Do you have enough solar to go off grid in winter?

[RKCRLR]

What angle are those panels at? I'm helping @outdoors with an off-grid solar project up north also. We chose a pitch of ~40 degrees for the solar array. Hoping that's a sufficient angle that the snow slides off quickly. Another idea is to basically make a solar 'fence' with the panels at a ~90 degree angle so the snow won't stick at all. Not very useful in the summer but will help a lot in the winter.

Building an off grid Solar Powered (EV charging) Campground​

Maybe put solar panels on a hinged structure so they lay flat with the roof in summer gut can be tilted up during the winter. Would need to be robust for storms. Or perhaps a permanently mounted snow screed that can be pulled with a rope or something that can wipe snow off the panels (probably won't work real good if the snow turns to ice).

 

[sunwarriors]

Thank you for the suggestions!

The trouble with more solar panels is that solar panels don't work when they are covered with snow. Or even when they aren't but there's heavy cloud cover. Our minimum production on a clear day in late December is 30 kWh, which is adequate to be off grid. But it snows, so that doesn't happen very often. More panels covered with snow doesn't help us.

View attachment 874216

I will have to look into wood fired boilers. We already have a wood stove which is efficient and provides a lot of our heat.

Thanks again!

This is why I keep going back to the idea for truly off grid, one needs multiple sources of fuel. Solar can't be just it. More storage overall, generator, big propane tank for heat, wind if that ever gets more efficient or even if not, it can help, etc...What else is out there currently?

For me, winter is actually easier to go off grid since there is no AC use. I rarely get 2 days in a row of totally no sun. If you don't need to charge an EV, this is easier since EVs simply drain too much without solar.

Maybe we can all have a micro-nuclear reactor in a few (lol) years.

BYU profs create new micro nuclear reactor to produce nuclear energy more safely

BYU professor and nuclear engineering expert Matthew Memmott and his colleagues have designed a new system for nuclear energy production: a molten salt micro-nuclear reactor that may solve meltdown risks.

news.byu.edu

 

[h2ofun]

This is why I keep going back to the idea for truly off grid, one needs multiple sources of fuel. Solar can't be just it. More storage overall, generator, big propane tank for heat, wind if that ever gets more efficient or even if not, it can help, etc...

For me, winter is actually easier to go off grid since there is no AC use. I rarely get 2 days in a row of totally no sun. If you don't need to charge an EV, this is easier since EVs simply drain too much without solar.

you must have gas heat, which is an energy cost.

 

[nwdiver]

you must have gas heat, which is an energy cost.

Why does it have to be gas? A wood stove will do the job just fine. If you live in a rural area the only energy cost is a little exercise

 

[iPlug]

Electric vehicle home energy consumption not included here, but have found most underestimate the very large contribution of space and water heating.

https://cdn.fixr.com/ghostblog/2021/09/Residential-Energy-Use-by-Appliance-1.jpg
What Uses The Most Energy in Your Home

 

[sunwarriors]

you must have gas heat, which is an energy cost.

Will need to buy propane by the gallon from someplace. You can have propane or maybe a wood burning chimney as well for heat. We had one of those when I was young in snow country and it can get pretty warm (not the decoration stuff we all have in our city/suburban home of course).

 

[RKCRLR]

I have solar and storage and am a net producer but I wouldn't be able to make it through the winter unless I sometimes ran my generator. I have dual fuel propane furnace/heat pump. I have my furnace locked out down to 30F so it only runs when it is really cold or during the heat pump defrost cycle. I also have a wood stove and have more wood than I can burn.

My normal process in the winter is to have the heat pump warm the house in the morning and then get up and start the wood stove. The nice thing about dual fuel is if you know you are not going to have much solar you can switch to propane, or stoke up the wood stove for overnight. And the furnace will run off the generator if necessary.

