Affordable, Efficient Solar Power For Our Homes?

On 10/27/2018 at 1:58 AM, Rasmus Jorgensen said:

Yes and no. 

My argument is actually that you should not compare pros / cons and of installing a solar system to buying from the grid,  but rather compare it to having a diesel generator in the backyard. There are pros and cons to both and they have different economics. Personally, I would think that energy independence would be a massive plus, but downside being uncertainty about the reliabillity of the technology. 

As to reasons for converting - this discussion never made sense to. It can certainly not be boiled down to simply economics. A simple example : when comparing the diesel generator to solar panels - the solar panels are a lot quieter...  

A natural gas generator or micro-turbine would be far quieter. 

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19 hours ago, Refman said:

We recently built a new house and decided to install solar as part of the new construction, plus we also installed wiring and plugs for future EV charging. Last month my electric bill was $21, and it should be lower still this month as we only ran the A/C for a little bit in early October.

Its nice shaking the Utility companies Yoke off your back isn't it?

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5 hours ago, ronwagn said:

A natural gas generator or micro-turbine would be far quieter. 

A couple of people I knew in Oz living out in the sticks were primarily reliant on solar but also put in a micro CHP unit running on LPG (can also run on natural gas. They produce about 2KW of electricity and 3KW of heat. They had LPG for cooking so there was no additional fuel supply costs getting a bit of extra LPG delivered for the Micro CHP. The 3KW of heat was normally used to heat water.  

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9 hours ago, ronwagn said:

The question is how much did it cost for the addition of the solar?  Do you have battery storage that makes you independent of the grid?

I would consider it a great investment for young people who plan to stay in the home a long time, but not for those intending to recoup their investment upon resale. 

Solar was $15K for an 8.2kW system, and does not include a battery storage system. I did look into a battery system but it really doesn't make sense right now. I may look into adding it later when the technology matures and prices come down some more.

This will be our retirement home, so we have plenty of time to recoup investment.

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7 hours ago, ronwagn said:

Off topic Dan, but if we are talking battery backup why not just use a natural gas generator or home sized turbine (I understand they are available in Europe}. You would have to have good workmen available for repairs. Most homes have natural gas already. It seems like it might be much more affordable. It could be very low power if you are always charging the batteries. 

https://www.youtube.com/watch?v=Al8elCF816g micro turbine

See, this where you get into the "you need to want" to go this route because, for me, I want a system that does NOT require me to do much extra.  Aside from that, 400,000 RPMs!!!!!  Wow!  But then they said it generates 400W.  Isn't that pretty low?  My wall mount shower heater uses 6kW.

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(edited)

1 hour ago, Dan Warnick said:

See, this where you get into the "you need to want" to go this route because, for me, I want a system that does NOT require me to do much extra.  Aside from that, 400,000 RPMs!!!!!  Wow!  But then they said it generates 400W.  Isn't that pretty low?  My wall mount shower heater uses 6kW.

The turbines are available in all sizes, I was thinking for a battery system. I doubt solar would work with your shower system without a battery system. 

Edited by ronwagn
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1 hour ago, ronwagn said:

The turbines are available in all sizes, I was thinking for a battery system. I doubt solar would work with your shower system without a battery system. 

I would expect I would be getting hot water from the solar water heating system and storage tanks.

What I meant about the wattage was that the little turbine produces only 400w, which seems quite small for such device to be useful.  Change the example to a hair dryer drawing over a 1000w.

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A regular Natural Gas generator would be far more practical. You can always add a better muffler to quiet it down more.

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On 11/2/2018 at 6:25 AM, ronwagn said:

A natural gas generator or micro-turbine would be far quieter. 

Probably. I do not know that technology. I was just trying to point out alternative pros and cons.. 

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On ‎11‎/‎2‎/‎2018 at 2:36 PM, ronwagn said:

The turbines are available in all sizes, I was thinking for a battery system. I doubt solar would work with your shower system without a battery system. 

No need for expensive batteries when the storage medium is heat.

 Install a hot water cylinder served by a heat pump. That way in a hot climate you will get approx 4kwh of hot water for every kw of electricity.

Run on a time switch in the day time to maximise use of solar power (and get the best efficiency out of the heat pump)

https://australianhotwater.com.au/install-service-repair-systems/heat-pump-water-heaters/

Very common in Oz and much cheaper to run than gas fired water heating.

To get 300 litres from 20 degree C to 60 degrees C you need about 3.5 - 4 kwh of electricity.

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(edited)

On 10/26/2018 at 3:28 PM, Dan Warnick said:

Convert me!

My advice to you is don't install a photovoltaic system. It doesn't make sense in your situation.

That said, I solar water heater system tends to work quite well in your environment, and they can be quite inexpensive. My great grandfather put one on a roof in the 1930s, just a tank on a roof in Florida, painted black to absorb heat. And he was too cheap to bother with a electric/gas/oil backup. And only the first person got a hot bath. Quite a wait on the recharge. But compared to the old farm house with a big pot over a large fireplace, quite an improvement! 

By code a new house were I live now is pre-wired for a grid based solar system, and roof trusses also built anticipating the weight. So the incremental costs to add a system for me, coupled with the local residential electricity rates and net metering, whether to solar or not is a different equation. But the best thing in building the house is building it for efficiency, a much better payback avoiding consumption, not financing production. 

Edited by John Foote
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22 minutes ago, John Foote said:

My advice to you is don't install a photovoltaic system. It doesn't make sense in your situation.

My advice would be to do all the sums, as everywhere will be different.  Next door's roof slopes the wrong way, but they still fitted 2kw pv to their detached garage which slopes opposite to at least get some benefit..

WRT to hot water, a separate solar heater would make sense: Our family installed a "Solarhart" system in Perth in the late 60'sand it's still on the family home 50 years later.

There's not much to a rooftop solar system, but if you don't have electricians that are competent to put one in for you, I would not risk it.  We installed our 5.5Kw pv grid connected system many years ago and have never paid an electricity bill since.  Were I doing the same today, for an extra five thousand dollars I could go completely off grid (inclusive of 9.6Kwh battery storage and a 2Kw backup generator).  Payback for us would be around 6 years.  An idea of local costs is here.  

 

 

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