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

[RKCRLR]

My daily solar production drops from an average of 62 kWh in June to 15 kWh in December, with many days close to zero in winter. I would need to significantly upsize my system to get through winter even though I have 3 Powerwalls. I have dual fuel heat pump/propane and a wood stove for heat, a tankless propane water heater, a gas dryer, and a gas stove. I have frequent power outages in the winter and wouldn't consider converting anything else to all electric (perhaps the dryer). I'll go 100% electric when my power becomes 100% reliable.

 

[BGbreeder]

My daily solar production drops from an average of 62 kWh in June to 15 kWh in December, with many days close to zero in winter. I would need to significantly upsize my system to get through winter even though I have 3 Powerwalls. I have dual fuel heat pump/propane and a wood stove for heat, a tankless propane water heater, a gas dryer, and a gas stove. I have frequent power outages in the winter and wouldn't consider converting anything else to all electric (perhaps the dryer). I'll go 100% electric when my power becomes 100% reliable.

I hear you. Resiliency is important. We are considering more electric, but also ramping up generator systems, plural, to meet the winter demand. It would be 1,000% easier if Tesla supported generator charging off grid...

All the best,

BG

 

[h2ofun]

My daily solar production drops from an average of 62 kWh in June to 15 kWh in December, with many days close to zero in winter. I would need to significantly upsize my system to get through winter even though I have 3 Powerwalls. I have dual fuel heat pump/propane and a wood stove for heat, a tankless propane water heater, a gas dryer, and a gas stove. I have frequent power outages in the winter and wouldn't consider converting anything else to all electric (perhaps the dryer). I'll go 100% electric when my power becomes 100% reliable.

I have 30 kw system. I make 185kwh in best, and now about 32kwh. I have a large 99% electric house. I could double the size of my solar and still could not cover the heat pumps and EV. Just not possible with only electric real time

 

[nwdiver]

I have 30 kw system. I make 185kwh in best, and now about 32kwh. I have a large 99% electric house. I could double the size of my solar and still could not cover the heat pumps and EV. Just not possible with only electric real time

You don't need twice as much solar... you just need some solar that's aligned better for winter production. I've started a solar fence in my backyard. It's doing great this time of year. They're producing >50% more than my rooftop panels.

 

[skepticcyclist]

You don't need twice as much solar... you just need some solar that's aligned better for winter production. I've started a solar fence in my backyard. It's doing great this time of year. They're producing >50% more than my rooftop panels.

So just having the ability to tilt your panels to align with the winter sun angle will be enough for most people?

Of course you would still need to consider the shorter total sunlight hours and weather by region (west coast rainy season is winter, so winter is also has fewer sunny days than summer on the west coast.)

 

[nwdiver]

So just having the ability to tilt your panels to align with the winter sun angle will be enough for most people?

Of course you would still need to consider the shorter total sunlight hours and weather by region (west coast rainy season is winter, so winter is also has fewer sunny days than summer on the west coast.)

Solar panels are cheap enough that it's not worth the effort of tilting the panels, just have more. Literally just bolting them to an existing brick wall. Cheap and effective. With cooler temperatures they also perform better AND mounting them vertically further assists in lowering the temperature to improve performance. When solar was >$0.50/w it made sense to maximize the annual yield per watt. I'm seeing solar at ~$0.25/w fairly regularly. AND you can often use your existing inverter to just add capacity. Vertically mounted panels aren't going to be curtailed as much since their production seasonally compliments the existing system.

Researchers shed light on mysterious, higher energy yields in vertical PV systems​

 

[sunwarriors]

Are there any bad/fossil fuel power options that isn't the old school generator? What else is out there? For generators, since they are the known working solution, how much does it cost to even run them regularly for all your needs if one was off grid and how much fuel does it actually take? I haven't experienced outages much at all so maybe someone else can chime in.

During the winter, the IOUs in CA aren't just going with solar neither I don't think.

If there was a robust solution for no sun, no matter how bad/dirty, then at least that's a solution if someone truly wanted to test off grid. I think most typical residential homes just aren't designed for it since a roof can't hold a lot of panels for most people.

