EEVblog #484 - Home Solar Power System Installation

[EEVblog]

Not in NSW they can't, the tarrifs are regulated.

No, they are voluntary on the part of each energy company based on the IPART recommendations.

Smart metering means that you pay 48c/kWh during peak, about 20c/kWh shoulder and 12c/kWh low. I've been monitoring it for a while and it averages out to around 25c/kWh with our current usage. So the power companies are buying power from you at a very low rate to sell back to you at a much higher rate.

Only if you get smart meters. They didn't install those on mine, so it seems they have no way to know my time of day usable to put me on such a scheme.
Smart meters are more popular and possibly mandatory for new installations in VIC?

[c4757p]

is an example of an absurdly neat US (and apparently canadian too, given by the original file name)

Neat freak here - looks just like mine!  I am proud of my absurdly neat wiring 

[DrGeoff]

Not in NSW they can't, the tarrifs are regulated.

No, they are voluntary on the part of each energy company based on the IPART recommendations.

Interesting, I didn't realise that. Makes it even worse than I thought.

Smart metering means that you pay 48c/kWh during peak, about 20c/kWh shoulder and 12c/kWh low. I've been monitoring it for a while and it averages out to around 25c/kWh with our current usage. So the power companies are buying power from you at a very low rate to sell back to you at a much higher rate.

Only if you get smart meters. They didn't install those on mine, so it seems they have no way to know my time of day usable to put me on such a scheme.
Smart meters are more popular and possibly mandatory for new installations in VIC?

We didn't have a choice. They were mandatory when the new house was built. I have 3 phases coming in and three smart meters (one includes the ripple control receiver as well). The metering box is on the outside wall and the distribution panel with around 30 RCD's on it is on the inside wall of the garage.

[EEVblog]

Interesting, I didn't realise that. Makes it even worse than I thought.

Yup 

We didn't have a choice. They were mandatory when the new house was built.

Ah, interesting. Mandatory for all new houses?
Who was the energy provider? Mine is Endevour Energy.

[DrGeoff]

We didn't have a choice. They were mandatory when the new house was built.

Ah, interesting. Mandatory for all new houses?
Who was the energy provider? Mine is Endevour Energy.

Energy Australia, or whatever they are calling themselves this week.
They just turned up and slapped 3 smart meters on the metering board and connected the cable between our pole and the street pole (wiring is underground, like yours).
The bill comes in with a whole lot of time-of-day usage information, but I've no way of checking whether it is accurate or a complete swindle!

[EEVblog]

I aso believe the smart meter rate and peak times are variable between providers as well.
Origin for example in VIC has a "peak" time from 1pm to 8pm, whcih would catch most people's major home usage. Nasty 

[EEVblog]

The bill comes in with a whole lot of time-of-day usage information, but I've no way of checking whether it is accurate or a complete swindle!

Yep, that's the shitty part.
Check to see if someone has hacked your meter and you can extract the data out yourself. Or the commands are available in the manual or whatever.

[DrGeoff]

The bill comes in with a whole lot of time-of-day usage information, but I've no way of checking whether it is accurate or a complete swindle!

Yep, that's the shitty part.
Check to see if someone has hacked your meter and you can extract the data out yourself. Or the commands are available in the manual or whatever.

There's an IR port which moght be interesting to connect to, and I got the meter manual from an online source which has the commands and button sequences. No detail on the interface though, but it is probably fairly rudimentary since the meter reader bloke uses it.

Energy Aust has peak time at 2pm - 8pm and shoulder from 7am to 2pm so they catch you from when the kids get home from school right through dinner time, when you use the most power. On weekends and public holidays there is no peak, it is shoulder from 7am to 10pm. In this case the solar installation would be providing power to you ate 20c/kWh, rather than into the grid at 6c/kWh so it has its uses, particularly at weekends.

[EEVblog]

In this case the solar installation would be providing power to you ate 20c/kWh, rather than into the grid at 6c/kWh so it has its uses, particularly at weekends.

