can turn on your hot water heater instead of letting it go to waste.
If you already maintaining a set temperature throughout the day the BTU's your hot water heater is losing is always going to be steady. It's not going to cost you anything more.
The other thing is if they have a very high demand situation they can turn it off, this is preferable to a blackout.
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As soon as it's heating element goes off, the water begins to slowly cool. If you wanted to begin using that heat 6 hours later, I would suspect that most of the heat would be gone.
We make hot water with our coal boiler however it goes from there into an electric hot water heater first. We do this because you occasionally have to turn the boiler off for maintenance and if something happens to the boiler we still have hot water. It's always turned off,the water going into it is going to be between 140 and 180 depending on the season. You'd have to go 24 hours before you'll notice the water beginning to cold.
A water-heater is not a very good device for storing energy.
As soon as it's heating element goes off, the water begins to slowly cool. If you wanted to begin using that heat 6 hours later, I would suspect that most of the heat would be gone.
There are thermal-banks designed for home heating and storing heat, but I think they start at 1,000 gallon sizes and they are more expensive.
Actually water heaters make great storage devices. They have a diversified demand of about 1 kW per cycle. There's no need to keep one off line for 6 hours. Normal operation is a 20 minute cycle. The benefit is that you need a water heater anyway, so the capital cost is just the control system.
They are trying to prevent waste, the grid is very inefficient and there is a lot of wasted electric. When electric is generated it has to be either immediately used or stored. If they have an excessive amount of electric they can turn on your hot water heater instead of letting it go to waste.
If you already maintaining a set temperature throughout the day the BTU's your hot water heater is losing is always going to be steady. It's not going to cost you anything more.
When an outside force, turns your water-heater on and off at their discretion, your water-heater can not maintain a set temperature through-out the day. It can only heat when it is on.
When the Utility Company decides for you to have hot-water, then you can have hot-water. Otherwise your water-heater is cooling down.
Whether this would cost more, or less, would depend on other factors. It would certainly NOT cost you the same amount.
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... We make hot water with our coal boiler however it goes from there into an electric hot water heater first. We do this because you occasionally have to turn the boiler off for maintenance and if something happens to the boiler we still have hot water. It's always turned off,the water going into it is going to be between 140 and 180 depending on the season. You'd have to go 24 hours before you'll notice the water beginning to cold.
Actually water heaters make great storage devices. They have a diversified demand of about 1 kW per cycle. There's no need to keep one off line for 6 hours. Normal operation is a 20 minute cycle. The benefit is that you need a water heater anyway, so the capital cost is just the control system.
Our home heating system uses a Thermal-bank, consisting of four electric water-heaters in series [they are plumbed but not wired]. I can not tell how quickly they cool. During the heating season, the water is circulating through our radiant flooring.
I have looked at expanding our Thermal-bank, and I have been told many times that a purpose built thermal-bank tank will hold heat far better and longer than water-heaters will.
When an outside force, turns your water-heater on and off at their discretion, your water-heater can not maintain a set temperature through-out the day. It can only heat when it is on.
Turning it off would be unacceptable to me other than a emergency situation where brownouts or blackouts are imminent. Turning it on to bring the water up to the desired max temperature you have already set is not an issue.
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Whether this would cost more, or less, would depend on other factors. It would certainly NOT cost you the same amount.
It runs in cycles, there might be spread of 5 or 10 degrees or whatever. It's going to cycle eventually and turning it on beforehand is not going to affect your bill. Letting it sit for six hours requires about the same amount of energy as maintaining it over six hours. Note this only applies to electric, short cycling natural gas, oil or anything that uses a flame is less efficient than firing it for a longer time.
Turning it off would be unacceptable to me other than a emergency situation where brownouts or blackouts are imminent. ...
"emergency situation"
How often do you experience brownouts and spikes now?
Our household UPS devices click a lot when either of these happens, which is fairly frequent. Not daily, but way more than to say weekly.
To my understanding a 'blackout' is a 'planned event' done by the utility company on purpose. Whereas a power-outage is just the normal event when the grid is down. I am not sure how frequently we experience 'blackouts', as distinct from grid down. 3 or 4 times a month is the norm. Mostly for less then 4 hours at a time. Though we do usually see at least one power outage of 2 to 4 days, every few months.
What makes this into a 'emergency situation' ?
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