Floating solar panels

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#2174065 6-Feb-2019 17:10

afe66: The idea of covering our lakes with solar panels is a definite no for me. Lakes aren't wasted space.

We have probably tens of millions square meters of industrial roof tops without anything on them.
Panel these. This has added benefit of already being connected to power grid and not need cables and infrastructure to be built near lakes.

Auckland Council recently put a tender out to look at using their buildings for exactly this purpose given they have a significant property portfolio.

It incls both roof surfaces for for generation and also walls for storage / batteries.

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richms

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#2174066 6-Feb-2019 17:14

When I got my solar and it all looked good to use all the power it made and get a decent payback timeframe it was based on a high per unit charge.

Now that I am on a 17c (or thereabouts plan) per kwh and I get the monthly report from enlighten about what the inverters say they have made (I still have no way to confirm this information with an alternate meter etc) and I multiply it out and see that the solar took $50 or $60 on a good month off the powerbill it all seems a bit pointless.

Sure, I would have needed the roof redone eventually, and that was about 40% of the total cost for getting the solar in, but even without that the return is stuff all.

Add batteries in if I wasnt using all the power during the day and it becomes even more pointless.

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#2174067 6-Feb-2019 17:15

Main issue for me with PV right now is that the payback period doesn't quite stack up for any personal use case i have done the nos. on. Much like EV's.

BUT!

This is changing rapidly with panel supply costs dropping significantly over recent years.

I look forward to the day when the payback/NPV stacks up and I have a solar tile roof + battery storage.

+ Tesla Roadster to complete the package - dreams are free :)

richms

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#2174069 6-Feb-2019 17:20

The install price isnt dropping however. I have found that now if I want to add more microinverters to my install, I will have to add some gateway box between the breakers and the roof which is now legally required on new installs, and also there was some change with how the cable has to be run. This is even if I was to add more panels to a totally different building and they were talking about all the inverters have to run back via the same single gateway box.

Then there is the cost to vector to get them to "permit" you to install them. Which is absurd since they don't require you to beg permission to use power. And then all the scaffolding costs, etc etc to just chuck some panels up on the roof and get them wired in.

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tdgeek

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#2174085 6-Feb-2019 17:35

If the payback period was say 12 years that’s 8% per annum. Good value. But they are guaranteed for 25 years albeit at probably a slight reduction in input. That’s 12 years of a sound investment and then 13 years at savings on zero investment. And they won’t fail at 25 years might go another 5 or 10.

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#2174089 6-Feb-2019 17:43

driller2000:
Main issue for me with PV right now is that the payback period doesn't quite stack up for any personal use case i have done the nos. on. Much like EV's.

I think there's a real future to Vehicle-to-grid, in particular parked outside large commercial facilities.

https://en.wikipedia.org/wiki/Vehicle-to-grid

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#2174101 6-Feb-2019 18:34

kingdragonfly:
driller2000:

Main issue for me with PV right now is that the payback period doesn't quite stack up for any personal use case i have done the nos. on. Much like EV's.

I think there's a real future to Vehicle-to-grid, in particular parked outside large commercial facilities.

https://en.wikipedia.org/wiki/Vehicle-to-grid

I looked into this a while back, although it was just a few Googles.

What I took from it was... its harmful to the battery as an EV battery is not designed for this. Theoretically, if you discharge the EV battery at night into the house, its just "driving" at night. But it seems that type of usage doesn't work well for the battery. Maybe its the level of usage into the house? I cannot recall, but the end result was its not good for it.

There must be many who are just short of justifying PV or EV, and if you can use the EV as a battery, and also use the PV as a charger, that surely must bridge the gap for many? It's well worth looking into, Im not electrically minded, but I definitely recall it was a bad idea. If thats the case, there may be seen gadget that can make it more EV friendly? It wasn't just a case of more cycles = battery decline, it did go beyond that I'm sure

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#2174107 6-Feb-2019 18:43

Watched part of your video, it backs up what I said, we need special bi directional charging, which currently is too expensive. Interesting how they mentioned Uber and AirBNB to share energy.

Aredwood

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#2174156 6-Feb-2019 21:12

Best case round trip efficiency listed in that wikipedia page, was 70% So 30% electrical losses combined with more battery wear. V2G struggles to stack up economically. Even if you can get the power for free, once it has charged and discharged a battery. That power is then more expensive than just buying grid power.

Some people might charge their EV for free from a public charger, then run their house using that power. But the savings will be due to leaching the subsidies that give us free EV charging. And from not paying your fair share of lines fees.

Free EV charging won't be around forever. Especially as other drivers who need to get somewhere won't like having to wait to charge their EV. When the chargers are all occupied by the leaches.

