ToxicBunny
Oi! Leave me out of this...
*jealous*
Wish I had the money to make this kind of thing happen.
Wish I had the money to make this kind of thing happen.
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Solar Power Thread
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Sinbad
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Here's the system exporting 3.4kW to the grid at 08h29 today 15 Nov 2012.
Grid is running at 246VAC, whereas the house is regulated to 230V (+-1%). The PV array is generating 5kW already.
The PowerStar has a TCP/IP connection, which means I can manage it from anywhere. Marvellous machine.
That's freakin awesome.
Which size powerstar do you have, and mind if I ask what it cost?
Arthur
Honorary Master
I have the PowerStar II 12kVA model, on 48V DC and single phase AC. Pricing available from MLT Drives, but should be under R60K (bought mine in 2010).
Arthur, any chance of sharing which PV panels you went for and why and what your effective system losses (DC/AC conversion,wiring etc) are aggregating at? Also perhaps your stats on peak output and best cumulative daytime production to date?
Also with the benefit of hindsight, anything you would do differently?
Arthur
Honorary Master
Hi etwylite
I have 40 x Tenesol TE1901/220-54P A-grade polycrystallines, rated at 210W nominal power. They're locally assembled, in Cape Town. Have tempered glass. Why did I go for them? Got a good deal from the supplier/installer, MLT Drives. They're a professional crowd who've been doing this seriously for years.
There are two 20-panel arrays on different buildings. The farthest is approx 130m from the MPPTs in the Utility Room where everything comes together at the meter and DB.
The PV array's nominal rating is 8400W, but the best I've measured at the MPPTs is 7880W in full midday sun, so the loss is around 500-550W, largely through transmission. I've just checked today's nett generation (16h24) - sitting at 56.4kWh, with perhaps another 1-1.5 kWh to go in the remaining light. This is more than enough for summer (to cover days and night re-imports), but I'm concerned that there won't be enough to cover all consumption in winter.
In hindsight, what would I do differently? On the PV system itself, nothing immediately comes to mind ... I'd thought about this for a very long time, and worked through all the options, at least technically.
I regret not running two strands of Cat6 cable down the conduits from the arrays - I had a whole reel and never though of it when they pulled the cables, which are now reburied under paving. Could kick myself. This would allow for various security and visual monitoring systems such as IP cameras to keep an eye on the arrays.
The biggest problem with my installation is the location of the arrays themselves. The property is surrounded by tall trees to the east and west, which means early shade and hence reduced direct sunlight hours, especially in the afternoons. The first panels start getting shaded around 15h00 at this time of year, and this dramatically affects power output (even a hand on a cell drops the panel's output by 70%). Both my arrays are pretty much shaded by 17h00 even through the sun is high west, and that costs me at least 10-20kWh a day in summer, I reckon. I don't really have any other options given the topography and biology.
All that said, I don't regret the installation for one femtosecond. Ever picowatt I can generate independently of our miserable and corrupt local authority and its exorbitant electricity tariffs reinforces my delight at finally having made the decision to go solar.
I have 40 x Tenesol TE1901/220-54P A-grade polycrystallines, rated at 210W nominal power. They're locally assembled, in Cape Town. Have tempered glass. Why did I go for them? Got a good deal from the supplier/installer, MLT Drives. They're a professional crowd who've been doing this seriously for years.
There are two 20-panel arrays on different buildings. The farthest is approx 130m from the MPPTs in the Utility Room where everything comes together at the meter and DB.
The PV array's nominal rating is 8400W, but the best I've measured at the MPPTs is 7880W in full midday sun, so the loss is around 500-550W, largely through transmission. I've just checked today's nett generation (16h24) - sitting at 56.4kWh, with perhaps another 1-1.5 kWh to go in the remaining light. This is more than enough for summer (to cover days and night re-imports), but I'm concerned that there won't be enough to cover all consumption in winter.
In hindsight, what would I do differently? On the PV system itself, nothing immediately comes to mind ... I'd thought about this for a very long time, and worked through all the options, at least technically.
I regret not running two strands of Cat6 cable down the conduits from the arrays - I had a whole reel and never though of it when they pulled the cables, which are now reburied under paving. Could kick myself. This would allow for various security and visual monitoring systems such as IP cameras to keep an eye on the arrays.
