777 replies to this topic

[Tom Braybrook]

...looks like this...

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[Mike K.]

Wowzers, 6x the power during the peak of summer.

[LeoVictoria]

Posted Today, 12:30 PM

dasmo, on 13 Mar 2019 - 10:55 AM, said:
hydro - photovoltaic, hot water - single panel on roof (gas backup), woodstove for heat (gas furnace backup seldom use), stove gas. big house - gutted and insulated on purchase 5 yrs. ago, new windows, doors, etc.

solar install was $13K - GIC pays 2%, say $260/yr - hydro bill was $55/month, now $0, plus $300 surplus sale back to BCHydro - net $700/year or 5.5% roi - (all numbers approximated)

started this as a reply to electric car charge tax, will cross post anything else at https://vibrantvicto...-sources/page-9

What’s the total kW capacity of your system. You said 14 panels but how many Watts each?

[Tom Braybrook]

What’s the total kW capacity of your system. You said 14 panels but how many Watts each?

325 watt x 14 = 4.55 kWh

 

a sunny day in august in pic

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Edited by tommy, 13 March 2019 - 12:23 PM.

[dasmo]

 

...looks like this...

 

That's better. Thanks so far!

[dasmo]

Our house is 100% electric including heat - everything. Family of four and we have been having Work-Away guests pretty consistently so that's another two people part time. Our monthly consumption is around 520 kWh at the low and and 2600 kWh at the peak.  So I would need a crap ton more panels to make any impact. 

We also have a septic system and a water pump for the well on this too. I have yet to investigate how much energy the water pump uses.

[LeoVictoria]

325 watt x 14 = 4.55 kWh

 

a sunny day in august in pic

 

Nice.  Capacity factor is normally assumed to be 1100 in Victoria (yielding 5005 kWh/year) but you are exceeding that.  

[LeoVictoria]

Our house is 100% electric including heat - everything. Family of four and we have been having Work-Away guests pretty consistently so that's another two people part time. Our monthly consumption is around 520 kWh at the low and and 2600 kWh at the peak.  So I would need a crap ton more panels to make any impact. 

We also have a septic system and a water pump for the well on this too. I have yet to investigate how much energy the water pump uses.

 

Impact of panels is always constant.   Getting to zero net is a purely arbitrary target.  In fact impact is higher at Step 2 consumption levels.

[LeoVictoria]

 

Posted Today, 12:30 PM

dasmo, on 13 Mar 2019 - 10:55 AM, said:

hydro - photovoltaic, hot water - single panel on roof (gas backup), woodstove for heat (gas furnace backup seldom use), stove gas. big house - gutted and insulated on purchase 5 yrs. ago, new windows, doors, etc.

 

solar install was $13K - GIC pays 2%, say $260/yr - hydro bill was $55/month, now $0, plus $300 surplus sale back to BCHydro  - net $700/year or 5.5% roi - (all numbers approximated)

 

started this as a reply to electric car charge tax, will cross post anything else at https://vibrantvicto...-sources/page-9

 

 

 

 

A small niggle about this calculation.   You are assuming that the system lasts forever.  It doesn't of course, but you can expect at least 25 years out of it.  

 

I wrote an article ( https://househuntvic...se-in-victoria/ )

and developed a spreadsheet ( https://househuntvic...7/10/Solar.xlsx ) to calculate real return from solar a little while back.  

 

With your system amortized over 25 years (taking into account diminishing capacity of panels and increasing hydro rates at historically normal levels), return is about 2% per year.   So about the same as a GIC.    Of course that is assuming that the whole system is worth zero after 25 years, which is unlikely to be true but it's quite possible you need to replace some inverters at that point so it gets hard to predict.

Edited by LeoVictoria, 13 March 2019 - 01:51 PM.

[dasmo]

Impact of panels is always constant.   Getting to zero net is a purely arbitrary target.  In fact impact is higher at Step 2 consumption levels.

Good point about simply reducing the amount of step 2 consumption. Would need to look at that because of course we don't cross that barrier until there is less sun to generate power. 

Thanks for the spreadsheet FYI...

Edited by dasmo, 13 March 2019 - 02:22 PM.

[LeoVictoria]

Good point about simply reducing the amount of step 2 consumption. Would need to look at that because of course we don't cross that barrier until there is less sun to generate power. 

Thanks for the spreadsheet FYI...

 

Aren't you shaded anyway?   

 

As for step 2, you don't benefit during the summer, but assuming you generate a net positive in the summer months, you will still earn those credits and they will be applied in the fall when you get into step 2 rates. 

