diy solar

diy solar

Ive had solar for a year and now the utility company charges a demand fee... not cool.

vwaudiguy said:
Just one 5 ton heat pump that is showing its age...
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Think we found it. Old heat pumps are horribly inefficient. Personally, I'd have to think hard about replacing it with ground source, though. While very efficient, the capital cost of a well or buried loops often makes the payback many years longer than just buying air source heat pumps. You almost certainly have ducting as well, and most leak like sieves.

I live in Maine, so we know cold. None of the three buildings with heat pumps have backup strips, and all provide heat at below zero. I also track use with Emporia Vues in all main buildings. It was 8F here this morning, and our buildings were all toasty. At no time has the heat pump in the building I'm in exceeded 3.56 KW this morning, and that happened for about 2 minutes, in a defrost cycle.It was under 2 KW for the vast amount of this chilly morning I just checked this months peak 15 min demand for the heat pump in our home and it was 1.73 KW.

So, I'd start with a heat pump changeout, and strongly consider multiple units over a ducted system if those ducts can't be sealed. I might also consider some automation that temporarily suspends charging your EV when demand begins to exceed some threshold (e.g., a relay controlled by inexpensive home automation, communicating with the Emporia Vue. Personally I use Hubitat but not for the purpose I just described (no EV). Bottomline: Addressing this first with batteries seems like an expensive route. I'd try improved efficiency, starting with that old heat pump, first.
 
vwaudiguy said:
I think I'm going to have to try.. my car charger runs a solid 3.8kw for 5 hours straight each day typically.. I can't keep the heat pump or water heater from running during that 5hr period.. Inevitably they all three run at the same time.
Click to expand...
If you had thermal storage it would go a long way, but would require an air to water heat pump.

I see a few choices, one a standalone system with batteries to recharge the car. Another choice is to use the power as you make it, energy storage can come in several forms, it doesn't have to be in just a chemical battery.

Think out of the box.

I had a demand meter at my old shop and it actually wasn't that high for the utility bill. 3 phase and a 15 hp air compressor was the reason for the demand meter. In summer the utility bill was about $70/month back then.
 
Madcodger said:
Think we found it. Old heat pumps are horribly inefficient. Personally, I'd have to think hard about replacing it with ground source, though. While very efficient, the capital cost of a well or buried loops often makes the payback many years longer than just buying air source heat pumps. You almost certainly have ducting as well, and most leak like sieves.

I live in Maine, so we know cold. None of the three buildings with heat pumps have backup strips, and all provide heat at below zero. I also track use with Emporia Vues in all main buildings. It was 8F here this morning, and our buildings were all toasty. At no time has the heat pump in the building I'm in exceeded 3.56 KW this morning, and that happened for about 2 minutes, in a defrost cycle.It was under 2 KW for the vast amount of this chilly morning I just checked this months peak 15 min demand for the heat pump in our home and it was 1.73 KW.

So, I'd start with a heat pump changeout, and strongly consider multiple units over a ducted system if those ducts can't be sealed. I might also consider some automation that temporarily suspends charging your EV when demand begins to exceed some threshold (e.g., a relay controlled by inexpensive home automation, communicating with the Emporia Vue. Personally I use Hubitat but not for the purpose I just described (no EV). Bottomline: Addressing this first with batteries seems like an expensive route. I'd try improved efficiency, starting with that old heat pump, first.
Click to expand...

Madcodger said:
Think we found it. Old heat pumps are horribly inefficient. Personally, I'd have to think hard about replacing it with ground source, though. While very efficient, the capital cost of a well or buried loops often makes the payback many years longer than just buying air source heat pumps. You almost certainly have ducting as well, and most leak like sieves.

I live in Maine, so we know cold. None of the three buildings with heat pumps have backup strips, and all provide heat at below zero. I also track use with Emporia Vues in all main buildings. It was 8F here this morning, and our buildings were all toasty. At no time has the heat pump in the building I'm in exceeded 3.56 KW this morning, and that happened for about 2 minutes, in a defrost cycle.It was under 2 KW for the vast amount of this chilly morning I just checked this months peak 15 min demand for the heat pump in our home and it was 1.73 KW.

