Author Topic: Going Solar  (Read 5436 times)

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Offline Billzbub

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Re: Going Solar
« Reply #75 on: November 29, 2018, 03:56:39 PM »
Thanks guys for the discussion.  I agree with you and told the saleswoman that I'd have to wait a few years.

After crunching the numbers, I pay an average of $97 per month in electricity alone.  The 29 solar panels she quoted me were based on my electricity usage over the last 2 years and are meant to give me just enough KWh credits to cover that usage 100%.  If the panels generate more, then I start building a bank of KWh credits that I can't change into money or into credit for the gas portion of my bill (which is actually significant after all).

At this point, I'm definitely not taking out a 12 year loan with $137 monthly payments just to take $97 off my power bill just so I don't have to pay for electricity starting in 12 years.  The sales lady was telling me to look at it over 20 years and it would make sense, but I need that money now for my kids in college.  I will look at it again in 3 years or so.  Maybe the prices of solar panels will come down and the price of electricity will go up so that it makes better sense.
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gleefully altering one’s beliefs to accommodate new information should be a badge of honor

Offline Alex Simmons

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Re: Going Solar
« Reply #76 on: November 29, 2018, 10:43:25 PM »
I think that is a wise choice.

I'm still amazed at how much more expensive a solar PV system is over there though.

Offline Alex Simmons

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Re: Going Solar
« Reply #77 on: December 04, 2018, 10:23:49 PM »
So while the system I installed has been going for nearly 6 weeks, the "official" start date is somewhat later as that begins when the energy retailer upgraded the meter box with smart meters (for main circuits and also one for the off-peak hot water circuit).

So in the first 15 days since then my electricity costs have dropped from $13.58/day to $2.97/day.

Keep in mind $1.73 of that is a flat daily fee for being connected to the grid.

Offline Billzbub

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Re: Going Solar
« Reply #78 on: December 05, 2018, 03:37:03 PM »
If you had one more solar panel, would you be selling back enough electricity to have a zero bill, or would that fee still be charged to you and you'd just be building credits for a rainy day?
Quote from: Steven Novella
gleefully altering one’s beliefs to accommodate new information should be a badge of honor

Offline Alex Simmons

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Re: Going Solar
« Reply #79 on: December 05, 2018, 11:38:13 PM »
If you had one more solar panel, would you be selling back enough electricity to have a zero bill, or would that fee still be charged to you and you'd just be building credits for a rainy day?

Well I can go bigger but my export power output is limited to 9kW, so once my system starts putting out 9kW more than I am using, it automatically caps the export. I have 11kW of panels with a 10kW inverter. At present it's rare to have export capped as during peak production times I'll have pool pump going + other house stuff.

Occasionally I do hit the limit of my inverter 10kW.

It's typical to oversize panels by 133% of the inverter size but spending another $1.5 - $2k to have another 8 panels seemed overkill.

It's also a function of roof space and azimuth alignment of panels - you need to be careful how the panels strings are set up. I already have 40 panels on the roof.

Offline Alex Simmons

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Re: Going Solar
« Reply #80 on: March 12, 2019, 07:24:08 PM »
Bit of an update.

I've plotted a cumulative daily total of what my bill would have been without our solar PV system, what we actually pay, and also what we could have been paying if we were on a different electricity plan, being Time Of Use (TOU) charging.

The start date is set to the day the energy retailer's smart meter was commissioned (even though we had the system in operation for 24 days up to that point, and this was worth $330 of savings on our bill).



For the time period in the chart (113 days), the savings so far are $1,222, an average of $10.81/day.

The additional saving we might have achieved on a TOU plan is $190, an average of $1.68/day.

If I add the $330 of savings made during the 24 days before the retailer's smart meter was commissioned, so far our savings have been $1,552 over 137 days, an average of $11.33/day.

Keep in mind this period is Summer here. As we move into Autumn the daily saving will drop a little, but so will our bills. Mainly because of the reduction in use of air conditioning, which is our single biggest component of our energy demand.

