Green / Eco-Friendly

Solar + Battery for new construction off the grid - feasible? Possible?

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  • Jul 16th, 2017 9:55 pm
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Solar + Battery for new construction off the grid - feasible? Possible?

Hi All,

Close friend of mine has property in a somewhat rural area and is in early planning stages for building a hose. There's currently zero services at the property.

For all heating and cooling, including heated floors, he's likely going to be doing geothermal.

For electrical, he loves the idea of using solar in addition to the grid. However he's learning that the cost from the local utility to get electrical service to his property is going to be over $30,000. If a minimum of $30,000 is going to be spent, I start to wonder if it's feasible or even possible to put that towards solar and batteries and have no electrical service at the property from the local utility.

Now, I assume a lot of work will be needed to get an idea of what capacity would be necessary. I'm curious about a product like the Tesla Powerwall, though not sure if it's even officially available in Canada.

If this is feasible at all - multiple power walls and many solar panels, I imagine it will be quite expensive. Curious though - any thoughts how how feasible or even possible something like this would be?

Any feedback is appreciated!
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Feb 28, 2015
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He'll never be able to produce enough power off grid for the geothermal+ power the house. Unless he has more money than brains he might want to scrap this idea immediately.
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skoalman123 wrote:
Feb 12th, 2017 8:26 pm
He'll never be able to produce enough power off grid for the geothermal+ power the house. Unless he has more money than brains he might want to scrap this idea immediately.
Thanks for the reply.. I guess.

I never said that he has this idea and wants to do it, I'm merely trying to learn if it's even a feasible option.
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skoalman123 wrote:
Feb 12th, 2017 8:26 pm
He'll never be able to produce enough power off grid for the geothermal+ power the house. Unless he has more money than brains he might want to scrap this idea immediately.
I wouldn't say never. Since he is in the early stages of designing a house, he has options to deploy in the design stages... sure, it will cost more initially but with the craziness of hydro rates and probability that they won't be going anywhere but up in the next few years, the initial cost might be feasible depending on how long he plans to stay in the house.

Here's a link to a firm that builds net-zero houses (produces as much energy as it consumes in a year) in Calgary - http://mattamyhomes.com/calgary/communi ... -zero.aspx. While many of the things used might be a bit 'nuts' in terms of payback, there's probably a few good ideas that can be employed to increase efficiency since the house is at the design stage.
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As for something like a Tesla PowerWall, you don't need to go for the cost of one of those... People have been using batteries in solar installations for decades. The PowerWall just made it sexy in a small space. I'm assuming that since the property is out in the middle of nowhere with no services, the land was relatively cheap and lots of it was available. If that's the case, spend the money on old tech batteries as they would be cheaper to deploy now rather than going with what's sexy.
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skoalman123 wrote:
Feb 12th, 2017 8:26 pm
He'll never be able to produce enough power off grid for the geothermal+ power the house. Unless he has more money than brains he might want to scrap this idea immediately.
Rural person here with a 3 year old geothermal system here. I use about 100kW per day during the winter and 60kW per day during the summer.

I got several quotes for a grid tie system (aka no batteries) that would zero out my usage for $60k-75k. Batteries and charge controller would bring the total to at least $100k.

I pay about $6k a year in hydro so my repayment is around 10 years given hydro costs will just keep going up.

There are a lot of rural areas where a hydro hookup cost can cost $20k+
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I'm late to the party but geothermal, off grid and 30K is not going to work.

First ditch the geothermal and heated floors (you don't need them), and insulate above code to bring heating loads to net zero or better levels. Get an expert to design the building who specializes in this type of efficiency.
Some information (don't depend on this, just for inspiration)
https://buildingscience.com/documents/i ... zeroing-in

Next heat with minisplits depending on location. Some models will work well below -20C and are vastly cheaper then geothermal

Third, solar power is great and batteries are available, 30K is a bit tight but a powerwall or even deep cycle lead acid for now (can upgrade later) is feasible, again hire someone to plan this out who has experience in this area. The savings from the heating/cooling bills, lack of geothermal and heated floors can double that to 60K or more, that will cover the batteries needed.

You want to understand how much energy will be used by figuring out usage patterns now and planning for them, and reducing power usage in order to bring down system cost. You can build a solar/battery system for any price, be it 1K, 10K, 30K, 50K or 100K. It all depends on how much juice you need to generate and store.
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How big is this house? If it's 6,000 sq.ft vs 1,200sq.ft will make a pretty sizable difference. Also, how many people are plausibly living in it?
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Thanks for all the replies. Much appreciated.
craftsman wrote:
Feb 13th, 2017 1:42 pm
As for something like a Tesla PowerWall, you don't need to go for the cost of one of those... People have been using batteries in solar installations for decades. The PowerWall just made it sexy in a small space. I'm assuming that since the property is out in the middle of nowhere with no services, the land was relatively cheap and lots of it was available. If that's the case, spend the money on old tech batteries as they would be cheaper to deploy now rather than going with what's sexy.
Not completely in the middle of nowhere, definitely rural, but just minutes way from the city and areas with services. Definitely don't need what's sexy, just referenced powerwalls as I'm not familiar with other battery options.