 

[h2ofun]

Electric vehicle home energy consumption not included here, but have found most underestimate the very large contribution of space and water heating.

https://cdn.fixr.com/ghostblog/2021/09/Residential-Energy-Use-by-Appliance-1.jpg
What Uses The Most Energy in Your Home

Yep, this is what I keep talking about that I see. I use MUCH more energy for my heating with heat pumps compared to AC. A LOT more!! And I have a large house. So while so many love to talk about their zero electric cost, I say one needs to work towards a zero yearly energy cost! I do this with 30kw of solar, 7 batteries and a solar hot water setup which uses a propane water heater when needed. I have a super negative energy bill no matter what temps I keep the house all year long. And I could still charge a number of EV's and still be ahead. I have yet to need to use my 22kw generator in a long time, but if needed, I am ready for the worst of the worst case. Was not cheap, but it is SO nice not having to worry about playing with this setting or that. It just works.

 

[outdoors]

Why does it have to be gas? A wood stove will do the job just fine. If you live in a rural area the only energy cost is a little exercise

Much agreed. So as I was referenced I would say my situation would be considered off grid not using any type of connection.

Off grid living is very different, yet its path to success can be easier if one starts at ground zero on a build. Even from a property selection standpoint up onto and continuing to build.

Our build would be considered rural. I think many are discounting the proper build. A passive home or near passive reduces significantly heating costs, sorry I don't think cooling. So does size of home. Our life is very active, and spread out. We have changed the view of value of home vs. other things in life. So our build is somewhere around 800-1100 sq feet. Will also have an ADU on property that will be used in the summer or winter when one of us isn't there. Also a small generator would be used based on our solar calculations. 4-7 days per month in winter. At the end of the day our solar panels will double from our existing build on other thread, and this year our bank will 60kWh. The propane could be removed if VTH ever happens in Tesla. Much of the power is hydro nearby. In those winter months I could charge and add enough to make it a non issue for those months. Does that remove it from off gridness? I don't know.

I would agree it would be pretty hard to go to most existing homes and try to go net zero or prepare to completely disconnect and expect the same experience. The home and all of its contents were not' meant for it. Sometimes not even the occupants.

Side note. Most of the wood used for us is harvest wood. Not Paul Bunyan chopping down trees. Just a gather on a daily walk on wood that would have burned in a forest fire anyway. I think many envision a rip roaring fire in front of a gigantic fireplace. Burn with efficiency.

 

[DrGriz]

What angle are those panels at? I'm helping @outdoors with an off-grid solar project up north also. We chose a pitch of ~40 degrees for the solar array. Hoping that's a sufficient angle that the snow slides off quickly. Another idea is to basically make a solar 'fence' with the panels at a ~90 degree angle so the snow won't stick at all. Not very useful in the summer but will help a lot in the winter.

Building an off grid Solar Powered (EV charging) Campground​

The installer (who really knows his stuff) shared that the ideal for year-round production pitch is equal to your latitude. For us that is 45 degrees, and the barn is at 43 degrees while the garage is about 40. Sliding depends on temperature, cloud cover, and how soon the sun hits the snow in the course of the day. That is to say, even though sun hitting the panels from the side at 0900 doesn't produce any significant electricity, it starts loosening up the snow so that it slides hopefully before your maximum production for the day. I understand that there are panels now marketed specifically to slide snow. Came after our install, so I can't link or tell you whether they are worth it.

Also, on the low garage, I have a plastic bladed roof rake and sometimes take the time to scrape the snow off the panels myself.

Obviously, like you say, having the panels at the steepest pitch clears them of snow the best, but production is best when the sun is up for the longest. So, you wouldn't want to mount them at 90 degrees. You would end up really cutting your summer production.

 

[DrGriz]

Much agreed. So as I was referenced I would say my situation would be considered off grid not using any type of connection.

Off grid living is very different, yet its path to success can be easier if one starts at ground zero on a build. Even from a property selection standpoint up onto and continuing to build.

