Author Topic: Going Solar  (Read 5450 times)

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Offline Alex Simmons

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Re: Going Solar
« Reply #15 on: September 18, 2018, 05:36:57 PM »
Thought I'd revive an old thread. Just to share my experience so far.

I've been going through the process of working towards solar power for our home. It's been quite an interesting exercise with various layers. Our annual electricity bill is $4000+.

The quote process was an experience as was the technical assessment and learning on my part. Being a home with 3-phase power meant some extra complications on the technical solution, particularly as I want a system to be ready to be able to integrate battery storage for the future and with technology that will enable battery storage to provide power to all 3 phases. That as it turns out is not as simple as it sounds. It's doable of course but the costs increase, so innovation in solutions was something I was looking for.

Then there has been getting our home "solar ready". By that I mean a roof that was made more suitable for the task of capturing photons. Before installing solar we wanted to do roof restoration work and repainting (the roof was a bit tired looking and the colour wasn't doing the home justice), and before that we needed to also do some tree felling and lopping. We had one massive gum tree that needed to come down. That was a heck of project in itself.

The tree work has been done and the roof restoration work is happening this week.

Which means I'll be pulling the trigger on the solar installation soon.

I'm going for an 11kW system with a suitable 3-phase inverter with smart monitoring system and have scoped it to be battery ready if ever the financial cost/benefit for a battery makes sense. While I can almost make battery storage work financially, the pay back period is still a bit too high a proportion of the warrantied life of the battery solution. Plus there is still a fair bit of an unknown with actual energy use patterns since we have dumb meters and only really know our quarterly usage patterns for last couple of years.

So gathering detailed time of day electricity usage data for each day over the course of a year or two will help with the modelling of whether battery storage makes sense and also some extra time for battery storage prices to fall.

I had quotes from three reputable installers and I gave them all a brief on the characteristics I was after and as much power usage history as I had (9 quarters of data). We are also located in a rural area and so there are some other considerations with respect to feed in capacity and distance to nearest transformer. They all visited to see the site and were all very good in assessing the issues.

Even so, the solutions suggested were actually reasonably different. The total power output capacity was similar for each solution but the technology and configurations varied. I've learned all about 3-phase inverters, hybrid inverters, micro inverters, layout configurations, monitoring systems, feed in limitations and approval processes, various battery options and so on (there are quite a few as it turns out but solutions for 3-phase power are much more limited).

I build a financial model to do the numbers and created as many relevant input factors as I could. Some factors are predictable such as the rate of solar panel efficiency decline over the years or the amount of solar generation for my location, others less predictable such as longer term grid power prices, so it will be interesting to see how well or not that turns out in real life. I also made an assumption about the proportion of self generated power we will use, factoring in we have some ability to reprogram some usage to daylight hours (especially pool pumps).

My assessment of NPV using a 6% investment comparison basis is being in the black by year 5 and a 10 year IRR of 25%.
On a straight cash basis payback period is 4 years.

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Re: Going Solar
« Reply #16 on: September 18, 2018, 07:20:50 PM »
Why do you need 3-phase power at your house?

Offline The Latinist

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Re: Going Solar
« Reply #17 on: September 18, 2018, 07:55:29 PM »
Yeah, I’ve never heard of anyone having three-phase power in their home.
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Offline BilLumberg

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Re: Going Solar
« Reply #18 on: September 18, 2018, 08:29:40 PM »
5 Years does not sound bad. Are there any websites that you would recommend for learning more about solar power. I have been interested for a while, but have yet to do the homework. 

Offline bachfiend

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Re: Going Solar
« Reply #19 on: September 18, 2018, 08:34:02 PM »
Yeah, I’ve never heard of anyone having three-phase power in their home.

When I was installing more solar panels on my house, the first question my installer asked was whether my house was three-phase or single-phase, and to send him a photo of the meter for him to determine.  So three-phase isn’t uncommon in domestic use (its apparently more energy efficient than single-phase).

I don’t remember whether I’ve got three-phase or single-phase.