Quentin5 wrote:
Mar 21st, 2017 3:33 am
I'm late to the party but geothermal, off grid and 30K is not going to work.

First ditch the geothermal and heated floors (you don't need them), and insulate above code to bring heating loads to net zero or better levels. Get an expert to design the building who specializes in this type of efficiency.
Some information (don't depend on this, just for inspiration)
https://buildingscience.com/documents/i ... zeroing-in

Next heat with minisplits depending on location. Some models will work well below -20C and are vastly cheaper then geothermal

Third, solar power is great and batteries are available, 30K is a bit tight but a powerwall or even deep cycle lead acid for now (can upgrade later) is feasible, again hire someone to plan this out who has experience in this area. The savings from the heating/cooling bills, lack of geothermal and heated floors can double that to 60K or more, that will cover the batteries needed.

You want to understand how much energy will be used by figuring out usage patterns now and planning for them, and reducing power usage in order to bring down system cost. You can build a solar/battery system for any price, be it 1K, 10K, 30K, 50K or 100K. It all depends on how much juice you need to generate and store.
Thanks for the info. Geothermal seems like such a good option though. I'll search and look at minisplits. Curious what this is.
ChubChub wrote:
Mar 22nd, 2017 6:41 pm
How big is this house? If it's 6,000 sq.ft vs 1,200sq.ft will make a pretty sizable difference. Also, how many people are plausibly living in it?
It's approaching 6000 sq ft in size. I know, definitely significant in size and won't be easy to power/sustain off the grid.
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Bawler wrote:
Feb 23rd, 2017 9:50 am
Rural person here with a 3 year old geothermal system here. I use about 100kW per day during the winter and 60kW per day during the summer.

I got several quotes for a grid tie system (aka no batteries) that would zero out my usage for $60k-75k. Batteries and charge controller would bring the total to at least $100k.

I pay about $6k a year in hydro so my repayment is around 10 years given hydro costs will just keep going up.

There are a lot of rural areas where a hydro hookup cost can cost $20k+
Thanks for the info. Good to get a rough idea. So you never went with the batteries as well then? Crazy using 100kWh on a winter day, though not surprising.
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Bawler wrote:
Feb 23rd, 2017 9:50 am
Rural person here with a 3 year old geothermal system here. I use about 100kW per day during the winter and 60kW per day during the summer.

I got several quotes for a grid tie system (aka no batteries) that would zero out my usage for $60k-75k. Batteries and charge controller would bring the total to at least $100k.

I pay about $6k a year in hydro so my repayment is around 10 years given hydro costs will just keep going up.

There are a lot of rural areas where a hydro hookup cost can cost $20k+
Your talking 30,000 kWh a year in electricity :facepalm:
A well designed house can use far less then this with just electric resistance heating and an energy star central air :rolleyes:
joey003 wrote:
Mar 22nd, 2017 6:57 pm
Thanks for all the replies. Much appreciated.

Not completely in the middle of nowhere, definitely rural, but just minutes way from the city and areas with services. Definitely don't need what's sexy, just referenced powerwalls as I'm not familiar with other battery options.

Thanks for the info. Geothermal seems like such a good option though. I'll search and look at minisplits. Curious what this is.

It's approaching 6000 sq ft in size. I know, definitely significant in size and won't be easy to power/sustain off the grid.
Building a 6000 sq ft house but 30K in solar/storage won't work. And geothermal works but its cost is astronomical. Paying 30K for a grid connection will likely be peanuts compared to the price of this house, we are talking million or two million dollar house here. My money is on over two million especially with geothermal and battery power

Geothermal is intuitively enticing but the economics are usually poor.
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Quentin5 wrote:
Mar 23rd, 2017 3:41 am
Your talking 30,000 kWh a year in electricity :facepalm:
A well designed house can use far less then this with just electric resistance heating and an energy star central air :rolleyes:



Building a 6000 sq ft house but 30K in solar/storage won't work. And geothermal works but its cost is astronomical. Paying 30K for a grid connection will likely be peanuts compared to the price of this house, we are talking million or two million dollar house here. My money is on over two million especially with geothermal and battery power

Geothermal is intuitively enticing but the economics are usually poor.
No no - not trying to squeeze all the solar/storage in 30K. Was just thinking about putting the cost of 30K grid connection towards solar instead (knowing full well that solar/storage necessary could probably hit 100K).