The biggest problem with my installation is the location of the arrays themselves. The property is surrounded by tall trees to the east and west, which means early shade and hence reduced direct sunlight hours, especially in the afternoons. The first panels start getting shaded around 15h00 at this time of year, and this dramatically affects power output (even a hand on a cell drops the panel's output by 70%). Both my arrays are pretty much shaded by 17h00 even through the sun is high west, and that costs me at least 10-20kWh a day in summer, I reckon. I don't really have any other options given the topography and biology.
All that said, I don't regret the installation for one femtosecond. Ever picowatt I can generate independently of our miserable and corrupt local authority and its exorbitant electricity tariffs reinforces my delight at finally having made the decision to go solar.
spiderz
Honorary Master
Jip, they are industrial batteries. Very expensive it I'm not mistaken.
Sinbad
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I just got a quote to set up a system at my place.
Powerstar 2 6kva grid tied inverter, 26 240w panels, batteries, charge controllers, commissioning, installation etc... R200k.
It sounds like a ****load of money, but I've done some calculations based on assumptions about the electricity price.
My average monthly elec bill is R1800 all in.
Assuming (conservatively) a 12% increase per annum (we know eskom have applied for 16), in 5 years my total electricity payments assuming current usage levels would be R137k, in 10 years R380k
16% annual increase, 5 year cost R148k, 10 years R460k
So imagine the real electricity costs will be somewhere between those figures.
Now to decide whether it's worth such a large initial investment.
If I knew that there was a future in feeding back to the grid, I could get rid of the batteries etc, and it would be considerably cheaper. But I also like the idea of NOT relying on eskom at all...
Powerstar 2 6kva grid tied inverter, 26 240w panels, batteries, charge controllers, commissioning, installation etc... R200k.
It sounds like a ****load of money, but I've done some calculations based on assumptions about the electricity price.
My average monthly elec bill is R1800 all in.
Assuming (conservatively) a 12% increase per annum (we know eskom have applied for 16), in 5 years my total electricity payments assuming current usage levels would be R137k, in 10 years R380k
16% annual increase, 5 year cost R148k, 10 years R460k
So imagine the real electricity costs will be somewhere between those figures.
Now to decide whether it's worth such a large initial investment.
If I knew that there was a future in feeding back to the grid, I could get rid of the batteries etc, and it would be considerably cheaper. But I also like the idea of NOT relying on eskom at all...
Arthur
Honorary Master
Not a bad price, Sinbad. Yes, it's a big investment. But the Power Star is the best tech of its kind in the world, and it's made for African conditions.
For me the overriding decider is your last point - being largely independent of the public grid. I'm no doomsday pessimist, but I do think supply problems are more than likely in the years to come.
The financial justification is of course the most pressing issue. Most people look at this only in terms of their electric bill. This is a mistake - what other major investment is justified only in terms of its consumption offset?
Another way is to look at ROA - return on asset. As I've mentioned before, going solar PV also capitalises consumption (or a very big portion of it), and should be considered as an improvement on your fixed property (assuming you own your house).
Assuming your electrical consumption stays constant, your R200K investment will produce around 10% after tax in the first year, rising with each passing year as the cost of electricity increases.
Again, assuming the same macro-economic conditions (ie no crash in the housing market), you should be able to recover all or most of your investment when you sell your house ... depending on where you are you might even get more than you spent because your house is the most attractive in the area.
If you stay grid-connected you'll never entirely eliminate municipal charges - my local authority levies R141.50/m for the meter & connection even if usage is zero. Also, allow R200/m or so in nett usage for cloudy days.
On sunny days my 8400W array produces around 45-55 kWh. My best day so far (since October this year) is Monday 26 November 2012, with 57.4 kWh. The lowest yet recorded on a darkly overcast day is on 4 December when 14.5 kWh was generated in total.
When sizing the system, consult the experts who know the typical daily solar radiation for your area. Consider local conditions such as tall trees that can shade the array.
If you're seriously considering this, look at your proposed site and start recording the direct sunlight start and end positions and times - this can all be useful when deciding how and where to site the PV array (if you have that flexibility).
For me the overriding decider is your last point - being largely independent of the public grid. I'm no doomsday pessimist, but I do think supply problems are more than likely in the years to come.
The financial justification is of course the most pressing issue. Most people look at this only in terms of their electric bill. This is a mistake - what other major investment is justified only in terms of its consumption offset?
Another way is to look at ROA - return on asset. As I've mentioned before, going solar PV also capitalises consumption (or a very big portion of it), and should be considered as an improvement on your fixed property (assuming you own your house).