So, I'd start with a heat pump changeout, and strongly consider multiple units over a ducted system if those ducts can't be sealed. I might also consider some automation that temporarily suspends charging your EV when demand begins to exceed some threshold (e.g., a relay controlled by inexpensive home automation, communicating with the Emporia Vue. Personally I use Hubitat but not for the purpose I just described (no EV). Bottomline: Addressing this first with batteries seems like an expensive route. I'd try improved efficiency, starting with that old heat pump, first.
Click to expand...
I totally agree about the heat pump... my peak 15 demand on that unit is 4.21kw so far in February.. it's running right now at about 4kw with defrost at about 2.5kw and it's 21*F here now... the main reason I would give the ground source a look is I have my own digging equipment to install the loop field and plenty of land. But a new air source may end up being a better option.
 
vwaudiguy said:
I have Ozark Electric Coop... here is what we got from them...
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I guess I am just dumb. I do not understand what this demand kW charge amounts to. Billing for kWh or for various monthly fees or even high demand periods (higher kWh rate) OK. But how do you charge for kW based on 15 minute and it not be a kWh charge?
 
vwaudiguy said:
I think I'm going to have to try.. my car charger runs a solid 3.8kw for 5 hours straight each day typically.. I can't keep the heat pump or water heater from running during that 5hr period.. Inevitably they all three run at the same time.
Click to expand...
As already stated, Controlling loads is way cheaper than adding battery capacity.
”Smart” EV chargers have the load shedding functionality.
Also no reason to run hot water heater and heat pump in same time. For them simple relay-based load—shedding could be enough to prevent them operating simultaneously.

A9C15913 - CDS - three phase load-shedding contactor - 1 channel per phase | Schneider Electric New Zealand

Schneider Electric New Zealand. A9C15913 - CDS - three phase load-shedding contactor - 1 channel per phase.
www.se.com www.se.com
 
Mattb4 said:
But how do you charge for kW based on 15 minute and it not be a kWh charge?
Click to expand...
It is easy for them. If your peak demand is 5kW and the rate is $3.75 per kW the your fixed charge is $18.75 a month. The fifteen minute is just the minimum time the peak is maintained. That would eliminate startup or surge loads. I suppose you could game it by only running ten minutes on and ten or fifteen minutes off and repeat.
 
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Mattb4 said:
I guess I am just dumb. I do not understand what this demand kW charge amounts to. Billing for kWh or for various monthly fees or even high demand periods (higher kWh rate) OK. But how do you charge for kW based on 15 minute and it not be a kWh charge?
Click to expand...
The way i understand is - Its like a speeding ticket for your electric bill 😅
 
Btw. Compared to wildly variable ”stock market pricing” here in Finland/Europe this should be relatively easy task.
Been popular option in last 2 years or so to install load controller boxes that fetch next day pricing from internet, select the cheapest hours based on your demand and turn on heating/boiler/ev charger during the cheap hours. Nighttime is typically the cheapest but sometimes the price can go negative also during the day! Electricity company pays you to consume more if you can time the consumption for those negative hours.
 
Ampster said:
It is easy for them. If your peak demand is 5kW and the rate is $3.75 per kW the your fixed charge is $18.75 a month. The fifteen minute is just the minimum time the peak is maintained. That would eliminate startup or surge loads.
Click to expand...
Thanks for the explanation. I guess as the generation ability of electrical companies gets more constrained these types of rationing plans is inevitable. Glad I am mostly Off grid now.
 
seneysolar said:
Its like a speeding ticket for your electric bill 😅
Click to expand...
Exactly. It is a fixed charge under the assumption that heavy users require more infrastructure. It makes sense in a commercial or industrial setting where that is true. They have been a component of commercial rates for years. I would hate to think it becomes common for residential
 
MattiFin said:
As already stated, Controlling loads is way cheaper than adding battery capacity.
”Smart” EV chargers have the load shedding functionality.
Also no reason to run hot water heater and heat pump in same time. For them simple relay-based load—shedding could be enough to prevent them operating simultaneously.

A9C15913 - CDS - three phase load-shedding contactor - 1 channel per phase | Schneider Electric New Zealand

Schneider Electric New Zealand. A9C15913 - CDS - three phase load-shedding contactor - 1 channel per phase.
www.se.com www.se.com
Click to expand...
As far as the water heater and heat pump running at the same time.. having 3 out of the 4 people living at the house taking showers/baths each night after work means the water heater is on for a constant 4 hours... turning the HVAC off for that time won't work... the water heater is a heat pump model which connects to wifi and such.. cycling its power on and off many not bode well... I am going to try a few things to reduce demand on my own before the demand charges are implemented in April..
 
In NH we don't have demand charges for residential service. But the meter for the well pump for our condo has demand charges. However, there's no demand charge for the first 5KW.
 