I know I can't add much more panels to my home.

 

[kpanda17]

I'm curious how many of you can go Off Grid in the Winter. I have 11.8 kW solar with 3 PWs and no way I can stay off grid in Winter. For example, I used 1100 kWh in December.
If you can go multiple days off grid in winter, please state your PV size and # of PWs

I’m in a usa, house New England cape style
It’s an avg size two story house with four bedroom and two baths
Electric Load: 2x EVs, central AC, LED lighting, work from home laptops and monitors, electric range oven
Gas load: dryer, gas range oven and gas heat
Avg electric use 20,000 kWh per year
My size roof can only produce 13,000 kWh per year
Therefore only 67% coverage
I cannot even convert washer/dryer to heat pump, range to 100% electric and heat/AC to heat pump for the coverage gets worse

Lesson learned with solar, buy a wide one story house for max solar panel count and best chance for 100% off grid coverage
I have to buy a different house

 

[nwdiver]

a roof can't hold a lot of panels for most people.

I know I can't add much more panels to my home.

I've started a solar fence in my backyard. It's doing great this time of year. They're producing >50% more than my rooftop panels.

Literally just bolting them to an existing brick wall. ..... Vertically mounted panels aren't going to be curtailed as much since their production seasonally compliments the existing system.

Researchers shed light on mysterious, higher energy yields in vertical PV systems​

 

[kpanda17]

How about bleeding edge new more efficient panels? How far do they go beyond rhe 400 watts for a 78”x40” panel?

 

[BGbreeder]

Are there any bad/fossil fuel power options that isn't the old school generator? What else is out there? For generators, since they are the known working solution, how much does it cost to even run them regularly for all your needs if one was off grid and how much fuel does it actually take? I haven't experienced outages much at all so maybe someone else can chime in.

During the winter, the IOUs in CA aren't just going with solar neither I don't think.

If there was a robust solution for no sun, no matter how bad/dirty, then at least that's a solution if someone truly wanted to test off grid. I think most typical residential homes just aren't designed for it since a roof can't hold a lot of panels for most people.

I know I can't add much more panels to my home.

I think that this is one of the "it depends" answers, but here goes.

You could power your generator with renewable fuel (biogas/methane, biodiesel, DME, ethanol, or even methanol). Not without issues, but it is completely doable.

Old school diesel generators run 0.7-1.2gal/hr, so at least $0.38/kWh on fuel costs, plus capital, and service costs. If you have a large generator idling along at 10% of capacity, it won't be happy and your cost/kWh could easily be ten times that number.

Inverter generators do a better job of matching fuel consumption to power produced, but at the end of the day the cost/kWh is similar, while the capital, and service costs are higher than old school. (Reliability is a TBD in my book.) If you run gasoline, figure 20% higher fuel costs.

Natural gas and propane prices are very local, and affect the costs dramatically. Whether they are reasonable sources in an emergency depends. As the fairly recent Texas freezes showed, natural gas isn't entirely reliable, and cost lots of Texans when it wasn't available. So, I think that you have to factor in that it may not always be available when you need it. (Ditto earthquakes) Enough propane to get through a prolonged outage can require truly enormous amounts of fuel, in part due to the inefficiency of energy conversion in generators, and storing that much compressed hydrocarbon fuel is not without fire risks.

I tend to think that these issues aren't yes/no, true/false, and are perhaps best handled by multiple, overlapping, solutions for the greatest resiliency, but that is rarely straightforward.

All the best,

BG

 

[CrazyRabbit]

What about the ecoflow generator which puts out dc 48-58.8v and connecting to solar inverter to charge powerwalls.

EcoFlow Smart Generator (Dual Fuel) - Smart Generator (Dual Fuel) - EcoFlow

Smart Generator (Dual Fuel) will be shipped in mid-October. • Dual Fuel: gasoline and LPG • 20kWh capacity with standard LPG tank for worry-free backup power • Save 40% of fuel by connecting to DELTA series and Power Kits • Remotely control and real-time monitor using the app • 4 ways to start •...

us.ecoflow.com

 

[SageBrush]

I'm seeing solar at ~$0.25/w fairly regularly. AND you can often use your existing inverter to just add capacity. Vertically mounted panels aren't going to be curtailed as much since their production seasonally compliments the existing system.