Yeah, use it or sell it cheap.
I pay 21.85 cents + 5 cents green, so 26.85 all day.
Presumably that will not change with the new meters.

[yellowfruit]

Jeeze, all these residential panels are to tiny compared to ones in the US. Ive seen bigger sub-panels in garages .

Off the topic of solar, and correct me if I'm wrong but:

That would be, I believe, for two reasons. First that houses tend to be larger in the USA. Second that the voltage is lower (120V in the USA vs 240V in the UK, or thereabouts) necessitating more circuits. For example, a household ring main (for your fridge, computer, TV etc) in the UK is usually 30A, to support that current in the USA would require much thicker cable which would be harder to work with, pull through walls, etc etc. But generally there are similar numbers of sockets so instead there would be two 15A circuits (which I believe are single ended, not a loop like the UK).

Matt

[manicdoc]

Yep solar generation and consumption are exactly out of phase with each other for us as well...

BTW - the only problem I've had over the years is the solar hot water pump controller 'failing' - when I cracked it open found a PIC and a cheap as chips mains relay that had burnt out on the contacts - replaced with a much higher rated relay and its been working fine since.. difference in cost - may 50c...

I also know a friend who was convinced to buy 8 evacuated tube units - to do combined hot water and pool heating - the 'con'tractor subsequently did a runner and she is now left with a half installed system doing nothing. I'm going to go round and check out how much is needed to get it going at least for the hot water. Shame she can't run a steam powered generator...

Funny you should say that, I've been at Rheem a few times over the control algorithms.
During summer the tank thermostat will occassionally trip (it is resettable though) and the electrical heater won't turn on. It's usually not noticeable until we get a cloudy day or two. The temperature monitors I have all over the system alert me when the tank water temperature is dropping below a threshold that the off-peak electrical booster should have switched on so I can reset it. Seems that when the collectors pump out water that is too hot (above 85C it seems) then the thermostat trips, even though the tank temperature is still only around 50C. Would be better if the pump had variable flow control so when it is hot the flow is increased to keep the differential temperature lower.

Hmm, that is crazy. I must admit I have been toying with the idea of getting rid of the mindless controller and hooking it up to something more intelligent. I have an integrated alarm (Comfort) and lights (CBus) via Linux box. Although want to split that function off to a really small form factor dedicated box (PC104); has a database in it, so can't really be a micro controller solution. This could be the straw that convinces me to do it..

[DrGeoff]

Hmm, that is crazy. I must admit I have been toying with the idea of getting rid of the mindless controller and hooking it up to something more intelligent. I have an integrated alarm (Comfort) and lights (CBus) via Linux box. Although want to split that function off to a really small form factor dedicated box (PC104); has a database in it, so can't really be a micro controller solution. This could be the straw that convinces me to do it..

The system I designed uses a little PIC18 + 10bT ethernet module I developed that has all the I/O on it and have several of these scattered around the house on a network. They talk to a linux box which has the event handlers and databases and web interface to allow monitoring and control functions. Since I have the Linux server running 24/7 for mail server, dns cache and other things, there was no problem adding the control system to it. It's fairly lightweight in power consumption, just a core-2 processor on a motherboard and a couple of enterprise drives.
This has been running for several years now and I have some nice trend plots of temperature and other measurements that allow me to evaluate aspects of the house design and make improvements where necessary.

[hpnut]

Hi Dave,

interesting, I have a similar set-up.

10 x Bosch 245 watt modules EU30117
Sunny Boy 3000TL  inverter
Sunny Webbox Solar PV monitoring system


I am waiting to have the system connected to the grid next week.  here are some photos.

In Malaysia, we have a good FiT system that rewards early adopters of solar PV and other renewables such as wind and biomass.  www.seda.gov.my has details of the FiT mechanism.

Oh, Dave, you should re-position your rooftop antenna.  It will create partial shading and will cause your PV output to reduce. 

cheers,

hpnut from Putrajaya, Malaysia

[hpnut]

more pictures

[hpnut]

Haha Dave, going through the installers toolbag 

hmmm.