I installed more solar panels in order to recharge the electric car when I eventually buy it.  Actually, I currently have far too many panels.  Towards the end of Winter, they’re generating some days more than 30 kW.hr per day (I actually use very little electricity - usually around 3 kW.hr per day).  At least I can think that the excess electricity going to the grid will be my carbon offset for when I fly to the other side of the world, which I do once a year.

I thought about batteries very briefly before rejecting them.  They don’t make any sense in a practical sense (storing excess electricity in batteries and then using it later loses at least 15% of the energy) let alone financially.  It’s better, on a global warming mitigation basis, to put excess electricity into the grid and reduce the electricity coming from fossil fuels.
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Offline The Latinist

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Re: Going Solar
« Reply #20 on: September 18, 2018, 08:43:33 PM »
At least in this area it is extremely rare; as I said, I’ve never heard of anyone having 3-phase power.  When I was looking at houses, I saw none with 3-phase power. Hell, in this area 3-phase power isn’t even available to business customers in many places. 
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Offline Alex Simmons

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Re: Going Solar
« Reply #21 on: September 18, 2018, 08:48:31 PM »
Why do you need 3-phase power at your house?
It's wasn't a question of need. The house had 3-phase already when we bought it. While most homes have single phase power, 3- (and 2-) phase is not all that uncommon here.

The property did have an old run down builder's workshop which had some 3-phase power outlets so I assume a prior owner had some equipment requiring the additional power capacity 3-phase can supply. I've since rebuild the shed into a mancave and retained a couple of 3-phase outlets. Who knows when/if they'll become handy?

Offline Alex Simmons

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Re: Going Solar
« Reply #22 on: September 18, 2018, 08:55:28 PM »
5 Years does not sound bad. Are there any websites that you would recommend for learning more about solar power. I have been interested for a while, but have yet to do the homework.
What are you looking to learn?

While the technology for domestic application will be similar across the world, there would be considerable differences in the local legislative environment, financial returns and the arrangements for connection of your domestic solar to the grid.

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Re: Going Solar
« Reply #23 on: September 18, 2018, 09:13:56 PM »
Yeah, I’ve never heard of anyone having three-phase power in their home.
Why do you need 3-phase power at your house?

I know people who have 3-phase, to power home workshop equipment. I know a bunch of blacksmiths and craftspeople who use machines that require 3-phase.
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Offline Alex Simmons

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Re: Going Solar
« Reply #24 on: September 18, 2018, 09:49:19 PM »
Yeah, I’ve never heard of anyone having three-phase power in their home.

When I was installing more solar panels on my house, the first question my installer asked was whether my house was three-phase or single-phase, and to send him a photo of the meter for him to determine.  So three-phase isn’t uncommon in domestic use (its apparently more energy efficient than single-phase).

I don’t remember whether I’ve got three-phase or single-phase.

I installed more solar panels in order to recharge the electric car when I eventually buy it.  Actually, I currently have far too many panels.  Towards the end of Winter, they’re generating some days more than 30 kW.hr per day (I actually use very little electricity - usually around 3 kW.hr per day).  At least I can think that the excess electricity going to the grid will be my carbon offset for when I fly to the other side of the world, which I do once a year.

I thought about batteries very briefly before rejecting them.  They don’t make any sense in a practical sense (storing excess electricity in batteries and then using it later loses at least 15% of the energy) let alone financially.  It’s better, on a global warming mitigation basis, to put excess electricity into the grid and reduce the electricity coming from fossil fuels.
The cost-benefit of battery storage is a little complex and is something requiring individual assessment.

Much depends on the price you pay for grid power, the price you get for selling any excess power to the grid and how each varies with time of day. And the cost of the installed battery of course.

For example, where I live the grid power price during peak period is nearly 4 times the price of off-peak power.
The solar power feed in tariff (what you can sell your excess to the grid for) is less than the off-peak power price and has no time of day variance.

Peak power pricing occurs during early evening and corresponds with little to zero solar power production.

