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

ksmithaz1 said:

Yea, but it's not EVERY month, only a couple of peak months when it's really cold and the heat strips are blaring. So maybe $250/year?

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If I had demand charges last year it would have added $786 to the year..

hankcurt said:

This is interesting news to me. I hadn't heard of utilities implementing demand based charges on residential customers. I wonder why this was chosen instead of time-of-use rates. The stated goal of both systems is to minimize the amount of generation capacity that has to be installed for peak demand and only gets used a small percentage of the time.

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This is what I thought a few months back, until a friend of mine started complaining. But it's really coming in vogue these days. I think it made its way into some widely-shared pointy-hair boss slide decks in the industry in the past few years and now coming to fruition.

A while back Emporia started targeting peak shaving, and it targets the entry level residential market. They're also based in Colorado, which has residential demand charges :laugh:

They're not bothering with demand charges here in California, but they did add hour-by-hour feed-in bonuses for the new solar tariff. Which is sort of the inverse. And some of the hour slots are insanely high in August/September, when our grid gets walloped pretty heavily in late afternoon/early evening

ksmithaz1 said:

Demand is the Achilles heel of the grid. The very nice thing about Arizona and solar is peak demand on the grid coincides very closely with solar production, as we need juice when the sun is baking the house. Unfortunately if you live in the frozen tundra, and have electric heat, your peak usage shifts to the cold winter nights when their ain't no sun.

Some things you might look into:
Brideidea makes an EV charging box, designed to go inline with a HWH or other appliance to run them both on the same circuit, giving priority to the non-EV device. I have one connected to my clothes dryer (primary) and HWH (secondary) to keep them from bringing demand up. When I scale up my panel another 50A I will probably get rid of it, but I actually don't notice.

If you kick on 15KW of heat strips, there is not a whole lot you can do without a buttload of batteries. With close to 4000 square foot of ranch housing, you are decidedly sub-optimal for efficiency by design as well. I was informed in another thread some heat pumps these days work way below zero, dunno how much cold you are dealing with, but I'd look into it for sure. Some of the power companies offer discounts/have gear that they hook into your HVAC/High load circuits that offer a discount if they can shut it off. There are home control products that can do the same, but they can get a little pricey.

Frankly ~4000 square foot is a lot of house. Not going to be cheap to run it no matter what you do. Probably not an easy way to shutdown portions of the house during high demand either.

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I am researching new air source heat pumps as well as ground source heat pumps.. also adding 2" of insulation to the exterior of the house while residing it... the plan to attack my high demand comes after the house is performing at its best. The hope is to never need the heating strips.. even with us getting down to -5*F

I do have some experience with an LG heat pump dryer. I purchased one last year as part of a long term plan to reduce air leakage of my house. I wanted to get rid of appliances that used conditioned air from inside the house and then dumped it outside. I got rid of my traditional resistance heated dryer and my gas water heater and replaced both with heat-pump models.

The heat pump dryer is slower. Plan on a couple of hours to dry a large load. For me this isn't a huge issue now, but it might have been a problem when I had three teenage daughters at home. However, one thing I can say is that the heat-pump dryer feels ... civilized .. I guess, compared to my old one. Meaning that I put in wet clothes, and a while later I have dry clothes in one compartment, and the water that was moved out of the clothes in another compartment. It's all a very closed loop, efficient system. It makes me happy.

vwaudiguy said:

I am researching new air source heat pumps as well as ground source heat pumps.. also adding 2" of insulation to the exterior of the house while residing it... the plan to attack my high demand comes after the house is performing at its best. The hope is to never need the heating strips.. even with us getting down to -5*F

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Stick with air-to-air. Water-to-air is a neat idea, that never seems to pan out as intended. Yea they were saying like -20C or so for some of the newer heat pumps if memory serves. Pretty amazing, but you ought to be able to get even lower, absolute zero is -270C or something.

hankcurt said:

It's all a very closed loop, efficient system. It makes me happy.

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I looked for one seven years ago and they were not ready for prime time yet. Sounds like it is time to look again.

zanydroid said:

This is what I thought a few months back, until a friend of mine started complaining. But it's really coming in vogue these days. I think it made its way into some widely-shared pointy-hair boss slide decks in the industry in the past few years and now coming to fruition.