Offline daniel1948

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Re: Going Solar
« Reply #81 on: March 12, 2019, 09:19:37 PM »
I will be having solar put on my new house and the cottage as soon as the installer can get the necessary permit from the electric utility. The utility will not buy my excess electricity because it is fully subscribed. With electric rates of $36 cents per kWh, solar is popular here. I'll get two PowerWalls for the house and one for the cottage to go along with the PV panels. I don't care about the ROI or the cost comparison. I just want to have solar. (I already have solar hot water, on both the house and the cottage.) My renter (in the cottage) is happy because her electric bill will disappear. And her puppy will be happy because he's a happy puppy. (I just had to throw that in.)
Daniel
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Offline daniel1948

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Re: Going Solar
« Reply #82 on: March 31, 2019, 04:24:43 PM »
I provided the solar installer with the paperwork he needs to start the application process before I left. Hopefully he'll have the permits around the time I get back there. It would have been more economical to get a slightly smaller system. Having enough capacity for my peak needs at the height of the summer heat is more expensive than drawing a little power from the grid for the peaks, but I hate fossil fuels, and though Maui has some wind power (I can see the windmills on the West Maui Mountains from my living room) it still burns a lot of fuel oil that is brought in by tanker ships. Just because I want to minimize the burning of oil, I'm spending a bit more to be able to produce all my own electricity. That will also mean that I'll have power when there are outages. I'm going to have something like 32 high-efficiency panels on the house, with two Powerwalls, and I think 16 panels and one Powerwall on the much smaller cottage. Of course, I will be charging my car in the daytime instead of at night. That would be a problem if I spent a lot of time driving, but I don't. And with 310 miles of range, or 250 miles if I baby the batteries by only charging to 80%, I could go days without charging if I had to.
Daniel
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Offline Alex Simmons

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Re: Going Solar
« Reply #83 on: March 31, 2019, 08:30:25 PM »
I'm going to have something like 32 high-efficiency panels on the house, with two Powerwalls, and I think 16 panels and one Powerwall on the much smaller cottage.
How much are Powerwalls there?

A Powerwall 2 installed here is ~A$14k.

Offline daniel1948

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Re: Going Solar
« Reply #84 on: March 31, 2019, 08:58:29 PM »
I'm going to have something like 32 high-efficiency panels on the house, with two Powerwalls, and I think 16 panels and one Powerwall on the much smaller cottage.
How much are Powerwalls there?

A Powerwall 2 installed here is ~A$14k.

I think they're around US$10K each, but I don't have the price breakdown in front of me. I just wanted to have plenty of capacity, both generation and storage, and was willing to pay whatever it cost.
Daniel
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"Anyone who has ever looked into the glazed eyes of a soldier dying on the battlefield will think long and hard before starting a war."
-- Otto von Bismarck

Offline Alex Simmons

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Re: Going Solar
« Reply #85 on: April 01, 2019, 01:37:02 AM »
I'm going to have something like 32 high-efficiency panels on the house, with two Powerwalls, and I think 16 panels and one Powerwall on the much smaller cottage.
How much are Powerwalls there?

A Powerwall 2 installed here is ~A$14k.

I think they're around US$10K each, but I don't have the price breakdown in front of me. I just wanted to have plenty of capacity, both generation and storage, and was willing to pay whatever it cost.
OK, yowser!

All the best with it. Would love to add a battery but the prices are so high.

I've been tracking my solar PV system's performance and financial impact.

This is where I'm up to:



The "With Solar PV" line is what I'm currently paying for electricity compared with the "No Solar" option. I am also tracking what would have happened had I been on a different type of fee structure - time of use - and it turns out it will be a good choice for us to change plans to TOU.

A battery just isn't worth it for us. At the moment it's got a payback of 50 years! It's also slightly greener to send the power back to the grid than to charge a battery (our grid is dominated by coal fired power).