So use of stored battery power during peak period may or may not make sense depending on how much the battery energy costs over its lifetime.

So for example - rather than send excess solar to the grid and only get $0.12/kWh, instead store into a battery and use it to offset power requirements when the grid price is $0.55/kWh.

Once I have better time of day usage data then I'll be able to build a model to assess the cost-benefit and scale a battery to suit.

Currently here in Australia battery storage is still ~$1200 per kWh of battery capacity installed. With a 10 year warranty and reducing to 80% capacity after 10 years, that's paying $0.365 / kWh over its warrantied lifetime assuming a full charge/discharge cycle once every day on average. That is quite a bit less than the peak power price, so that might seem to make sense.

However that's a pretty generous assumption on the average rate of full charge/discharge cycles, being once per day. If you are less generous in the assumed cycle rate you achieve, say once every two days on average then battery power now costs $0.73/kWh over its warrantied lifetime and it's now a more expensive way to pay for your peak period power needs.

The actual cycle rate will depend on the size of the battery, the "solar weather" patterns,how much power you use during the peak period and so on. You also need to consider whether you can actually use all the stored energy within the peak period. Some batteries have low power outputs and might be oversized for the job.

This is why having time of day usage data is really important, as is the ability to have a battery properly scaled to your usage patterns. The solution I have gone with will enable me to add battery storage in increments of 2.4kWh, so I can scale the system to maximise the battery cycle rate and be focused on providing my own power when the grid price is very high.

Above are $A, not $US.

Offline bachfiend

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Re: Going Solar
« Reply #25 on: September 19, 2018, 12:14:28 AM »
Yeah, I’ve never heard of anyone having three-phase power in their home.

When I was installing more solar panels on my house, the first question my installer asked was whether my house was three-phase or single-phase, and to send him a photo of the meter for him to determine.  So three-phase isn’t uncommon in domestic use (its apparently more energy efficient than single-phase).

I don’t remember whether I’ve got three-phase or single-phase.

I installed more solar panels in order to recharge the electric car when I eventually buy it.  Actually, I currently have far too many panels.  Towards the end of Winter, they’re generating some days more than 30 kW.hr per day (I actually use very little electricity - usually around 3 kW.hr per day).  At least I can think that the excess electricity going to the grid will be my carbon offset for when I fly to the other side of the world, which I do once a year.

I thought about batteries very briefly before rejecting them.  They don’t make any sense in a practical sense (storing excess electricity in batteries and then using it later loses at least 15% of the energy) let alone financially.  It’s better, on a global warming mitigation basis, to put excess electricity into the grid and reduce the electricity coming from fossil fuels.
The cost-benefit of battery storage is a little complex and is something requiring individual assessment.

Much depends on the price you pay for grid power, the price you get for selling any excess power to the grid and how each varies with time of day. And the cost of the installed battery of course.

For example, where I live the grid power price during peak period is nearly 4 times the price of off-peak power.
The solar power feed in tariff (what you can sell your excess to the grid for) is less than the off-peak power price and has no time of day variance.

Peak power pricing occurs during early evening and corresponds with little to zero solar power production.

So use of stored battery power during peak period may or may not make sense depending on how much the battery energy costs over its lifetime.

So for example - rather than send excess solar to the grid and only get $0.12/kWh, instead store into a battery and use it to offset power requirements when the grid price is $0.55/kWh.

Once I have better time of day usage data then I'll be able to build a model to assess the cost-benefit and scale a battery to suit.

Currently here in Australia battery storage is still ~$1200 per kWh of battery capacity installed. With a 10 year warranty and reducing to 80% capacity after 10 years, that's paying $0.365 / kWh over its warrantied lifetime assuming a full charge/discharge cycle once every day on average. That is quite a bit less than the peak power price, so that might seem to make sense.

However that's a pretty generous assumption on the average rate of full charge/discharge cycles, being once per day. If you are less generous in the assumed cycle rate you achieve, say once every two days on average then battery power now costs $0.73/kWh over its warrantied lifetime and it's now a more expensive way to pay for your peak period power needs.