A while back Emporia started targeting peak shaving, and it targets the entry level residential market. They're also based in Colorado, which has residential demand charges :laugh:

They're not bothering with demand charges here in California, but they did add hour-by-hour feed-in bonuses for the new solar tariff. Which is sort of the inverse. And some of the hour slots are insanely high in August/September, when our grid gets walloped pretty heavily in late afternoon/early evening

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Emporia does a good job tracking 15 minute peak demand.. I wish I could utilize their app for battery discharge peak shaving... but you must use their battery... I do plan to get their EV charger as I really enjoy their vue monitor/app

zanydroid said:

t's really coming in vogue these days. I think it made its way into some widely-shared pointy-hair boss slide decks in the industry in the past few years and now coming to fruition.

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I like the concept of the utility incentivizing customer feed in when its needed. These incentives would let customers benefit from using small battery systems to help out the grid.

This is much better than the 'pointy haired boss' option.

It's interesting watching the various Power Companies trying to squeeze more money from people who have Solar.
I suspect that at some point when a different administration in power the kids gloves are going to come off and they will enact even more direct policies to punish people who are grid tied.
I am slowly getting myself off the Grid for this very reason. I am now at 3.5Kwh per day from the Grid and using 40KWh total. In summer that will probably go up to the typical 55KWh and I expect grid usage to be at 8-10 KWh.
One more battery and a little more load management would fix the issue but the tiny little Bill just cannot justify buying another battery. Also I believe they are just going to make the penalty a minimum monthly bill that will be outrageous for people who only use a small amount of power.
At my age I get worried about coming off the Grid completely because my wife would be extremely unhappy.

hankcurt said:

I do have some experience with an LG heat pump dryer.

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hankcurt said:

Meaning that I put in wet clothes, and a while later I have dry clothes in one compartment, and the water that was moved out of the clothes in another compartment. It's all a very closed loop, efficient system. It makes me happy.

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Why does it condense and store the water in another compartment?

ksmithaz1 said:

Stick with air-to-air. Water-to-air is a neat idea, that never seems to pan out as intended. Yea they were saying like -20C or so for some of the newer heat pumps if memory serves. Pretty amazing, but you ought to be able to get even lower, absolute zero is -270C or something.

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Doesn't geothermal retain a decent COP at lower temp than A2A? That said, it feels like investing in a system to hand down to your grandkids...

hankcurt said:

Meaning that I put in wet clothes, and a while later I have dry clothes in one compartment, and the water that was moved out of the clothes in another compartment. It's all a very closed loop, efficient system. It makes me happy.

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robby said:

Why does it condense and store the water in another compartment?

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The reason for storing in another compartment is to avoid the need for a drain. You take the water from the compartment and dump it down the sink. Not sure why people don't just drain it the same hole as the washer. I guess it's for flexibility (the ones with a compartment can usually be configured to drain directly or to fill in a compartment). You can toss a dryer with a condensate compartment anywhere in the house, that has electricity.

One of the elegant things about the combo units is that the washer side already drains out anyway, so no reconfiguration is needed in the laundry space.

Another notion of "closed loop": a HP dryer is different from a HPWH or ASHP in that it doesn't necessarily cool the air outside. Rather, it recovers a lot of heat from condensing out the water that has been extracted from the clothes.

Ampster said:

I looked for one seven years ago and they were not ready for prime time yet. Sounds like it is time to look again.

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Take a look at the GE and LG full sized combos. They've been very hot the past 12-18 months in some circles.

robby said:

Why does it condense and store the water in another compartment?

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As @zanydroid said above, I could directly drain the water from the dryer. It wasn't convenient to drain it by gravity until I could stack the dryer on the washer, and I didn't want a hose running across the floor to the floor drain so I left it configured to catch the water in the compartment that is built into the dryer for that purpose. Now, I use the water from the dryer to water house plants since it has lower mineral content than the tap water.

hankcurt said:

As @zanydroid said above, I could directly drain the water from the dryer. It wasn't convenient to drain it by gravity until I could stack the dryer on the washer, and I didn't want a hose running across the floor to the floor drain so I left it configured to catch the water in the compartment that is built into the dryer for that purpose. Now, I use the water from the dryer to water house plants since it has lower mineral content than the tap water.

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Doesn’t the built in condensate pump lift it high enough for most situations? Or was it a convenience and not a law of physics thing?

zanydroid said:

Or was it a convenience and not a law of physics thing?

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It was entirely configuration of the drains and layout of the room, and where I was willing to run a hose.
So esthetics, not physics.

