Solar Power Thread

Unhappy438 said:
Errr well my colleagues and i did a bunch of tests and studies on renewable energy in the household a few years back and there is no exact answer to this question. Its greatly influenced by things such as quality of solar geyser, size of geyser, location , water usage plus other smaller variables. Conclusion is you will start getting money back but in some cases that can be up to 10 years :wtf: . From our study however average was about 4-5 years.
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Talking about my specific case.

Geyser cost me 10k after Eskom rebate. Saves R500 a month.
 
The financial justification depends on your circumstances and requirements. If you have cash, it's a somewhat different consideration from having to borrow.

Posting from my phone, so brief.

Another way to model is to look at after-tax return on capital.

What can you get after tax from a R200k investment?

How does that compare to your annual power bill, which has to be funded from after-tax income?

Then, project and compare power prices and after-tax income.

Another thing few people consider: this route essentially capitalises consumption, rather than the other way round. Yes, a liquid asset is converted to fixed property, but any estate agent will tell you it's recovered when you sell.

The intangible benefits are not trivial. Peace of mind. More than sufficient power during daylight. Reduced vulnerability when rolling blackouts resume next year. And the special relish of not paying highly loaded tariffs to the local yahoos ever again.
 
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if you are going to do solar lighting you have to switch to LED lights or you would wasting your time. I think eskom should start paying people who add to the grid also
 
My folks run off grid. The setup to date has cost my old man R120 000. It's a nice concept.
 
Paul_S said:
Agreed, solar heating water is the first step.
However it's a lot harder moving away from heating appliances.

Like my wife's 2000W hair dryer, 1000W microwave oven, 2000W kettle, etc.
There are some things that just work better on electricity than solar heating or gas.
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Jip, you need to reduce your power consumption before going off-grid. I'm currently using only 850kwh/pm. For that I requite a PV setup of at least 6.4Kw. At 600kwh/pm I'll only need 4.8Kw.
I think that after the hot water, my biggest power consumers is the pc's. But I'll need to get a monotoring system in place to see where my power is being used.
 
cbrunsdonza said:
exsolar.co.za are also a great place to get panels, etc.

From my previous employer we learn't alot about going solar, very expensive and ROI is unlikely. The only real advantage is where you need to compliment your existing feed, your running a business where uninterrupted electricity supply is crucial or its economically not viable to lay down electricity to a point like a shed or our garage (I installed one of those units from Builders, worked great for a few weeks but died on us).
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Found a pretty informative video on their site.

[video=youtube_share;agSfgsH97PE]http://youtu.be/agSfgsH97PE[/video]

http://www.exsolar.co.za/blog/
 
Interesting video.

A lot of money invested there, for 13kwh per day max, or R500 a month.

ROI in how many years? Ever?
 
The guy in the video mentioned that there would be prepaid meters available soon that will give you credits for pushing back into the grid. Anyone know anything more about when that's happening?
 
morkhans said:
The guy in the video mentioned that there would be prepaid meters available soon that will give you credits for pushing back into the grid. Anyone know anything more about when that's happening?
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Arthur has that going as part of a pilot project afaik.

Thing is, it's still only 13kwh per day. Just means you don't need batteries - but if the grid goes down at night you're farked.
 
morkhans said:
The guy in the video mentioned that there would be prepaid meters available soon that will give you credits for pushing back into the grid. Anyone know anything more about when that's happening?
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Probably never because Eskom are opposed to IPPs and NERSA/ANC/etc. have been dragging their feet for many years.
There is more chance of ICASA getting Telkom to unbundle the local loop than Eskom purchasing power from small IPPs.
The only way to do it at the moment is to enter direct agreements with municipalities.
 
Sinbad said:
Arthur has that going as part of a pilot project afaik.

Thing is, it's still only 13kwh per day. Just means you don't need batteries - but if the grid goes down at night you're farked.
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Batteries seem to be a large part of the cost though? So could be a way to phase the implementation of your system. I like the idea of what you put in during the day cancelling out what you use at night.
 
Four-quadrant prepaid meters (to measure imports and exports) are not yet available in SA, and neither will they be until the power retailers (usually municipalities) define and implement REFIT (renewable energy feed-in tariffs) at a consumer level.