Our build would be considered rural. I think many are discounting the proper build. A passive home or near passive reduces significantly heating costs, sorry I don't think cooling. So does size of home. Our life is very active, and spread out. We have changed the view of value of home vs. other things in life. So our build is somewhere around 800-1100 sq feet. Will also have an ADU on property that will be used in the summer or winter when one of us isn't there. Also a small generator would be used based on our solar calculations. 4-7 days per month in winter. At the end of the day our solar panels will double from our existing build on other thread, and this year our bank will 60kWh. The propane could be removed if VTH ever happens in Tesla. Much of the power is hydro nearby. In those winter months I could charge and add enough to make it a non issue for those months. Does that remove it from off gridness? I don't know.

I would agree it would be pretty hard to go to most existing homes and try to go net zero or prepare to completely disconnect and expect the same experience. The home and all of its contents were not' meant for it. Sometimes not even the occupants.

Side note. Most of the wood used for us is harvest wood. Not Paul Bunyan chopping down trees. Just a gather on a daily walk on wood that would have burned in a forest fire anyway. I think many envision a rip roaring fire in front of a gigantic fireplace. Burn with efficiency.

I was inspired to go net-zero (and then, hope for off grid) by a home built next door to an Idaho Power mucky muck who said net zero was "impossible" in our county. The home was, as you suggest, built ground up to be maximally efficient. Of course, they did it, and with far fewer solar panels than we have. Our home is 1980s construction, and we'd have to practically raze it to insulate it to the level I would like. I happened to have room on the outbuildings, and the right angle and directional facing of the roofs, to put in a lot of panels. Also, when it came time to replace the original windows, we went with lowE triple pane, which helps a little. So I have reached net-zero plus.

 

[nwdiver]

The installer (who really knows his stuff) shared that the ideal for year-round production pitch is equal to your latitude. For us that is 45 degrees, and the barn is at 43 degrees while the garage is about 40.

That's true if your goal is to produce the most energy annually but that typically only applies to grid-tied homes. In an off-grid situation it's FAR more critical to maximize production to the time it's used instead of maximizing annual production.

If you're seeking to maximize production in the winter months especially if snow cover is an issue an array at 90 degrees could be very useful. I'm helping a friend in Texas install an array at a ~75 degree angle in a few weeks. It will produce ~30% less annually than one at a ~30 degree angle but he has no net metering and really needs more generation in the winter but has plenty in the summer. This angle will produce ~20% more energy in the winter which is where he needs it most.

 

[DrGriz]

That's true if your goal is to produce the most energy annually but that typically only applies to grid-tied homes. In an off-grid situation it's FAR more critical to maximize production to the time it's used instead of maximizing annual production.

If you're seeking to maximize production in the winter months especially if snow cover is an issue an array at 90 degrees could be very useful. I'm helping a friend in Texas install an array at a ~75 degree angle in a few weeks. It will produce ~30% less annually than one at a ~30 degree angle but he has no net metering and really needs more generation in the winter but has plenty in the summer. This angle will produce ~20% more energy in the winter which is where he needs it most.

I see what you are saying. Yes, steeper slope helps with both snow clearance and winter production. I wouldn't mind having steeper roofs, but they happened to be what they are. Also, they point a little to the southwest, which means morning fog (when it happens) has often cleared by the hours of peak production. Just a thought.

 

[BGbreeder]

That's true if your goal is to produce the most energy annually but that typically only applies to grid-tied homes. In an off-grid situation it's FAR more critical to maximize production to the time it's used instead of maximizing annual production.

If you're seeking to maximize production in the winter months especially if snow cover is an issue an array at 90 degrees could be very useful. I'm helping a friend in Texas install an array at a ~75 degree angle in a few weeks. It will produce ~30% less annually than one at a ~30 degree angle but he has no net metering and really needs more generation in the winter but has plenty in the summer. This angle will produce ~20% more energy in the winter which is where he needs it most.

Hmmm...thanks for the ideas on additional panel locations!