Ampster said:
Exactly. It is a fixed charge under the assumption that heavy users require more infrastructure. It makes sense in a commercial or industrial setting where that is true. They have been a component of commercial rates for years. I would hate to think it becomes common for residential
Click to expand...
It appears there are only 3 electric cooperatives in the state of Missouri that's are implementing these demand charges this year... I'm sure we are some kind of test group for more expansion. There is a bill that is getting some discussion that could make the net metering laws more "solar" friendly so these rates are probably in anticipation of the bill passing.. who knows.
 
vwaudiguy said:
As far as the water heater and heat pump running at the same time.. having 3 out of the 4 people living at the house taking showers/baths each night after work means the water heater is on for a constant 4 hours... turning the HVAC off for that time won't work... the water heater is a heat pump model which connects to wifi and such.. cycling its power on and off many not bode well... I am going to try a few things to reduce demand on my own before the demand charges are implemented in April..
Click to expand...
You might want to also look at getting a second hphwh and running it in parallel with the first, that should enable you to stay on heap pump only mode indefinitely.
 
themizz said:
You might want to also look at getting a second hphwh and running it in parallel with the first, that should enable you to stay on heap pump only mode indefinitely.
Click to expand...
I have thought about that but the 80 gallon unit I have now was $2800 before rebates... do I spend another $2800 for a second unit to keep both on heat pump mode or build a battery/inverter setup to run the current unit "off grid". In heat pump mode it uses 400w but in high demand mode it can use 5000w.. it puts off a lot of cold air which is fantastic in the summer but not so good in the winter.. 2 of them running would be crazy I bet.
 
vwaudiguy said:
As far as the water heater and heat pump running at the same time.. having 3 out of the 4 people living at the house taking showers/baths each night after work means the water heater is on for a constant 4 hours... turning the HVAC off for that time won't work... the water heater is a heat pump model which connects to wifi and such.. cycling its power on and off many not bode well... I am going to try a few things to reduce demand on my own before the demand charges are implemented in April..
Click to expand...
Storage tank/boiler for water heater? Storing hot water is extremely cheap compared to storing same amount of electricity.
 
My co-op started what they also call a "demand fee" which is they take whatever your highest peak usage was for the month and then multiply that by a higher rate charge. Is this the same thing? It is basically impossible to "manage" for this to prevent it unless you just don't have any peak usages during the month. I know a person on the co-op board and they did this because it was the cheapest increase in monthly charges for those people on the board based on their previous electric bills when they simulated what affect it would have on them.. as opposed to implementing some other method such as time of use charges where you could at least manage when you used your power.
 
vwaudiguy said:
It appears there are only 3 electric cooperatives in the state of Missouri that's are implementing these demand charges this year... I'm sure we are some kind of test group for more expansion. There is a bill that is getting some discussion that could make the net metering laws more "solar" friendly so these rates are probably in anticipation of the bill passing.. who knows.
Click to expand...
Where did you learn about this? I've not heard anything about it yet.

In early January I did learn that Missouri COOPs are also trying to get a law passed to redefine net metering as something that is not metering.

Check out House Bills 1705 and 1854 and see how you read them.

Below is a snip from 1705. From my layman's understanding 1854 reads about the same. In essence it eliminates net metering.

1708268294592.png
 
rhino said:
My co-op started what they also call a "demand fee" which is they take whatever your highest peak usage was for the month and then multiply that by a higher rate charge. Is this the same thing? It is basically impossible to "manage" for this to prevent it unless you just don't have any peak usages during the month. I know a person on the co-op board and they did this because it was the cheapest increase in monthly charges for those people on the board based on their previous electric bills when they simulated what affect it would have on them.. as opposed to implementing some other method such as time of use charges where you could at least manage when you used your power.
Click to expand...
That sounds like the same thing.. how are the non nerd general customers supposed to understand how they are being billed.. and then once they do they will figure out there is very little they can do to combat it.
 
Mattb4 said:
Thanks for the explanation. I guess as the generation ability of electrical companies gets more constrained these types of rationing plans is inevitable. Glad I am mostly Off grid now.
Click to expand...
They've always done it for all but the tiniest commercial customers (40kW or less) but this residential trend is very recent thing.

How I would explain it when I worked for a utility back in the 90's is that we have to build and maintain infrastructure that is capable of supplying you the highest demand that you need regardless of how often you need it.

On a individual scale it's like having to buy 15kW generator to be able to start and run a well pump a few times a day but the remainder of the day you only need 2kW or less.
 
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