"What if the power goes out?"

[crokett™]

I have a whole house but manual cutover with a lockout on the breaker panel. Mine is manual because I got the generator used and did not want to rewire the house it came from to take the miswired transfer switch. A new transfer switch would have cost over 1k plus the circuit board on mine was cooked.

[slippy20]

I'm interested in doing something along these lines.  Is your solar system large enough to run your whole house?  Do you sell excess power to, or get a credit from, the power company? How long will the battery last when the power goes out and can you run everything in the house with it or just the critical stuff?  And - how much did it cost? 

Is it mounted on your roof or stand alone?

Its a whole house, grid tied system, so I do sell power back to the utility-in this case PG&E in California.  The battery is rated at 13.5kwh (I think, cant remember exactly) and it will run everything that I need it to, though it maxes at 5kw, 7kw peak...so, some motors can, apparently pose an issue, like A/C. You can simply add batteries, if you want to increase available power There is a good monitoring app, and when we turn some stuff off (like extra lights, mostly), we bumble along at about 3-400 watts, with the toaster oven or coffee maker spiking it to 1500 watts or so.  Neither the fridge, nor the heat exchanger seem to draw very much juice at all. We have even run the electric dryer, with no apparent issues.  Roof mounted solar-8kw system.  Total cost, installed, with permits, and battery included $30k. 

I think I would strongly consider buying one of the electric vehicles available that are capable of powering the house.  The kWh/price ratio is actually very good and one of those would my house for weeks, easy, and if/when it starts to flag, you could drive it somewhere that has juice and drive it home.

[jteneyck]

Its a whole house, grid tied system, so I do sell power back to the utility-in this case PG&E in California.  The battery is rated at 13.5kwh (I think, cant remember exactly) and it will run everything that I need it to, though it maxes at 5kw, 7kw peak...so, some motors can, apparently pose an issue, like A/C. You can simply add batteries, if you want to increase available power There is a good monitoring app, and when we turn some stuff off (like extra lights, mostly), we bumble along at about 3-400 watts, with the toaster oven or coffee maker spiking it to 1500 watts or so.  Neither the fridge, nor the heat exchanger seem to draw very much juice at all. We have even run the electric dryer, with no apparent issues.  Roof mounted solar-8kw system.  Total cost, installed, with permits, and battery included $30k. 

I think I would strongly consider buying one of the electric vehicles available that are capable of powering the house.  The kWh/price ratio is actually very good and one of those would my house for weeks, easy, and if/when it starts to flag, you could drive it somewhere that has juice and drive it home.

Thanks for the info.  The cost was in the ballpark I was thinking of.  Big swag for a system with which you have to make compromises.  I'd like to install a solar system, but if it can't run everything, I'd have to keep the generator, as you have.  It could still be a viable option by cutting my electric bill if the payback was something less than 7 years or so, but that seems unlikely since I only use about $1000 in electricity/year.  How did you justify it?  Huge rebate?  

Thanks again.

John

[slippy20]

Thanks for the info.  The cost was in the ballpark I was thinking of.  Big swag for a system with which you have to make compromises.  I'd like to install a solar system, but if it can't run everything, I'd have to keep the generator, as you have.  It could still be a viable option by cutting my electric bill if the payback was something less than 7 years or so, but that seems unlikely since I only use about $1000 in electricity/year.  How did you justify it?  Huge rebate?  

Thanks again.

John

So first off, I understand that the cost of fuel and electricity varies widely be region of the country, for a lot of different reason.  This likely affects the calculus, as does a property's solar disposition and climate.

The year before the system was installed, my electric bill was just shy of $2400.  We have made choices to use electricity where we used to use fuel. Since we installed the system, we added an electric car which my wife commutes in.  The system totally generates the energy to power her car.  That car gets driven just over 10k miles a year.  So-its about a 7-8 year pay back for me.  The system should last +/- 25 years, so 18 years or so of free electricity.

This doesn't include adjustments for inflation of the price of electricity, which I am guarded against.

This year Uncle Sam will be giving me about $8k for the solar installation (which is also not included in the pay back above).

One more thing about when "the power goes out", it costs a premium to run a generator, because a generator can't adjust to the load.  Most of my neighbors burned up over 100 gallons of propane.  I paid $0.  Thats also not factored in, above.

But...honestly, installing the system wasn't really based on a financial strategy.   Its a bonus that it works out well from that perspective.

[jteneyck]

So first off, I understand that the cost of fuel and electricity varies widely be region of the country, for a lot of different reason.  This likely affects the calculus, as does a property's solar disposition and climate.

The year before the system was installed, my electric bill was just shy of $2400.  We have made choices to use electricity where we used to use fuel. Since we installed the system, we added an electric car which my wife commutes in.  The system totally generates the energy to power her car.  That car gets driven just over 10k miles a year.  So-its about a 7-8 year pay back for me.  The system should last +/- 25 years, so 18 years or so of free electricity.

This doesn't include adjustments for inflation of the price of electricity, which I am guarded against.

This year Uncle Sam will be giving me about $8k for the solar installation (which is also not included in the pay back above).

One more thing about when "the power goes out", it costs a premium to run a generator, because a generator can't adjust to the load.  Most of my neighbors burned up over 100 gallons of propane.  I paid $0.  Thats also not factored in, above.

But...honestly, installing the system wasn't really based on a financial strategy.   Its a bonus that it works out well from that perspective.

Yeah, that's a big difference in electricity cost/year, but I suspect our total energy costs are more heavily weighted on my end.  If I didn't burn wood to heat my house in the Winter, the natural gas bill would be on the order of at least $1500 and probably over $2K, so there you are.   

Generators don't run at full power under low load.  They are just like other constant rpm motors, they flex their fuel consumption in proportion to the load.  But for a few hours, even a few days, I could care less how much fuel it uses, natural gas I my case, so I don't have to worry about how much is in the tank.  I have full use of everything in my house.  The generator cost $7K all in.  That will pay for a lot of natural gas until I hit the difference in price to your system.  Don't get me wrong, I want to install a solar system.  But I don't want to make compromises and the numbers have to make sense.  I can see myself going with something smaller, something that will pay for itself in less than 7 years, but still need the generator during power outages.  I'd be OK with that since I already have the generator.  My combined cost might be similar to yours then, with the benefit of no compromises, though it sounds like you would have none either if you chose to run the generator.  

Thanks for the added input.   

John