All the best,

BG

 

[zƬesla]

On the snow retention issue, this is where we've lucked out with pole-mounted PV and a crank that allows us to change the vertical angle throughout the year. Mid-winter, the angle is 70 which makes for great snow shedding. And mid-summer we're at 20. Not sure how much extra kW we get out of the adjustments, but it does make me feel like we're optimizing production. This is critical in winter time when the mini-split heat pumps are trying to keep up in freezing temps and we might require as much as 3-4kWh. Once it gets too cold though and mini-splits can't keep up, the oil boiler (used for potable hot water with an indirect tank) is also used for forced hot water heating through baseboards.

 

[DrGriz]

On the snow retention issue, this is where we've lucked out with pole-mounted PV and a crank that allows us to change the vertical angle throughout the year. Mid-winter, the angle is 70 which makes for great snow shedding. And mid-summer we're at 20. Not sure how much extra kW we get out of the adjustments, but it does make me feel like we're optimizing production. This is critical in winter time when the mini-split heat pumps are trying to keep up in freezing temps and we might require as much as 3-4kWh. Once it gets too cold though and mini-splits can't keep up, the oil boiler (used for potable hot water with an indirect tank) is also used for forced hot water heating through baseboards.

I like the concept of pole mounted systems, both for snow management and for sun tracking on a seasonal/daily basis. Does your system track during the day?

Obviously, there is a price to pay in terms of attention and maintenance. But it would probably be worth it in production. We discussed it, but our installer felt that where we had space to do it on our property was prohibitive in terms of cabling, etc, so we went with his advice.

 

[zƬesla]

I like the concept of pole mounted systems, both for snow management and for sun tracking on a seasonal/daily basis. Does your system track during the day?

I purposely did not get the sun tracker to avoid additional parts that can break. The mounts are from Home - MT Solar (see profile photo). The cabling is underground and only required a trench to the house. Much rather have the panels on the mounts rather than on the roof in case maintenance is required and to avoid potential roof issues.

 

[zƬesla]

The tricky part for me is how to handle hot water – both potable and backup forced hot water (baseboard) heating when it's really cold. My current setup is a 30+ year oil boiler and an indirect (potable) hot water tank. I'd love to get something like the Rheem potable water heat pump somehow inline but 1. can't find someone with a good solution on how, and 2. am told that without occasional calls for hot water the boiler is likely to rust inside pretty quick as it'll sit idle/unpressurized for long periods. Guessing the boiler will need to be replaced in the near future given its age but am unsure what to replace it with. Some kind of backup heating is needed and we don't have any gas.

 

[BGbreeder]

The tricky part for me is how to handle hot water – both potable and backup forced hot water (baseboard) heating when it's really cold. My current setup is a 30+ year oil boiler and an indirect (potable) hot water tank. I'd love to get something like the Rheem potable water heat pump somehow inline but 1. can't find someone with a good solution on how, and 2. am told that without occasional calls for hot water the boiler is likely to rust inside pretty quick as it'll sit idle/unpressurized for long periods. Guessing the boiler will need to be replaced in the near future given its age but am unsure what to replace it with. Some kind of backup heating is needed and we don't have any gas.

You might want to look into electrolytic (electronic) anode rod replacements for your boiler. They generate a small current to reduce rusting/corrosion. They are common on commercial systems, but less common on home systems. E.g.

https://www.amazon.com/Corro-ProtecTM-Eliminates-Corrosion-Limescale-Electrical/dp/B07DM2BW6F

Being pressurized isn't the issue for the boiler, it is being exposed to oxygen. There are many ways to reduce or eliminate it, from additives to the water, to gas systems.

I think that adding a heat pump water heater is straight forward. Any reasonable plumber should be able to redo the indirect heater into a HPWH system.

All the best,

BG

 

[charlesj]

...

There are also a outdoor wood fired boilers...

All the best,

BG

More pollution.