Assuming your electrical consumption stays constant, your R200K investment will produce around 10% after tax in the first year, rising with each passing year as the cost of electricity increases.
Again, assuming the same macro-economic conditions (ie no crash in the housing market), you should be able to recover all or most of your investment when you sell your house ... depending on where you are you might even get more than you spent because your house is the most attractive in the area.
If you stay grid-connected you'll never entirely eliminate municipal charges - my local authority levies R141.50/m for the meter & connection even if usage is zero. Also, allow R200/m or so in nett usage for cloudy days.
On sunny days my 8400W array produces around 45-55 kWh. My best day so far (since October this year) is Monday 26 November 2012, with 57.4 kWh. The lowest yet recorded on a darkly overcast day is on 4 December when 14.5 kWh was generated in total.
When sizing the system, consult the experts who know the typical daily solar radiation for your area. Consider local conditions such as tall trees that can shade the array.
If you're seriously considering this, look at your proposed site and start recording the direct sunlight start and end positions and times - this can all be useful when deciding how and where to site the PV array (if you have that flexibility).
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Sinbad
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Proposed site has no tree coverage at all 
I'm going to have to save up a bit though. I don't have 200k lying around
Maybe worth getting the inverter and a few panels though... To start with. I don't see the price of the inverter dropping but hopefully panels will!
I'm going to have to save up a bit though. I don't have 200k lying around
Maybe worth getting the inverter and a few panels though... To start with. I don't see the price of the inverter dropping but hopefully panels will!
spiderz
Honorary Master
IO think I must start doing that. Noticed the trees cast a shadow on my roof from as early as 4pm.
Hmmmm, will hookup a few Light-sensors to a Arduino to monitor it a bit.
Arthur
Honorary Master
My 8400W (nominal) solar PV array typically produces 52-55 kWh energy per day on full-sun days. Energy production days in December 2012:
>50 kWh per day : 15 days (no cloud)
40-49 kWh per day : 9 days
30-39 kWh per day : 4 days
20-29 kWh per day : 0 days
10-19 kWh per day : 3 days (100% cloud)
On full-sun days the solar PV array typically achieves a peak power output of 7.1-7.2 kW. On partially-cloudy days, transient peak output (not total energy production) rises to 9-10 kW owing to the Cloud Edge Effect on solar panels - as the cloud edge transits the sun, the cloud edge refracts the sunlight and increases irradiance, producing a sharply higher voltage & current.
This last point is important for DIY installers to remember when spec'ing the MPPT and inverter. Failing to allow for sudden irradiance peaks of up to 50% over nominal can trip some inverters (but not the PowerStar).
Last month was my first PV December. We've had lots of people staying over the hols, and the electrical load has increased substantially ... two extra geyers, two coolers running 24x7, fans, more oven, washing machine, dishwasher, etc... I've ordered an additional 14 x 240W panels which will be installed next week, taking the arrays to 11 760W nominal. This should help considerably to rebalance the imports and exports.
>50 kWh per day : 15 days (no cloud)
40-49 kWh per day : 9 days
30-39 kWh per day : 4 days
20-29 kWh per day : 0 days
10-19 kWh per day : 3 days (100% cloud)
On full-sun days the solar PV array typically achieves a peak power output of 7.1-7.2 kW. On partially-cloudy days, transient peak output (not total energy production) rises to 9-10 kW owing to the Cloud Edge Effect on solar panels - as the cloud edge transits the sun, the cloud edge refracts the sunlight and increases irradiance, producing a sharply higher voltage & current.
This last point is important for DIY installers to remember when spec'ing the MPPT and inverter. Failing to allow for sudden irradiance peaks of up to 50% over nominal can trip some inverters (but not the PowerStar).
Last month was my first PV December. We've had lots of people staying over the hols, and the electrical load has increased substantially ... two extra geyers, two coolers running 24x7, fans, more oven, washing machine, dishwasher, etc... I've ordered an additional 14 x 240W panels which will be installed next week, taking the arrays to 11 760W nominal. This should help considerably to rebalance the imports and exports.
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wetkit
Expert Member
I am glad to see this issue is being discussed here.
I have also been looking at solar due to my high electrical usage.
Unfortunately, until Net Metering is available, it is not really an option to go solar, for me that is.
So far I know, guys like Arthur is part of a pilot project.
According to my local council, they have net meters out for testing, but not sure if it would be available before the end of 2013.