Creative idea for DIY'rs

 

[doghousePVD]

Are there any bad/fossil fuel power options that isn't the old school generator? What else is out there? For generators, since they are the known working solution, how much does it cost to even run them regularly for all your needs if one was off grid and how much fuel does it actually take? I haven't experienced outages much at all so maybe someone else can chime in.

During the winter, the IOUs in CA aren't just going with solar neither I don't think.

If there was a robust solution for no sun, no matter how bad/dirty, then at least that's a solution if someone truly wanted to test off grid. I think most typical residential homes just aren't designed for it since a roof can't hold a lot of panels for most people.

I know I can't add much more panels to my home.

Very expensive to use typical generators. Direct fuel cost is typically 50¢ to $1/kWh. Small generators (propane or gasoline) usually have a useful life of 1,000 to 3,000 hours before uneconomic rebuild or replacement. Oil change every 50-100 hours.

Industrial diesel generators last much longer and are more efficient. Figure over $10 grand.

In some places (not many) wind may be able to supplement solar. Last time I looked residential wind equipment was not reliable or economic. The vast majority of residential wind turbines are merely kinetic sculptures.

YMMV

I live totally off grid and gave up using generators years ago.

 

[JMGNC]

My 9KW system produces at best 20KWH daily in late fall-winter-early spring. So I'm good until i charge the EV at about 50KWH every few days.

 

[Grayson73]

If you have 1:1 net metering, you could send thousands of kWh to the grid in the summer and use those in the winter, correct?

 

[Jeremy3292]

If you have 1:1 net metering, you could send thousands of kWh to the grid in the summer and use those in the winter, correct?

Not many people have 1:1 net metering anymore or yearly netting. Almost every utility has changed that for their own benefit and if people do have it, it is a legacy grandfathered plan.

 

[holeydonut]

I want to add a wind turbine to my system sooooo bad. It would make a massive difference in the winter which is high in wind and low in light. But it's hard to know exactly what would work well with the system and I think the cost would be too much.

I think TMC-Energy-Products should crowdsource a wind turbine and get @Vines to try and install it so he can learn the ins-and-outs… then we all add stealth turbines with his learnings. Then I’ll get a nasty-gram from my HOA.

 

[BGbreeder]

I think TMC-Energy-Products should crowdsource a wind turbine and get @Vines to try and install it so he can learn the ins-and-outs… then we all add stealth turbines with his learnings. Then I’ll get a nasty-gram from my HOA.

Nice thought, but wind power is not a panacea in my opinion.

Wind power has surprisingly little power below 15mph sustained wind speed (+/-), so very, very few sites will be practical sources of wind power, as the available power goes roughly as the cube of wind speed, with many caveats.

Wind-turbine aerodynamics - Wikipedia

en.wikipedia.org

Wind Energy and Power Calculations | EM SC 470: Applied Sustainability in Contemporary Culture

There are lots of choices, but having enough year round, or at least wintertime wind I think is important.

All the best,

BG

 

[holeydonut]

Nice thought, but wind power is not a panacea in my opinion.

Wind power has surprisingly little power below 15mph sustained wind speed (+/-), so very, very few sites will be practical sources of wind power, as the available power goes roughly as the cube of wind speed, with many caveats.

Wind-turbine aerodynamics - Wikipedia

en.wikipedia.org

Wind Energy and Power Calculations | EM SC 470: Applied Sustainability in Contemporary Culture

There are lots of choices, but having enough year round, or at least wintertime wind I think is important.

All the best,

BG

Ok then let's get Vines one of these things. It's zero-emissions so it'll qualify as a clean energy source under California NEM! Alternatively we can just park a Toyota Mirai on a treadmill in his yard and have someone put a brick on the go-pedal.

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