For geothermal, I've seen some pretty interesting quotes that are economically quite feasible.
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joey003 wrote:
Mar 23rd, 2017 6:23 am
No no - not trying to squeeze all the solar/storage in 30K. Was just thinking about putting the cost of 30K grid connection towards solar instead (knowing full well that solar/storage necessary could probably hit 100K).
I do not understand, what are you planning to do?
For geothermal, I've seen some pretty interesting quotes that are economically quite feasible.
Its rarely, rarely cost effective, cost overruns are common and operating it is energy intensive which means lots of money.
If your committed to doing it then nothing i say will dissuade you but the cost effectiveness is almost always a lie when you take lifetime costs into account.

From the sounds of this project it would be cheaper to buy 2-3 houses in Toronto
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Quentin5 wrote:
Mar 23rd, 2017 6:37 am
I do not understand, what are you planning to do?


Its rarely, rarely cost effective, cost overruns are common and operating it is energy intensive which means lots of money.
If your committed to doing it then nothing i say will dissuade you but the cost effectiveness is almost always a lie when you take lifetime costs into account.

From the sounds of this project it would be cheaper to buy 2-3 houses in Toronto
Well, it's not my project, just trying to give some advice to a friend. Most likely what they're doing is a grid tie in for electrical and geothermal for heating/cooling.

My thoughts were around the feasibility of putting 30K toward solar/storage and attempting no grid tie in, but with the size of the house and the electricity required I figured it would be very expensive or not feasible.

Definitely not the price of 2-3 Toronto houses, lol.

Not committed to anything yet. But I have a hard time seeing how the cost effectiveness is a lie. Been trying to get multiple quotes for geo as well as propane based systems + AC for heating/cooling. Long term the cost of geo seems to win out easily. Is there something else long term that would affect operation or maintenance beyond regular consumption?

Btw, definitely agree to the insulation topic you mentioned earlier. Funny, the article from building science you posted earlier I had seen a few years back. Definitely looking at some of these options for insulating.
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joey003 wrote:
Mar 23rd, 2017 7:28 am
Well, it's not my project, just trying to give some advice to a friend. Most likely what they're doing is a grid tie in for electrical and geothermal for heating/cooling.

My thoughts were around the feasibility of putting 30K toward solar/storage and attempting no grid tie in, but with the size of the house and the electricity required I figured it would be very expensive or not feasible.

Definitely not the price of 2-3 Toronto houses, lol.

Not committed to anything yet. But I have a hard time seeing how the cost effectiveness is a lie. Been trying to get multiple quotes for geo as well as propane based systems + AC for heating/cooling. Long term the cost of geo seems to win out easily. Is there something else long term that would affect operation or maintenance beyond regular consumption?

Btw, definitely agree to the insulation topic you mentioned earlier. Funny, the article from building science you posted earlier I had seen a few years back. Definitely looking at some of these options for insulating.
Sorry your friend's project
I'm not certified in this area but 6000 sq ft @ 200 sq/ft is 1.2 million dollars. Someone correct me if this is too low or high for custom rural construction.
Heating that is easily 75,000 kWh/year, he will want to insulate above code thats more money times 6000sq ft. Get someone who is certified to run numbers but insulation is usually cheaper then energy at a 25 year payback period. The equivalence point would be an interesting calculation.
Lets assume he uses 20,000 kWh a year in plug loads for such a large house, which is 1666.66kWh/month
If we go with 100kWh a day mentioned above for the geothermal system plus our monthly usage, and assume you want 1 week of backup (i would go with two weeks but lets say one) you would need 1100kWh of powerwalls. Thats 79 power walls, costing $7800 CAD each plus hardware, Tesla's site only goes up to 9 powerwalls for $70,200 and $3200 in hardware. So you need a powerpack, which they do have, the estimate for 1100kWh is $778,620
Glad i checked this out, 2 Toronto houses is not looking so bad! Face With Tears Of Joy
I'm going to stop here, we are already at 2 million dollars!
So i won't calculate costs for more insulation above code or geothermal costs or how much solar power will cost (COP 3 plus 20kWh times say $4/watt at maybe 1100 hours of sun a year), if your friend has 2 million to blow already he is loaded!

Edit: Heating may end up at 100,000kWh/year or even more, depends on a few factors but i think the point is well made.

Edit 2: I made a mistake on the powerpacks, reducing to 1140kWH total is only $778,620, cutting my estimate in half
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