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#2175172 8-Feb-2019 19:43

The Energy Storage Disruption
Tony Seba

"The outcome of the Clean Disruption is that by 2030

• Centralized Power Generation will be disrupted.

• Peaking Power Plants (Peakers) will be obsolete.

• All new vehicles will be electric.

• All new vehicles will be autonomous (self-driving).

• Oil will be obsolete.

• Coal, natural gas and nuclear will be obsolete.

• 80+ per cent of parking spaces will be obsolete.

• Individual car ownership will be obsolete.

• All energy will be provided by solar (and wind)"

SomeoneSomewhere

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#2175541 9-Feb-2019 16:50

Grid to vehicle and back is, IMHO, simply too damaging and inconvenient to consider doing with a personal car. Low efficiencies is one issue, but you also have problems with battery wear from all the charge-discharge cycles, and the chances of wanting to use your vehicle and finding it's 2/3 empty.

It might be more palatable with large vehicle pools. Still questionable and I think would need regulatory overhaul.

I am surprised there aren't more supermarkets and similar with solar, given the typically tens of kW base load for lighting and chillers, every day of the year, peaking when the sun does. Low cost per kWh of grid power at that scale I guess.

raytaylor

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#2181043 15-Feb-2019 17:30

I am a great supporter of the idea that

- any new house built in NZ should have a north facing roof
- any new house built in NZ 5 bedrooms or larger should have at least a 1.5kw solar system installed

More solar production during the day reduces our demand on hydro so the lake levels dont drop as fast
Hydro can then fill in for the evening peaks as the lakes are higher for longer

Excess solar could go into pumped hydro storage which is basically a big battery. Pumped hydro storage is typically about 70 to 80% efficient and well used in the UK

Ray Taylor

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richms

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#2181086 15-Feb-2019 19:12

I am opposed to any installation of solar being forced onto anyone building a house. It is entirely up to them to decide if it is suitable or not.

For someone who isnt home during the day and would be forced to spend on the gear and then export to the grid at $sfa per kwh it would be a huge additional cost to building that would possibly make the whole project unaffordable.

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#2181144 15-Feb-2019 23:29

raytaylor:
I am a great supporter of the idea that

- any new house built in NZ should have a north facing roof
- any new house built in NZ 5 bedrooms or larger should have at least a 1.5kw solar system installed

More solar production during the day reduces our demand on hydro so the lake levels dont drop as fast
Hydro can then fill in for the evening peaks as the lakes are higher for longer

Excess solar could go into pumped hydro storage which is basically a big battery. Pumped hydro storage is typically about 70 to 80% efficient and well used in the UK

UK has nuclear power that needs to run 24/7 So pumped hydro is something that can use that output during off peak times. In NZ there is either plenty of water in the hydro system, so why use water just to pump water, only to use that water later? Or there is not enough water (like currently) Meaning that you would have to use fossil fuel generation to get the power for the pumped storage. Lots more carbon emissions.

The hydro generators are only holding back water at the moment, as they are worried about a power shortage in winter. There is not going to be a summer electricity shortage.

Pumped hydro only makes economic sense, if you assume that the input power is free. In reality, it never is free. You still have to spend big money building a large dam. Then where would you build it where you can get lots of fresh water, without taking water from other hydro generators?

Load Management is far far cheaper as a method of managing peak demand. compared to building pumped hydro or peaking generators. Load Management and time of use is easy to implement via the smart meters. But then the stupid low user regulations make it virtually impossible to do so, while still giving a proper incentive to shift load.

Solar has stuff all output, unless all panels have full direct sun. So lots of houses will never be suitable for solar due to hills, trees, other buildings etc. Nevermind that doing so will just make new houses more expensive. When they are already too expensive. Meaning any savings on the power bill will be wiped out by extra purchase and interest costs to buy the house.

raytaylor

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#2181145 15-Feb-2019 23:58

In some winters, lake levels get quite low so it makes sense to hold back as much of that water as possible.

During the day, solar can be used to run the grid, more water is left in the lakes. Over a month or two that can make a big difference to lake levels, and delays the possibility of needing more dams to be built as no matter where you try and build a dam in NZ now its getting less and less possible with the iwi, Fish&Game etc opposition.

However there may be less opposition to pumped hydro where two lakes are used, excess electricity during the day is used to pump water up hill, then in the evening it is run back down.
To see that happen we would have to increase solar installations quite a bit.

A pumped hydro company will typically buy electricity when its cheap, and then sell it back for a higher price later (evening) so it could make sense with mass solar installations when our daytime solar, wind and geothermal production exceeds consumption at which point we can store it in pumped hydro for the evenings.

In germany they are making a huge success with solar - they have some of the highest rates of solar production in the world per capita, but even all of germany has less clear sky hours than invercargil (one of our worst areas)

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