Offline daniel1948

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Re: Going Solar
« Reply #86 on: April 01, 2019, 09:21:24 AM »
The grid in Maui is also dominated by fossil fuel, but it's oil rather than coal. However, solar is so popular there that the grid is now fully subscribed for plans that feed back in. New home solar cannot feed back to the grid (AFAIK). So without batteries I would pay full price (around 35 or 36 cents/kWh) for night time power. If they will accept my excess power, I'll give it to them for nothing, because that would reduce the burning of oil, but I don't think they will.

The entire cost of the solar installation is very small compared to the cost of the house, so once I got the best price I could on the house, adding as much solar as I could possibly need was a no-brainer. I'm very fortunate to be able to afford the house (and the solar) but unfortunate in having nobody to share it with. (All the women I know think I'd be a really good husband... for somebody else. That is, I've got all the qualities you're "supposed" to want in a partner, but none of the qualities anybody actually wants in a partner. All of which is by way of saying that I no longer feel any guilt at all about having enough money to buy a very nice house in paradise and buying a bigger solar installation than pure economics would dictate. I've become cynical and a bit of a misanthrope.)
Daniel
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"Anyone who has ever looked into the glazed eyes of a soldier dying on the battlefield will think long and hard before starting a war."
-- Otto von Bismarck

Offline Alex Simmons

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Re: Going Solar
« Reply #87 on: April 01, 2019, 04:53:07 PM »
I recall reading some years ago that places in Hawaii had reached peak solar PV for the grid to be able to cope and so new installations were prevented from exporting (it's a setting in the inverter). Hopefully we will get better in the future at management of distributed production. Batteries are definitely one solution for this in locations with high net energy generation costs.

Given your lack of feed-in tariff, export ban and the high cost of oil generated grid power, then batteries make much more economic and environmental sense.

For a PW2 you'll do well to get 30,000kWh out of it over 10 years (I guess you'll do less since you have several of them, prob depends on how much evening air con you run). But at 30,000kWh, given they are $10k installed, that's 33.3c/kWh, which is a touch less than your current cost of grid power.

For me the difference between grid import and export tariff is less than US10c/kWh, which is why batteries don't make financial sense for most Australians. There are a few places where the numbers are closer to being financially plausible, but not for the vast majority and only after some generous state govt incentives.

Of course as you outline, financial considerations are not the only factor. For them to make environmental sense then the battery has to store solar PV that would not otherwise offset fossil fuel generation. In Australia, there are export power limits on domestic solar PV systems but they are not zero (except for some isolated examples). Most on single phase can export up to 5kW, those on 3-phase usually quite a bit more, up to 30kW. I'm permitted to export up to 9kW. Hence excess daytime solar PV production is already offsetting fossil fuels here.

Then there are other reasons for purchase of such systems, not everything is about the money. In your case though, the money is about break even and the environmental benefit is definitely there, which is great - every bit helps us all. And you'll also get UPS level of grid outage backup if the PW2s are installed with the right firmware and set up right. Easier if on single phase power. On 3-phase it's more complicated (you can only back up one phase per PW2 - they don't have a 3-phase solution at present).

Offline daniel1948

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Re: Going Solar
« Reply #88 on: April 01, 2019, 09:49:31 PM »
I just know it's something I've wanted for decades, and now that I can, I'm going all-out.
Daniel
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"Anyone who has ever looked into the glazed eyes of a soldier dying on the battlefield will think long and hard before starting a war."
-- Otto von Bismarck

Offline Alex Simmons

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Re: Going Solar
« Reply #89 on: April 01, 2019, 10:26:18 PM »
Speaking of Maui's dependence on oil generated electricity, I read this item today about recent approvals for grid scale solar PV and storage projects in Hawaii, including on Maui:
https://www.hawaiianelectric.com/six-low-priced-solar-plus-storage-projects-approved-for-oahu-maui-and-hawaii-islands

On Maui a 60MW solar PV farm + 240MWh of storage, with an energy cost of 8c/kWh.

So like so many places now, the costs of the technology has fallen so much that a rapid transition to renewables is increasingly feasible, and becoming a no-brainer in locations with an expensive dependence on fossil fuel generation.

 

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