Got it. I don’t know much about plumbing but I sort of assumed it’s possible to find some kind of Y adapter that can dock with the drain hole and accept both the drain of laundry machine and of the HP dryer.

zanydroid said:

Another notion of "closed loop": a HP dryer is different from a HPWH or ASHP in that it doesn't necessarily cool the air outside. Rather, it recovers a lot of heat from condensing out the water that has been extracted from the clothes.

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I have an air to air condensing dryer in our rental condo. It adds a lot of heat to the place, they say.

After I raised it from the floor onto a shelf, to insert a washer that was top load, it wasn't drying.
My shelf support let it tilt slightly, and water didn't drain out of the air path to sump.

I always ignored that stuff about "must be level", but it matters for condensing dryers.

zanydroid said:

Got it. I don’t know much about plumbing but I sort of assumed it’s possible to find some kind of Y adapter that can dock with the drain hole and accept both the drain of laundry machine and of the HP dryer.

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Ours has a skinny enough discharge hose that it fits in the same hole.
Otherwise, you could certainly assemble a Y.

Peak shaving - I'm now playing with Sunny Boy Storage + LG RESU-10H + Wattnode.

Adding Wattnode was the key to getting it to do anything, because configuration at this time will discharge only to the point of zero import, and charge only to the point of zero export.

I've tried to set the modes "Force charge offpeak" and "discharge on-peak" but they aren't doing anything yet.

It has quite early firmware, plan to update but firmware available calls for 3 lower number updates first. Not on SMA's website, so I have support request for them to provide those.

robby said:

It's interesting watching the various Power Companies trying to squeeze more money from people who have Solar.
I suspect that at some point when a different administration in power the kids gloves are going to come off and they will enact even more direct policies to punish people who are grid tied.
I am slowly getting myself off the Grid for this very reason. I am now at 3.5Kwh per day from the Grid and using 40KWh total. In summer that will probably go up to the typical 55KWh and I expect grid usage to be at 8-10 KWh.
One more battery and a little more load management would fix the issue but the tiny little Bill just cannot justify buying another battery. Also I believe they are just going to make the penalty a minimum monthly bill that will be outrageous for people who only use a small amount of power.
At my age I get worried about coming off the Grid completely because my wife would be extremely unhappy.

Click to expand...

I started building my addiction a year ago

Load shaving (time of use) saves me approximately 100 / month on H VAC in the summer. I burn wood in winter. I have more panels now. So now I need more inverter and battery. Next biggest cost is hot water. I shower launder etc as much as possible during off peak. Next will be a heat pump water heater. I also plan to run it on heat pump only mode. Reducing its peak demand....

I sort of understand the peak demand cost . Infrastructure does cost. I am pricing my new inverter now... 3k inverter vs 5 vs 12.. As I reduce my grid usage the power co wires still cost the same. Huge debate in my state over transmission cost. Lobbyist got our rates lowered for commercial and increased on residential. Allegations of Residential not paying their fair share....

Air source vs ground source heat pump. Absolutely ground over air. The ground has a constant temperature (dig down far enough). Will absorb energy more consistently, has more energy than air at low ambient temps where air to air struggles. In summer, the hotter the air, the harder it is to pump heat into it. I too have the availability to dig my own ground loop. Just have not wanted to dig up the yard or making the investment yet. Especially with wood heat. I am considering installing before my age prohibits the cost saving of self installing the loop... Otherwise it will be an air source..

Google heating fuel comparison calculator and look for an xls spreadsheet. I downloaded it years ago. Could not find the link easily. Found one the state of Maine.gov seems to be the same... It has almost every form of energy and you can enter the efficiency and cost per unit of your gas, oil, electric, pellets, coal as your energy source. Then it will tell you how many dollars it cost to make or move the BTU's. Learned this decades ago. We had to calculate the daily cost of Nat gas vs oil because we got charged demand usage. We fired our boilers off fuel oil on those days. We had to have both for redundancy etc...So we just ran the cheaper fuel of the day....

As for the OP ROI and independence are motivating factors for me...

hwy17 said:

Turn off aux heat and set the HPWH to heat pump only mode would go a long way here. You could get a williams direct vent wall furnace to use instead of the aux.

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Another thought is looking to upgrade the heat pump to a true cold weather rated heat pump like a Gree Multipro or Mitsubishi hyper heat. I have a Gree Flexx at my house and it has never kicked on aux heat even in -9F ambient weather with -15 to -20 wind chill.