The actual cycle rate will depend on the size of the battery, the "solar weather" patterns,how much power you use during the peak period and so on. You also need to consider whether you can actually use all the stored energy within the peak period. Some batteries have low power outputs and might be oversized for the job.

This is why having time of day usage data is really important, as is the ability to have a battery properly scaled to your usage patterns. The solution I have gone with will enable me to add battery storage in increments of 2.4kWh, so I can scale the system to maximise the battery cycle rate and be focused on providing my own power when the grid price is very high.

Above are $A, not $US.

Agreed - if your prime concern is in saving money, then very considerable analysis of the economics of installing batteries and the changing tariffs during the day are very important.  If your prime consideration is global warming mitigation, not so much.  In Perth, we don’t have smart meters yet.  Electricity is charged at around 28 cents/ kW.hr regardless of the time of the day.  When I installed an extra 16 solar panels, I lost the 40 cents/kW.hr feedin tariff, leaving just 7 cents/kW.hr for excess electricity exported to the grid instead of 47 cents (I knew that was going to happen).

It’s advised that if you should use electrical devices while the sun is shining in order to reduce your electricity bill.  I don’t bother with that - using just 3 kW.hr of electricity it hardly makes any great difference financially.

I’m still amazed at how the Australian government is so global warming denialist.  Crikey.com this morning noted that Scott (Old Man Coal) Morrison (the new prime minister) is even more denialist than Tony (‘climate science is crap’) Abbott.
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Offline Alex Simmons

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Re: Going Solar
« Reply #26 on: September 19, 2018, 04:09:10 AM »
The reduction on CO2 emissions (most of our power comes from coal) is a nice side benefit but the reality is financial considerations are primary, as they will be for the majority of people using power in Australia.

If you are in Australia and have non-shaded roof real estate that you own, then solar is a bit of a no brainer provided you can fund the up front costs.

Those for whom environmental considerations are primary will first be reducing their power usage as much as possible.

Offline moj

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Re: Going Solar
« Reply #27 on: September 19, 2018, 06:20:28 AM »
a little off topic but If I had the money would love to get one of these solar powered catamarans, a captains license and spend the rest of days in the Caribbean picking up fares when needed, lounging a lot. Sure its a huge upfront cost but not having to pay for fuel on a boat is a huge cost saver.

http://www.solarwave-yachts-pacific.com/


Offline bachfiend

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Re: Going Solar
« Reply #28 on: September 19, 2018, 06:31:47 AM »
The reduction on CO2 emissions (most of our power comes from coal) is a nice side benefit but the reality is financial considerations are primary, as they will be for the majority of people using power in Australia.

If you are in Australia and have non-shaded roof real estate that you own, then solar is a bit of a no brainer provided you can fund the up front costs.

Those for whom environmental considerations are primary will first be reducing their power usage as much as possible.

There aren’t many products that you can buy the cost of which the government subsidises.  My current system is a 6 kW one and cost only around $4500.  It was the third similar system I’d purchased this year - the other two were on residential properties I own.  I think they make the rental properties easier to rent.

If you believe (as I do) that AGW is real and likely to have serious effects, then it’s also necessary to make sacrifices.  Not that the sacrifices were difficult in my case.
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Offline Alex Simmons

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Re: Going Solar
« Reply #29 on: September 19, 2018, 07:19:15 AM »
The most effective thing I can do wrt AGW is to vote for politicians who will enact rational energy and environmental policies.

Yes, domestic solar receives some govt incentives, however total government handouts and support to the fossil fuel industry are many times greater. While that policy imbalance remains, it means significant inertia to effective action to address AGW will persist in Australia.

Tied up with that is the upfront cost of domestic solar, even with incentives, means a large number of people simply cannot afford it. Of course many live in apartments and solar is simply not an option.

In any case, my investment should not only be financially beneficial but also reduce my carbon emissions by about 60%. If I can sort through the battery conundrum then that might extend to a 90% reduction.

 

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