 

my service provider technicians had a Prova Solar Module Analyzer, I was jealous 

http://www.tes.com.tw/solare.htm

[Corporate666]

In this case the solar installation would be providing power to you ate 20c/kWh, rather than into the grid at 6c/kWh so it has its uses, particularly at weekends.

Yeah, use it or sell it cheap.
I pay 21.85 cents + 5 cents green, so 26.85 all day.
Presumably that will not change with the new meters.

Have you done any calculations about your total expected monthly generation vs. your bill?  Forgetting time-of-day issues, would you be a net exporter or net importer of grid energy? 

And I am guessing there must be companies making/selling some sort of energy storage solutions so you could save your overproduction for times when you have underproduction, no?  If so, is is not cost effective?

[DrGeoff]

I guess you also have to be careful about where you site it, and the owner takes on the risks if a neighbour plants a big tree or adds an extension or rebuild that overshadows the PC collectors and renders the system useless. I have heard of a couple of instances where an apartment block was built near some houses and wiped out a lot of their power generation with large shadows.

[senso]

Dumb question..
Why are the solar cells not full rectangles but instead have a triangular bit cut in the corners?

[ataradov]

They are made out of regular silicon, which comes in round discs. They don't cut to perfect squares because it wastes more material.

PS: I have no idea why they've cut corners from non-square cells shown above.

[jnissen]

http://pvoutput.org/intraday.jsp?id=19133&sid=16981

Catch up with me Dave! The tax incentives and rebates made a large system a reality for me. Yes I'm benefiting unfairly off your tax dollars! BTW - I didn't go solar to save the planet and all that garbage I only did it becuase I'm cheap! That and the fact the stock market of late has been up and down I invested in my home. It pays me monthly and not many investments were doing that for me. Here in central Texas the generated electricity can accumulate over the year. I generated quite a surplus earlier this year in the cool months when the AC was not running. Eating into the account now but still no electric bill yet this year!   

[EEVblog]

Have you done any calculations about your total expected monthly generation vs. your bill?  Forgetting time-of-day issues, would you be a net exporter or net importer of grid energy? 

Importer in winter.
Potential to break even in summer perhaps.

And I am guessing there must be companies making/selling some sort of energy storage solutions so you could save your overproduction for times when you have underproduction, no?  If so, is is not cost effective?

Nope, not cost effective, and maintenance hassles. No need for that.

[EEVblog]

Oh, Dave, you should re-position your rooftop antenna.  It will create partial shading and will cause your PV output to reduce. 

No, it doesn't. The support wires were already moved a bit.

[duskglow]

Interestingly, I found this video just a few hours ago.



He created a battery backup system for his house that costs about 700 pounds, and can power everything for eight hours and only the essentials for three days.  I wonder if, connected to a solar system in a clime that works in (the UK isn't, apparently, such a clime) if it could double as a smoother.

[DrGeoff]

Importer in winter.
Potential to break even in summer perhaps.

I'm interested to see what you get during Summer, when the panels themselves cold be at 80-90C. I wonder how much that will restrict their generating capacity over the sunnier months. It may work out the same as the Winter generation.

And I am guessing there must be companies making/selling some sort of energy storage solutions so you could save your overproduction for times when you have underproduction, no?  If so, is is not cost effective?

Nope, not cost effective, and maintenance hassles. No need for that.

Damn right there. Vanadium redox batteries looked promising, but they seemed to have stalled, Otherwise not much really suited to a domestic situation with minimum maintenance and reasonable lifetime.

[EEVblog]

I'm interested to see what you get during Summer, when the panels themselves cold be at 80-90C. I wonder how much that will restrict their generating capacity over the sunnier months. It may work out the same as the Winter generation.

Yes, could very well be the case. More light hours though and higher solar insolation.
I'm approaching 10kWh now in winter on a good day, so expecting a bit more in summer.
We can't break even money wise of course given the rates, but might be able to get close in actual kWh generated/consumed.