NERSA has for many years had REFIT policy documents, but everyone is dragging their feet, which is very frustrating. An additional obstacle is that current policy framework and discussion documents require that a consumer be a nett consumer, though the actually metering period is not defined.

A fairly recent (2010) document, NRS 097-2-1:2010, discusses issues around RE SSEGs (Renewable Energy Small Scale Embedded Generators), and defines a number of technical, safety, and other specifications. For example, it is critical (life and death matter) that exporting grid-connected SSEGs island correctly and within specified parameters so that energy is not fed back into the grid when it is taken down for maintenance.

The basic conceptual problem for municipalities to overcome is the erroneous notion that RE SSEGs will take away revenue and profit from local authorities, who are increasingly using utility tariffs to raise additional revenues.

I've proved to my local authority that their profit actually increases if the consumer becomes a nett exporter. The reason is very simple: municipalities buy from Eskom at say 55-65 cents per unit, and sell to the consumer at typically double that (ie 50% gross margin, or 100% markup). Because there is currently no payment for exports, the municipality is getting every exported unit as zero cost and reselling at consumer rates, and all is pure profit.

In other words, Mrs Municipality, the greater the nett export from my SSEG, the greater your profit.

My 4Q meter is a Landis+Gyr ZMD310, with E22 TCP/IP comms module. This is a 3-phase meter configured for single phase.
 
Arthur said:
I've proved to my local authority that their profit actually increases if the consumer becomes a nett exporter. The reason is very simple: municipalities buy from Eskom at say 55-65 cents per unit, and sell to the consumer at typically double that (ie 50% gross margin, or 100% markup). Because there is currently no payment for exports, the municipality is getting every exported unit as zero cost and reselling at consumer rates, and all is pure profit.

In other words, Mrs Municipality, the greater the nett export from my SSEG, the greater your profit.
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I'm trying to figure out how to phrase this in a way that will get Joburg Municipality on board, but I can't figure out how to give them a personal kickback out of the system for looking into something like this, so I fear it will never happen.


Also, isn't the idea that they should start paying/crediting for exports? Otherwise you don't actually benefit at all...?
 
Sinbad said:
Also, isn't the idea that they should start paying/crediting for exports? Otherwise you don't actually benefit at all...?
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The benefit is substantial even if there's no compensation for exports - provided you can do nett metering, ie pay only for nett imports.

This means you effectively use the grid as a battery, saving a massive cost in long-life glass-jar batteries.

This can only work if your power supplier agrees to exports and nett metering - and this is biggest obstacle.

I've set my system to export only my average nightly consumption, though it can do quite a bit more. This means I produce a surplus during the day, and reimport it at night when the PV array is dormant, so my nett consumption is effectively zero over a 24-hour period.

Of course a PV array should be spec'd for winter when daylight hours and energy production is lowest.
 
Arthur said:
The benefit is substantial even if there's no compensation for exports - provided you can do nett metering, ie pay only for nett imports.

This means you effectively use the grid as a battery, saving a massive cost in long-life glass-jar batteries.

This can only work if your power supplier agrees to exports and nett metering - and this is biggest obstacle.

I've set my system to export only my average nightly consumption, though it can do quite a bit more. This means I produce a surplus during the day, and reimport it at night when the PV array is dormant, so my nett consumption is effectively zero over a 24-hour period.

Of course a PV array should be spec'd for winter when daylight hours and energy production is lowest.
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OK, nett metering I'd consider as credit for exports... :) Same page!

I've sent the wording of your last two posts to my local councillors. Maybe they can start up something similar in Joburg.
 
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The only way is to make an appointment with the boss (eg City Engineer, Head of Utilities) and speak face-to-face. Also, take a firm proposal and project plan.
 
Here's a Project Plan Outline (zipped PDF) for those interested in submitting a case to their Municipality for a RE SSEG pilot project, ie energy exports using a PV and grid-tied inverter + special meter for nett metering.

Edit as appropriate.

My system is now fully operational and exporting energy to the grid.
 
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.


exporting.jpg
 
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