They also sent me all the required application documentation and all I can tell you is that there is LOADS of legal and safety requirements to be for filled before you can export solar power onto the grid.
Solar for your own consumption is no biggie, except for the cost of the batteries
Although the MLT units is brilliant, the cost is just too high for me.
With a normal grid tied invertor, the battery side of the unit is removed, making the units much more affordable.
Also note that the solar array voltage on these units then goes up to around 500V, so sizing the panels and the system becomes tricky.
For anybody looking at solar, I would recommend installing a power meter first.
This way you can have a look at your consumption and make changes first so that you can optimise your current usage.
That would also benefit you in the longer run when you need to size a solar system, as you would already have all your consumption figures at hand.
For instance everybody thinks their geyser is the biggest culprit, but it is not always the case.
For me it is actually all my flipping PC's running 24/7. Now 750W does not sound like a lot compared to 2kW of a geyser, but the PC's run 24/7 where the geyser only runs 2 to 3 hours a day!
Since installing my meter, I have been able to reduce my max demand from 6kW down to 4kW and overall consumption from 65kWh/day to 50kWh/day.
Investing in a solar pool pump system was also not worth it for me, as I do not run the pump in winter, so all that solar power will then be wasted
Also as Arthur suggested, he is now changing his consumption curve.
Where a normal household will use more electricity at night, he is now moving his peak to the daytime.
I have also been looking at solar due to my high electrical usage.
Unfortunately, until Net Metering is available, it is not really an option to go solar, for me that is.
So far I know, guys like Arthur is part of a pilot project.
According to my local council, they have net meters out for testing, but not sure if it would be available before the end of 2013.
They also sent me all the required application documentation and all I can tell you is that there is LOADS of legal and safety requirements to be for filled before you can export solar power onto the grid.
Solar for your own consumption is no biggie, except for the cost of the batteries
Although the MLT units is brilliant, the cost is just too high for me.
With a normal grid tied invertor, the battery side of the unit is removed, making the units much more affordable.
Also note that the solar array voltage on these units then goes up to around 500V, so sizing the panels and the system becomes tricky.
For anybody looking at solar, I would recommend installing a power meter first.
This way you can have a look at your consumption and make changes first so that you can optimise your current usage.
That would also benefit you in the longer run when you need to size a solar system, as you would already have all your consumption figures at hand.
For instance everybody thinks their geyser is the biggest culprit, but it is not always the case.
For me it is actually all my flipping PC's running 24/7. Now 750W does not sound like a lot compared to 2kW of a geyser, but the PC's run 24/7 where the geyser only runs 2 to 3 hours a day!
Since installing my meter, I have been able to reduce my max demand from 6kW down to 4kW and overall consumption from 65kWh/day to 50kWh/day.
Investing in a solar pool pump system was also not worth it for me, as I do not run the pump in winter, so all that solar power will then be wasted
Also as Arthur suggested, he is now changing his consumption curve.
Where a normal household will use more electricity at night, he is now moving his peak to the daytime.
Sinbad
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Well, on 13 December I installed a geyserwise to complement my solar geyser. What a difference. My consumption curve now peaks during the day while the pool pump is on. My geyser element has run for 2 hours total since I installed the geyserwise, and my consumption for december was 780kwh, my previous lowest ever was over 900.
Winter will be a different story I'm sure... but still expecting savings.
Once I can get the usage down lower, then it becomes feasible to go solar.
Winter will be a different story I'm sure... but still expecting savings.
Once I can get the usage down lower, then it becomes feasible to go solar.
spiff
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just out of curiosity - has anyone ever used a diesel generator to charge up banks of batteries during the day, ready for use at night? instead of PV cells?
what are the pro's & con's?
what are the pro's & con's?
The pro's are you can be independent of Eskom.
The cons are the cost of fossil fuels make the exercise very expensive.
A modern diesel generator uses between 0.28 and 0.4 litres of fuel per kilowatt hour produced.
Using the 0.28 figure, at the current price of diesel that works out to R2.89 per kWh excluding the losses in charging the batteries which is a tad higher than the ~ R1.20 per kWh consumers are paying municipalities for electricity.
What would be funny is if/when the electricity tariffs pass the R3/kWh mark and people start using diesel generators at home to go off the grid.
Sinbad
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Even if electricity hits R3/kwh it will still cost less to use eskom than Diesel.
Your batteries will cost you at least R500 per month in maintenance.