[Tom Braybrook]

A small niggle about this calculation.   You are assuming that the system lasts forever.  It doesn't of course, but you can expect at least 25 years out of it.  

 

I wrote an article ( https://househuntvic...se-in-victoria/ )

and developed a spreadsheet ( https://househuntvic...7/10/Solar.xlsx ) to calculate real return from solar a little while back.  

 

With your system amortized over 25 years (taking into account diminishing capacity of panels and increasing hydro rates at historically normal levels), return is about 2% per year.   So about the same as a GIC.    Of course that is assuming that the whole system is worth zero after 25 years, which is unlikely to be true but it's quite possible you need to replace some inverters at that point so it gets hard to predict.

thanks for the links - they look good

 

the calculation was a reply to an "ish" request as in approximate numbers - i have never done the actual calcs but will plug numbers into your spreadsheet and see what comes out (did it - 3.23%  returnwith 2018 numbers, paid off in 14 years, cost of hydro lower than hydro rate after 12 years)

 

i am guessing hydro rates will go up a little faster than historical, but even at 2% as you suggest it at least equals the GIC - and saving after-tax dollars.

and as you said, the system will have some residual which if plugged back in to formula would increase real return,  n'est-ce pas?

[LeoVictoria]

thanks for the links - they look good

the calculation was a reply to an "ish" request as in approximate numbers - i have never done the actual calcs but will plug numbers into your spreadsheet and see what comes out (did it - 3.23% returnwith 2018 numbers, paid off in 14 years, cost of hydro lower than hydro rate after 12 years)

i am guessing hydro rates will go up a little faster than historical, but even at 2% as you suggest it at least equals the GIC - and saving after-tax dollars.
and as you said, the system will have some residual which if plugged back in to formula would increase real return, n'est-ce pas?

Yup. Will be interesting to see how hydro costs evolve. You’re probably right that they will increase faster than the historical average given we have to pay for site C and the deferral accounts.

[dasmo]

Aren't you shaded anyway?   

 

As for step 2, you don't benefit during the summer, but assuming you generate a net positive in the summer months, you will still earn those credits and they will be applied in the fall when you get into step 2 rates. 

Not full shade but rather part shade. In the summer I think the roof might not get a lot of that tree shade though.  It was more that it affected my solar gain through the windows come wintertime. I have four trees in front. I am 15 deg of of due south though. But yes, I might have even more shade at the roof level in the winter because the sun is lower. 

[Tom Braybrook]

Yup. Will be interesting to see how hydro costs evolve. You’re probably right that they will increase faster than the historical average given we have to pay for site C and the deferral accounts.

...you wouldn't happen to have a formula for wood heat - one that takes into account wood splitting, chiropractor, massage and physio for these old bones - would you? ;-)

[LeoVictoria]

...you wouldn't happen to have a formula for wood heat - one that takes into account wood splitting, chiropractor, massage and physio for these old bones - would you? ;-)

Haha. My brother put in a wood stove a while back. A year later he put in a heat pump as well.

Well you always have that spare $300 worth of power you can use towards one

My parents house is entirely heated by wood. And since I am not a high level government bureaucrat with access to a log splitter I did a lot of chopping growing up.

[dasmo]

Haha. My brother put in a wood stove a while back. A year later he put in a heat pump as well.

Well you always have that spare $300 worth of power you can use towards one

My parents house is entirely heated by wood. And since I am not a high level government bureaucrat with access to a log splitter I did a lot of chopping growing up.

It wasn't only my crappy lungs that stopped me from putting in a wood stove. I also chopped a LOT of wood growing up.  

[Mike K.]

I currently chop a lot of wood

[LJ]

A small niggle about this calculation.   You are assuming that the system lasts forever.  It doesn't of course, but you can expect at least 25 years out of it.  

 

I wrote an article ( https://househuntvic...se-in-victoria/ )

and developed a spreadsheet ( https://househuntvic...7/10/Solar.xlsx ) to calculate real return from solar a little while back.  

 

With your system amortized over 25 years (taking into account diminishing capacity of panels and increasing hydro rates at historically normal levels), return is about 2% per year.   So about the same as a GIC.    Of course that is assuming that the whole system is worth zero after 25 years, which is unlikely to be true but it's quite possible you need to replace some inverters at that point so it gets hard to predict.

When I went to the Tesla presentation they expected inverters to last about 10 years, but some had been failing after just 2 years. They are guaranteed for 10. 

[LeoVictoria]

Depends on the product. Enphase microinverters have a 25 year warranty. Whether the product and the company will actually last that long is another matter...